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.
Today we celebrate the model in techno-pop song, and not only the human ones, but also the ones that give us hope (or not) for rain in Arizona. (Advisory: If you listen to the Kraftwerk 1980s tune above, you won’t be able to get rid of that melody all day!) Speaking of today, see farther below after lesson in reading spaghetti.
Below, two model outputs for the almost the exact same time separated by only 6 h of obs as input for the late afternoon and evening of Wednesday, April 23rd.
One outputm the first one, suggests we’re in for another, unseasonal, blazing heat wave like the current one for Arizona. while the other a wet, cold blast into the Great Basin, with windy conditions here and a major cool down just ahead; the latter leads to sequence of troughs that leads to rain here, with eventually exceptionally COLD weather, and considerable snow in the mountains!
Repeated-annotated for emphasis
In the East, the first one above suggests that winter will seem likes its continuing into summer with a super cold wave for late April, while the model output below shows nothing special going on at all.
Sadly, the one above with the oven lit here (big ridge in the West and the amazing vortex in the Midwest_, is the one that was computed on data 6 h LATER than the one below, the one that looks pretty exciting for us, even if its just a cool down with a bunch of wind. “Later”, as you imagine, usually implies more accuracy.
Who you gonna call to see which of these astoundingly different model outputs has the most credibility, which one is the most likely model ghost buster? The NOAA spaghetti factory! See below:
On the map above, the deep vortex in the Midwest has almost no support at all (you would have to see a LOT of blue lines in the US and not in Canada for that support), while the West Coast has a lot of support for a big trough to blast in (lots of blue lines along the West Coast).
In sum, it would appear that the chance for rain late in the month is not completely bogus, but a very a big heat wave is. Rather, keep coats handy for later in the month. See rain in AZ below associated with the more credible output (from IPS MeteoStar’s rendering):
Valid Saturday morning, April 26th. Wouldn’t this be great!
Clouds….
About like yesterday. But there’s a real “storm” up there of sorts. If you were on Mt Everest and Mt Everest was here where Ms. Mt. Lemmon is, there would be a real blizzard up there at the top; 50 kt winds, light, dust-like snow off and on all day. In normal speak, there will be lots of Cirrus, Altostratus (huge gray areas), those former clouds composed of ice crystals, some Altocu (droplet clouds) mixed in.
A lot of snowbirds head home when the temperature goes above about 85 F (30 C) because they can’t take it like we can, which is what will be happening today and for a couple more days before some thick middle and high clouds move in toward the weekend with their often accompanying blazing sunsets/sunrise to go with the blazing temperatures. So, expect some extra traffic on the roads in the next few days. If this blog was a grammar school playground, I’d be calling them “little crybabies” when I saw them leaving.
But, while the hot regime digs in now, “I want to leave you today with this final thought”1but one in the form of a weather map:
384 h from now, or about two weeks. From last night’s WRF-GOOFUS model run which can’t be trusted this far out.
For credence, and transparent, or “clear water” credibility2, we look to the NOAA spaghetti bowl to see if that map above has any support:
Valid the day before of the map above. I think I can see something here that would support unusual rains in Arizona in later April…. Its my job. Those red lines (contours that reflect where the troughs are), at least kind of dip down in our area. But for real credibility, we those blue contours, not red ones.
The End
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1This phrase is kind of a literary device, a trick really, often used to keep people reading, thinking that the piece is going to end without them investing too much more time. But then it goes on some more.
2Though it would be a good name for a band, its not a strained and awkward allusion to the 60s band (“Creedence”3 CR) that broke up because of all the infighting and never got back together to do legacy tours of all their great hits and make a lot money like the Eagles did when they resolved all of THEIR infighting (almost). I guess Hell hasn’t frozen over for CCR. Too bad. I remember seeing CCR live at the Santa Clara County Fairgrounds, and how the whole audience leaped up in unison and as if by command when they launched into their hit, “Proud Mary” with those big, booming chords we all learned to play on our guitars!
3A common misspelling of the word, “credence.” The band was not known for spelling, but man, to name your band with a misspelled word, wow.
