Water continues to flow in most of our washes and dry creeks, day after day, long after the rain has gone.
But look at these early February California totals (table at right in graphic) from the California Nevada River Forecast Center (with lots of rivers above flood stage right now)!
This winter will go down in history as one that was so majestically unanticipated and points to the difficulty of seasonal forecasts.
Still looking for major storms in AZ toward the end of next week, as suggested in those spaghetti plots of old.
Well, it will be pretty obvious, ludicrously so to spaghetti lovers, the sequence shown below. It goes from “warm in the West (again); cold in the East pattern to another undercutting flow from the Pacific, the kind we’re having right now under the “soft underbelly” of a big blocking high, except that the tropical flow from the Pac this time is a little too far to the north to give us anything.
But, it will be another floody situation for northern Cal in the coming days. Some places, mainly north of “Frisco”, have already picked up 4-6 inches in the first blast which hit yesterday. Ten to 20 inches more is likely over the next week at favored locations. Having quite the water year there, really a lot of water year.
You may recall that the current situation, alluded to in the “break on through to the other side” refrain used here about ten times, was well predicted about two weeks in advance! That’s what spaghetti can do for you!
OK, enough jabbering, let us move on to the current exciting examples that popped out from last night’s global data ( there are outputs after adding little errors at the start of the model run, to see how the flow is changed with them in it. Sounds crazy, I suppose, but is considered a huge advance in forecasting, a stupendous tool, that is, to make errors in models at the beginning of the run). Heck, they even do that in climate models that simulate 30-50 years from now, and you’d be amazed at how the tiniest fraction of a degree change the beginning makes (see Deser et al 2012).
Valid Sunday evening, 5 PM AST, February 12th (TIme at the top is Zulu Time, as we used to say, or CUT, Central Universal Time, which takes in a lot of territory IMO. This is one you look at and say, “Its gonna happen.” What? A big blocking high pressure ridge along the West Coast in a little more than a week. Done weather deal. Period. The dip to the south in the blue lines over there by the Great Lakes says that cold air will be extruding into the eastern US. So, we have a Nike swoosh in the jet stream across the whole Pacific and then it makes a sharp left turn up into Alaska, and NW Territories of Canada. They must be jumping up and down now, seeing this.
Well, the first one’s not so exciting since we’re dry and hot for this time of the year, and its a common one that can get stuck for weeks at a time, so you REALLY hate to see models project a bulging ridge poking north along the West Coast. It could mean a rainless February here, if it persisted.
Here’s the exciting follow up, though, pretty unexpected given the above, showing a sudden collapse of the West Coast ridge regime, and strongly suggesting that wet spell has begun in Arizona, including regions of Catalina and Saddlebrooke:
Valid at 5 PM AST, Friday, February 18th. Given a day or so off, we would be looking at a rainy spell beginning somewhere about this time or a day or around it. The thing that really jumps out is the clustering of the red lines (564 decameter) contour lines. ALL the way across the Pacific right into central Cal and the Great SW. This means that the jet stream will once again break through a ridge at lower latitudes just as its doing now, but in this case, a little farther S, which should mean periods of rain for us, keeping those washes going, or restarting the flow in them if we’re lucky.
So, you’ll want to get outdoor work done before this.
Historical note of interest, added value content, etc.
Some of you may remember that the 564 decameter contour (those red lines) at this level (500 millibars or around 18,000 feet above sea level on average) was used in the early years of forecasting before computer models (50s and early 60s) by southern California forecasters to demarcate where rain would fall in California–at and north of where that 564 decameter contour intersected the coast when upper troughs came in. The Old Forecaster remembers, though not much else…
So those red lines barging into southern Cal after a LONG fetch from the subtropical Pacific in the plot above mean central and southern Califs better watch out for some major rains a little before we ourselves get a dousing around the 18th of Feb.
Isn’t it great what spaghetti can do, that is, constrain our future weather to fairly certain outcomes two weeks in advance!
There was a sunset yesterday, btw:
6:06 PM. Altostratus with tiny virga illuminated by a setting sun. haha Guess I didn’t need to say the sun was setting.
Upper level snow flurry passes south of Tucson! Trying to generate some excitement here….
Since we have nothing better to do for quite a dry while here in AZ, and CMP is from southern Cal, where he kept a weather and a cloud diary1 and played baseball2, here’s the latest on the Cal drought we’ve heard so much about, below, from the Drought Monitor folks at the University of Lincoln Cornhuskies University as of January 24th.
Added to this map is a couple of rainfall totals in the drought affected regions from January 1st through the 23rd, 2017 (i.e., only partial monthly totals) from the CNRFC, a superb site, btw:
Well, as you can see, it takes India monsoon caliber rains3 to end drought completely in California. Or, maybe the DM folks are just a little behind; could be. Avalanche hazards have been moderate to “extreme” during this period due to the tens of feet of snow that have fallen in the Sierras. Yay for California water supplies THIS water year!
Here is a table of the top 20 rain totals through January 23rd from the CNRFC:
The End
————————————– 1Perhaps you don’t believe me that I kept a weather and cloud diary growing up. Here a report from the San Fernando Valley:
2Perhaps you don’t believe me that I played baseball… Here’s one of my favorite pieces of evidence for having played baseball. Sure, I cost us the game, but then, I was mentioned in the article!
