And, will there be a tornado today, too? Arcus cloud almost a certainty. Get cameras ready! Read on…farther down.
4 (FOUR!) inches at Park Tank, Reddington Pass area by 6 AM ! Incredible for so early in the storm! Check more totals out from your friendly Pima County ALERT regional gauges. Mods on track to verify those huge amounts that were predicted the day before yesterday! Washes will be running! Flowers happy! I’m happy! Lot of excitement here! ! !
Only 0.15 inches here in Sutherland Heights/Catalina…. so far (6 AM). :{
Yesterday’s study in gray
Today!
Some excitement just now, after seeing that a major rain band had passed by, and we’re now in a break in the rain.
Will it rain more? Tune in at 11 to find out….. (hahahaha; we don’t do that here! More excitement.)
Went to U of AZ mod run from 11 PM AST last night, the very latest, then saw that a narrow, heavy band or precip, maybe a squall line, something out of the Midwest, was foretold for us Catalinans this afternoon!
Then went to examine upper air and positioning of vorticity maximums ejecting out of our incoming trough (vorticity maximums represented by redness in the plot below from the University of Washington’s Weather Department– color scheme by Mark Albright, the color man up there:
Positioning of “red curly air” (vorticity or rotational areas) in the atmosphere at 1 PM AST today, looking for the cause of the afternoon rainband. The approach of red curly air is accompanied by upward motion in the atmosphere. When I looked at this, I exploded with a “yikes!”. more excitement, today’s theme.
This was exciting due to incoming “red curly air” this afternoon above us, AND, due to those spreading out of the contours over us (see arrowhead). Diffluent contours are indicative of air spreading out aloft, something that leads to enhanced upward motion.
And, to blab on, the air aloft will be cooling off on top of our high-for-winter dewpoint air (50s), which should lead to large Cumulonimbus clouds, likely organized in a line of thunderstorms, as all this happens this afternoon or evening.
And, going over the edge here some, as is my wont, we might well see a funnel cloud somewhere today. This is the kind of situation that you can get them. So, to sum up today:
Possible funnels! Will they reach the ground somewhere in AZ? Maybe. Lightning! Hail likely, too! Rain rates likely to reach an inch an hour, though that rate may not last an hour unless you’re real lucky and get shafted real good.
Will be watching intensely for all these manner of things today! Haven’t been this excited since Oct 2nd, 2010, I think it was when they had that tornado in PHX!
Remember, too, our motto:
Right or wrong, you might have heard it here first!
The weather way ahead
While a long spell of dry weather comes after this 2 day event, the mods have popped up with a heavy dose of rain in two weeks. Of course, normally this would be considered Fantasy 101. HOWEVER, a slight amount of credibility is added when such a pattern that brings rain strongly resembles the one you have now. Check out these upper level flow maps out, as rendered by IPS MeteoStar, that has just moved their pay wall to March from February (yay!). The first one below is for today’s situation, and the second one for Valentine’s Day in two weeks. Look pretty similar don’t they.
You see, weather has a memory like your horse. You ride to Deer Camp way up in the Catalinas; you’ve never been there before, nor has horsey, and then you head back, but you’re not sure of the way.
Well, horsey will remember for you!
(To continue with the extra excitement theme of today’s blog!)
Well, the weather has a memory that we call “persistence”, likes to do the same thing over and over for awhile, and so when a similar pattern turns up in the models that you have now, we give it a little more credibility than none when its two weeks out, maybe 30% chance of actually happening (i. e., still a bit of a long shot).
Here’s what we have today; low off Baja spinning moist air from the far southern latitudes into AZ.Valid at 5 AM AST, February 14th, Valentine’s DayThe big rain accompanying the Valentine’s Day Storm.
Actually, there are no thoughts about the Super Bowl here. The title was just another cheap attempt to attract a reader that might be both cloud-centric AND a football fan, creating a moneyful increase in web traffic for this blog.
First you had your Cirrus, the highest of all clouds except for stratospheric nacreous clouds which kind of mess things up up there by eating ozone. We will not display n-clouds.
Cirrus, as you know, ALMOST always precedes lower clouds since they’re moving so much faster than the lower ones. So we get a sequence of clouds before it starts to rain that generally is the same, over and over again as in that movie about weather, Ground Hog Day. But let us ramble on…
First, patchy Cirrus, then maybe a sheet of Cirrostratus, then the lower stuff as Cirrostratus thickens downward to become that gray sheet called Altostratus. Throw in a few Altocumulus clouds that become a sheet underneath, and voila, your in Seattle, with rain on the doorstep. Yep, that’s the Seattle, and well, the Middle Latitude Pre-Storm Cloud Sequence (MLPSCS)2.
7:41 AM. Birds on the wire, waiting for the storm, notice the invading Cirrostratus fibratus. Low smog plume moves NW out of TUS and into Marana again (at very bottom of image).
10:49 AM. What a fine example of Cirrus spissatus (Cis spis) trailing larger ice crystals, certainly these would be “bullet rosettes”, looking something like a cholla bud, except the spines that stick out all over in this type of ice crystal look like hexagonal columns radiating out of a tiny center crystal. The ones NOT falling out are likely stubby solid columns, plates, prisms, and “germs”, the latter not really germs, but tiny, amorphous ice crystals not having grown a particular shape yet, all too small to have appreciable fallspeeds like the bullet rosettes. A whole sheet of this cloud having so much ice falling out would constitute what we would call, “Altostratus”, gray and deep.
11:46 AM. Another interesting scene. Are these Cirrus clouds spreading out, or is it perspective? Note bank of thick Cirrus on the horizon, too. (I think they were actually spreading out some.)12:49 PM. Here comes the next lower layer, Altocumulus clouds. However, note that ice formed in or just above this layer of Altocumulus, indicating that although it is one comprised of droplets (liquid) it is VERY cold. What is your next thought? HTCs (High Temperature Contrails) or “APIPs”, where aircraft that fly through them seed them by producing huge numbers of ice crystals due to extra cooling provided by over the wing flow, jet exhaust water producing extreme supersaturations, or prop tip cooling. Cause hasn’t been quite nailed down, but cooling is the leading suspect where the air is cooled to -40 C or so, and ice has to form in moist conditions.2:26 PM. With the Altocumulus and Cirrocumulus displays came periods of iridescence in the clouds, indicating tiny droplets less than 10 microns in diameter. There were more grandiose displays, but they were so gaudy my photos looked fake.
4:04 PM. Out ahead of the invading sheet of Altocumulus were these CIrrocumulus clouds with a cool herring bone pattern (“undulatus”). While called, “Cirrocumulus”, these clouds were actually at the same level as the invading Altocumulus clouds shown in the next photo. Its the fineness of the granulation that makes us refer to them as “Cc” clouds, even when they are in the middle levels, and not truly high clouds as the prefix “Cirro” would suggest.
