About real clouds, weather, cloud seeding and science autobio life stories by WMO consolation prize-winning meteorologist, Art Rangno
Author: Art Rangno
Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.
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!
1) The quarter inch predicted/hoped for here fell on Borrego Springs, CA, (0.27 inches) instead. So, it was pretty close. We received a measly trace in the past 24 until we got 0.05 inches just now! Barely made the 0.05 inches, thought to be the least that could fall. So, in humility, will be expanding limits of storms, maybe go with 0-5 inches possible amounts for every next storm. Should hit those.
2) Mods still think more rain is ahead over the next few days, beginning on Thursday. This period of rain has always been predicted to be more than yesterday anyway.
3) As an outstanding weather note for my reader, I thought I would post this photo from a friend in Seattle of the exceptionally warm weather for this time of year they had yesterday in Seattle (60s). A young1 woman at Green Lake in Seattle displays how warm it is by dawning a bikini, near where the present writer used to live. “Smells like global warming”, as Seattle’s own Kurt Cobain1 might have said about yesterday, if he wasn’t dead.
While there have been studies about cherry blossoms and that kind of thing coming out earlier in the spring back East of late, maybe there should be one about bikinis coming out earlier, too. How many weeks earlier in spring than during the Little Ice Age, do we see bikinis nowadays? How long has the bikini season been lengthened? Is it commensurate with lengthening of the growing season? That would be a VERY interesting scientific question to address, one that needs to be fully addressed via graphs and photo documentation. Applying for NSF global warming grant monies now…..
Yesterday afternoon at Green Lake in Seattle. A young woman dawns a bikini! Unheard of in January in Seattle! Thought I would display this full size so that you could see how warm it is. Thanks to Bob S, Ballard District, for supplying this datum.
Yesterday’s clouds
8:31 AM. Rainband encroaches from the south horizon. Flow was from the southeast, but movement of band was to the north. The clouds in the foreground are two layers of Altocumulus. The banded rain cloud moving toward us would be Nimbostratus.11:30 AM. Dammitall, its still not here, and now the rain coming out of the band is so slight you can see through to the other side! Nice birds of some kind on the wires, upper left. Makes me think of that Leonard Cohen song, Bird on the Wire, best interpreted by Judy Collins, of course.
11:31 AM. Lotta birds on the wire. I thought you should see this. Above, Altocumulus/Stratocumulus, with a higher layer of Altostratus.4:08 PM. After the trace and clearing, a new bank of Altocumulus/Stratocumulus and rain band approached from the south. Virga can be seen on the horizon, too. Hope building again for measurable rain.4:19 PM. From the corral, a display of Altocumulus/Stratocumulus lenticulars downstream from the Catalinas. Nice lighting on hills, too.4:30 PM. Cloud maven juniors should have noticed that the lower layer of clouds here (left of center), are LOWER than the clouds that passed over earlier. That means the incoming rainband had a better chance of producing measurable rain though it didn’t.4:40 PM. Another great sign that measurable rain was on the doorstep though it didn’t were these faint Cumulonimbus tops showing up beyond Pusch Ridge. Gettin’ excited here, as you were no doubt. Some pretty hard radar cells came up out of Mexico then.
That’s it. No more photos, no rain last night, either, but in some kind of rain miracle, it has just put 0.05 inches in the gauge! So, the forecast from this typewriter that 0.05 inches was the least that could occur in this “storm” has been verified!
Conditions not ripe for much more, though a few light showers are still upwind. Clouds oughta thin as the morning goes along, with huge breaks in the clouds this afternoon.
Mods suggest more rain beginning as early as Thursday night. This one has more potential for rain here, somewhere between 0 and 5 inches, i. e., only a 10% chance of less than zero; less than 10% chance of more than 5 inches. There, that should do it….
The End
———
Composer, lead singer for that Seattle band, Nirvana. You can see Kurt in a cloud of smoke singing, “Smells like air pressure here“, a Bill Nye parody of the true Nirvana hit where Cobain sings in a lot of smoke, “Smells like teen spirit.” Compare versions.
There are more “panels” with rain for Arizona than there are for Seattle over the next 15 days1, this as seen in last evening’s 5 PM AST crunch of global weather data by our best model (rendered here by IPS MeteoStar).
Hmmmm2.
Let us review the NOAA spaghetti factory output to see if this long run of intermittent rains in Arizona has any veracity at all:
Valid at 5 PM AST, February 9th, 15 days from now, or is it? This was based on the same global data as the many rain panels.
