“Delta model”? Will someone have cold spaghetti on their face?

Yesterday, after I finally saw the model run based on global data from 5 AM AST  for Feb 6th, CMP (the writer) was gloating that bit.  The troughy, cold spaghetti for AZ, that which had been excitedly written about yesterday,  was being confirmed; the interpretation right on, it seemed.  Why even look at more model outputs until later January, I thought.
Then,  just now in the pre-dawn darkness, I examined the computer outputs from last night’s 5 PM AST global data, also for Feb 6th, 5 PM AST.    That is, global data crunched just 12 h later than the first panel I was gloating over, feeling really great about.
But, a completely, ghastly different weather regime had popped out!
How could this be?  We don’t know.   Relatively small changes would be expected, but the model outputs should gravitate back to where spaghetti placed the high and lows aloft.  But this change was ridiculous, and must be rejected.
Some people, like neighbor and big professor “emeritius” of meteorology at Colo State U,  Bill Cotton, refer to such differences as “delta model”.    “Hence”, if that word is still used, today’s title.
(For snowbirds who have just moved to Arizona, the maps below have been annotated to show where you are relative to the rest of the US).
Yikes!
The first regime is cold, maybe some snow down in Catalina at some point about this time (early Feb),  whilst the 2nd regime for the same time is suggests warm conditions, and definitely dry;  no rain nowhere.
CMP (the writer) spoke of a high probability, based on ensemble spaghetti, of cold and lots of precip chances here in Catalinaland beginning at the end of January through the first week of February  So, what’s up with that, this dichotomy?
Moving on to a new topic, let us look at last evening’s sunset rather than ponder what happened to the weather computer model, that is, which panel  above is  likely correct1:

6:09 PM. Cirrus uncinus and other forms of Cirrus provided a beautiful sunset highlight.

 

The End.

—————————————

1The first regime above, the troughy, cold one, is strongly supported by ensemble outputs whose crazy-looking output plots are fondly referred to as “spaghetti”.  The second panel served up from just last night’s 5 PM AST global data is not.
Have not looked at last night’s ensembles, but will ignore the bottom run anyway;  will not panic as weaker elements might, that is, change my overall interpretation of troughy conditions in late Jan, early Feb., that is#2, reverse course now, predict drought and warmth  for early Feb. , that is#3, “yo-yo”, as forecasters describe reversing course, confuse the public, lose credibility, where are my pills?
……yet. :}.
Still, “egad re this delta model”,  as Bill likes to say.  Its astounding!  A total joke!  The later one to be totally and completely rejected!
In no way did I expect to see what’s in the bottom panel, which is now above here!  Trying to not panic real hard.  (more kidding)
Still, how can there be an outlier of that magnitude as we see from last night?  Must be a real bad error somewhere (maybe 2 kts of wind, 1.5 deg in temperature, wind direction, 5 decameters in geopotential height, etc), not an itty-bitty error as ensembles start with.  Maybe Russian2 hackers did something, the North Koreans, or the Chinese?  Just kidding
with weather noise and pseudo-paranoia, your Catalina cloud-maven of sorts.
Speaking of Russia,  my great-grandparents emigrated from the Ukraine, here’s the cover of my latest book, published a few years ago.  Well, its not my book per sé, but all the cloud photos in it are mine!  How great izzat?
A book about flying. I asked that my contributions be dedicated to A. M. Borovikov, the great Russian cloud physicist. Did a lot of airborne stuff in the 1950s and 60s.  The cover photo above I took while in KWAJEX in 1999, a tropical cloud study featuring several research aircraft centered at Kwajalein Atoll, Marshall Islands.  Of note, seeing a monument to the bravery of the Japanese soldiers (fair enough), and seeing a Japanese military plane land there during our six weeks.  Gorgeous clouds!  Kwajalein Atoll is the terminus of missle launches from Vandenberg. Alerts on TEEVEE tell you when they’re coming in.  Unlike in Hawaii where people panic when missles are coming in, folks on Kwajalein go out to “see the show.”

