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.
That’s pretty much it for the weather just ahead. Nice upper low passes overhead in the next coupla days, but it really needed an steroid-like injection of tropical air from way down south to do much for us in the way of measurable rain. Oh, sure, we’ll still get some clouds and isolated showers, maybe one or two with lightning somewhere in the whole state of Arizona, but our chances of measurable rain here in Catalinaland have gone way down because the moist tongue hasn’t materialized in time to reach us, but rather will be shunted to the east. But, the skies will be spectacular, even if they’re dry for us.
For a psychological lift, in addition to the one provided by large amounts of coffee, generous rains will fall in drought-stricken NM and west Texas as our little disappointing low approaches and moves over us. OUR tropical air will be just a little too far east, but great for them.
BTW, the Canadian model, the one that had so much rain in our area as late as 36 h ago, has bailed on rain here, as well in the past two model runs. Probably won’t be going to Canada now for any vacations in the near future; pretty bitter about those misleading forecasts. I think they smoke too much up there, too.
Yesterday’s clouds
First, in case you’re mad at me for predicting measurable rain, 0.05 to 0.25 inches, have some kind of “rain rage” going on now, a picture of a cute dog to help you get back in control of yourself:
Photo of a cute dog.10:04 AM. Flying saucers! Altocumulus lenticularis clouds sometimes trigger calls to the police department that a flying saucer is about. Had a real scare back in the 50s around Mt. Rainier, Washington due to an Ac len (true story).12:12 PM. This one looks painful. Never seen anything like it before, a kind of yoga for clouds, “downward dog” cloud formation.
12:12 PM. Wouldn’t want to be flying under this one; suggests extreme turbulence to me.12:44 PM. That shredded, ragged base below the lenticular in the center indicates heavy turbulence below it. The smooth cap is due to a temperature inversion that allows some give, a dome, a hump in it, but nothing more.1:46 PM. An example of almost invisible Cirrus/Cirrostratus. “Invisible Cirrus”, btw, is kind of a hot research topic since clouds affect the radiation budget of the earth. That kind of cloud is just ice crystals floating around up there that are too low, and small, in concentrations to be seen, but can be captured by aircraft instrumentation., which is how it was discovered. This is about as close to “invisible Cirrus” as you can get. Look hard and you will see the faintest whitish hazes around and above the flecks of Ac len clouds; the one a left center has a trail of fine ice crystals coming out of it. Ac len remain stationary while the air flows through them, so the ice ejects on the downwind side. But, no sign of an Ac len having produced the whitish haze above and to the left of that cloudlet, though. Personally I have never seen invisible Cirrus.
The weather way ahead
NOAA spaghetti plots suggesting that tropical air ahead of a trough may yet bring us rains in early June. Check it out.
Other than that, our only chance for measurable rain is in the next 48 h when MAYBE a rogue shower might hit. But, no matter what, pretty skies anyway for the next couple of days. Have camera ready.
Moisture’s not flooding in quite yet, but just to see the dewpoint creep above 0 F lately has been satisfying. Here, from the U of AZ Weather Department, this plot from early this morning:
Plot of surface station data for 4 AM AST this morning. Numbers on the lower left are dewpoint temperatures; 18 F (!) at TUS, but 38 F over there in Yuma. Even higher dewpoints are headed our way!
Currently, ejecting out of equatorial waters toward Catalina, are banks of middle and high clouds, which, along with lower level moist air from the Gulf of California and waters to the south, will be moving into SE Arizona en masse tomorrow and Friday. You can see this process unfolding here from the University of Washington’s Weather Department’s western hemisphere satellite loop for the past 24 h. Take a look down in the lower right hand corner of these images, by the Equator, and watch those clouds begin to roll northward. Pretty exciting to think that clouds that were near the Equator will be here in 36 h or so.
US model has a paucity of rain, whilst the Canadian mod continues to have a much “juicier “solution for us as the big upper low now over southern Cal wobbles around for a day or then trudges east. The Canadian mod calculates, as it consistently has, that this low will be going slightly farther south as it passes over Arizona than the US model, with the center of the low eventually crossing directly over Catalina on Saturday at 5 AM AST.