3Rainfall totals can be over 100 inches a month at the monsoon’s peak in India. The record is 366 inches in ONE MONTH at Cherrapunji in the NE corner of India in the Assam region. Of course, CMP must go there; its on the “bucket list.”
One passed over at 9:19 AM with a hard multi-second, surprise rain shower. One person reported a couple of graupel, or soft hail particles. Tipped the bucket, too; 0.01 added to our Sutherland Heights storm total. Its now at 0.23 inches. Of course, there was no damage, but putting that word in a title might draw “damage trollers”, increase blog hits….
The rest of the day was clouds withering, getting mashed down on tops as bases rose and tops settled back, then suddenly, about 3:30 PM, small areas of ice crystals began to show up in a couple of spots, and, boy, did things take off after that. Tops were lifting to higher temperatures, likely due to an approaching trough, one that otherwise is too dry to do much else.
Honest to goodness cold, wintertime Cumulonimbus clouds formed, though not very deep ones. Probably of the order of 2-3 km thick is all (eyeball estimate).
But with our cold air aloft, tops were well below -20° C (4° F), lots of ice formed in them and produced streamers of ice and virga across the sky, and in tiny areas, the precip got to the ground.
And with “partly cloudy” conditions, there were lots of gorgeous, highlighted scenes around the mountains.
Let us review yesterday’s clouds and weather and not think about the future too much, starting with an afternoon balloon sounding temperature and dew point profile from IPS MeteoStar:
The Tucson balloon sounding (“rawinsonde” in weatherspeak) launched about 3:30 PM yesterday. Takes about an hour to reach 60,000 feet, but goes higher. Cloud bases were just about at the top of Ms. Mt. Lemmon. Tops were only around 18,000 feet above sea level, but were extremely cold for such small clouds. Hence, they were only about 9,000 feet thick at their maximum.
So what do clouds look like when they have tops as cold as -28°Ç?
Well, I really didn’t get a good profile shot of those clouds, they were either too close, obscured by other clouds, or too faraway, so instead let us look at two dogs looking at something as a distraction:
4:11 PM. Dogs observing a plethora of glaciating Cumulus clouds, transitioning to Cumulonimbus.
Well, let’s start this when the ice first appeared in a cloud, much later in time than what was thought here yesterday morning. If you logged this “first ice” you are worthy of a merit, a star on your baseball cap:
3:24 PM. FIrst ice of the day, finally, spotted on the SW and WSW horizon in two little areas. The file size is huge so that you can see it for yourself. I had just about given up on ice in clouds, Notice, too, how small the clouds are at this time.
Well, while flawed from a cloud profile sense, here’s what they were looking at, it was the best I could do:
4:19 PM. Note sunlit shower reaching the ground. The hazy stuff is ice crystals, a lot of them all over the place.4:22 PM. A close up in case you don’t believe me that the rain was reaching the ground. I sometimes find that credibility is lacking here.4:39 PM. Eventually a cluster of precipitating clouds developed near the Catalina Mountains and here are dropping snow and graupel trails.
Let us go zooming:
4:39 PM. Shaft up close. That dark, narrow line in the middle is without doubt a soft hail (graupel) strand. THere might be others, but this one is obvious. The “verticality” is due to faster falling particles comprising that strand, which graupel are because they are ultimately snowflakes that have captured cloud droplets on the way down, making them much heavier than just a snowflake.4:45 PM. Just light snow falling out here on the Catalinas, no real “verticality” in this shaft, which would be a sign of graupel falling out.4:46 PM. An opening allowed this zoomed cross section of a cold, wintertime Cumulonimbus (capillatus) cloud streaming a shield of ice and virga downwind. On the left sloping-upward part, the Cumulus turrets still contain liquid droplets (have that ruffled, hard look associated with the higher concentrations that go with droplet clouds compared to all ice clouds). Sometimes, in spite of the low temperature, here, from the sounding the top is likely approaching the minimum temperature of -28°C, droplets can still survive for a short time before freezing, giving way to lower concentrations of ice crystals. That appears to be the case here at the tippy top. of the cloud in the back What is interesting here, an enigma, is that the foreground cloud in front of the cloud I was just discussing, is clearly all ice from the smallest element to its top and mimics the cross section of the background cloud. Could it be that its simply older and ice generated in the colder regions has permeated the whole cloud?
Below, diagrammed:
Same photo with writing on it since the written explanation didn’t seem very satisfactory.5:07 PM. Graupel in the Gap (the Charouleau one). Well, maybe its a little beyond the Gap, but it sounded good to write that.. This started to fall out of a Cumulus congestus transitioning to a Cumulonimbus. The first particles out the bottom are always the heaviest, hence, graupel or hail.
Looking elsewhere, there are snow showers everywhere!