Sutherland Heights logs 0.22 inches yesterday; Jan now at 1.32 inches; average is 1.60 inches, water year at 1.71 inches

0.22 inches was, indeed. how much rain fell in the form of drops  from Nimbostratus clouds yesterday as a modest little rain band generated by a rapidly moving trough swept through during the afternoon.  Regional precip values can be found here.  Our local area got the most, up to about a quarter of an inch, as often happens in marginal storms.

Yesterday’s storm marked the beginning of the new, more normal weather regime for southern Arizona, as has been blabbed about here in recent weeks.  No more week after week of droughty weather with temperature far above normal, the kind of weather that has marked this whole fall and winter so far!  I. e., “Thank you very much, a snowbird might say,  but get the hell out!”,  the rest of us might conjure up, thinking about the needs of our  desert’s wildlife and vegetation.

Indications are now that below normal temperatures and above normal precip are ahead for us and all of Arizona in late Jan and early February.

The evidence for these claims?

Below, the stunning, jaw-dropping evidence for this seemingly outlandish assertion in the form of an ensemble (spaghetti) plot generated by NOAA last night.  I have followed these charts for almost ten years now, and I cannot remember when such a strong signal (clustering of flow lines) 15 days out has occurred before in our region.

So, excessively excited this morning when I saw it!  Its been annotated with excitement text.

This troughy pattern begins to take place on January 30th.  Until then, a strong but dry cold front with a lot of wind comes by in a few days, on the 25-26th.

Valid at 5 PM AST, February 4th. You can pretty much count on a trough hereabouts in two weeks. Since the blue lines, the colder portion of the jet stream,  do not dip down this way so much, our troughiness likely would be in the form of something we call a “cutoff low.”   A full latitude trough extending from the “blue jet” up there in Canada, instead of a “cut off”, would be excessively cold.  We probably don’t want that anyway.

 Yesterday’s clouds

The whole interesting, if excessively gray story is shown below:

7:24 AM. It was breezy already, and with Cirrus underlain by Altocumulus lenticularis clouds in the lee of the Catalina Mountains, you knew that a storm day was ahead without turning on your favorite TEEVEE weatherman.
8:53 AM. With Cirrus and Altocumulus spreading rapidly from the SSW, lenticulars downstream from the mountains, the wind gusting to 25-35 mph, you knew a great gray cloud day was in store!
11:32 AM. Before long, an entire sheet of Stratocumulus spread over the sky, making you sure that rain would fall.
12:50 PM. First drops begin to fall on Sutherland Heights. That layer of Stratocumulus appeared to be deepening as it approached from the SSW to where the tops were getting just cold enough upwind of us to produce ice and snow that melted into those sparse drops.  Not enough ice /snow formed to hide the bases, though, in virga.
1:26 PM. Snow begins to fall on the Lemmon.
2:04 PM. Lower Stratocumulus clouds begin to show up below the original deck that overran us.

 

3:16 PM. Pretty and dramatic.  Stratocumulus piling up over and upwind of our Catalina Mountains/Pusch Ridge.
3:19 PM. Oh, so pretty.
3:27 PM. Crazy, I know, but I thought these scenes were so pretty!
3:28 PM. As that rain band approached there were some nice lighting highlights.
3:40 PM. Here comes that rain band  across Oro Valley/Marana.
4:19 PM. A truly great scene for a desert; mountains partially obscured in precipitation.
4:19 PM. Nimbostratus. Its hard to get a better photo of rainy Nimbostratus than this. Drops coming off the roof, NOT raindrops, can also be seen.  This was at the peak of the rain, too!  Very exciting.
5:54 PM. Sunset Stratocumulus, hold the ice. Yet, that Stratocumulus was cold, way below freezing.

 

The weather way ahead

The title sums up where we are now.  Will we go have more rain? Oh, yeah.  But not right away, as you already know.