A more southerly trajectory means more moisture is like to wrap into our low before it gets here. The best of the rain would fall just before the center arrives.
The start of scattered showers in the area is still later tomorrow and would continue through Saturday morning. The range of amounts for Catalina/Sutherland Heights is still probably “light”, in the range of 0.05 inches to 0.25 inches. However, with thunderstorms likely at times, a lucky hit might make that top end a much greater amount.
For quantitative predictions, go to the U of AZ mod output, ones that will be based on the US overall model, but downscales what the US model predicts a much finer grid of local terrain. So, those calculations, which weren’t done yet from the 11 PM AST data, are likely to be a little less even that what CMP sees. It will be interesting to see which of us has foreseen the more accurate future, the Beowulf Cluster at the U of AZ, or CMP in the game of “Beat the Computer.” (The human usually loses….) ((Oops, just saw now that there is no updated run from last night’s data, a shame, and may be due to lack of funding. How bad is that?))
Should have clouds similar to yesterday today, which is already what’s out there this morning.
Moving ahead to yesterday…
Yesterday’s clouds
Started appearing around mid-day yesterday, those non-Cirrus clouds we call Altocumulus. Some lenticularis here and there as well. I was pretty happy for you now that you could see some non-Cirrus for some excitement.
How high were they? Oh, about 17,000 feet above sea level, or about 14,000 feet above Catalina. Here’s the TUS sounding profile, launched about 3:30 PM. Where the two lines pinch together is where the clouds were, and, if you follow the sloping lines of temperatures to the lower left, you will see that the top temperatures of those clouds were pretty cold, -16 C, around 4 F, cold enough for some ice crystals to form, but not a lot. Below a few shots or your cloud day yesterday.
Tucson balloon sounding (“rawinsonde”) for 5 PM AST yesterday.
1:02 PM. Altocumulus lenticularis dot sky north of Catalina. No ice visible.1:02 PM looking south from Catalina. Altocumulus perlucidus patches with scattered lenticulars. Here’ where you should have been logging your first ice sighting. Look at the delicate, very transparent veils between the clouds. Of course, you would have been estimating less that one per liter concentrations of ice, too, in your cloud diary. The droplet clouds are easily detectable because “cloud condensation nuclei” are far more numerous than ice nuclei. Here, droplet concentrations are likely 100-200 thousand per liter; ice crystals, less than 1 per liter! Those factors make droplet clouds sharply defined, and ice clouds “wispy.”
4:38 PM. Droplet Ac clouds with ice falling out below. Interestingly, nature’s ice nuclei like to form a liquid drop that then freezes rather than form a crystal directly (except at really low temperatures, like -35 C or so).
7:24 PM. Ended up with a nice sunset again. Some ice falling from these Altocumulus clouds is visible, with a hint of a “sun pillar”.
Blazing heat still in the cards once our low passes on Saturday; temperatures will “recover” rapidly to max temperatures of 100 F or so for a good week beginning next week, but a an early June rain is also shaping up.
Had maybe a pixel of “rain” over us prior to last night’s run based on global observations made at 5 PM AST yesterday. Now, from those obs there’s widespread rain in SE Arizona from the little low that drifts across SE Cal and just to the S of us. First showers now shown to move in overnight Thursday, continue off and on, for about 24-36 hours. Expect to hear thunder. Sticking with best rain total prediction, generated when the models had none, of between 0.05 to 0.25 inches. Tongue of moist air now seen to be injecting from tropics into that upper low!
Who cares what other mods calculate? We just hope the Canadian model results above are not some kind of confluxion.
———-
Off on another tangent:
The “strangely believe it” side of science, cosmology: Two weeks ago, in a Science mag editorial, it was pointed out that the entire Universe (!) as we know it today, even with those 50 billion new galaxies that the Hubble telescope disclosed back in the 90s, began with a particle SMALLER than a proton! The Science Editorial, however, did not disclose how that incredibly dense (!) particle got there, what was it doing before that, nor why, in 10-35 seconds, it blew up to be a couple hundred light years across, the very parts I was hoping to learn about. This is, perhaps, a more amazing scenario than one that brings rain to Arizona in May!