So, there you have it.
The End, sans all but one sunrise photo3
7:10 AM. Under lit Altostratus with virga.
—————————-
1This includes today’s late afternoon through tomorrow morning’s sprinkles or light rain.
2Recall the NOAA Climate Prediction Center’s experimental long range forecast of 4 inches of rain in TUS in January, and SIX inches in February made in early December? Could it possibly have any veracity?
Hmmmmmmmm.
3Compulsive-neurotic cloud photo documentation of the day being blunted presently by social engagements with out-of-state visitors and having to do things indoors, and not able to run outside without causing inexplicable voids in ongoing colloquies. My apologies.
The report below was supplied by stalwart metman, Mark Albright, U of WA, who snooped around to see if a forecast of 50-100 mph in southern Cal made from this blog onJANUARY 18th had any credibility at all for a 50-100 mph wind event in southern California:
“Looks like your forecast of 2 days ago1 has already verified. Sill Hill, 20 miles NE of San Diego at 3556 ft, reported a gust to 86 mph (75 knots) at 13:50 UTC this morning.
“0430 AM NON-TSTM WND GST 9 SSW JULIAN 32.95N 116.64W
01/24/2015 M75 MPH SAN DIEGO CA MESONET
Its rare when forecasts go the way they should, and I thought I would put on a display of exceptional exultation today.
Now comes the time that the upper air disturbance that produced that 50-100 mph wind sits off the Baja coast, scoops up some moisture from the deep tropics and sends its back over southern Cal and the Great Southwest. Still looking for a thunderstorm or two in that cloud mass somewhere, most likely west of us, as it rolls northward tomorrow.
The bottom line in this loop is the Equator, and that cloud band just north of there is the Intertropical Convergence Zone, where the trade winds meet. The water is a little warmer than normal down there, not enough to qualify as more than a minimal “New Niño (the “Classic Niño, the one next to Peru, is completely gone). But modestly warmer than normal water temperatures still helps a little to send up Cumulonimbus clouds which eject moisture from the Tropics into middle latitude and sub-tropical latitude disturbances and that’s what’s happening in that sat loop; an ejection of clouds and water vapor into that formerly dry, 50-100 mph Santa Ana wind forecast-verifying-producing upper low, a forecast that was made 6- days before it happened! Really incredible.
A view of sea surface temperature ANOMALIES, with important annotations:
As of January 24th, 2015.
We’re sticking with the range of amounts previoulsy foretold here that could occur in Catalina, that range being pretty high due to model vagaries. From this keyboard, the least that could fall is a puny 0.05 inches, and the most remains at 0.50 inches, which would be very nice. Averaging those two gives 0.275 inches, also quite nice, and the most likely amount if averaging like that has any credibility at all. This is the fun part of weather forecasting.
It has to be mentioned that the WRF-GFS nested model from the U of AZ indicates that the larger total is going to occur, this from the 11 PM AST run from last night. That would be so GREAT! Take a look at these great totals as they pile up, ones accumulated over the 24 h from mid-day tomorrow to mid-day on Tuesday. So fine.
And, to make the news even better, more rain is increasingly likely two or three days after this episode!
Yesterday’s sunset:
5:55 PM. Curling Cirrus
Today; mostly high ice cloud (Cirrus, Cirrostratus, Altostratus) broken to overcast skies with thin spots from time to time. Nice sunrise, hope you caught it.
The End
———————————————-
1It was on January 18th, not “two days ago”, that that astounding forecast was made, so long before it happened I might get an award of some kind, maybe the Amer. Meteor. Soc. Rossby Medal… That would really be great!
7:20 AM. Altostratus with pouches of virga7:23 AM. Ditto. Ac len is the fine line cloud upper center.7:27 AM. Ditto, pretty much.7:30 AM. Nice lighting (not lightning) for just a few seconds.8:19 AM. Altocumulus trailing snow/virga. Tops, though the coldest part of the cloud, are composed of mostly of droplets at temperatures far below freezing. A few ice crystals form and drop out leaving the supercooled droplet cloud mostly intact.
12:55 PM. Just about the first boundary layer cloud, this a Cumulus fractus fragment. Hope you recorded this event in your cloud diary. Its pretty mandatory to note developments like this if you want to move on to the next level of cloud-mavenhood.