 

 

Sky to do to a lot of things today

Keep cameras at the ready.  Have some nice lenticulars in the lee of the Catalinas this morning if u look.

FROPA (weather text for “frontal passage” and cold air burst into Oro Valley and Catalina likely to be fronted by a lower arcus-like cloud that comes over the Torts later today.  That should be dramatic, though personally I will complain about cold air right after it hits.

Still riding the forecast wave  of 0.3 inches, though mods have varied from nothing to about that now.  Yay!

 

Since its already windy, there’s a good chance of more windy (from the SW) right up until FROPA when the wind will turn to the NW for a while.

The End

The top 100 weather blogs; the weather ahead still filled with rainy portent

“Rainy portent”;  is there a better phrase for a desert than that?  I don’t think so.  See mini-discussion below, and below that, some soapboxing!  Very excited today!  Where are my pills?

Now, let us discuss the top 100 weather blogs:

Bob Maddox‘ superb site,  representing Tucson, makes the list ! This note and info from pal and fellow weather fiend and fellow science investigator, Mark Albright1:

Top 100 here

“Some notable blogs in the list, Mark notes:
 1) Watts Up With That
 2) Roy Spencer
11) Cliff Mass Weather and Climate (U of Washington Huskies!)
28) Judith Curry, Climate Etc (once worked at U of Washington Huskies as a visiting grad student
30) RealClimate  (from the Huskies)
33) Wasatch Weather Weenies, Jim Steenburgh    (graduated from from the U of Washington Huskies!)
65) Mike Smith
70) Madweather – Bob Maddox (Tucson AZ) (Was grad   student of mighty prof and neighbor, Bill Cotton, whose heard of the Huskies!
83) West Coast Weather – Michael Fagin”
 
Not sure if “we” (to distribute poor performance beyond a single author) even made the top 1000; the list doesn’t go that low (or high). 
 
But, we’re not really a weather site, per se, to put a positive spin on a glum finding.  We talk mostly clouds here. not so much weather.  Contains sophomoric, droll, and tongue in cheek “humor”, too.  Maybe Cloud Maven Person’s blogulations would make the top 1000 CLOUD sites!

 The weather ahead and beyond ahead

Cool with passing rains every coupla to few days, maybe some snow with one of those events, as they continue into February.  The first storm begins on January 20th, and then its one threat after another.   This new “troughy” regime should bring the January rainfall total in Catalinaland over average of 1.60 inches (1978-2017).  Currently, we’ve logged 1.10 inches in a NWS style 8-inch diameter gauge. 

Looking for tiny green sprouts out of our desert soil now.

The End

(except for all the footnoted sci commentary below)


sci commentary and soapbox module——

1Mark Albright routinely calls attention to suspect temperature data that’s out there, and other questionable aspects of some climate statements2.  He is widely well thought of for these conscientious efforts in bringing temperature errors to people’s attention3.   Mark was former State Climatologist of Washington State, to be redundant, for many years.  Was more or less fired for questioning claims of HUGE snowpack losses in the Pac NW between the late 1940s/50s (a cold era that started after a warm era in the 30s and 40s) and the late 1990s (a Niño-filled warm decade); to wit, it was a cherry-picked study,  as we learned later via Stoelinga et al 2010 pdf, and by the mountainous snows that  occurred immediately after that bogus claim was published in the Bull. Amer. Meteor. Soc.

Could snowpack go down gradually over the years in the Pac NW due to warming? Sure! But there was no need to cherry-pick data to create the appearance of an imminent calamity! It destroys credibility when objective investigators like Stoelinga, Mass, and Albright check into them.  Michael Mann, of Penn State and “hockey stick” fame, also fueled the fires of skepticism and doubt needlessly by refusing to give the details (data and methodology) on how he created “The Stick” which eliminated such climate anomalies as the Medieval Warm Period and the Little Ice Age that followed.  If you read Science magazine, they often refer to the MWP and LIA!  What’s Up With That?  It can’t be both,; didn’t happen but did happen????!!!!!  Dammital.