First, pretty nice sunset yesterday evening, which is redundant because sunset always occurs in the evening.
7:18 PM. Altostratus with slight amounts of virga, underlit in the evening sunset. Haha, “evening sunset.”
7:19 AM. Liked the way was splayed over a house in the foreground. Sort of perty.
7:42 AM. The thicker Cirrus clouds are Cirrus spissatus, or “Cis spis” for short, though not in polite company. Should be the State Cloud of Arizona, we see so much of it, those white or gray patches of ice cloud. Kind of fed up with just “Cirrus-ee” skies these days.
7:43 AM. Looking north-northwest from Catalina toward Mt. Humphries, a delicate blend of Cirrus uncinus fibers (upper half of photo) with thicker Cirrus spissatus in the distance (thicker appearance not due to perspective).
OK, enough great information on clouds and things we can see from Catalina/Sutherland Heights, now for the rain ahead….
Rainshowers, some thunderstorms wrap around this low that drifts from over San Diego to over Puerto Peñasco, Mexico (aka, Rocky Point) by Saturday. Here the Canadian version of what the weather configurations will be this coming Saturday morning:
Valid at 5 AM AST, Saturday
As you can see, a little bit of tropical air gets whirled into this low from someplace down Mexico way, and, viola, showers and a couple of thunderstorms erupt. This could happen anytime between Thursday night and Sunday morning, maybe even a couple of days of scattered showers.
Rain here in Catalina? I think so. Likely range, not a lot, but from a low end of just 0.05 inches, to as much as a quarter of an inch by Sunday morning (10% chance of less; only 10% chance of more, as a first take on this). Gorgeous, dramatic skies are guaranteed, and likely some strong winds here and there emanating those high-based thunderstorms we can get this time of year.
BTW, not reporting on the US model forecast since it shows the low next weekend passing a little farther to the north, i. e., doesn’t take as favorable a track for rain here as the Enviro Can model shown above.
The weather way ahead
After the little “lowboy” goes by next weekend (producing some great, badly needed rains in NM and TX), the Arizona oven is turned on. Look for a string of 100+ days beginning in about a week.
Coming to weather theaters next fall and winter, “The Ninja (?) Nino.” Looks warmer and warmer down there in those key “Classic” and “The New Nino” equatorial ocean zones off South America to Hawaii. CPC’s (Climate Prediction Center) is getting pretty worked up about it, too. Check it out below and here:
Sea surface temperature anomalies from NOAA, valid for May 19, 2014. OK, here we go!CPC
Of course, as we know here, the effect on the summer rainfall season is not really well documented. But things can wetten up in late summer and fall due to tropical storms that drift farther north toward us, remaining a bit stronger because the ocean temperatures that maintain them are a bit warmer. This enhances the chance of a wet spell or two then. Mainly, with a good Nino, the chances of a wet winter go up a lot, particular the mid and later parts.
In the meantime, let us dream about September and October 1983, as the Great El Nino of 1982-83 was fading, but still was associated with colossal rains in Arizona those two months. In case you forgot, this recap about those days and TS Octave. During that water year of that Great Nino, October 1982 through the first couple of days of October 1983, just a year and a couple of days, Catalina recorded a Seattle-like 32 inches of rain!
This message with these astounding reports was passed along the evening before the dust hit Catalina by Mark Albright of the U of WA. I didn’t see it until yesterday morning. In fact, Mr. Cloud Maven person did not see the dust coming yesterday, was asleep at the wheel doing a professional task1.
Still, these reports passed along by buddy Mark seem remarkable enough to pass along to my two readers:
“Last evening (May 10th–we’re behind real events here) the Bicycle Lake ASOS (KBYS) northeast of Barstow CA (35 16 49.909, -116 37 48.106) reported a wind speed of 108 knots (124 mph) behind the cold front which passed in the late afternoon. At the same time east of Barstow, CA along I-40 a major dust storm related accident closed the roadway for many hours.