5:08 PM. Nice shafting over there near Romero Canyon. Pretty straight up and down, so likely has a lot of small graupel in it.5:08 PM. Looking down Tucson way, this is NOT a graupel shaft, but rather gently falling large snowflakes.. Sure the particles are large, but look at how they’re just kind of hanging there getting mixed around by a little turbulence, almost forming a mammatus look. There are likely aggregates of dendrites, fern-like ice crystals that grow like mad around -15° C, and because of being complex forms, often lock together when they collide. Its not unusual to have 20 or more single stellar. dendritic crystals locked into a single snowflake. Where the bottom disappears, likely around 3000 feet above sea level, is where those big aggregates are melting into rain drops.5:10 PM. Interrupting the tedium with a nice neighborhood lighting scene as a sun poked between clouds. We’re not completely cloud-centric here, but close.5:26 PM. This strange scene of a very shallow snow cloud, completely composed of ice and snow, obscuring the tops of the Catalinas, but being very shallow, hardly above them may explain the cross section enigma. The snow cloud here is all that remains of a much deeper cloud that converted to all ice, then those crystals just settling out, the whole cloud dropping down as a snow flurry. It may well have been as deep as the cloud top on the left or higher before converting to ice and just falling to the ground “en masse.” Or is it, “en toto“? What makes this odd is that there is usually some “cloud ice” (ice particles too small to have much fall velocity) at the level from which the precip fell from. You don’t see that here; just a belt of light snow. Maybe this is why there was that shallow, glaciated cloud in the Cumulonimbus cross section shot….. That shalllow cloud was not a new portion, but rather a tail dragger like this stuff, once having been much higher and was actually ice settling out, not new rising, glaciated cloud. From the back side, you can see that this ice cloud would appear to slope up if viewed from the east instead of the west like our cross section iced out cloud. Setting a record for hand waving today. IS anybody still out there? I don’t think so. Maybe I need another dog picture….5:34 PM. Here’s the last of that unsual snow cloud as its last flakes settled to the ground.
The day concluded with a very nice sunset:
5:53 PM. Sunset color with shafts of snow turning to rain down Tucson way.
Now, the long dry spell… Break through flow from the Pacific under the “blocking high” eventually happens about a week away now, but more and more looks like that flow might stay too far to the north of us, rather blast northern Cal some more, and not bring precip this far south. The blocking high needs to be in the Gulf of AK, but now is being foretold to be much farther north…
The End, gasping for air here. More like a treatise than a quick read!
I guess “billows” (“undulatus” in cloudspeak) two days ago in the late afternoon wasn’t enough of a sign that the weather was changing. Yesterday we had fast moving Cirrocumulus with rainbows in it, and as the sun was setting, “jet streak Cirrus”, a line of Cirrus clouds often seen in the very core of high altitude, powerful jet streams passed overhead.
How hard was the wind blowing up there in that Cirrus last evening? Oh, our Tuscon balloon sounding, lifting off around 3:30 PM, going up about a 1000 feet a minute to, indicates that the max wind up there at Cirrus level was 146 knots (just under 170 mph)! Yikes. Poor balloon. Must be in France by now.
The storm has been a bit of a disappointment in rain production. We’ve only logged 0.22 inches1. Not as much as foretold here, 0.33 inches, but that forecast was a better prediction than by “Weather Underground Robotics” (0.58 inches). Its great to beat a robot!
We had another sign yesterday in the fastest moving Cirrocumulus clouds I think you’ll ever see around here (about 100 mph), ones at just 18,000 feet above sea level, 15 kft above Catalina: rainbows of color near the sun called iridescence (also called “irisation”). Here, as is the norm here, are a few too many shots of the same thing2.
10:54 AM. The fist of weather is used as a prop to indicate that these colors are forming a ring around the sun. Usually you try to find a light standard somewhere…maybe a “gopro cam on a stick” might do it. Just don’t look at the sun when you do this.10:57 AM.10:57 AM, pulling back some for perspective. As we often say here, “so pretty.” And look at how tiny the granulation is in this Cirrocumulus cloud is!
The colors themselves, of course, don’t warn of something about to happen, but the fast movement from the southwest did; a powerful jet stream is over you. That strong stream, the result of temperature gradients in the atmosphere, is dividing deep warm air from deep cold air, and steers the alternations of high and low pressure centers, and with those alternations of lows and highs along the jet stream, air is drawn from different latitude zones and the boundaries where those different masses of air meet at the surface, is called fronts. Here, such as last night, its nearly always cold ones.
The rest of the day was pretty exciting, the wind arising suddenly yesterday morning, along with our usual great visibility, and darker blue wintertime skies, made the clouds stand out more.
7:56 AM. Looking to the west at a scattering of Stratocu patches.7:57 AM. Highlight on the hills above Saddlebrook. Stratocumulus overhead.8:42 AM. This patch of Stratocumulus was the result of a lift zone that often produces clouds headed our way in southwesterly flow. The difference here is how limited in size this patch was allowing you to see where that lift zone was. Downstream, though, descending motions creamed this cloud, one that sat there most of the early part of the day. Usually a whole layer is over us, with a clearing visible toward the SW horizon.11:02 AM. Still out there pretty much near the same spot, still limited in size. Wind here now 20-30 mph with stronger puffs.
11:40 AM. By this time it had shifted closer to us, still forming on the southwest end, dissipating at the downwind end where the cloud is so ragged due to mixing with dry, descending air.12:42 PM. Creeping closer, but still a standing wave, dissipating as it came toward us. It was about this time that it disappeared, the sky becoming more complex with no simple standing waves.