“Fellow investigator”, CMP? Oh, yeah, baby! Your CMP likes questioning exaggerated cloud seeding reports after they’ve been published in peer-reviewed journals!  Or checking into suspect cloud reports *(after all, he is the “Cloud Maven”) that are the foundations of seeding results. He’s even gone to foreign countries (well, one) to check out suspect cloud reports, help the people of that country understand their clouds.

While CMP   has a number of peer-reviewed pubs  that are critical of cloud seeding (nearly all co-authored with the late mighty Prof. Peter V. Hobbs),  maybe today,  as do so many good scientists and others,  those critiques would just be in blogs?  I dunno.

Journal editors have tremendous power over your getting in these days via who they give your manuscript to to review.  (Well, that’s always been the case).

But today that power has grown enormously since they (a single  editor or an editorial board) can refuse your manuscript on first sight (its “D. O. A.)” and not even send it out for peer-review! This is an intolerable situation since non-objective factors will certainly creep in to such a process.  As an example of unwanted but valid science, Stoelinga et al took years to get into the J. of Climate.

Note to journal editors: Send the damn thing out! Let legitimate, even adversarial reviewers,  determine the fate of a manuscript, with the stipulation that the author (s) have a chance to rebut adversarial reviews which will likely reject a manuscript prima facie. They’re the best ones!

And, no “pal reviews”! They’ve cost us so much in the early published cloud seeding claims here, and in Israel , believed to be accurate by our best scientists and national panels, but cost us and Israel  tens of millions of dollars of worthless cloud seeding based on those ersatz published results.

2Some professors and students at the U of WA delete Mark’s e-mails on arrival; they prefer not to hear about discrepancies or other weather data that might cast doubt on today’s climate issues.  As far as I know, only Prof. Cliff Mass has,  from time to time,  openly supported Mark’s findings putting him even more in the cross hairs of some of his fellow faculty members and especially some other climate scientists and students/post docs since he has often scrutinized and found wanting  some gross claims on climate change.   We are in a science era where questioning  even the magnitude of the warming ahead, even if we believe its coming,  is seen as untoward.  Science is not as it should be!

3If you believe that, I also have some ocean front property in Nebraska I’d like to sell you.

Regime change still ahead, as are more Cal blasters

Check it out, spaghetti1 lovers:

Valid at 5 PM AST, January 20th. Bulges toward the Equator indicate areas of stormy weather in “troughs” and we’re in one! Will January have above average rain in Catalina? I think so now. How much is that? Oh, only 1.53 inches and we have 1.10 inches now.
Valid at 5 PM AST on January 24th. A second trough with its stormy weather, or threat thereof, is indicated for Arizona and the SW! These storms look strong coming into California, representing good news for filling reservoirs after the early winter drought, but bad news for mudslides in those huge burned areas. The last storm produced 4-7 inches in 24 h, with rainrates sometimes exceeding an inch an hour, about as high as they get in wintertime in Cal.

So, enjoy the warm, dry spell we’re in now, if that’s what you like and that is why you are in old AZZY, since you probably won’t be as happy after the 20th or so.

Pretty excited about this change coming up, one that will break five months of below average rainfall here in Catland with January’s total likely to be above average now!  Yay for desert greening, too, that soul-filling spring phenomenon we all need as much of as possible.

The End

—————————-
1You can go here and see the whole sequence from the NOAA spaghetti factory (aka, ensemble factory).

Sutherland Heights rain total ponies up to 1.10 inches!

That was about three times more than CMP (me) expected, and it was such a fabulous a rain!  That soaking amount should start the spring greening that we love here.   With more rains in the pipeline, eventually, after another longish dry spell, maybe the spring bloom won’t be as bad as it once looked.

As we who love the Sonoran Desert know,  its a pretty special place when it comes to rain.  But only recently did I learn that the SD is the ONLY desert in the world (!!!) with TWO rain seasons, so great for a cloud-loving meteorologist1, though three or four rain seasons would be that much better.   Now, after some interesting information, clouds: yesterday’s, of course:  a study in gray2, more or less.