Stn: BICYCLE LAKE U S ARMY AIRFIELD CA
Lat: 35.2833 Lon: -116.6167 Elev: 716 m / 2349 ft
Raw weather gibberish below for weather technicians:
DY STA TP HHMM N CIG VSBY WEA SLP T TD DIR SP GS PK ALT TEND 1H 3H6H 24H SNW Tmx Tmn COMMENT
10 KBYS SA 2355 0>120 8 1000.6 74 20 230 32 46 29.62 6 36 0 0 80 71 AO2 402650148
11 KBYS SA 0055 6 20 3 H 999.7 72 20 270 24 40 45 29.59 0 AO2 PK WND 23045/0002
11 KBYS SA 0155 3>120 3 H 997.0 67 21 270 46 69 78 29.50 0 AO2 260V320 PK WND 29078/0106
11 KBYS SA 0255 3>120 2 H 997.8 63 22 270 49106 29.51 5 32 0 0 AO2 250V310
11 KBYS SP 0306 1>120 2 H 997.3 63 23 270 58108 29.51 0 AO2 250V320
11 KBYS SA 0355 0>120 3 999.1 63 19 270 48 84 29.56 0 AO2 250V320 PK WND 31084/0343
11 KBYS SA 0455 0>120 10 1004.3 63 21 290 31 45 59 29.72 0 AO2 PK WND 28059/0406
11 KBYS SA 0555 6 36 3 H 1006.1 62 20 320 24 30 33 29.78 3 84 0 0 74 62 AO2 PK WND 29033/0456
Mostly ordinary speak below here, giving some more details-reservations on the gibberish above:
0730 PM NON-TSTM WND GST 4 ENE FORT IRWIN 35.28N 116.62W
05/10/2014 E98.00 MPH SAN BERNARDINO CA ASOS
ASOS REPORTED GUSTS UP TO 124 MPH WHICH WERE NOT
REPRESENTATIVE. CALLED THE MILITARY BASE AND THEY
REPORTED THAT SUPPLEMENTAL SENSORS IN THE AREA WERE
REPORTING 92 TO 104 MPH. THE ESTIMATED REPORT IS THE
AVERAGE OF THESE SENSORS. HIGH WINDS OCCURRED FROM 604 PM
TO 906 PM.
0733 PM DUST STORM 11 S MANIX (UP240) 34.81N 116.59W
05/10/2014 SAN BERNARDINO CA LAW ENFORCEMENT
*** 2 INJ *** DUST STORM CONDITIONS CONTRIBUTED TO A
PILEUP ON INTERSTATE 40 INVOLVING APPROXIMATELY 10 BIG
RIGS. THE HIGHWAY WAS STILL CLOSED AS OF MIDNIGHT. THERE
WERE AT LEAST TWO REPORTED INJURIES.
——————————-
Dust up as it approached Catalina at 7:40 AM AST yesterday morning.11:35 AM. Pretty much the high point of dust invasion, looking toward the Catalinas. Took a lot of photos yesterday, and this was the densest one to me, and that was the one I wanted you to see. Also, see view toward Oro Valley in the next shot.
11:37 AM. View toward Oro Valley from Sutherland Heights in the heart of the dust episode.
Wonder if any joshua trees will be coming up now in our desert with all the Mohave Desert soil, maybe some Palm Springs sand, here now? Kind of neat when you think about that possibility, joshua trees mixing it up with the yuccas and saguaros we have. Maybe a few extra poppy seeds from the National Poppy Preserve there, too. Now all we need is some rain…
Rain? Let us dream about May 1992 for a moment, a year with an El Nino in formation, as we have now.Look at the rainfall of May 1992; nothing like it before or since: 1992 May AZ NOAA climo data
What an amazing month May 1992 was! Almost seven inches of rain at Alpine! About 15 days with measurable rain around the State; looks more like July.