The sky at last, considering the power of the trough approaching, FINALLY began to fill in. Started looking around for the first sign of ice having formed in these clouds as the air aloft became cooler. Along with this filling in by Cumulus and Stratocumulus clouds, some sun highlights began to appear on our mountains, contrasted by the darkening skies above.
1:55 PM. Stratocumulus clouds bank up against the Catalinas, Samaniego Ridge.2:03 PM. While Stratocumulus banked up against the mountains, huge temporary clearings occurred elsewhere. Notice how shredded the tops of these clouds are and how the tops lean to the right. They’re revealing the great increase in the wind with height, and yet, how dry it was above this layer (that, by the ragged cloud tops mixing with the very dry air just above them.)3:38 PM. Here comes the Jet Streak Cirrus! Also about this time, the frontal windshift line, marked by low scud clouds in the cold air, began to appear on the NW horizon. It was an exciting moment. Here we go! FROPA within a coupla hours maybe. Well, took longer than that….3:52 PM. A little ruffle of Cirrocumulus leads the advance of the jet streak Cirrus.4:11 PM. Cloud line forming above the frontal windshift line. Was progressing this way at this time, but was to stall, maybe back off.4:11 PM. Zooming, floating over Saddlebrooke, this close up of our FROPA and windshift line. Ended up backing off, dissipating, maybe reforming later after dark. These lowest clouds form in the colder air associated with the windshift line at the nose of the front as the moist air ahead of the front mixes with it and is lifted. We see this with most of our incoming cold fronts, and in our summer thunderstorms. The best cases form “arcus clouds”, a solid line just above and behind the windshift at the ground. These kinds of ragged clouds, in cloudspeak, are called “pannus.” Was pretty excited here, as no doubt you were, that FROPA (frontal passage) was imminent, might happen within the hour. Nope.4:40 PM. In the meantime, our jet streak CIrrus, above the Stratocumulus clouds, moved overhead, the clearing behind this thin band leading to some memorable fading sun highlights on the Catalinas.5:40 PM. No words needed.5:43 PM. “Fading sun and rain gauge.” Another one of those exceptional scenes you won’t find anywhere except on this blog. Tell your friends. A small mammal, termed a “packrat” is decimating my prickly pear wind protection for this gauge! A lot of rain loss occurs due to wind. drops missing the collector! It very upsetting to see this happen.5:43 PM. Even the often despised teddy bear cholla can be so beautiful in this fading sun, the spines capturing it so well.
Eventually our jet streak Cirrus provided the background for another great sunset scene:
5:56 PM.
A 300 millibar (about 30,000 feet above sea level) with an IR satellite image for yesterday at 5 PM AST. The Cirrus layer extended from about this height to around 35, 000 feet above sea level. according to our TUS balloon sounding. Arrows denoted the jet streak Cirrus cloud thatpassed over us, enhanced in the downwind region of the Baja mountains. Note that the wind at San Diego max wind was even slightly stronger than our wind max was at this level at152 knots. This map is the courtesy of the University of Washington Huskies Weather Department.
Today’s clouds and weather
From that map above, you’ll see that there’s a “tail-dragger” trough still to the west of us and about over Sandy Ego (haha). That’s going to keep the air over us extremely cold, and with some sun, the Cumulus clouds that arrive are expected to have tops colder than -15 to -20° C, plenty cold enough for the formation of ice.
Ice means precip, snow up there, rain down here in spots. So, we could still pick up a few more hundredths if a shower happens to drop by. The chance of isolated very light showers in the area is 100%, but no one can tell you if one will actually land on us. You’ll have to be watching, mostly after 12 noon. Look to the west toward the Tortolita Mountains, terrain that ought to spawn one or two of those.
Looks like a longer dry spell ahead; several days to a week, maybe more.
The End
—————————-
1CoCoRahs gauge, btw. NWS-style gauge had only 0.20 inches, likely due to enhanced wind loss associated with my collapsing prickly pear protector. 2 I was driving and had to park and jump out of car to get these. You only have seconds or maybe a minute or three to capture stuff like this.
Its not something a weather-centric sailor would say, but its what happened yesterday before today’s certain storm. Maybe sailors should consider it…but with no cussing, though.
The Weatherunderground weather site forecast for Catalina has 0.58 inches predicted for our storm. Such forecasts, I have to say, are “objective” and are based are model outputs that yo-yo forecasts every time a new model output comes in.
To educate you on how bad this is, why just yesterday, based on the SAME model but a different set of global data, the model said we would have, 0.59 inches. So, its already changing our forecast, diminishing it! How bad is that?
The problem with those forecasts is that they are heavy with “objectivity”; there is no human intervention. Its the work of a robot of sorts. And we know what robots are doing to the economy and jobs.
Here, straight from a human heart, we had a forecast of 0.33 inches total from this storm, one laden with emotion and often based on wishful thinking when large amounts are forecast. They’re often, based, too, on pattern recognition (“looks like that storm that brought us that much last time, or look where the core of the jet stream is!”)1
That forecast of 0.33 inches in the gauges right here in Sutherland Heights is not going to change just because some new data came in!