Yesterday’s clouds

7:53 AM. The sky had kind of a mellow gray cast to it as the day started, not much detail as rain falling out of the gray clouds obscured the usually ragged bases. This is a very peaceful scene if you stare at it for ten minutes, letting your mind empty all of that clutter in it.  This clutterless scene will help…
8:11 AM. Misty rain continues to fall from Stratocumulus clouds, though Nimbostratus would be an OK name, too. Cloud tops were beginning to come down.  Those shred clouds might be called, “Stratus fractus”, to add more unneeded detail.
9:27 AM. A great example of Stratus, hardly any detail can be seen at the bottom. Also, drizzle was falling from this layer (as can be seen in the slight bit of “haze”). Tops were really coming down, and its likely that no ice was involved. For some reason, this scene, looking across Oro Valley, appeals to me, though it might not be for everyone.  You felt you could almost reach up and grab some of of this Stratus, it was so low.
9:31 AM. The study in gray continues. This heavier, but still light rain, implies that it formed in deeper, mounding tops. Still doubtful that ice was involved, but really don’t know. If I had that Lear jet at my disposal, I could have maybe gone up and been able to tell you. I wonder if crowd funding could get me one?
12:44 PM. Am sensing gray fatigue in the reader, so need to break up the gray with something. This coyote was pooping in the middle of Equestrian Trail Road when I came around a corner. I felt I had to stop and let him finish. Then he just kind of sauntered off, in no hurry. Maybe he was thanking me, too.
2:08 PM. All rain had ended, cloud tops descending below the ice-forming level, and the winds aloft were coming around from the west. Often a cloud street launches from the Tortolita Mountains in these situations as we saw yesterday.
4:45 PM. Eventually the Stratocumulus began to open up and allow those wonderful highlights and shadows on the Catalinas. You can never tired of scenes like this!  Well speak for myself, anyway.
4:46 PM. Nice.
4:46. Zoomed view of nice. Nicer.
5:14 PM. We’ve been so long without low clouds, I have to overdo these lighting shots today.

And then the great sunset of underlit Stratocumulus clouds…

5:46 PM. No words required.

Notice that in the afternoon shots, no virga or ice was seen in any cloud!  What up with that?  Well, of course, if you’ve been coming to this site, you will know its because the cloud tops have descended to something above -10° (14°F) or so where ice begins to form naturally in these  parts on most days.  (There are exceptions, such as when drizzle or rain drops form in clouds; then ice can form almost spontaneously and readily at temperatures higher than -10°C, and that may have happened as yesterday’s storm ended.)

But, in a  further educational (?) diversion, here’s the TUS sounding launched from the U of AZ around 3:30 PM yesterday (goes up at about 1000 feet a minute, btw).

This demonstrates the fairly warm tops of clouds during the afternoon, ones showing no ice. I wanted to show this so I could be right about something after missing the rain forecast by a factor of three…  In spite of all the clouds around, there were no echoes in practically the whole state of Arizona at this time!  Pretty remarkable.

The weather ahead and beyond

Still looks like a regime change is in the works after our dry spell, one that ends around the 20th.  At that time it still appears that winter will take on a more normal aspect; a few dry days followed by rain/snow threats, that is, not weeks of dry spells!


2One of the interesting things about me is that my favorite color has always been gray; even in grammar school when I crayola-ed gray skies instead of a blue one with the sun stuck on it somewhere like the other kids did.

Sutherland Heights rain: 0.97 inches and counting (as of 9:54 AM)! Thunder, too!

What an amazing and “productive”  little rainband that was just after midnight!  And more rain is likely with weaker bands just upwind here at 4 AM.  Could we really approach an inch?  Amazing.  Didn’t seem possible in this small mind that we could amass that much.  For a full regional rain table, go here to the ALERT gauge records.