Is there a big El Nino taking shape? Well, let’s look at global SSTs. As you can see the New Nino (“Region 3.4“) and the Classic Nino (off Peru) regions are both warmer than normal! Also notice that the whole eastern Pac is warmer than normal. Hmmmm. Not sure what that will do, if it hangs on.
As of May 8th. Notice all the yellow and orange along the Equator beginning on the west coast of South America indicating above normal ocean surface temperatures. You’re probably as excited as I am looking at this! However, El Ninos don’t seem to affect summer precip too much, just winter and especially later winter into spring. However, an El Nino will aid in the maintenance of any tropical storms that heads toward us later in the summer and fall. They’ll tend to stay together longer because the ocean is a little warmer. So, the chances of a rogue tropical storm rain in the early fall are enhanced.
Nothing in sight as far as rain goes, but one on the pleasant temperature side, due to the nesting of weak troughs here over the next couple of weeks; heat extrema will be pretty short-lived. Looks like not-a-bad May overall. Now, if we can just grab some tropical air in one of those troughs, could be a great May!
The End.
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1It will seem quite remarkable to those who visit this site that Mr. Cloud Maven Person is still deemed viable as a reviewer of manuscripts submitted to scientific journals, such as the Journal of the Atmospheric Sciences, published by the American Meteorological Society. Have a deadline for submitting this review coming up and I wanted to make sure I found a lot of things wrong with this manuscript, the sign of a good review!
From your Pima County ALERT gauges, these 24 h totals ending at 3 AM this morning (covers the whole storm):
Gauge 24 Name Location ID# minutes hours —- —- —- —- —- —- —————– ——————— Catalina Area 1010 0.04 Golder Ranch Horseshoe Bend Road in Saddlebrooke 1020 0.20 Oracle Ranger Stati approximately 0.5 mile southwest of Oracle 1040 0.08 Dodge Tank Edwin Road 1.3 miles east of Lago Del Oro Parkway 1050 0.20 Cherry Spring approximately 1.5 miles west of Charouleau Gap 1060 0.55 Pig Spring approximately 1.1 miles northeast of Charouleau Gap 1070 0.08 Cargodera Canyon northeast corner of Catalina State Park 1080 0.08 CDO @ Rancho Solano Cañada Del Oro Wash northeast of Saddlebrooke 1100 0.04 CDO @ Golder Rd Cañada Del Oro Wash at Golder Ranch Road
Santa Catalina Mountains 1030 0.75 Oracle Ridge Oracle Ridge, approximately 1.5 miles north of Rice Peak 1090 0.00 Mt. Lemmon Mount Lemmon 1110 0.75 CDO @ Coronado Camp Cañada Del Oro Wash 0.3 miles south of Coronado Camp 1130 0.24 Samaniego Peak Samaniego Peak on Samaniego Ridge 1140 0.83 Dan Saddle Dan Saddle on Oracle Ridge 2150 0.12 White Tail Catalina Highway 0.8 miles west of Palisade Ranger Station 2280 0.20 Green Mountain Green Mountain 2290 0.24 Marshall Gulch Sabino Creek 0.6 miles south southeast of Marshall Gulch
The absence of precip at Mt. Lemmon is not because the storm went around it, but rather because it fell as snow.
Here in the Heights, 0.08 inches fell between 1 PM and 3 PM. Clouds accompanied the rain.
But what kind? That’s why I am here for you. See way below.
First, some techno-babble. Rain was an on and off event for Catalina and environs in the models run after run. A forecaster friend sent many e-mails that went from “looks good for rain” here, and just about as many that said, “doesn’t look good for rain.” In fact, the (WRF-GFS) model run for just 12 h before it rained, had no rain here, but just a bit to the north. What happened?
Extra sag.
Here’s the amount of trough “sag” (“amplitude”, as we would say) over Arizona predicted just 14 h before it started raining in Catalina yesterday afternoon:
12 forecast valid for 11 AM yesterday morning. Note that the wind maximum is NORTH of Catalina, and over central AZ.