So, which one do you want? A forecast that yo-yos every few hours as demonstrated by the Weather Underground one? Or one that stands tall against new data?
I think the answer is obvious.
OK, enough about “robots” and weather; on to yesterday’s afternoon billows:
12:49 PM. Layer of Altocumulus opacus moved in during the mid-day hours. Looked a lot like “Altostratus” to some, I am sure. But if you looked carefully as I always do, you’d have seen the sun’s disk in the brief thin spots. You can’t see the sun’s disk in Altostratus because its full of cloud and precipitation-sized ice crystals, which cause enough interference with the incoming sunlight to prevent the outline from being seen due to diffraction. So if labeled it even momentariy as “Altostratus” you will get a demerit at the next meeting of Cloud Maven Junior club when your cloud diary is inspected by the other members.1:59 PM. Showed signs of devolving into a Altocumulus opacus perlucidus layer as small cloudlets began to show up. No billows here, but let’s look over there next, but an hour an a half later.4:06 PM. A very billowy sight! Or, as we cloud technicians would say, Altocumulus or Stratocumulus undulatus. The individual elements are a bit large for true Altocu, yet the layer is still quite high off the ground, about 7,000 feet above Catalina, or about 1,000 feet above the top of Lemmon. (This from the TUS sounding.)3:07 PM. Billows galore!3:07 PM, but a little more over there.3:10. Billows to the north!3:35 PM. Just going on and on!3:38 PM. The billows (undulatus) structure was fading quickly, here almost two perpendicular waves are interacting with this cloud cutting it up into square elements resembling waffles.3:38 PM. The billows were pretty much gone, and the sky cleared spectacularly after this.
Well, there you have it, another tediuous contribution from the CMP.
The End here, but the beginning of the next storm!
———————————– 1Analogs to previous weather patterns are also part of the forecasting arsenal used by computers and other forecasters these days.
A few more hundredths fell after 7 AM yesterday, boosting our storm total to a remarkable 1.42 inches, January now about twice our long-term average.
Here’s what all that precip did to our beloved Cañada del Oro Wash:
3:53 PM. The CDO in full flow at East Wilds Road, road closed.
Yesterday’s clouds
8:04 AM. A Stratocumulus overcast with areas of virga and light rain showers began the day.
After a few more hundredths of rain, the skies broke open, and as we know well, some of our most spectacular scenes occur under deep blue skies punctuated by puffy Cumulus clouds, shadows and highlights on our now snow-capped Catalina Mountains.
10:36 AM. Cumulus clouds race toward Catalina borne on brisk west winds. In looking at this scene you can feel them coming at you.10:36 AM. Deeper clouds capable of producing ice and precip still lay to the SSW of us.11:19 AM. Heavy Cumulus line the Catalinas, spewing ice farther downwind. Glinting rocks highlight the scene.1:38 PM. Coming at you. The south end of the Tortolita Mountains is a common formation point in westerly and northwesterly flows for cloud street development, a line of clouds that stays in the same place, but elements are replaced.1:38 PM. The end of this cloud street shows that its tops got high enough to form a little ice, seen by that veil like cloud coming out the downwind end.2:57 PM. Samaniego Ridge and its new coating.3:06 PM. Cloud streets continuing to stream off the Tortolita Mountains, but are now half the depth they were 2 h ago. No ice will form now.3:48 PM. “Devil’s Post Pile” to the left of Samaniego Peak catches a sun break.4:01 PM. Last of the Tort cloud streets, shallower yet (estimated depth, 1000-1500 feet) is about to fade into oblivion, wherever that is.
In the meantime, more highlights on Sam Ridge:
4:50 PM. So pretty!4:50. Drawing back a bit for perspective on the scene.
Finally, that incredible sunset afterglow on our mountains:
5:46 PM. I hope we never take such sights as yesterday’s for granted.
The End.
Oops, oh yeah, storm tomorrow, supposed to begin in mid-day to afternoon hours. Looks like a third of an incher. Also looks to be a bit colder than the last storm, may see a flake or two by Tuesday morning.
In case you don’t believe me that over an inch fell, this digital record from Sutherland Heights with writing on it:
Your last 24 h of rain in the Sutherland Heights, Catalina, Arizona, USA. Total resets at midnight.
Probably a little more to come, too. Got some blow damage, I’m sure. Will be looking for roof shingles around the yard today.
12:45 AM. Your radar and IR satellite imagery for our blast last night from IPS MeteoStar . That tiny red region near Catalina represents hail and/or extremely heavy rain.
And, as everyone knows from their favorite TEEVEE weatherperson, “New Storm to Pound SE Arizonans!” Begins Monday night, Tuesday AM. May have snow in it as it ends.
Your know, its no fun telling people what they already know, so lets look ahead beyond the normal forecast period of great accuracy, beyond not seven days, not eight, but beyond TEN days!
First, we set the stage with a ten day look ahead (from last evening) in a NOAA spaghetti factory plot:
Valid for 5 PM, Monday, January 30th. If you’ve not seen this, you’ll be screaming “warm in the West, and damn Cold in the East.” Its a common pattern often associated with some of the driest years in the West when it recurs over and over again during a winter.