An even more dense collection of rain totals can be found on the Weather Underground map for the Catalina/Tucson area *click on the precip button when you get there, radar, too).  We seem to have done better than just about anywhere else in the state, with 2.94 inches at Biosphere 2 leading the way (thanks to those “TSTMS” and the rain gushes with them, I am sure.)

Now, after this ends, a long dry spell has to be endured, at least until around the 20th of Jan, at which time we hope the troughs and rain threats at least,  will begin to barge in every few days, namely, and pattern more typical of winter sets in.

Yesterday’s clouds

8:31 AM. Typically lenticular clouds form in the lee of the Catalinas as storms approach. Lenticular clouds are good signs of deteriorating weather ahead since they are usually accompanied by strong, moistening winds aloft.
8:31 AM. Zoomed view of one lurking just beyond the crest of Ms. Mt. Sara Lemmon. The higher clouds were Cirrus (which can have grayness when the sun is low).
10:24 AM. Wasn’t long before this deck of Stratocumulus raced over the sky, adding that feeling that rain is a comin’.
11:32 AM. Some tendency to form the new supplementary cloud feature, termed, “asperatus undulatus” is shown here at the base of the Stratocumulus deck.
1:13 PM. Got excited when ice began to show up, with virga and light rain showers here and there.  Can you see that icy top receding from the Catalinas?  It wasn’t that high and cold, either.
1:14 PM. Nice highlighted view of Biosphere 2, with light rain showers in the background. Whodda guessed Bio2 would get 1.93 inches overnight? Not me!
1:59 PM. Light rain showers began to fall from that Stratocumulus layer, now pocked with buildups (Stratocu castellanus?) as temperatures aloft above cloud top cooled.  The haze is due to rain falling from overhead.  It did not measure.
1:59 PM. Looking upstream and the Stratocumulus deck whose tops were just ascending to the ice-producing level as they approached Catalina from the SSW. That clearing on the horizon maintained throughout this cloud and shower period suggesting it was caused soley by the lifting of the air as it approached the higher terrain of Catalina and the mountains. It was soon to disappear.
3:02 PM. Falling apart.
3:49 PM. Gone.  Yes, once again, the clearing before the storm.  A storm is approaching, 100% chance of rain within 10 h, and yet, the clouds are disappearing!  This is a common here; a dry slot in the moisture field OFTEN precedes storms here.  To some folks it may mislead them into thinking the storm’s a bust.  But not to us CMP’s, who seen this happen over and over again.
5:09 PM. Temperature’s in the low 70s; its getting to be a nicer day by the minute. Where’s that storm?
5:43 PM. Our storm and cold front marches toward us from somewhere over the horizon, though visually you’d never know it.  Wonder if the native Americans knew this odd sequence–probably.

The weather ahead

After the last drops fall today, we’ll suffer through another dry spell and warm up though about the 20th when a major trough passes by.

The End

Oops….  Have cameras ready for a great day of cloud shots once the sun breaks through.

Sun and Altocumulus clouds combine to provide a colorful sunrise and a sunset on the same day! Rain on tap!

“Rain on tap” does not  refer to a microbrew, for those who’ve accidentally stumbled onto this site.

Our nice sunrise and sunset, featuring supercooled1  Altocumulus clouds:

7:22 AM.
7:26 AM.
7:29 AM. Ice crystals trail down from this region of cloud cover toward the north. Was it hers or ours? This Altocu layer was at -15°C (about 4°F), cold enough for some natural ice, but not as prolific as this. The fact that the ice does not trail downward much indicates the crystals in this virga were really small, also suggesting a non-natural event since an aircraft can produce thousands per liter of ice crystals, none of which can grow to very large sizes. Maybe ours?
9:20 AM. Well, what’s a day in Arizona with supercooled Altocumulus without an ice canal caused by an aircraft. So, they were occurring yesterday.  We don’t see them much in the summer because the Altocumulus clouds are warmer.