Areas of rain forecast to fall in the 6 h ending at 11 AM AST yesterday morning. Rain just a tad north of Catalina.A computer analysis of the actual winds at 5 PM AST yesterday showing that the trough had more amplitude (sag, droop, etc.) as it crossed Arizona yesterday than was forecast just a day or so in advance. That meant we in Catalina were more embedded in the deeper, and colder clouds with this trough. The jet stream circumcribes those clouds during the cool season here in AZ and most of the SW US. See rain totals at top of blog.
In case you think I am lying again, just because I am a meteorologist and say a lot of wrong things, below is the REAL map for last evening with wind data from rawinsonde balloons on it.
From the Huskies, this 500 mb map over satellite imagery. Strongest winds in our trough run from San Diego, Tuscon, to El Paso, with the tightest spacing of contours and strongest winds at this level in extreme northern Mexico
I hope you’re happy now.
Here’s what the temperature did as the windshift and rain began, in case you missed it:
Yesterday’s temperature trace for Sutherland Heights.
Yesterday’s clouds
The sequence: cloudy, sunny “sucker hole” (one of Biblical proportions), cloudy, raining, sunny, dusty.
6:06 AM. Altostratus and Cirrus combine to produce a gray start to the day.9:44 AM. Lower level moisture layer produces an Altocumulus lenticularis just beyond Pusch Ridge. Seems sky will cloud up real good at this point.Also at 9:44 AM. Looks real bad off to the N, too, in dense Altostratus and lower Sc or Ac.
10:57 AM. Sucker hole! Its real sunny, warming up. You’re thinking as you ride your horse as I was, “What a bad weatherman we have! Said would be windy, cold, and might rain, and yet here is the sun and warmth. What a bad weatherman we have!” (Weatherman is laughing in the background.)11:44 AM. Sucker hole starts to fill in… Haha! “Dreamer” is the horse there.12:10 PM Sucker hole filling in more and more! You’re starting to feel real bad that you made fun of your weatherman, but he’s still laughing at you.
1:17 PM. Rain showing up to west-southwest, upstream. Wind shift hits and ten degree cool off begins. You’re glad you finished your horseback ride none too soon.3:54 PM. A remarkable thing is happening. While there’s plenty of dust in the air. it is also still raining slightly, almost from drizzle-sized drops. Eyeballing the cloud depth at the backside of the rainband clouds from which the drops MAY have fallen from, your CM opined that these drops originated with melted aggregates of needle or sheath ice crystals that, as single crystals before aggregating, were in high concentrations (10s to 100s per liter) in those clouds, implying that a strong ice multiplication phenomenon was at work inside them. Was really a weird scene to have so much SUN and drops falling from clear sky overhead. I would be very proud of you if you noticed this few-minute event at the end of our little rain.
Rawinsonde balloon temperature and dewpoint profile near the time that it rained in clear air from the backside of our rainband. As you can see, cloud tops were around -10 C or a little cooler, pretty warm for raining clouds here. The main part of the rainband likely had somewhat cooler cloud tops. Thought you like to know. This sounding supports the idea that an ice multiplication process was at work, at least on the back shelf of these clouds that rained. I wanted to confirm prior ground speculations with more speculations from the sounding at rain time, though it was launched around 3:30 PM AST way over there by Davis Monthan Airbase. Wondering now if I will finish this blog today….4:34 PM. Shelf of rainband exits the Catalinas. Nice lighting, though.6:32 PM. While the rain may have washed a lot of dust out of the air, more dust invaded the area as soon as the rain ended.
Its not a breakfast at a restaurant chain, but a sharp cold front passage later this morning, say between 10 AM and Noon. Should be pretty interesting. Temperature will drop about 10 F in an hour. Expecting/hoping, too, for a little measurable rain with this “FROPA” (frontal passage in weatherspeak). The brisk winds, as they always do, have activated a lot of the nighttime wind detector lights in the neighborhood.
The usual post-frontal clearing in the afternoon and a pretty cool day, maybe 20 F cooler than yesterday afternoon which got to 88 F here in the Heights, the Sutherland ones, that is. Of course, our media weather stars are all over this weather situation, so nothing much to be added here.