This plot indicates that the pattern of a towering, storm-blocking ridge is certain along the West Coast by ten days–will be developing for a day or three before this, That ridge represents an extrusion of warm air aloft over the entire West Coast extending all the way into Alaska. The couple of red lines in and south of AZ are due to the change of a minor, likely dry, cutoff low in our area about this time (plus or minus a day).
In other words, this plot suggests a warmer, dry period develops over AZ, and storms are shunted from the Pacific Ocean, located west of the West Coast, all the way to Anchorage and vicinity, They will be welcoming a warm up in weather up thataway at some point in this pattern.
Is that it, then, for the AZ winter precip? It could happen. Just one more storm after the current one fades away today?
Hint: Sometimes anticyclone ridges like the one in the plot above get too big for their britches, and fall away, or, break off like a balloon from a tether, and a warm blob of air aloft sits at higher latitudes, often floating off to the northwest.
The exciting ramification of this latter scenario is that in the “soft underbelly” of the “blocking anticyclone” (as in American football), the jet stream throws something of a screen pass, goes underneath the belly of the blocking high, and races in toward the West Coast at lower latitudes. Having done so, such a break through pattern (“Break on through to the Other Side”) results in heavy rains in Cal and the Southwest.
Izzat what’s going to happen?
Let us look farther ahead, unprofessionally, really, and see if there is evidence in spaghetti for such a development and you already know that there must be because it would explain why I am writing so much here. Below, the EXCITING spaghetti plot strongly indicating break through flow breaking on through to the other side, i.e., the West Coast, from the lower latitudes of the Pacific:
Valid on Thursday, February 2, at 5 PM AST. Flow from the lower latitudes of the Pac will, in fact, break on through to the other side, as told in song by the Doors1. Who knows what they were talking about but here we’re talking about a jet stream….
Well, we’ll see in a coupla weeks if CMP knows what he is talking about.. I think this is going to happen, resembles what’s happening now, and weather patterns like to repeat, more so within the same winter. However, how much precip comes with this pattern will be determined by how much flow breaks on through to the other side….
Yesterday’s clouds
Let us begin our look at yesterday’s clouds by looking back three days ago before the Big Storm. We had a nice sunrise. Here it is in case you missed it:
7:21 AM. Altostratus sunrise. Virga is highlighted showing the precipitating nature of Altostratus. Amount of virga can vary.7:31 AM. Same kind of view, different colors.7:40 AM. Highlight on the Tortolitas. This is why you carry your camera at all times.9:04 AM. Pretty much solid gray after that nice sunrise for the rest of the day with cloud bases lowering and raising. Early on, cloud bases were well above 10,000 feet; i. e;, above Mt. Lemmo, and would be called, “Altostratus opacus.” The virga is very muted, and there are embedded droplet clouds as well as a droplet cloud layer (Altocumulus) encroaching on the right. Estimated ceiling here: 12,000 overcast.” (Pronounced, “one-two thousand overcast” if you want to make your friends think that maybe you were a pilot at some time in your life.)12:58 PM. Clouds began to appear on Samaniego Ridge as the moist air above us lowered steadily. However, due to lowering cloud tops, the ice in the higher overcast layer was gone. Here there are two layers above the scruff of Stratus fractus (I would call it) on the ridge. The lower one looks like its a Stratocumulus, and the higher one a solid layer of “Altocumulus opacus.” Its already rained some, and we were in between storm bands.2:48 PM. Looked like the Altocumulus opacus (stratiformis, if you want to be exactly correct) was breaking up just enough for a sun break. But no; it kept filling in as it headed this way from the southwest. No ice, or virga evident, so tops are pretty warm, probably warmer than -10° C (23° F) would be a good guess. Hah! Just now looked at the TUS sounding and tops were indicated to be at -11° C, still very marginal for ice (absent drizzle drops in clouds, which causes ice to form at much higher temperatures, but you already knew that.)4:24 PM. Small openings allowed a few highlights to show up on the Catalinas underneath that Altocumulus opacus layer. And clouds were still topping Ms. Mt. Lemmon, indicating a good flow of low level moisture was still in progress.
Moving forward to only two days ago, the day preceding the nighttime blast: a cold, windy day with low overcast skies all day, shallow, drizzle-producing clouds, something we don’t see a lot of here in Arizona.
8:08 AM, January 20th, 2017, btw. “Gray skies, nothin’ but gray skies, from now on”, by Irving B. Stratus fractus underlies an overcast of Stratocumulus. Some light rain is falling toward Romero Pass on the right.8:10 AM. A really special shot. Stratus with drizzle, shown here, is a very difficult photographic capture. I can feel how enthralled you are with this scene toward Oro Valley. You know, I do this for YOU. Look how uniform the gray is! It just takes your breath away!9:44 AM. Before long, drier air down low moved in, eradicating our beautiful Stratus layer, leaving only holdouts (Stratus fractus) along the Catalina foothills below the heavy layer of Stratocumulus.10:20 AM. The wind had now shown up, and these ragged, shredded shallow Stratocumulus shedding drizzle or very light rain showers stormed across the Catalina Mountains. This was quite remarkable sight, since such shallow clouds as these are more often seen in clean maritime locations like Hawaii. Scenes like this suggest that the cloud droplet concentrations were very low, and that there were larger than normal cloud condensation nuclei on which the drops could form, getting a head start in the sizes needed to produce collisions with coalescene (larger than 30 microns in diameter (about one third to one half a human hair in diameter, for perspective.)