4:09 PM. The invading sheet of Altocumulus perlucidus translucidus (no shading, honey-comb, flocculent pattern). On the horizon, Seattle-like solid veil of Cirrostratus, something that’s pretty rare here. This was an exciting scene because of the advancing layers, the darkening on the horizon, in the context of the major rain ahead.4:17 PM. You have to have ice in your veins if this shot doesn’t give you goose bumps. So pretty, all that uniform flocculation3 up there in Altocumulus perlucidus translucidus.4:24 PM. I can feel that you want more flocculation…
4:31 PM. Maybe just one more… Feeling pretty great now now that I’ve flocculated you so many times today. Three or four is about my limit.5:08 PM. APIP line, or HTC (“High Temperature Contrail”)–ones not supposed to occur at the temperature of this Altocumulus perlucidus translucidus, but they do anyway. Last evening’s TUS sounding pinned this layer at -24 C (-11 F!). Note that no other ice can be seen falling from these very cold clouds. The “castellanus” appearance of a contrail is extremely unusual, and may indicate a sharp decline in temperature at the level the aircraft flew. However, then it begs the question about why the Ac clouds aren’t turreted, at least, SOME. You’ll probably have to take CM’s word that its an ice trail. Note indication of a hole in the droplet cloud at far left of trail. That’s a clue.5:08 PM. To the southwest and west, layers of Altocumulus, some having turrets, and with a beautiful veil of CIrrostratus above, advance on Catalina. I love shots like this, though sans color, due to their rainy portent, even though our rain is not supposed to being for another 24 h, or this evening.
The weather just ahead
Of course, everyone, including media weathercasters, are all over the incoming stupendous storm event. For a more technical discussion, here’s one by Mike L., U of AZ forecasting expert, who got excited enough about our storm to come to send out a global e-mail. I think you should read it, though I left out all the graphics. I’ve already been too graphic today.
———–Special Statement by Mike L———————————-
“A very unusual heavy precipitation event is forecast for the next few days across Arizona and New Mexico as extremely moist air interacts with multiple short waves. As seen in the below data from the NWS, the maximum monthly IPW for Jan is about 28-29mm. If the various WRF forecasts verify, the upcoming storm will set new a new January IPW record.
The 12z WRFGFS indicates very high moisture levels being advected towards Arizona due to a low latitude low located west of the Baja spur. While IPW has slowly decreased from the previous storm over much of the area, La Paz is seeing a upturn in observed IPW.
As seen below, at 5pm today, some convection is forecast near to the low. Lightning data has indicated there has been some strong convection during the day today. Model initializations are normally suspect so far from any upper air stations, but it seems that both the NAM and GFS seem to have the intensity and location initialized well. One item of note is that during the past few days, the models have had a trend of moving the heaviest precipitation back to the west. Initially, the heaviest band was well in to NM whereas you’ll see later, it is now over much of eastern/central Arizona.
By late tomorrow afternoon, the low has only moved eastward slightly, but IPW continues to increase over NW Mexico and into Arizona. Precipitation begins mainly over the higher terrain of eastern Arizona.
By Wednesday morning, the mid level low has intensified as a strong short wave dives down behind the mean trough along with CAA into the back side.
Significant synoptic scale lift is present over southern Arizona and into northern Mexico by this time.
Extreme IPW is forecast to be present during the morning hours on Friday and combined with the favorable dynamics, widespread moderate to heavy rain is predicted. As the low becomes cut off, there will be an extended period for precipitation.
Precipitation rates are forecast to be above .25″/hour in some locations during the morning hours.
Partial clearing is forecast by Friday afternoon which allows some heating. Combined with cooler air aloft and high IPW, moderate amounts of CAPE are present during the afternoon.
By later in the afternoon, as Bob Maddox pointed out, convection forms and results in some locally heavy precipitation.
Tucson’s vertical profile is quite impressive with 700 J/Kg of CAPE and some vertical shear to support organized convection. Hail is also a threat.
Convection continues into the evening over southern Arizona with a continued threat of hail and some lightning.
The 3 day QPF is very impressive with widespread 1 inch amounts with some areas receiving over 3 inches. Some of these areas are associated with the strong convection present on Friday afternoon/evening. Confidence is low to medium due to the lack of upper air data and lack of run to run consistency as discussed previously. Also, the output in this discussion was solely from the 12z WRFGFS. The WRFNAM from last night had the heaviest precipitation somewhat to the east. It will be informative to see the next suite of model runs overnight to see if this westward trend ceases. There is a chance that it could continue and the heaviest precipitation is actually farther west than depicted below.
Very little of this precipitation falls as snow except at the very highest elevations, above 9k feet due to the sub tropical air-mass and lack of cold air.
Note that this discussion will only be available for organizations who are (or have) supported the Arizona Regional Modeling Program. This change will take effect before next monsoon season. Private individuals not associated with commercial/governmental agencies will continue to receive the discussions. If your agency would like to support the Program, please email me for details. “
————–End of special statement by Mike L—————————
The End!
1Let us not forget Simon and Garfunkel’s telling descriptions of Patterns of life; they repeat in clouds, too. (Pretty funny lead in commercial where Bryant Gumbel is asking, “What is the internet?”)
2Back in the old days when cloud forms were used to tell weather, Cirrostratus sheets, those high thin sheets, often with a halo, foretold rain 70% of the time here in the US (see Compendium of Meteorology, 1951). Deserts don’t much see this sequence. Cirrus are mostly meaningless in them, just indicating some withering tail of a system with rain that’s far away most of the time.
a lot….beginning tomorrow afternoon or evening, not today. Today is “pause” day. Also, its trash day today here in Catalina, mentioned here as a public service.
Slow moving, sub-tropical system to drop several inches of water content in rain/snow in mountains, sez our best model, that run by the U of AZ. Thank you, U of AZ, btw. Below a snapshot of the total precip from that 5 PM AST global data crunch, “nested” for AZ. This plodding gigantostorm should keep the water coming down the washes, luxuriate our sprouting wildflowers, some of which, like desert asters, are beginning to emerge and even bloom1:
Total precipitation ending just after midnight, Feb 2nd, as seen by the WRF-GFS model run from 5 PM AST last evening. Catalina/Oro Valley appears to be in a bit of a shadow, so while Ms. Lemmon and vicinity are forecast to get several inches of water content in rain and snow, Catalina gets an inch–though hard to see in this graphic. Why? Likely south to southeast flow coming downslope off the Catalinas. But, I think its WRONG!
Lot’s of gray sky photograph opportunities ahead. Get camera ready. Not much in the way of rain seen in mods after this, so enjoy this rain “chapter” of your life as fully as you can.
Yesterday’s clouds
After another light shower boosted our storm total another 0.02 inches, a fabulous, wonderful, almost Hawaiian like day followed with a little humidity in the air, deep blue skies, and white puffy clouds, ones a true cloud maven would call, Cumulus clouds and would be ashamed if he just said they were “puffy clouds.”
7:34 AM. Sun tried to break through some puffy clouds over the Catalinas after our 0.05 inch shower. A few, very small shower cells were around, but didn’t look like much at this time.7:53 AM. Gee, a strong, though narrow rainshaft developed SSW of Catalina, upwind! Suggests a Cumulonimbus-like protruding, icy-looking top up there on top of the shaft.
8:08 AM. The three amigos rainshafts, headed this way, evnetually dropped another “surprise” 0.02 inches. Earlier model runs had indicated the rain would be over by dawn yesterday.
8:34 AM. One of the “amigos” hit Ms. Lemmon and Sam Ridge nicely. Ms Lemmon racked up 0.59 inches out of the storm overall. Very nice, considering our 0.07 inches total.8:53 AM. As we know so well, sometimes the best, most dramatic shots are those after the rain passes, and the rocky surfaces glisten in a peak of sunlight, here enhanced by crepuscular rays due to the falling rain. A rainbow was also seen, but not by me somehow.
8:54 AM. Closer look at glistening rocks toward the Charouleau Gap.
11:45 AM. The deep blue sky, the puffy clouds topping Sam Ridge, the strong sun, the bit of humidity, the bird flying along on the left, gave the sense of one being in Hawaii I thought.12:32 PM. Puffy clouds still top Samaniego (Sam) Ridge.