You won’t find such small Cumulus so full of it as they were yesterday very often. But with cloud bottoms and tops as cold as -15 C (5 F) and -25 C (-13 F), respectively, it was bound to happen. Cloud bottoms were located at 16,000 feet Above Sea Level (ASL), or about 13,000 feet above the ground above Catalina. That was a LONG way for a melted snowflake to fall, though it did appear that some sprinkles may have reached the ground toward Tucson town later yesterday afternoon and during the early evening. I was driving down into Tucson to see friends play in a band1 at the appropriately named, “Nimbus2 Brewery” and saw those clouds up pretty close as I went.
Here’s the late afternoon sounding for yesterday, providing the backdrop for those icy clouds, as rendered by the Cowboys of Wyoming3:
The temperature and dewpoint profile above Tucson, measured between about 3:30 PM and 4 PM AST yesterday afternoon. The balloon making these measurements rises about 1,000 feet a minute.
Here’s your cloud diary for yesterday, starting with a shot of some wildflowers taken while being bored waiting for the icy Cumulus mentioned yesterday to develop:
9:53 AM. By 9:52 AM, boredom had turned to worry; “Where were the Cumulus clouds?!! Was I going to be wrong again?”, until one minute later, 9:53 AM, when I saw this one and could relax, have a cup of coffee or something, lay around pretty worry free. You might need a telescope to see that Cumulus cloud…
11:48 AM. Almost 2 h later, the Cumulus are really piling up toward Saddlebrook. Feeling great now, though we don’t have any ice showing yet. Recall that even these little guys are about -15 C (5 F) at their bases, maybe a little warmer because the bases get higher (colder) as the afternoon wears on.
3:19 PM. Pretty typical of the afternoon hours; tremendous amounts of ice (frizzy areas) originating in Cumulus clouds maybe but 2,000 feet thick at this time.
4:23 PM. Cumulus really piling up over Saddlebrook now, the larger ones quickly converting from droplet clouds to ice clouds.6:18 PM. Looking S along Oracle Road at some pretty heavy virga. A drop or two may gotten to the ground below that one puff (all snow at this point up there). Clouds likely got to 3 or 4 K thick here. From the “Not taken while driving” (because that would be crazy) collection though at first glance it does look like it.
6:35 PM. That heavy virga made for some nice sunset scenes, though this is not one of them.
The clouds ahead
Not much weather ahead besides excessive warmth, but, a nice surge of middle and high clouds this coming Friday and Saturday (12th and 13th), maybe some sprinkles.
The End.
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1Randy Prentice Band, perhaps the most eclectic collection of folks that has ever been in a rock band, featuring famous photographer, Randy Prentice on lead guitar and vocals, and African grey parrot and Pima County residential appraising expert, Dr. Diana May, on bass and vocals. Paul Daniels drums away and also sings; probably has a Ph. D., too.
2“Nimbus”, which means rain, is not a cloud of itself but is an appendage applied to clouds, like Cumulonimbus, or Nimbostratus. Why would a weatherman go anywhere else?
3Shouldn’t WE be the “Cowboys”, as in University of Arizona Cowboys? Don’t we have more of them, at least folks who ride horses than Wyoming, a state where hardly anybody lives, but they’re quite happy anywaya for some reason? And is the moniker we have now, one that refers to feral cats that great?
I can’t believe how many footnotes I’ve put in already and I’m only on the first 10 lines or so! Better slowdown, go easy on the readers, though those many footnotes do give the “piece” an ersatz academic aura.
aOBJECTIVE HAPPINESS BY STATE 001 I inserted this once before a long time ago, but thought you should read it again. Folks in WY are happier than folks in AZ, it says. See state listings.