3:12 PM. Lower, drier air moved in, eradicating the Stratocumulus and revealing the rarely seen Nimbostratus precip-producing layer. This layer, considered a mid-level cloud, is usually obscured by, you guessed it, Stratocumulus clouds.
By the end of the day, the clouds had lowered again, and we were about to have a very interesting night!
5:01 PM.
The End
———————- 1Remember how great we hippie relics thought that first Doors album was? Later, the Doors, and that era were to be made fun of by 80s punk and humor group, The Dead Milkman in “Bitchin’ Comaro.” (Its worth a listen.)
Catalinans experienced a FOURTH cloudy day in a row, and, over the past few days, including yesterday’s few drops that fell at 4:24 PM, have experienced over an inch of rain!
Some grumbling has started concerning muddy, pot-holed and puddled up dirt roads, about the washes running across roads lately, water and mud splashing on the car day after day, and brutally low temperatures dipping to well below 50° degrees in the morning now for several days in a row. Its 40° F here as I write this.
While a brief respite is in progress now, Catalinans were discouraged to learn that more strong storms are due in this weekend, bringing possibly damaging winds and heavy rains that will augment the poor road conditions.
How much rain?
Let us look below and see how much has been calculated by our best model at the University of Arizona’s Wildcat Hydro and Atmos Sci Dept (I am so glad they provide this service; I donate to the Dept, as we all should!):
Precip totals by 8 PM, January 23rd after a few storms have gone by. As you can see lots of red and yelleows in Arizona’s critical mountain regions for snowpack, and we’re in the inch or so of rain, pretty much like the amount produced here by the last storm. What a January this is turning out to be!
Hah! We can’t complain too much about inclement weather compared to California’s pluvialities. Here is a table and map of precip amounts for that State through just the first 14 days. Prepare to gasp:
A map and table of the highest 20 rainfall totals in California and Nevada just through January 14th. Astounding! And 10-20 inches more are expected at some of these sites before the month is out. Yep, by Jan 14th, one station was closing in on 40 inches of rain!
The remarkable aspect of this rainfall anomaly on the West Coast and in the Southwest, which is also quite wet, is that it could not be seen in climate forecasts days to a couple of weeks in advance. Its not that the folks at the Climate Prediction Center aren’t the best that we can get, its just a statement about how hard it is to get a longer term forecast right. Many are right, but lately, recalling the “Big Niño Bust of 2015-16” where the forecasts of a wet Southwest and central and southern California went terribly awry, those forecasts have taken a beating. Here’s what was expected this winter by the CPC, first, for January, a forecast made on the last day of December. when the forecast models we use day to day would have had some influence:
The precipitation forecast for January 2017 by the CPC.
As can be seen, the extreme rains that hit California, and our own well above normal precip, though on the doorstep on December 31st, were unforeseen. That’s how tough it is.
Below, the forecast for January through March, also going astray, though a recovery could be had by a very dry Feb and March in Cal and the Southwest, something not likely to happen now.
Below, the forecast for the three month period of January through March, also now going astray.
Glad I’m not forecasting for a month or three months! Gads, yesterday we had ice galore here and there, and I had predicted that morning that it was doubtful that ice could form in our clouds yeserday and how about that rainbow yesterday afternoon, to change the subject quickly, but smoothly; hardly a ripple, something gleaned from the election debates:
4:59 PM. A rainbow, an implicit indicator of ice in clouds yesterday. There was a lot in some areas, particularly over the Catalinas in the late afternoon.
Some additional views, including a horse, which should increase web traffic:
Horse, muddy corral, and supporting rainbow evidence for why the corral is muddy. Horse “Chero-key”: “Why is that rainbow on my butt?”Rainbow empties into a NWS-style, 8-inch diameter rain gauge. Real weathermen have real rain gauges, not the cheap plastic toy types. Just kidding, CoCo and rainlog, orgs that use cheap plastic toy-type gauges. Just kidding again, CoCo and rainlog. orgs.5:09 PM. Here a completely different rainbow, because I moved a few feet, and the rain drops in the prior bows have fallen to the ground, empties into yet another 8-inch diameter rain gauge, a tipping bucket one which is online at KAZCATAL4. Its been under-measuring the rain, however, for some time.