3:03 PM. Those boundary layer clouds, Cumulus ones, were reaching their maximum depth about this time. This would be a Cumulus mediocris, estimated depth 2500 feet or so.5:14 PM. Whilst clouds locally never got beyond the “mediocre” stage, or produced ice under them, to the north where the air was colder aloft, Cumulus clouds were able to grow taller and become Cumulonimbus capillatus (hairy looking with ice) incus (the last term just meaning it has a flat anvil, a flat head.)
5:47 PM. This post sunset shot shows layers/lines of smog at the same level where some flat Cumulus remains are. The smog is so visible because the air is ALMOST saturated near those clouds at their level, and some of the smog particles (hygroscopic ones) have deliquesced, have gotten much larger by absorbing water vapor, or might even be haze droplets where water has condensed on them (“smoglets”). It therefore, by definition, cannot be a “pretty sunset.”
The model rain ahead; two episodes
The low that plunks down off the coast of Baja this weekend from southern California, circles around out there for a couple of days, before deciding to move back over southern California with clouds and rain. If it was a song, it would be The Wanderer. Yes, that fits. Its expected to scoop up a generous helping of middle and high clouds from the deep tropics as extra baggage. The “extra baggage” (model predicted rain) arrives here late on the 26th (Monday) and continues off and on through Tuesday night. The first clouds, of course, high ones like Cirrus, will begin arriving a day ahead of the actual rain, on Sunday.
It is virtually certain that there will be some high-based Cumulonimbus clouds and thunderstorms in these masses from the tropics, though maybe not here. Most of the rain is projected for eastern California and western Arizona where rain is really needed–and how great is that?
However, we should be in for a quarter inch or so, anyway. Last time I guessed limits on a storm, even the lower limit of 10% chance of less than 0.05 inches wasn’t even realized. Pretty pathetic forecast. But, moving forward and forgetting past errors, this one seems to have a similar range of possibilities, the least amount 0.05 inches, the most, 0.50 inches. The chance of measurable rain here in Catalina in this first 36 h storm period is probably, from this typewriter, about 80%.
“But wait! There’s more!” “Maybe!”
A second system floats in right after that and from Jan 29th through early in Feb, and more welcomed showers are possible.
You can check out these prognostications in a more professional way at IPS MeteoStar, this link to the latest model run from 11 PM AST last evening.
The most wetness I could find for Catalina residents is in this here model run from last evening, 11 PM AST. Rains on the 27th into the 28th, as was mentioned as a possibility here some days previously, then it rains from the 29th into February 1st (new!) Prior model runs before this one last last night are much drier; are not shown, nor will they be discussed.
Gut feeling, which is what we meteorologists went on before the era of computer models, and frankly, its a feeling coming from a forecaster who suffers from “desert precipophilia1“, makes me think this wetter model run will be more correct than the bad, drier model runs that preceded it.
However, the rain in the first episode, 27th-28th, this from that system deep in the tropics, looks awful light, probably from mid-level clouds. Just looks like its not going to have much left when it gets here. An awful of rain, however, will have fallen on the ocean west and southwest of Baja California, though, before it arrives.
The later storm at the end of the month looks stronger. See the panel below, which I have pinched off IPS MeteoStar and have placed here since I suspect you won’t really look at it and I have to do pretty much everything for you:
Valid at 11 PM, January 30th. The colored regions denote those area where the model has calculated that precipitation has fallen during the PRIOR 12 h. Blue denotes heavier precip. A bunch of arrows have been added to show approximately where we are in Catalina, AZ. This is from our WRF-GFS model output based on last evening’s 11 PM global data, as rendered by IPS MeteoStar, a company who will be soon charging for these images it appears, they are that good. Nice rains in TX and OK, too.
Is spaghetti supportive of a wet Catalina in the near future, this latest off-the-computer-presses-to-you model run?
Not so much.
But then spaghetti let me down when I told a friend that “it was in the bag” for rain in Monterrey, CA on the 17 or 18th of Jan, about 12 days ahead of time, based on spaghetti. Didn’t rain at all. “Hey, take a bite out of credibility.”
So, we’ve been chastened royally here, as a British citizen might say; the deliberate errors in the “ensemble” plots sometimes aren’t big enough apparently compared to the goof ball measurements that sometimes come in. So, I’ve downplayed the idea that spaghetti is all knowing. It could be WRONG/misleading at times, anyway.
However, to balance the spaghetti picture, the encroaching trough coming in over us tomorrow WAS well predicted, long in advance. Unfortunately, it looks a little too dry to produce measurable rain, just a drop in temperatures. But, there should be some nice cloud scenes.