2:28 PM. Small puffy clouds provide a “postcard” view of Catalina, Saddlebrooke and environs. Visibility here well over 100 miles. Never get tired of these views! You got some Cirrocumulus up there, too.
2:51 PM. Another postcard view of our beloved Catalina. Rail-X Ranch and the Tortolitas off in the distance, left. Nice patterned Cirrocumulus up top above the little puffy clouds.
5:58 PM. The day ended with a nice sky-filling sunset as a Cirrus layer was lighted from below by the fading sun. The lines of virga show that while Cirrus clouds don’t have a lot of water vapor to work with up there at -40 C (also -40 F), the crystals that form are still large enough to settle out as precip.
The End
————————-
1Desert Aster (I think) in bloom seen on the link trail from the Baby Jesus Trail to the Deer Camp Trail.
Seen on big hike, Jan. 22nd. This plant will be so happy by next week!
When one first encounters this title with its unexpected play on words, we wonder what the author had in mind. Of course, most of us know that at Christmastime, we are often regaled by a Christmas tune called, “Frosty the Snowman1“. But here, we are surprised as we continue reading the title that instead of encountering the word, “snowman,” we encounter the word “Lemmon!” Hah!
What is meant here? What is author trying to tell us? Perhaps the word, “lemon”, has been misspelled. But if so, why would a “lemon” be frosty? Perhaps there was a cold spell in Florida and the author is harkening the reader to a long ago memory. Or, perhaps misspelling “lemon” was a literary device to emphasize that word in an eccentric way.
Yet, upon further investigation, we find that the issue is more complexed than first imagined. We find that there was an art teacher, nurse, and eventually, a self-educated botanist from New England, Sara Plummer Lemmon, who, with her husband and another worker, hiked to the top of the Catalina Mountains right here next to us, and while doing so, they logged the vegetation that was unique to the area. In their excitement when reaching the top, they named that highest peak after Mrs. Lemmon.
So, what does this piece of history add to our literary dilemma encapsulated in the title?
Perhaps Mrs. Lemmon did some work in the field of glaciology as well, hence, the word “frosty” as a possible hint of that work. Yet, upon investigation, we find no mention of work on ice crystals, hoar frost, nor glaciology not only in the work of Mrs. Lemmon, but neither in the work of any the team that mounted what is now known as Mt. Ms. Lemmon. We add that the note that the Lemmons, J. G. and Sara, were on their honeymoon at this time, historians tell us. Perhaps there is another avenue we can explore due to that latter element.
Could it be, too, that we are missing a characterization of Ms. Lemmon by our author? Perhaps she was shy, seen inadvertentlhy as “cold” by some, or was not particularly interested in the physical advances of her husband, J. G. The word “frosty” alert may be alerting us those possibilities.
Ultimately, we remain perplexed by this title; it forms an enigma that may never be confidently resolved.
But then good titles, and good books, are supposed to make us think, try to imagine what the author is telling us through his/her use of metaphor and other literary devices, and this title has done that.
We, of course, reject the most plausible, superficial explanation, that the author’s play on words was merely describing a local, snow and rimed-tree mountain named after Ms. Mt. Lemmon, as in the photo below. No, Occam’s Razor, the idea that the simplest explanation is usually the best one, will not do.
4:43 PM. Those trees are rimed, like the airframe of an aircraft that collects drops that freeze and cause icing. Here the wind blowing across the mountain top, and cloud droplets that were below freezing, hit the trees and froze over a period of many hours, creating this scene. Its not snow resting on the branches. That would’ve blowed off in the strong winds up there.
———End of Literary Criticism Parody Module———-
There was a rousing 0.24 inches of rain yesterday! Our storm total has topped out at 0.89 inches!
In other photos from yesterday:
9:42 AM. Altostratus translucidus again, with a few scattered Altocumulus cloud flakes, but this time with bulging Stratocumulus topping Samaniego Ridge, giving portent of a good Cumulus day if the As clouds will only depart and allow a LITTLE warmth. They did.
10:24 AM. Before long, cloud bases darkened here and there, indicating mounding tops above a general layer, and with the low freezing level of about 7,000 feet, the formation of ice and precip was not far behind.10:51 AM. Mountain obscuring showers were soon in progress due to both a little warming, but also because of a cloud energizing swirl in the upper atmosphere that passed over us at 1 PM AST. Did you notice that windshift aloft as that bend in the winds went by up there? You probably noticed that it was no dice, er, no ice, after 1 PM as the mash down of air that follows “troughs” did that very effectively after 1 PM.
10:52 AM. As the clouds (weak Cumulonimbus ones) broke, there was a fantastic rainbow for just a seconds to the north, landing on my neighbor’s house. It was even better before this, but was slow getting to the camera! Dang.
10:54 AM. “Pictures a poppin’ ” now as breaks in clouds allows those fabulous highlights of glinting rocks and scruffy Stratus fractus or Cumulus fractus clouds lining Sam Ridge, those highlight scenes that we love so much when the storm breaks. And these scenes change by the second, too!
11:00 AM.Also 11 AM. Out of control with camera now…..
11:12 AM. Meanwhile, back upwind… This line of modest Cumulonimbus clouds fronted by a weak shelf cloud roared in across Oro Valley to Catalina. What a great sight this was since now there was a chance of some more decent rains! Before long, the rains pounded down, puddles formed, and another 0.18 inches had been added to our already substantial total of 0.65 inches.
12:01 PM. But that wasn’t the end, was it? Before long, a heavy line of Cumulus and weak Cumulonimbus clouds formed again to the southwest and drenched Catalina with another round of rain, this time, only 0.06 inches. And with it came the End. This line of showers was spurred by that upper level wind shift that was going to occur over the next hour.
1:01 PM. Sometimes those clearing skies, the deep blue accentuating the smaller Cumulus clouds provide our most postcard scenes of the great life we have here in the desert.2:13 PM. While it was sad looking for ice in the afternoon clouds and finding none, the scenes themselves buoyed one. The instability was great enough that even brief pileus cap clouds were seen on top of our Cu.2:21 PM. Pileus cap cloud (right turret) tops honest-to-goodness December Cumulus congestus cloud. No ice nowhere.
2:28 PM. And if the sky and mountains splendor isn’t enough for you, then consider our blazing fall-winter vegetation as evidenced by a cottonwood tree in the Sutherland Wash,’ that yellow dot, lower center. We have it ALL now!2:48 PM. And, as the cloud tops are kept low, we get those fantastic, quilted, richly colored scenes on our Catalina Mountains we love so much. Here, looking toward Charouleau Gap and Samaniego Peak. I could show you so many more like this from just yesterday!
5:08 PM. Even our lowly regarded teddy bear chollas have luster on days like this, the weak winter sunlight being reflected off its razor-hook-like spines, ones that many of us know too well.
5:12 PM. And like so many of our days here in old Arizony, closed out with a great sunset.
Possibility raised in mods for giant southern Cal floods, maybe some flooding in AZ floods, too
Something in the spaghetti plots has been tantalizing as far as West Coast weather goes. They have been consistently showing a stream of flow from the tropics and sub-tropics, blasting into the West Coast. Recall that yesterday, that tropical flow was so strong and so far south, that at least one major gully washed was shown to pass across central and southern California on New Year’s Day, but weaken and shift to the north of southern AZ after that.
Well, my jaw dropped when this model run from yesterday at 11 AM AST came out, re-enforcing, even raising the bar on flooding, in central and southern California, and with those stronger storms, the possibility of flooding and major winter rains here in Arizona was raised. The severity of the pattern shown aloft is not one I have seen before, and for that reason alone, might be considered somewhat of an outlier prediction, one really not likely to occur.