OK, now for the rest of the day, your daily cloud diary:
8:09 AM. You got yer normal TUS exiting smog plume heading for Mark Albright’s house in Continental Ranch over there on the right. There is some Stratus fractus in that plume as well. The damp air has caused some of the hygroscopic particles to swell up; be deliquesced, which increases the opacity of smog. Such an effect is particularly bad on the East Coast ahead of cold fronts when warm, humid, smog-laden air is brought northward ahead of fronts. Gads, its awful. Even when the sky is cloudless, you can hardly tell its blue! Above the smog, Stratocumulus.9:36 AM. Had evidence of a little smog up thisaway, too. Again, the whitish haze is due to deliquesced partilces. As the air dries out and the day warms up, this effect disappears. even though the aerosol particles that were “deliquesced” are still around. The Five Satins, “Still Around.” Gads, that takes me back a-ways when I was 2 inches taller than now….10:10 AM. Smog plume, as sometimes happens, begins to drift northward as the mountains start launching Cumulus clouds and cause the wind to move toward them. Can’t say too much about the central cloud feature, a gesture of some kind it would appear.10:27 AM. Nice lighting scene I thought. Cumulus turrets were rocketing upward at this time.1:48 PM. Not much going on. Underlying Cumulus bases lifted, some Cumulus spreading out adding to the slightly higher general Stratocumulus deck. No ice around, as was forecast.3:02 PM. Something is going terribly WRONG with the anticipation of no ice producing clouds yesterday. Rain begins to fall on the Catalinas.3:20 PM. A totally humiliating, completely glaciated tiny Cumulonimbus remains breaks into view from the Stratocumulus deck. On the other hand. another fascinating day of ice multiplication here in Arizona! Look at that little guy, all ice, and tops almost certainly warmer than about -12° C from sounding data. This would mean that those 10s to hundreds per liter of ice that you’re looking at are needles and hollow column ice crystals called “sheaths.” Man, I wanted to sample that cloud so bad! What happened to cause this cloud was that at one point its top got a couple of degrees Celsius colder than the surrounding clouds that did not produce ice. Rain was reaching the ground at this time o er there even though it is in the dissipating stage, too.3:43 PM. In the meantime, the showers emitting from the clouds over the Catalinas were getting more enthusiastic (read, “personally insulting”). No doubt if you could get on top, they would have looked exactly like that dissipating Cb shown above.
But, then there were some great sun and lighting scenes in those showers, not to mention the brilliant rainbow that was to come:
4:47 PM. Its a little crazy, I know, but I just love these rainy, sunlit scenes on our mountains, or those sun and shadow scenes that I post so many of. Just never will get tired of them.4:51. More of same. Notice inclusion of man-sized rain gauge in foreground. Its a nice touch if you, too, have one, which I hope you do. It really says who you are.
What a nice steady rain with honest-to-goodness drizzle mixed in over the past two days. We’ve now had 4.24 inches in the past 30 days!
And yesterday, you saw the rarely captured on film, drizzly Stratus clouds, essentially something akin to wallpaper in the sky, but with misty visibility below its base. I hope you got a lot of photos of it; occurrences like that in Airizona1 its like finding a clean-shaven Lincoln penny.
And, of course, you knew that with misty, drizzly rain, clouds were shallow, no matter how dark they looked! Here’s the afternoon TUS sounding (from IPS MeteoStar) confirming that assertion2:
Tops are indicated by this sounding to be around 12,000 feet above sea level and at about -10°Ç.
The drizzle likely fell from shallower parts of this cloud, while the accumulating rains, ones that “tip the bucket”, were likely associated with clouds all the way to that -10° C, where lots of ice would have formed. Drizzle occurrences and lots of ice in clouds at surprisingly high temperatures such as those tops we had yesterday are common, mutually inclusive observation in airborne studies of clouds then the tops go much below -4° C. But, its an unusual occurrence in AZ since we rarely have shallow clouds like yesterday’s with droplets in them large enough to form drizzle.
So, drizzle and what we call, “ice multiplication” occurring in our clouds yesterday made it a rare day, indeed for Arizonans to enjoy even if the mid-40s temperature all day was “less than optimum.”
Next up, more substantial rain after a couple of pretty nice, but maybe not thermally optimum days. Below, the latest output from the U of AZ supercomputing weather calculator showing the cumulative precipitation over the whole SW during the next week, starting from last evening. Quite fun to see the totals build up in that link above:
Cumulative precip ending by 5 AM AST January 23rd. Our precip is pretty much over by late on the 21st.
Being from southern Cal, what I find interesting is that another 10-15 inches of precip is forecast by this model’s output in the northern mountains of Cal, on top of the 20-30 inches they’ve already had JUST THIS MONTH!
Some cloud highlights
11:59 AM, yesterday. This is just an astounding scene. You can hardly have a more spectacular, photogenic photo of Stratus! I get goose-bumps looking at this scene! The view, if you can’t tell, is toward Saddlebrooke. The dismality of yesterday’s skies is also well captured.
It pretty hard to top a photo like this one, so maybe I will just quit here. Wait to see what interesting clouds today brings for us. They’ll be shallow again as an inversion clamps down on the tops even a little more so than yesterday’s afternoon sounding shows, and the Stratocumulus and Cumulus clouds will be thinner, higher bases, lower tops, marginal for ice formation. So, not expecting to see ice in clouds today, but, then I wasn’t expecting so much rain, either from this little system that went through….
OK, one more:
2:14 PM. Horse and drizzle.
The End
————————— 1Misspelled on purpose to emphasize the quality of the air we have in Arizona, at least yesterday. Chamber of Commerce, are you listening? “Airizona,” as our new State name, would work great to attract people from smog-laden regions. I’m sure! Hmmm, or maybe just a good, new athletic shoe would do it, “Nike Airizona”… Nike, are you listening? 2One of the great moments in a life, as we all know from time to time, is in confirming an assertion, which also might be accompanied by gloating.