Still have plenty of higher ice clouds overhead right now at daybreak, but look for an invasion of Cumulus and Stratocumulus within the couple of hours after daybreak. They should appear first on the Lemmon, topping it, then fill in after that as the cold slam gets closer.
Yesterday’s clouds
The full complement of expected clouds was not really observed yesterday. Missing in action for the most part locally were Altocumulus lenticulars downind of Ms. Lemmon. Cirrocumulus clouds were also pretty much a no show. You can see some of those high lenticular formations that did occur WAY downwind of Ms. Lemmon and the Catalinas if you view the U of AZ Weather Department time lapse movie for yesterday between 11 AM and 1 PM, then another pile of Ac len just at sunset (7:15 PM) in their movie.
Below, what we did see, various varieties of Cirrus, and eventually those thickening to Altostratus ice clouds. And a hole was out there that allowed a brief colorized sunset rather than a gray one.
9:20 AM. Main feature is Cirrus spissatus, with Cirrus fibratus (lines at upper right) and some uncinus (center left) also present.1:13 PM. Looking at incoming Cirrus to the WSW… More Cirrus spissatus (patches) in the distance with some hooked Cirrus (uncinus) upper center.1:14 PM. Looking N at the traces of Altocumulus lenticularis clouds (e.g., sliver cloud above road in distance), possible Cirrocumulus top center of photo.6:21 PM. By this time, the leaden look of Altostratus pretty much dominated the sky; dosen’t look good for sunset color at this point.7:03 PM. Sunset bloom began as bottom of Altostratus got lit up. Note how similar the cloud bottoms are in this photo compared to the one just above.7:06 PM. Heavy line of Altostratus with a higher overcast of CIrrostratus adds interest to the fading sunset.
Well, its not windy1 yet, but it will be, and everyone knows it. The infamous “Tonopah Low”, as the ancient weathermen called it, is now in formation over Tonopah, Nevada, as a big bad trough roars into California, over the Sierras, and into the Great Basin today and tomorrow. We should have noticeable winds by mid-day, a dramatic accompaniment to some pretty Cirrus clouds, ones that will be chugging along up there at 100 mph or so. The U of AZ mod also suggests a few mid-level clouds, ones likely to be brief Cirrocumulus patches (those clouds having tiny granulations that make them look higher than they really are) or Ac lenticulars NE of Ms. Lemmon; also off to the north of Catalina, as the moistness aloft increases later in the day. Cirrus likely to devolve into thicker Altostratus. Watch for a great sunset today, since holes far to the west of us in these higher clouds are possible that would allow the fading sun to light up the bottoms of the high and middle clouds after it sets. Hope so, anyway.
I am really happy for you today since this will be the really first interesting cloud day in awhile. You might consider leaving work around lunchtime so you don’t miss anything, like some iridescence around the Cc.
Of course, the late April cold air blast, mentioned here so long ago in a blog that I might get a forecasting award of some kind2, will hit tomorrow as the cold front (sudden drop in temperature, barometer rises instantly, and wind shifts) hits later tomorrow morning. Have jacket ready.
Looks like this cold front, with the jet stream sagging over us or slightly to the south, will be enough for a little rain now, a tenth of an inch likely the most that can fall. Still, it will be something to break up the monotonous string of zero precip days.
Now I will look at the AZ mod precip output and see if there is any credibility to that rain amount mentioned just above. (Oh, fer Pete’s Sake, accum precip run ends at 1 AM today here a few minutes before 5 AM AST.)
Well, the WRF GOOFUS model run, based on global data taken at 5 PM AST yesterday, did have some rain here tomorrow morning. Rain for Catalina and environs has been coming and going in various outputs for days on end.
The Cirrus will be gone tomorrow, but with lots on interesting lower clouds, some having ice in them, will produce nice picaresque views of the Catalinas as clouds and shadows of clouds roll across them after the front goes by and the clearing takes place.
The Weather WAY ahead:
Very “troughulent”, in a word.