Now, while there is some support in this model flooding “solution” in the spaghetti plots, the main reason I am going to present a series of what a disastrous Cal flood looks like is just FYI and how it develops. The closest analog to this situation was in January 1969 when a blocking high in the Gulf of Alaska (GOA), forced the major jet stream far south across the central and eastern Pacific on several occasions producing disastrous floods in southern California in particular, where one mountain station received more than 25 inches of rain in ONE DAY!
Also that blocking high in the GOA in Jan 1969 also forced unusually cold air into the Pac NW, where Seattle (SEA-TAC AP) accumulated 21 inches of snow over the month, still a record.
Here we go, in prog maps of our WRF-GFS rendered by IPS MeteoStar:
In the Beginning, the blocking high, shunting the jet stream to the south and to the north takes shape in the GOA. Note low far to the south between Hawaii and southern California. Get sand bags out now! This is for 11 PM AST, 28th of December.
24 h later:
Valid at 11 PM AST 29 December. Southern Cal flooding underway. Cold air pocket in Oregon has slipped southwestward helping to energize the lower band of jet stream winds by bringing cold air out over the ocean. The greater the temperature contrast between the north and the south, the greater the speed of the jet stream between the deep warm air to the south, and the deep cold air to the north. Note, too, high is getting farther out of the way in the Gulf of Alaska.
The situation continues to strengthen, and leads to this Coup de Gras, 11 PM AST January 1st. A system this strong barging into southern Cal is mind-boggling, and this panel is what brought this part of the blog, to show you what a devastating flood in that area would look like:
Valid at 11 PM, January 1st. In my opinion, I doubt the Rose Bowl game between the Oregon Ducks and Florida State would take place in Pasadena, CA, if this were to transpire.
Now for AZ. Here’s the prog for 12 h later, 11 AM AST January 2nd, Cactus Bowl Day in Tempe, AZ between the Washington Huskies and the Oklahoma A&M Aggies, to continue with sport’s notes here. Rain would be expected for that game should this pattern persist:
Valid at 11 AM AST, January 2nd. This is an unbelievably strong wave that has roared in from the lower latitudes of the Pacific. While it rushes through Arizona in a hurry, heavy rains, and some flooding are likely should things transpire like this.
Now for a gee-whiz, scary analog….one from WAY back in the winter of 1861-62 when the situation decribed above was likely very similar to what it was in that terrible flood; severe cold in progress in the Pac NW, as it would be in the upcoming situation; a tropical torrent raging in from the Pacific. This 1861-62 flood episode is still remembered. However, it went on for 30-40 days (!) with recurring episodes turning much of California’s central valley into a lake, Los Angeles area, too, where there was a report of 35 inches of rain in 30 days.
What’s ahead, really?
Well the models are going to fluctuate on the strength of this breakthrough flow “underneath” the blocking high in the Gulf of Alaska. But almost certainly one major rain event will break through as that this happens. Its kind of a fragile flow regime, so it usually doesn’t last long.
Whether it will be stupefyingly historic, or just another ordinary southern Cal gully washer, can’t be pinned down. But, if you lived down there, you’d want to be looking around and seeing what you could do to divert water, fix a roof, etc.
There would be strong, damaging winds with one of these “coming-in-underneath”, too, and, for surfers, giant waves!
Interesting times ahead! “Floodmagedon”, as we like to say these days?
No real weather here for awhile, except around Christmas when a mild cold snap, and a little chance of precip occurs as a cold front goes by.
The End, for awhile.
—————————–
1The most intellectually satisfying version of “Frosty the Snowman” was, of course, has been rendered by Bob Dylan.
Looked for a time that the rain might be over by mid-afternoon and early evening here in Catalina with only a disappointing 0.40 inches here, but the rains kept coming overnight, piling up a nice 0.98 inches 24 h total for the storm. In the meantime, Ms. Mt. Lemmon has gotten 4.29 inches! Check out these eye-popping totals from the Pima County network, ending at 7 AM AST today (just updated. These are so great in view of last October’s trace of rain:
Gauge 15 1 3 6 24 Name Location
ID# minutes hour hours hours hours
—- —- —- —- —- —- —————– ———————
Catalina Area
1010 0.00 0.00 0.00 0.24 0.71 Golder Ranch Horseshoe Bend Rd in Saddlebrooke
1020 0.00 0.04 0.04 0.28 1.06 Oracle Ranger Stati approximately 0.5 mi SW of Oracle
1040 0.00 0.08 0.12 0.43 0.94 Dodge Tank Edwin Rd 1.3 mi E of Lago Del Oro Parkway
1050 0.00 0.16 0.20 0.67 1.26 Cherry Spring approximately 1.5 mi W of Charouleau Gap
1060 0.04 0.16 0.20 0.83 1.93 Pig Spring approximately 1.1 mi NE of Charouleau Gap
1070 0.00 0.08 0.20 0.59 1.14 Cargodera Canyon NE corner of Catalina State Park
1080 0.00 0.00 0.00 0.31 0.91 CDO @ Rancho Solano Cañada Del Oro Wash NE of Saddlebrooke
1100 0.00 0.12 0.28 0.55 1.06 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Rd
Santa Catalina Mountains
1030 0.00 0.04 0.08 0.55 1.57 Oracle Ridge Oracle Ridge, approximately 1.5 mi N of Rice Peak
1090 0.08 0.31 0.67 1.42 4.96 Mt. Lemmon Mount Lemmon
1110 0.04 0.12 0.12 0.71 1.61 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 mi S of Coronado Camp
1130 0.00 0.24 0.47 1.89 3.46 Samaniego Peak Samaniego Peak on Samaniego Ridge
1140 0.04 0.12 0.24 0.39 1.73 Dan Saddle Dan Saddle on Oracle Ridge
2150 0.08 0.12 0.28 1.14 3.50 White Tail Catalina Hwy 0.8 mi W of Palisade Ranger Station
2280 0.00 0.04 0.12 0.31 1.93 Green Mountain Green Mountain
2290 0.04 0.08 0.20 0.75 2.40 Marshall Gulch Sabino Creek 0.6 mi SSE of Marshall Gulch
Misty drizzle with very low visibilities is still falling here in Sutherland Heights, Catalina, at 3 AM. The Catalina Mountains are not visible from just a couple of miles away. This suggests the clouds overhead are now “clean and shallow” and rain is forming via collisions of cloud drops with coalescence rather than because of ice in the overhead clouds, often called “warm rain,” a rare occurrence in Arizona. You’ll definitely want to log this in your cloud diary!
“Clean” means that the clouds have low droplet concentrations, viz., are not choked with anthro and natural “continental” aerosols but are more “maritime”, almost oceanic in composition, something that easily leads to “warm rain/drizzle” formation. In oceanic clouds far from pollution sources droplet concenrations usually are less than 100 cm-3. They average about 60 cm-3 in Cumulus clouds in onshore flow along the Washington coast, as an example. Cloud appearance should look a little different to the discerning eye, too. With low droplet concentrations, the clouds appear “softer” than usual, not a hard.
Normally, our clouds likely have a few hundred per cm-3 or more and appear darker from below since higher droplet concentrations is also associated with bouncing more sunlight off the top of the cloud1.
With vort max (aka, curly, or curling, air) still well to the west of us at this time (3 AM AST) as seen here. This sat imagery also shows plenty of shallow clouds upwind of us, so it seems like the very light rain and drizzle will continue well into the morning, likely adding a few more hundredths to our generous totals. Remember that the air likes to slide upward as curly air approaches, that is, produce a lot clouds, and today, a last bit of precip. Did pretty good last night, too!