6:05 AM. Pretty ripples in Cirrocumulus below some Cirrus. What a fantastic and subtle scene this herring bone pattern was!9:34 AM. Pretty much a whole Cirrocumulus morning, punctuated by a few Cirrus clouds. Why isn’t it Altocumulus? Granulation is too tiny; no shading. BTW, no ice evident though this layer was colder than -20 C (-4 F).10:30 AM. An aircraft has punched this very thin Cirrocumulus layer and left a tell-tale ice trail that looks like natural Cirrus. Same cause for that second, white ice patch farther to the west. Its almost impossible to detect something like this since the ice trail from the aircraft is almost exactly in the form of a Cirrus uncinus. The absence of natural Cirrus is a clue about what happened.10:34 AM. The aircraft-induced Cirrus is passing overhead, and if you look VERY closely you can see that tiny “supercooled” cloudlets of Cirrocumulus are still there around it. The ice crystals fell below the Cc layer and disappeared over the next 15 minutes.2:27 PM. Later that day….widespread natural Cirrus overspread the sky, with a very thin patch of Altocumulus on the right (granulation is a bit to large for Cc).3:44 PM. Those Cirrus clouds thickened and lowered some, trending (as we would say today) toward Altostratus (translucidus–the thin version).
Today’s clouds
Today our passing cold-core trough is overhead and in the middle of it, the moisture is low enough to trigger Cumulus and small Cumulonimbus clouds as the middle and high clouds exit “stage right.” Should be an interesting day since these cumuliform clouds will be so high-based (above the Lemmon summit) and cold that lots of ice will form, producing virga, and in some places, sprinkles. A hundredth or two is possible, but that’s about it. Heck, I guess there could be some lightning here in southern Arizona as well.
This will be the last interesting cloud day for awhile, as you likely know.
Below, your weather map for 5 PM AST when there should be plenty of ice action all around:
Sent to ME just yesterday from an El Niño expert in Monterrey with the NOAA SW Fisheries Center, this update:
“(An El Nino is coming)….faster than you might think: http://www.esrl.noaa.gov/psd/map/clim/sst.shtml Looks to me that we’ll have what I’d consider a ‘full-blown’ El Niño in the tropics by the end of the month, maybe even sooner. And it looks like it’ll be on the big bad side …”
I felt like a recipient of insider trading info! But what do I do with this info? Guess I’ll just pass it along verbatim to you. Maybe you’ll be as happy as I am, hearing this news. El Niños generally lead to wetter conditions throughout the SW, so maybe we’ll get some substantial water next winter, but then if it floods like in Jan ’93 like it did with that El Niño, I am sure we’ll be complaining (almost 17 inches of rain that month at the old Tonto Creek Fish Hatchery/Oak Creek Canyon area). Thirty-eight inches (!) of rain that Jan ’93 month at one southern Cal mountain location, Lytle Creek Ranger Station, I think it was.
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Upper trough trudging across area today, tomorrow and into Sunday, a mostly dry one. However, some Cumulus should form later today, maybe with a couple of Cirrus/Altocumulus/CIrrocumulus at times, too. The air aloft should be cold enough by late today, but especially tomorrow, to spawn large enough Cumulus clouds with tops cold enough to contain ice, viz., small Cumulonimbus clouds of the kind we had a couple of weeks ago with virga and dust eruptions. So there is a chance of a sprinkle or a hundredth or two tomorrow afternoon here. Check here for the great U of AZ model output from 11 PM AST last night–not finished yet at at 4:37 AM. But it will likely have some precip around the Catalina area tomorrow afternoon when the calcs finish.
Its for this coming Tuesday night into Wednesday morning, from our best computer model. As you can see by the caption, its valid, too.
Valid.
If you visit the models day in and day out, you will have noticed by now that this has been a pretty normal rain year in model rain, model rain for Catalina often showing up 10-15 days in advance, but then disappears as the predicted rain day gets a little closer. This situation has gone in the reverse direction where no rain has been foretold in the models anywhere near us until this run from overnight, a nice change from the usual give and then take away aspect.
The difference from dry to wet is how the models have been foretelling where the jet stream in the middle of the troposphere will be located–in the SW, rain falls under and on the interior side1. All along they have been forecasting it to be north of Catalina/southern AZ. But now, without even looking yet, just seeing that rain on the map, you can bet that the jet is south of us. Let’s look and see if C-M is talking through his hat; big ranch, no cattle:
Valid at 11 PM AST, the same time as the rain map above. “Rain map”? Could be a movie I think. Sounds familiar.From a recent hike: “Happy Together.” If it rains, we’ll be just as happy.