 

4:36 PM. Our steady diet of Altocumulus yesterday is topped here by a veil of CIrrostratus, all leading one to expect a colorful sunset.
5:52 PM. So pretty again….

 

5:52 PM. Wider view of the same scene.

 

Rain on tap?  Oh, yeah….finally.  One forecaster friend is predicting 0.5 inches!  How nice would that be?  The rain will likely begin toward midnight–check it here from our nice U of AZ Weather Department.

Looking for more rain in AZ after mid-month, toward the 20th.

The End

Cloud patterns excite Catalinans; storms continue to pile up for January

A swatch of Altocumulus perlucidus translucidus (sorry, that’s the way we talk around here) passed over Catalina early yesterday afternoon, each “unit” nearly perfectly evenly spaced with its fellow cloud element creating a brief period of cloud awe for those Catalinans (or is it, “Catalina-ites”?  “Catalinians”?  Who knows, who cares?).  Here it is, in case you work indoors and missed it.  It was truly a fabulous sighting!

1:16 PM.
1:16 PM. Starting to take too many pictures of the same thing!
1:16 PM.
1:16 PM, of course.  So pretty.

The afternoon was marked by a melange1 of middle clouds:

1:52 PM. Altocumulus opacus with a Cirrostratus above.
3:11 PM. Some equestrians on horses (haha) went by the house.  Sometimes we focus too much on just clouds here, and so we offer the reader who visits here an occasional relief from cloud fatigue.
3:12 PM. Those equestrians were being shaded by a Altcumulus perlucidus and by an overcast of Cirrostratus.  If you look real hard, you can see a faint halo.  The Cirrostratus was thickening upwind as an upper level wave approached and was increasing the amount of rising air aloft over us. The Altocumulus clouds also thickened toward sunset.  See below.
5:07 PM. Heavy Altocumulus approached from the SW, keeping the sun from under-lighting the Altocumulus as it went down, so no flaming sunset last night. The Cirrostratus overcast continues. All in all, a fine day for Catalinians!

The weather just ahead

The local TEEVEE met men are, of course, pounding out the good news rain is just ahead for Catalina.  Looks like, oh, 100% chance to CMP (Cloud Maven Person) starting after midnight Tuesday to Wednesday.  How much?

This is a potent, but fast moving trough.  Maybe will have only 2-4 h of rain with the passage of the cold front and its rainband.  But, coming from the sub-tropics, should have a appreciable rain band with it.

I would expect rainrates to reach “moderate” as the heart of the band goes by for a coupla hours, anyway.  Moderate rain is defined by the NWS as 0.1 to 0.3 inches per hour.  So, only two hours of moderate rain should be at LEAST  0.2 inches, and most likely more.

We’re thinking here that there’s a 90% chance of more than 0.15 inches, and a 90% chance of less than 0.70 inches.  So, averaging those two leads to a best estimate in CMP’s opinion of 0.425 inches!  Wow.  Nice.

Now, I will look at the U of AZ nested model and see what it thinks.  Kind of game we play here, seeing how a seat of the pants forecast, made over a coupla minutes, measures up to a computer model with billions if not trillions of calculations:

Cumulative rainfall ending at 3 PM AST Wednesday afternoon. Catalina is in the GREEN, indicating that the Beowulf Supercluster thinks we’ll have over half an inch (Ms Mt. Lemmon, over an inch!) I am so happy!

The weather way ahead

After the nice rain just ahead, we have to get through the week-long dry spell before we move into a new stormy regime.  First, a spaghetti depiction of the ridge after our nice storm:

Valid at 5 PM on the 14th. Huge ridge has stacked up along the West Coast, making it look like the drought will continue ad nauseum.  You’ll be discouraged when the middle of January comes around (though by then, everyone will know this is a straw ridge, will collapse in almost hours from this time from the outputs made in real time then.)