Honestly, you really want to get out and experience our misty, drizzly rain (drop sizes mostly between 200 and 500 microns in diameter; a few human hair widths), before it ends; the kind of precipitation that makes riding a bicycle even with a big hat impossible. You might even try the near impossible trick of photographing the drizzle drops, too, as they land in puddles, see if you can catch the tiny disturbance made by drizzle drops. That would be great photo! I know, too, that experiencing real drizzle will give you a bit of a chuckle as you think of all those less informed folks, some of whom are even on TEEVEE, who call a sparse fall of raindrops, “drizzle.” Oh, my, WHAT has happened to our weather education?!
Yesterday’s clouds
Lots of gray cloud scenery yesterday, including a stunning example of Nimbostratus (Ns), the steady rainmaker (at least here we had that, anyway.) In other places, Cumulonimbus clouds were also contained within that rainy cloud mass and dumping an inch or so in an hour in TUS with LTG (weather text for “lightning2“), as you likely know. Didn’t hear thunder here, but coulda happened since I was off to the new Whole Foods market at Ina and Oracle as the steady rain from Ns moved in it because it said online that they had Brother Bru Bru’s African Hot Sauce which I had been looking for for a long time but when I got there they didn’t have it! The grocery manager apologized profusely and then we started talking about haloes and the ice crystals that cause them. So, you never know when your cloud mavenhood will come in handy in everyday conversations, maybe make that friend you’ve been looking for:
7:14 AM. The many layered remnants and distant rain creeping toward Catalina from the southwest are evident soon after dawn
7:34 AM. New round of rain begins on the Catalinas. Shafting here implies mounding cumuliform turrets on top, likely glaciating. From up there they would probably look like soft Cumulonimbus capillatus clouds, ones with weak updrafts.
8:34 AM. One of the prettiest sights around here can be just a tiny little cloud (Stratus fractus) like this one when a glint of sun falls upon it. It looked so CUTE! Imagine, you could be up on that little knob and run in and out of it, maybe play hide and seek with your friends, except that being a “clean” cloud, the visibility would be pretty good inside it, not like the shallow, impenetrable fogs you sometimes get around Bakersfield, CA. There, in one of those, you could play really great hide and seek! I’m guessing that if you’re reading this far, you may not have a lot of friends. :}1:23 PM. In the midst of our mid-day light rain, a clear example of Nimbostratus with underlying Stratus fractus and Stratocumulus. Remember, its not the LOW clouds that are raining, its the deep Ns layer above them. However, it is OFTEN true that the lower clouds ADD to the rain because as the rain falls from the Ns layer, those drops often collide with the floating drops in the lower clouds thus making a raindrop bigger. That’s one main reason why rain and snow are so much more on the upslope side of mountains just due to that collection of non-precipitating cloud drops! Its so cool! Away from mountains, you likely won’t have so many low clouds at the bottom of Ns, and the rain is less.
2:50 PM. After the rain ended, suddenly this lower cloud line formed representing a wind puff from the west. It headed toward the Catalinas, but then, within a few minutes, pooped out with no precip having fallen out. It was quite a bit fatter before this photo, too. That dissipation indicated that whatever wind source had produced had died out. But anyway, when you see a cloud line like this, think “windshift.”
4:57 PM. Expansive deck of Stratocumulus with spots of very light rain in the distance promises, along with the curly air feature (an upper level vortex) being so far to the west of us at this point, promises that the rain is not over.
The weather way ahead
Dry for almost two weeks. However, a crazy NOAA spaghetti factory plot suggests rain in about two weeks, around the 23-25th, as you can plainly see here:
NOAA spaghetti factory plot (aka, “Lorenz plot”, after chaos scientist, Edward N. Lorenz–he would really like THIS plot!) valid for 5 PM AST Oct 23rd. Rain is hinted at by the loopy lines in Arizona dipping down to the south. Will keep you posted on that, but not very often.
The End. Its really amazing how much information I have passed along today! Most of it correct, too!
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cCoCoRahs gauge, not Davis tipping bucket which seems to have a problem of late.
1This is the concept behind kooky schemes to defeat potential global warming which hasn’t happened for 18 years or so by polluting oceanic clouds, making them “brighter” on top, darker on the bottom by inserting extra aerosols into them. Ghastly thought! Haven’t we polluted enough?
2Recall that weathermen and women were WAY out in front when it came to what we now call “texting”, as in “2KOLD4me” that kind of thing.
Let me give you an example from the 50s when we were rocking around the clock: “M8BKN15OVC2R-F68/661713G24989 R-OCNLY R”, a text phrase that would take a paragraph to unravel, to paraphrase language maven, Noam C3,4., except in those days we had our own private symbols which I can’t duplicate for “BKN” (a circle with two vertical parallel lines in it) and “OVC” (a circle with a plus sign in it). Weather typewriters and teletypes came with those private symbols!
3Wow, a footnote in a bunch of footnotes! Breaking ground again I think! What Noam C. said: “takes a phrase to tell a lie; a paragraph to unravel it.”
4Factoid, one not having to do with weather: Language maven, NC, really liked Pol Pot and his “restructuring” of society back then until he learned about all the millions of skulls were piling up along with that “restructuring.” You can hear about Pol Pot (and hypocrisy) here in Holiday in Cambodia, one of the defining songs of the 1980s IMO, as interpreted by The Dead Kennedys featuring lead singer, Jello Biafra. (You remember Jello don’t you? Ran for president a while back. Kind of surprised we didn’t elect him…)
While waiting for the remnants of former H. Simon to pass over us during the next couple of days, bringing some rain, starting overnight, got distracted while looking to see how many rainfall measuring stations they have in Baja Cal, and found this about the Great O from NASA. Its a pretty fascinating read I thought, which you will also find fascinating. Sure, intense hurricane O’s floody remnants missed us here in Catalina/Tucson, but it did produce some prodigious rainfall on its path across Baja and points northeast from there into NM. NASA’s Tropical Rainfall Measuring Mission (TRMM) radar estimates that over the ocean off southwest Mexico that about 33 inches fell over a ten day period while O was meandering around down there with some other disturbances, probably raising sea level that bit. And up to 5 inches per hour was falling in rainbands as it entered Mexico from the Gulf of Cal! O was deemed the strongest hurricane (tied with 1967’s Olivia) to ever hit southern Baja since sat images became available.
You will also see reprised in the “Diary of O” the huge rainfall totals that were expected in the TUS area but rains that missed us, the sad part of the story for some folks, who we will not mention. But, as Carlos Santana said, “Those who do not know history, are doomed to repeat it.”
For that reason, in view of the prodigious rains predicted in southern AZ again, but to the west of us, I thought we should be prepared for disappointment by recalling O’s “terrible” miss for TUS.
Here are some graphics from our very fine U of AZ Weather Department’s Beowulf Cluster computer outputs from just last evening at 11 PM AST, ones that can be found here, in case you don’t believe me again, a seeming theme around here. First, when the computer model thinks it will start raining, Figure 1, and in Figure 2, the expected gigantic totals expected along and near the US border where we really shouldn’t go unless you 1) go in an armored vehicle of some kind, 2) make prior arrangements with the appropriate ruling Mexican drug cartel for that part of the US that you just want to visit some rain, nothing more:
Figure 1. Valid for 2 AM AST tonight. The leading edge of the rain has reached Catalina. You might want to stay up for that. That wet desert aroma as rain begins is so awesome!Figure 2. Valid for 3 PM tomorrow afternoon. One small, mountainous area around Organ Pipe Cactus National Monument is forecast have more than TEN inches by then, likely slowing the amount of incoming drugs. Organ Pipe Cactus NM is a US national park that you are warned not to visit, or if you do, you might be shot or have some other untoward happenstance if you go hiking. So you probably shouldn’t drive down there to see this once in a century rain. How sad is THAT?