A lower latitude trough will be affecting this area not too long after this current big boy passes starting a few days into May. With those lower latitude troughs usually comes just high and middle clouds with their spectacular sunrises and sunsets, and their presence keeps the temperature from spiking to astrological levels due to those clouds, but also because the air aloft is a little cooler in a trough than when an upper level high pressure area (a region of deep warm air) is squatting on top of us. So, really ovenly weather will be MOSTLY held at bay as we roll into May. Yay.
Once in a while, one of those persistent troughs, too, can scoop up some real moisture from the tropics and bring some rain here, so there’s even a chance of May rain as this situations develops. This troughy situation begins to develop about 8 days out now, around May 4th, but persists beyond the 10th.
Check out the spaghetti for the morning of May 10th to see what I am talkin’ about:
See arrow that points to the general area in which you live. Note, too, where all the red lines are, big gap over the West until the blueish lines, indicating a pretty darn reliable forecast even this far out.
The End
————
1TItle is a pathetic reference to a popular but crappy IMO song from the 60s.
2Actually, I didn’t think it up by myself, that forecast of cold air late in April, but relied on the NOAA spaghetti factory to give me a heads up, so that if I was to get an award, I would have to acknowledge and thank the NOAA folks who produce spaghetti for their work in supporting my efforts, and I couldn’t have done it without them.
April 12th, 6:57 PM. In case you missed it or forgot about it already.
Still looking like a couple of pokes of cool air in the last ten days of April, no rain indicated with them, just wind.
Some sprinkles maybe on Friday or Saturday from mid-level clouds like Altostratus or large clumps of Altocumulus with virga, some of the latter likely large enough to transition in name from Altocumulus (castellanus) to Cumulonimbus clouds. As with the last sprinkle a few days ago, any rain will be from clouds whose bottoms are well above Ms. Mt. Lemmon.
A great sunrise/sunset or two is almost guaranteed on Friday and or Saturday. This cloud action due to a weak wave/trough in the subtropics that creeps toward Arizona in the next few days. You can see it now in the sat imagery from the Washington Huskies Weather Department here. Its that little thing spinning around in this loop east of Hawaii with a big plume of high and middle clouds streaming NE from the Equator toward the West Coast to the east of the upper low. Expecting nothing more than passing Cirrus before Friday.
Some sprinkles/radar echoes passed overhead early this morning. Will check, as you will, for drop images in dust on solid outdoor surfaces to possibly report a trace due to drops that reached the ground. Going out now with flashlight, to heck with that coyote over there. Result: looks like there were a few isolated, larger drops that fell last night. Below, confirmation of echoes overhead from WSI Intellicast’s 24 h radar-derived rain for AZ:
Radar-derived precip ending at 5 AM this morning from WSI Intellicast
Nice sunset with late sudden bloom after looking like there might not be any color at all.
6:54 PM. Mammatus -haped virga hangs down from heavy patches of Altostratus providing sunset highlights. Dimly seen are flakes of Altocumulus clouds, as seen below as well.6:18 PM. Doesn’t look like much of a sunset will get through this solid-looking cloud cover of Altostratus, Cirrus, with flakes of Altocumulus below.10:13 AM. Bright patch of CIrrus is from an aircraft; the Altocumulus flakes with virga hanging down are natural. Only a greatest of the Cloud Maven Juniors would be able to make such a discernation, if there is such a word.10:12 AM. Over this way, a mix of Cirrocumulus and Altocumulus (larger globules).
Expect another middle to high cloud cloudy day with nice breezes. Weak jet stream to south (see map below) as upper level trough passes today, the main criteria for cool season rain in AZ (some 90-95% of all measurable rain in AZ falls only when the jet stream in the middle troposphere (about 18-20 kft above sea level) is south of us. However, while that criteria is met today, just not enough moisture has leaked in over the Baja and southern California mountains for clouds low enough to produce rain. So while its a virtually necessary condition, its not always sufficient.
Forecast winds at 500 mb (18.5 kft ASL) at 11 AM AST. Strongest winds at this level coming onshore in Baja, Cal.