Here’s what’s been exciting for a few days now, and below, from last evening’s global model output:

Let’s see what the actual and very latest model run from IPS Meteostar has for us:

From the 11 PM AST last evening global model output this big boy. Unlike so many prior troughs that were bogus this winter at this time ahead (two weeks), this one has spaghetti support and will be real!!! And, it won’t be the only one!!! I’m shouting again!!!

How much these coming rains can benefit our spring wildflower bloom and spring grasses I don’t know, but I sure hope they can resuscitate what otherwise will be a dismal spring.

Expecting a snow event during the “new regime” that takes over after mid-month,  too.  Be ready!

 

The End

Trace of rain ruffles drought in Catalina! New storm approaches in five days or so followed by a several day dry, warm period followed by more storm threats a few days after that; January beginning to look wetter than December though it wouldn’t take that much rain to exceed Deember’s meager total of just 0.27 inches

Yep, unless you were outside yesterday morning, you probably missed the few drops that fell.   But fall they did, giving us officially a trace of rain for January!  In case you don’t believe me, here is a shot of the incoming shafts of rain.  OK, “veils” of rain.

8:22 AM. Rain reaches the ground from thick Altostratus/Altocumulus clouds.

Now, a historical forecasting criteria note after that paragraphical blog title, a criterion that still holds true:

In the 1950s and 1960s, the Los Angeles forecast office used the 564 decameter height on  500 mb weather maps (those made for about 18,000 feet above sea level)  to delineate where the rain line was for incoming troughs.  North of that, rain fell; south, no rain.
It was remarkable how well that worked.
Don’t know it that height criteria holds here in AZ, probably not, but the 500 wind max seems to be a good discriminator for TUS for rain; under or north of that max seems to be a necessary (though not sufficient) criteria in wintertime.  (That wind max does not hold in Cal; rain often falls south of the 500 jet max; only east of the Sierras and coastal ranges does it hold.)
Lately, as winter gets colder,  the NOAA spaghetti factory has recently lowered the red line heights to 564 dm in their 500 mb spaghetti plots, you can see that in 5 days from last night’s 00Z run, rain is virtually assured in southern Cal using that criterion, and we hope that rain gets here, too.
Check out where red lines are in the plot below.  I’ve helped you to find red lines on this plot by annotating them with an arrow:
Valid at 5 PM AST. See red lines. See red lines move east from California.
But after that trough whooshes by like a Nike logo, in ten days (2nd plot), we’re doomed again to be in the midst of a long warm, dry spell:
Valid on January 14th, at 5 PM AST.

But what about after that next warm, dry spell?  The weather way ahead

 In a less professional comment than the usual ones posted here, reaching beyond the 10 day forecast limit, that domain of the models where things that are forecast beyond ten days often go to hell with just the next model run, these spaghetti plots foretell a collapse of that big fat, storm blockin’ ridge after our next warm, dry spell!  It collapses into a muddle down, oh, I dunno, way down in subtropics somewhere.  Yay!  I can feel your happiness as I write this for you!
That ridge collapse means, first of all, that strong storms will blast Cal with needed flooding (well, big rains, anyway), and its likely that those Cal blastin’ storms will reach into all of Arizona providing a much needed hiatus in our drought, that is, will bring appreciable rains right here into Catalina as well.  You can see if I have made this up by looking at the whole sequence here, keeping an eye on where those red lines are foretold to be.
So, that’s it, that’s my take on the longer term weather pattern:
A Change Gonna Come,” as so eloquently sung by the master, Sam Cooke, when that 500 mb criterion was being used in LA, and apropos here because a change is gonna come, not that long from now.    (Warning:  The historical video scenes with Sam’s heartfelt tune will bring tears I just learned…  Everyone should see it.  Yep, we’ve been through a lot since he sang that song….)
Will keep you up to date every so often if it looks like my take, cribbed from the spaghetti plots is going to be correct in that  drought bustin’ part I’ve described beyond ten days. In the event this “take” goes bad,  it will, of course,  not mentioned again.  May have to fall back on writing about aircraft ice production in supercooled clouds to distract you.
The End