Right now, as of 4 AM AST on Thursday, this model thinks Catalina and vicinity will get less than half an inch. Be prepared for more, though, rather than less. Note the streamer of heavy precip associated with Simon in Figure 2. Well, recall that O’s heavy precip streamer was going to be right over us, but then shifted eastward in the models and in real life at the last minute. The above prediction would only have a bit of a “westward bias” (the real streamer is EAST of where its shown now) to give TUS and vicinity a memorable, drenching October rain. This is what occurred with O’s streamer of torrential rain which was expected to pass over TUS, but ended up a little east of us. So, anyway, given all the little uncertainties in model predictions at this point, the watchword here is “watch out” which is actually two words. The view from here, incorporating a positive rain bias as you know, is somewhere around an inch for Catalina. The grassy green is gone, most annuals in serious wilt or crispy now, but could an inch bring some green back? Clueless on that score.
Yesterday’s Clouds
6:06 AM. Nice Cirrus sunrise, maybe some Cirrocumulus at far right, and off on the left horizon.
5:05 PM. Altostratus translucidus with an Altocumulus layer on the horizon.
5:07 PM. A “classic” view of Altostratus translucidus (sun’s position can be discerned through it), and here, an all ice path to the sun. Liquid cloud elements would appear as dark flakes, or would obscure the sun’s position. Sounding indicated that this layer was 26 kft above the ground in Catalina!
First, a tedious note about the Big One of two days ago.
While the Davis Vantage Pro 2 tipping bucket gauge registered a whopping 4.18 inches, a smaller plastic gauge from CoCoRahs here had 4.63 inches, after subtracting some rain (half an inch) I forgot to dump due to a brain cramp. A neighbor a couple hundred yards away here in Sutherland Heights, measured 4.65 inches in her gauge, and I now think that the 4.63 inches is the correct amount of rain for this spot. This goes with two other reports of 4.48 inches at Our Garden, and another one of 4.50 inches just a bit on the west side of Lago del Oro Parkway, and the 4.59 inches at the Samaniego Peak ALERT gauge just E of us. We seem to have been in the heaviest band of that storm! (Makes up for all the misses during the summer.)
The Vantage gauge is mounted above the ground, and some loss occurs due to wind, and also when the rain falls too hard, the tipping bucket can’t keep up. The CoCo gauge is ground mounted, and is protected from wind by surrounding natural desert vegetation (aka, “weeds”).
Below, from the University of Arizona’s rainlog.org, is a map of rain totals in our area and the northern areas of TUS. (The Our Garden and Samaniego Peak totals of 4.48 and 4.59 inches, respectively, don’t show up because they are not members of rainlog.org but probably should be so’s we can get all the rain we want to see in one site! I have added those values
Rain totals for September 8, 2014. The green values are for Our Garden and Samaniego Peak, along with the revised total for Sutherland Heights. Recall a neighbor here measured 4.65 inches!
In the meantime, from CDO at Wilds Road videos I took in heavy rain as the Sutherland Heights rain started to eclipse 3 inches, this larger wave that formed. I think it could have been surfed.
10:55 AM. From a frame of a video taken at the CDO wash and Wilds Road intersection, this monster. Must have been 6 feet high in total height! So, you CAN “surf Arizona!”
Yesterday’s clouds
First of all, it was real disappointing to see so much haze in the air after so much rain! Not sure where it came from yet, will have to do some back trajectories to find out, but later…
6:14 AM Sunrise Cumulus6:54 AM. Crepuscular rays outline a Cumulus turret.6:54 AM. Distant Cumulonimbus offers hope for a similar scene later in the morning over the Catalinas, a scene that was NOT realized.8:17 AM. A great example of crepuscular rays and bad air.12:53 PM. Promising Cumulus congestus that really went nowhere.2:03 PM. However, it was not a completely rainless day, as can be seen, “dead ahead.” Some clouds got thick enough to rain lightly. In this Arthur’s opinion, this rain was due to the collision with coalescence rain process, not the ice one which I deem with a 51% confidence level.4:26 PM. Kind of losing interest in the whole day now as Cu disappear in favor of an Altocumulus opacus deck, one originating right out of Norbert if you saw the satellite imagery.
The weather ahead
Still pretty confident in more summer rains and tropical air after the current dry spell of a few days, this partly associated with the next tropical storm, likely to be named “Opal” or something like that with an “O” as it takes shape. Of course, we could look up what name it will be, but it will be named soon enough, so why bother?Its already a numbered tropical depression (a weak area of low pressure) down there off Guatemala now.
If you’ve ever been to Indian State of Kerala and the western Ghats, you know that yesterday, with the warmth, the thick, pounding rain with cloud bases at tree-top levels, visibility a mile or two, and with little or no lightning, was a true sample of India in the summer, maybe a July day in the western Ghats.
Congratulations for having experienced India and a TRUE monsoon day without having to go anywhere1.
The totals? 4.48 inches at Our Garden on Columbus Avenue, wettest day in their 37 year record. 4.59 inches on Samaniego Peak. The largest amount I could find was at Stewart Dam by the Salt River, 4.79 inches, all in 24 h, though most of these totals fell in less than 3 h. Below a shot of the CDO wash at or near its peak at Wilds Road, the latter a “street” if I may, one that might now surpass in difficulty the Charoulou Gap for the 4-wheeler and ATV crowd judging from the way it looked yesterday.
BTW, the shots below are from a video taken by yours truly in the pounding rain as the total here in Sutherland Heights surpassed the 3 inch mark, on its way to 4.18 inches. I was the only one there, except for Jessie, who runs Our Garden, who also showed up in the pounding rain right after I did, saying, “I thought I’d find you here.” Huh.
10:55 AM. Rainfall in Sutherland Heights was now surpassing 3 inches when this was shot.
11:00 AM at the Canada del Oro Wash at Wilds Road. 11:00 AM at the Canada del Oro Wash at Wilds Road, looking upstream from near there.
This was twice as big and fast moving as anything I had seen in the prior seven summers, though doesn’t compare to the August 2003 flood in which the CDO wash at this location got all the the way to Lago del Oro Parkway, a hundred yards wider than this.
With yesterdays soaking wet air over us, it didn’t take much to send turrets spaceward, and it MAY have been that those car-floating rains in the Phoenix area had something to do with what happened.
A gust front moving this way was evident in the satellite and radar imagery as new echoes raced to the SE from that whopper after midnight. The gust front appeared to dissipate before getting here, but then not long after the heavy rains began, the wind came up from the north after calm conditions marked the first inch or two. And the rains intensified. Clearly, wherever that wind shift came from, it gave the clouds above us another boost, to push an already memorable rain into historic proportions by helping generated the second two inches. (I hope you logged the time of this important windshift in your weather diary yesterday.)
Here are some shots from that historic day, one that we will likely not live to see again:
5:54 AM. Stratocumulus clouds with a higher layer of clouds reddened in the sunrise that provided a rosy glow where there were break and thin spots in the overcast. The clouds are only maybe 2000 feet above the ground at 59 F (15 C) or so, incredibly warm-based.