The End
—————- 1Not so for most of the country. This relationship becomes exactly the opposite by the time you get into the East and southeast US: rain falls BEFORE the jet core in the middle of the troposphere gets to you as you can see on that same rain map above for the areas of the Midwest as humid tropical air streams north ahead of that big low forming in the Texas panhandle. There’ll be some big weather out there in the Plains States and eastward as our powerful trough exits AZ.
Rained, too, between 3:42 PM and 3:47 PM, actually 273 seconds, if you had your stopwatch out. It was great. I ran around trying to get wet, but couldn’t do it.
3:44 PM. Proof that rain drops did fall yesterday afternoon. Don’t forget to recycle stuff and also don’t forget that this kind of rain is NOT “drizzle”1. Drizzle are fine close together drops that almost float in the air. Tough to bicycle in drizzle if you wear glasses, in fact, I would say its impossible even if you’re wearing a baseball cap and helmet on top of it because the drizzle blows underneath the cap and onto your glasses so you can’t see anything right away. Rain drops fall too fast for this to happen. This from personal experience in Seattle. Always wear a helmet when bicycling.10:23 AM. After a completely clear morning, Altocumulus clouds formed rapidly over and downwind of Mt. Lemmon. Before long, most were shedding ice.11:45 AM. Distant Cumulus cloud forms just underneath some Altocumulus clouds. Here’s where you KNOW that the day is going to be pretty good as far as convection and virga go because these clouds were so cold, and its late March when the sun is strong.1:51 PM. Two hours later the sky was full of glaciating Cumulus clouds, and isolated heavy virga trails, ones heavy enough to reach the ground with a few drops. Looking SW over Oro Valley and toward Marana.2:31 PM. Thunder was heard just a minute prior to this photo, The storm was just west of the Tortolita Mountains.3:29 PM. Part of the cloud mass that brought the sprinkles (coded as RW–) to Catalina. Probably measured below that little streamer, dead center. The virga hanging well below solid young cloud bases told you that those bases were far below the freezing level yesterday. How cold? Sounding indicates that the bottoms of the Cumulus clouds were about -12 C (10 F). The higher tops were colder than -30 C (-22 F)6:36 PM. Residual Altocumulus cumulogenitus containing a lot of ice if you look closely..
Today’s clouds
Still enough moisture for very shallow Cu fractus, Cu humilis, hold the ice (tops too warm). Skies will also be overrun with Cirrus, maybe verging on Altostratus, as part of low and trough barging into northern California today.Will get nice and breezy this afternoon, as the low zips on into the Great Basin and makes its presence known here. Instantaneous puffs might reach 40 mph this afternoon. No rain possible with this system, darn.
However, deeper Sc and Cu with ice in them should be visible up toward the NW-NE horizon today since a little rain and snow is expected on the M-Rim today, this from the U of AZ super mod’s 06 Z (11 PM AST) run, here.
The End.
—————————- 1Here’s the interesting story behind getting THREE public service messages in a single caption/photo: I wanted to both better serve my public by getting some public service messages out there while at the SAME time, documenting some weather singularity, in this case, one of the rare rain events in the Catalina winter of 2013-14. Suddenly, in the midst of the rain I was dancing in, I noticed some shiny drops on the lid of the recycle bin, and things just “came together” you might say for a remarkable photo.
You can see it highlighted in red on forecast maps here from the Huskies, the Washington ones. Have cameras ready for various forms of Cirrus and Altocumulus clouds, the latter later.
U of AZ Wildcats local model thinking just pretty Cumulus tomorrow as central region of low up there passes overhead. Some with virga, maybe reaching small Cumulonimbus size, with some wisps of precip on top of Ms. Lemmon; a little measurable rain is even foretold for east central and northeast Arizona tomorrow! Nice.