Some recent clouds
5:52 PM, Jan 18th. Nice patchy Cirrus clouds with a couple of flakes of droplet Altocumulus clouds floating around below them.2:25 PM. Patchy Cirrus fibratus or “intortus”–the latter meaning kind of a tangled mess in appearance.4:43 PM. Cirrocumulus undulatus, those just-formed clouds on the right, and at the upwind side of this complex (air movement from right to left up there). Those clouds on the right likely start out as very small droplets, but then freeze almost instantaneously, followed by fine trails of ice crystals that begin to settle out. You can see this fallout happening in the older thin Cirrus clouds at the upper right. Gravity waves like this, resembling ocean swells, ones that produce the “undulatus” variety of clouds, are common in atmosphere. When the air is very near saturation, we get to see them.4:56 PM. Kind of the same thing happening here, though a old contrail has messed things up a bit (angles toward the right lower corner). Middle right, you can see the very fine trails of ice crystals heading down.
The End
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1Does not appear to have a biogenic culprit. The origin of this affliction is currently unknown.
I accidentally mistyped “Digging” and that’s what came out, Diggomg.” I can’t pronounce it either. Then I thought, you know, that it could be quite a hook for a blog, a word no one’s seen before, and would want to know more about it. Maybe more than the two general readers I get would want to look into what “Diggomg” is. So, I have left it intact as an cheap blog attraction strategy.
Besides, things happen for a reason, even if its just a mistyped word due to sloppy fingering…
Here’s the “dig”:
From last evening’s 5 PM WRF-GOOFUS model run, as rendered by the folks at IPS MeteoStar, is valid for 11 PM Jan 23rd. The current pointed to by the arrow is something we call “digging”, going south, but this one in its velocity of 50 knots and more all the way past the latitude of Acapuccalo, MX, is truly extraordinary. What’s the impact on our weather? Nothing at this time. But in southern Cal, those strong winds out of the northeast aloft can mean an extra strong Santa Ana hot desert wind episode in the canyons and coastal areas, a July in January situation, and with that up goes the fire danger.
“Digging”1 is a common phenomenon in weather and jet streams, that’s usually the way storms get all the way down to Arizona because storms and jet streams plunge southward or to the southeast from the Pacific and that process we call, “digging.”
But here, an extraordinarily narrow current filled with little disturbances (kinks in the winds aloft) goes all the way from Spokane to Socorro Island in the tropics off Mexico, and that makes this map so unusual. You won’t see this everyday. You might want to archive it.
Here’s the next panel, 24 h later, and, as the current going to the south ends, it does so with a very strong current passing over southern Cal.
Valid at 11 PM AST January 24th. It has a lot of rain portent for Catalina a few days later, but here, it could be a devastating Santa Ana, winds 50-100 mph below favored canyons.
What’s the portent for Catalina weather?
Plenty!
The End
Hahaha—Just kidding. Ending right there would be cruel. It would be like TEEVEE people do, as in, “Will it be cold tomorrow? Stay tuned for a few hours and we’ll tell you!” We don’t do that here. Read on…..
Low pressure centers form in response to all this current plunging south off Baja, and those centers that form are WAY down off southern Mexico where its so unusual to have that happen in the wintertime. Down there, they get loaded with water and then begin moving north, almost like tropical storms, though having far weaker circulations.
That, my fellow weather friends, is the excitement ahead: plunging jet, surface low pressure centers forming deep in the Tropics, ones that then move north and are likely to affect the Southwest with generous rains. Its not in the bag, though, since lows like that are not well handled by the models, seem to have a mind of their own. So, in the end, the models are pretty clueless about where these juicy systems will end up.
HOWEVER, if you do rummage through the IPS MeteoStar progs, and I strongly recommend that, you’ll see that the rains begin affecting us possibly as early as the 27th. All in all, an unusual situation is unfolding in front of us over the next few days, more clouds and rains to dream about helping to spike our wildflower bloom that bit more.
BTW, that mod run from last night also had quite the Cal rain blaster beginning on the 30th, likely leading to flooding. Presently, none of that rain gets far enough south to affect us.
The Real End
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1Many of you probably won’t remember the little known, but nevertheless classic Bob Marley take on digging:
Who can forget those classic words, “Archaeologists are no wacko scientists.” (“Wacko” in the reggae dialect is pronounced like “waco”, as in Waco, TX.)