6:32 AM. This extraordinary shot. “Huh,” you say? Its beginning to drizzle from these shallow Stratocumulus clouds over there by the Catalinas, a RARE event in Arizona. When cloud bases are so warm, and therefore, contain so much water in them, water that is converted into larger than normal cloud droplets they can then reach the “Hocking threshold” (about 38 microns in diameter) for collisions with coalescence to occur, and that in turn allows drizzle and rain drops to form without ice! Rare to see Hocking’s threshold exceeded in our clouds! The day could have ended right here and have been a happy, memorable one. True drizzle even fell here in Sutherland Heights from these clouds just after 7 AM, too, and before the big rains hit. Did you know that this process of rain formation, called collision-coalescence, has produced the biggest rain drops ever measured, about a centimeter in diameter. And that was in clouds that did not reach the freezing level! And, nearly all of that western Ghat rain is due to that mechanism, in hurricanes, too. So, don’t need no ice for blinding rains when the air is so tropical as the air here was yesterday. Ice in those tropical situations is often more like fluff icing on a rainy cake, to make a strange metaphor, than a real contributor to what falls on the ground.
7:17 AM. Before long, heavier rains, this area fronted by a weak arcus cloud, were breaking out. With no thunder, and weak looking, “stratiformy” looking clouds, you do intuit that no ice may be involved, even if the rains are heavy. Look how thick and fog-like it looks in that rain area. About a half an inch fell out of this according to one “personal weather station” out there.
8:05 AM. Outside of some brief true drizzle drops, it hasn’t done anything here yet, but, “hey” this looks interesting as it approaches, though no rain was falling out of it. Recall, too, that lower portions of cloud like this indicate an area of updraft feeding a Cumulus base. Must be too shallow for rain to form…. Or was it? This is going to be a VERY tedious blog today.8:10 AM. Look! Just five minutes later, a little rain is falling out now and its heading this way and that updraft area is holding up. Maybe it will be enough to measure! (Note: Here’s where the rain ball got rolling, to make another awkward metaphor; it dumped 0.22 inches in a few minutes as it unloaded on Sutherland Heights. Note also that there is just stratiform (flat) and higher clouds behind this. Didn’t look like much more was going to happen. Perhaps it would be “too cloudy” and cool for good rains, something we often hear around here, and is largely true.
OK, its pretty hard to take pictures of rain, but these two below were the best I could do, and I hope you appreciate it. I have no idea why I took 85 pictures of heavy rain; they don’t look that great in retrospect, but it was exciting to be taking them…kind of lost control.
9:28 AM. What Oro Valley looks like from Sutherland Heights when its raining two inches an hour. Photo looks west.Also taken at 9:28, but 21 photos earlier than the one above, of the runoff from a local resident’s roof when its raining two inches an hour. Wow, snapped 21 photos in a minute! Hmmmmm… maybe some counseling is needed on self-control…
The rest of the day was truly history, and by afternoon, things were clearing out, and by late in the day left those usual, “memorable” scenes of our mountains decked in clouds. The mountains seemed greener, washed up as it were, more than usual after good rains.
5:11 PM. Residual Stratocumulus castellanus (because they have little turrets) top “Sam” Ridge.6:08 PM. Another just a pretty scene of our well-washed mountains. Samaniego Peak got 4.59 inches yesterday, as mentioned before.
Today…..U of AZ mod run from 11 PM last night sez no rain around here today or tomorrow. With the residual moisture we have, and clouds topping Samaniego Ridge this morning, it would be hard to imagine that early on in the day, later this morning that a few huge Cumulonimbus clouds won’t arise over the Cat Mountains before the drying takes hold. So, we might see some great clouds right away, and then watch them wither as the dry air manifests itself.
In the longer term, yesterday’s 12 Z run was amazing since it had more heavy rains down the road, a week or so out, with another “Norbert” like storm traveling up the Baja coastline. Imagine! And on last evening’s run at 5 PM AST, it has it in almost an identical trajectory as Norbert. Check this out. Never have seen that before, such a replication of something fairly strange in the first place. I just saw this now, and am so excited am going to slip it here adding already to “blog excess” and “reader fatigue”:
Valid on September 16th at 5 PM AST, this duplicate of yesterday’s map! UNBELIEVABLE!
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1In the southern peninsula region of India, east of the Ghats in during the time of the SW monsoon, there are giant thunderstorms with incredible LTG, but they’re more scattered around than the “24/7” monsoon rains in the Ghats, rains that can produce up to 300 inches in a month, though averages are closer to 100.
A measly 0.01 inches is all we got here yesterday in a Seattle-like rain from an overcast that sputtered drops drown over a couple of hours, one that could barely wet the pavement, if we had any here in Sutherland Heights. Of course, we surely drooled at the close call that drained Saddlebrooke yesterday afternoon (see below). Probably washed more golf balls into the CDO wash like that storm did last year…
Also, 0.75 inches fell, too, where Ina crosses the CDO wash yesterday, “so close, and yet so far away”, as the song says. Oh, well, another missed rain that I have to crybaby about1. Will get some final pictures of the 2014 summer greening today before it fades away in the many dry days ahead to help make me feel better now that its over.
Here’s your cloud story for yesterday. It was pretty neat one, full of hope, even if that hope was eventually dissipated unless you lived in Saddlebrooke… The U of AZ time lapse film for yesterday is great, btw.
6:31 AM. I am going to say these are Altocumulus castellanus clouds, though they are a little low and large for that genera.
6:33 AM. This was a pretty scene… Here an isolated Ac cas rises up. Distant small Cumulonimbus clouds, weak ones, can be seen on the horizon.
9:18 AM. Before long, those pretty Cumulus clouds were springing to life off the Catalina Mountains, the sky so blue behind them.
9:19 AM. A rare “High Temperature Contrail” (HTC) slices through some very thin Altocumulus perlucidus. This aircraft phenomenon has also been called, “APIPs” for Aircraft Produced Ice Particles.) Recall that Appleman (1953) said that an aircraft couldn’t produce a contrail at temperature above about -35 C. But, he was WRONG. They can do it in a water-saturated environment at much higher temperatures, even as high as -8 C (see Rangno and Hobbs 1983, J. Clim. and Appl. Meteor., available through the Amer. Meteor. Soc. for free, an open journal kind of thing.)11:48 AM. Before noon, all thoughts of past glory were gone as the Big Boys arose in a hurry. What a dump here! The cloud, since it is not showing an anvil nor obvious fibrous appearance, still pretty cauliflowery even though the discerning CMJ would not be fooled by its icy composition, it would be a Cumulonimbus calvus (“bald”).3:40 PM. Probably THE most hopeful scene of the day. A large complex of Cumulonimbus clouds was emerging from the Tucson mountains, heading in this direction. But more importantly, were the cloud bases forming over Oro Valley ahead of it, likely, it seemed to be pushed upward by the outflowing winds ahead of the distant cells. Also, that cloud bases were forming and extending westward from the distant cells offered another rain-filled scenario that could happen as they approached from the SW.
4:14 PM. When the southwest wind arrived, it did in fact cause the clouds overhead to swell up like aphids on a Seattle rose bush, but as bad luck would have it, they were piling up just to the north of us and over Saddlebrooke where they all all those amenities and don’t really need a lot of rain.
4:40 PM. After the first base dropped its load a little beyond Saddlebrooke, another cloud base darkened and expanded over Saddlebrooke, but this time, began to unload there. Here, like the seldom seen pileus cloud, these strands of the largest drops being to pour out of the collapsing updraft. You have about two minutes to see this happen because if you look away, the next time you look there will be nothing but the “black shaft.”