In the meantime, a nice poppy photo for your enjoyment from a hike just a coupla days ago .
Logged on March 22nd1. Someone’s inside it.
The End.
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1Its not a “poppy”, for Pete’s Sake, but rather a Calochortus leichtlinii. Wanted to see if you were paying attention and know ANYTHING at all about the fabulous wildflowers we have here. A quote from the Flower Essence Society about this flower: “The nurturing qualities of Mariposa Lily draw the soul (and apparently, the worm in the photo above) into a deep interior space like the chalice of the flower itself.”
Looky here, valid in only about 9 days, that is, just off the forecast confidence horizon, predicted rain for SE AZ! Valid for April Fool’s Day, at 5 PM AST. We hope its not another model cruel joke, since time is running out on the chances of cool season (Oct-Apr) rains.
SInce I know you love spaghetti, here’s some for about that same time, the evening before the map above, and it has a strong indication of a strong trough moving into the SW from the Pacific. Count on it. At the least, it will get real windy when this happens, count on it, and with a little more luck, there will be enough amplitude in the jet stream, that rain WILL occur.
Valid at 5 PM, the day before the predicted map, that is, 5 PM on March 31st.
The last batch of spaghetti was disappointing, that shown here about two weeks ago. Sure, there’s been a “trough bowl” in the SW as was predicted way back then; that’s what was producing the pretty clouds we’ve been seeing, the passages of weak troughs aloft over us, ones that have been also keeping the temperatures reasonable.
But, that predicted “trough bowl” so far back did not have the amplitude necessary to bring rain as was thought could happen back then. “Trough bowl” turned out to be more of a “plate”, than a “bowl.”
Here’s what I mean, below, from the first panel of spaghetti from last evening: see the little dent toward the south in the contour lines passing over Arizona? That represents a trough where clouds like to form, such as yesterday’s Cirrus clouds..
Map for last night as model runs begin.
But we need the big polar jet stream over us to get rain in the cool season, not a wispy jet up at Cirrus levels as we have been having. You may have noticed how fast the Cirrus clouds were jetting along up there. Well, for the past couple of days, they were zooming along at over a hundred miles an hour.
What we need are deep, cold troughs where the red height contours (5700 meters in the above map) are way south of us. Here’s why rain is predicted in the first map, as an example. Below is the configuration of the jet stream for that day that rain is predicted, showing that the 5700 meter contour and the core of the jet stream is over central Baja California. Now THAT is a rain map for AZ!
Let us begin by breaking up the weather talk monotony with a photo of a bee evaluating a thistle1, this from a hike yesterday to some weather petros2, to resume the weather talk.
10:31 AM. “Sentient Bee-ing and Thistle” $1800. (See link to Sci Am article below if you don’t think bees think about stuff.)8:46 AM. Crossing strands in CIrrus fibratus. Indicates that they have formed at different heights in layers of air with vastly different wind shear (change of direction with height). Rarely do you see this because at Cirrus levels (here around 30-35 kft above ground level, the wind direction usually does not change much. The strands running from left to right across the photo is the higher Cirrus cloud.
9:14 AM. Several species of CIrrus here; fibratus, uncinus, and spissatus (lower right).
9:35 AM. After the delicate Cirrus forms passed, lower blobs of dense Cirrus spissatus with some castellanus *turreted” versions) followed.
9:45 AM. Cirrus fibratus radiatus–last of the delicate Cirrus clouds left a memorable scene as they disappeared past the Catalina Mountains. However, the look of radiating fibers may be due to perpspective, not sure.
11:32 AM. Strands of Cirrus fibratus mimic the branches of a mesquite tree, both seemingly reaching out. A blob of the rarely seen Cirrus castellanus is on the horizon, lower left.
The cloud day pretty much ended with a brief appearance of Cirrocumulus overhead, enhanced by iridescence:
2Below, an early weather forecasting icon petroglyph indicating that the forecaster was anticipating a sunny day except for some Cirrostratus clouds, ones expected to produce a halo. Pretty sophisticated I thought.
10:17 AM. One of several weather forecasting petroglyph icons.