4:45 PM. A remarkable transformation. How can so much water, you wonder, be up there in a cloud?
6:05 PM. As the threat of any significant rain faded away, there was at least some “lighting” excitement, produced for just seconds as the sun shone on this….Stratus fractus cloud. Again, you must be watching at all times to catch these little highlights.
6:58 PM. Time to say goodbye to Cumulus and Cumulonimbus clouds like these, until maybe next summer.
The End. Probably will go on a hiatus now.
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1Its good to remember that there is a little crybaby in all of us, isn’t there?
Been looking around at quite a number of model runs (well 2, anyway) trying to find the best one for you. Here it is. Its yesterday’s WRF-GFS run that was based on 11 AM AST global data. Has some great rains for us here in Arizona. Those rains, and that incredible hurricane that saunters up the coast of Baja in about ten days, aren’t depicted as well in later model runs, so there’s not much point in showing them. If you want a great, OBJECTIVE forecasting, you know, go to Bob, or the NWS, or wait for Mike L’s detailed one from the U of AZ later this morning! You’re not going to find “objectivity” here when it comes to forecasting rain for a desert region1. Let’s look at two examples of weather excitement in that now-obsolete-run-but-doesn’t-mean-it won’t-happen-anyway-just-because-its-a little-older-run”1: 1) Lotta rain in Arizona (that’s a different near-hurricane over there in the SW corner of the map, one that in one model run from Canada, formerly went over Yuma! Sorry Yuma, and all of Arizona, both of which would have gotten, in that event, a bigger dent in the drought than shown below. Oh, well.
Valid on Thursday at 11 AM AST. Green pixels denote those areas where the model thinks rain has occurred during the prior 6 hours. Most of AZ covered in green pixies! Sweet.
2) Fascinating near-hurricane just off San Diego on the 29th of August, likely surviving so well due to the California Niño mentioned here lately. BTW, this particular hurricane is predicted to be exceptionally large and intense out there when it revs up in a few days, maybe a Category 4 at its peak, looking at some of the model runs. “Let’s go surfin’ now, everybody’s learnin’ how….” The Beach Boys, 1962, sayin’ it like it was for us near-beach bums way back then when the summer hurricanes in the Mexican Pacific sent huge waves poleward on to our southern California beaches, as the one below will2.
Valid in ten days, Friday, August 29th at 11 AM AST. Near hurricane brings rain to San Diego. Colored regions now denote where the model thinks it has rained in the prior TWELVE hours (coarser resolution because its not going to be that accurate in the placement of highs and lows anyway, so why waste time over-calculating stuff?
Yesterday’s clouds
What an outstanding, if surprising day it was! After it appeared, in later model runs available late yesterday morning, that the late afternoon/evening bash from the high country wasn’t going to happen after all (producing local glumness), we had a remarkable in situ explosion of cloud tops. Those clouds just erupted from an innocuous, patchy group of Stratocumulus that invaded the sky around 5 PM. Still, even with the early turrets jutting up there, it didn’t seem possible, at 7 PM, there would be much more growth into showers, let alone, thunderstorms with frequent lightning lasting several hours that happened. Eventually rain even got into Sutherland Heights/Catalina, with 0.17 inches here, and 0.12 inches at the Golder Bridge, and that didn’t seem possible since the rain shafts were so locked onto the Catalinas, and east side for so long. Dan Saddle, about 5 mi S of Oracel, counting the mid-afternoon thunderstorms that locked in upthere, got a 2.68 inches over the past 24 h! That should have sent a little water down the CDO. BTW, a location in the Rincons is reporting 4.09 inches in the past 24!
5:50 AM. Day started with “colorful castellanus.” Hope you saw this.12:26 PM. After a late morning start, the Cumulus congestus tops were streaming away from the origin zone of Mt. Lemmon to over the north part of Saddlebrooke and the Charouleau Gap. No ice evident yet, but it was just about to show itself. BTW, the “51ers” have a nice baseball team in Vegas (of course), this brought to my attention by neighbors recently, showing that a degree of strangeness permeates American life, as also shown in these blogs.
12:44 PM. Ice virga now seen in the right hand side falling out as I passed the budding wildlife overpass now being constructed on Oracle Road. I guess scents and signage will be used to direct wildlife to the overpass.
1:49 PM. Took about an hour more of rain and development for the thunder to start from these locked in turrets that kept springing on The Lemmon.
4:54 PM. Long before this, it was “all over’, the rains no doubt up there had helped to put the fire out, so-to-speak, and with no anvils advancing toward us, there was even hardly any point to remain conscious. It is finished.6:54 PM, 2 h later. Shallow grouping of Stratocumulus provided a nice, if boring, backdrop to the setting sun’s light on Samaniego Ridge.7:04 PM. Only ten minutes later, and I’m out wondering around in the backyard looking for a nice sunset shot, when I see this shocking sight for the time of day, a protruding turret far above the other tops. Still, I pooh-poohed anything happening but a ragged collapse in the minutes ahead. It was too late in the day for heating or anything else to generate rain in situ from these lower clouds (now topping Mt. Lemmon). Nice pastel colors, though.
7:32 PM. Though “pinkie” in the prior photo did fade, new turrets kept bubbling upward, and in disbelief, this one reached up beyond the ice-forming temperature threshhold (is probably topping out between 25-30 kft, not huge) and a strong rain shaft emerged on the Catalinas. After a little while longer, lightining began to flash to the east as the Reddington Pass area started to get hammered. Eventually in the early nighttime hours. these cells propagated to the west, giving us that bit of rain here in The Heights of Sutherland. How nice, and how mind-blowing this whole evening was!
Today
Got some Stratocu (castellanus in some parts) topping Sam (Samaniego Ridge) this morning, an outstanding indication of a lot of moisture in the air, moisture that’s not just at the surface. U of AZ has thunderstorms moving toward Catalina during the late morning (!) and afternoon from the SW, not the usual direction we’re accustomed to. So, keep eyeball out toward Twin Peaks or so for exciting weather today! Oh, my, towering Cu top converted to ice, must be 25-30 kft up there right now at 7:06 AM! Also, notice nice shadow on lower Ac clouds.
The End
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1“Truth-in-packaging” portion of web blog statement.
1Its chaos in the models due to errors in them we don’t always know about, chaos that we try to get a handle on with plots from the NOAA spaghetti factory. But you know all that already, so my apologies for repeating myself again and again. I thought I would see what would happen if I put TWO “1” footnotes….
2Of course, in those days, we had little knowledge about how many hurricanes there were down there due to the lack of satellite data and ship reports. But when the “Weather Bureau”, as it was called in those days did know, there was always good surf on the south facing beaches, like Zuma Beach. So going to the beach, unlike now where wave forecasting is so good, was a real crap shoot. You’d come over that first viewpoint of the ocean on Malibu Canyon Road, on your way to Zuma. one that over looked the ocean a little offshore from Malibu, and either go, “Holy Crap!”, or hope for the best. It was a swell time for lightly employed youth. Below, the best “Holy Crap!” view coming around to that viewpoint, early September 1963 (never saw anything like it before or afterwards; swells were never visible so far offshore from this spot, meaning Zuma would be gigantic). Still remember those Zuma waves, so far out to sea, as the height of small telephones…
Nearly drowned that day at Zuma, me and my pal ignoring lifequard’s advice not to go in. HELL, we’d been body surfing the biggest ones we could there for years by then. Fortunately, he didn’t have to come and get me, which saved a lot of face.
