Clouds go round and round with a sprinkle-rain landing close by last night

One of the things I like to do when I am wrong, yesterday having predicted a trace to a few hundredths of rain last night from that disturbance going by to the south, is to spend a LOT of time talking about how close I was.

Its true the zuperkomputer, the Beowulf Cluster, at our U of AZ Weather Department, did NOT predict rain here at all, but it did not have the sprinkles as close as they came to us, either!  Exulting here that bit.  Going to look on “trace detector” (car parked in dust and sun outside) now, just in case there is a drop image somewhere.  Will report back on that later.  Stand by.

Also, you should be looking around for drop images in the dust on stuff, too.  If you’re going to be a “trace king”, you have to look hard in AZ so you don’t miss anything.  A lot of reported traces shows that you are indeed a true CMJ!  A trace of rain is incredibly important to microbes; a drop is like the ocean to them.  Think about it the next time it sprinkles on you.

Below, the evidence of how close we came to one drop of sprinkle-rain last night (remember, it would NOT have been “drizzle” had it occurred; drizzle falls from LOW-based clouds that hug mountains, not from Altostratus clouds such as we had):

Sprinkle from Altostratus deck just to SE of Catalina at 2: 40 AM AST today.  Will be looking on car parked outside (trace detector) just in case a drop fell here.
Sprinkle from Altostratus deck just to SE of Catalina at 1: 40 AM AST last night.


Arrow added into the same image above in case you did not see how close that sprinkle came to us the first time.
Arrow added into the SAME image as the first one in case you did not see how close that sprinkle came to us when you first looked at it.  I really want you to know. I feel its quite important.

Loop of clouds and sprinkle rain going round and round here.

As a CMJ (Cloud Maven Junior), you would have seen and logged the low hanging virga extruding downward in one spot from that thick layer of Altostratus at sunset, that As band that also had something that looked a bit like an anvil extruding from it.  Here is the “documentation” for these claims:

5:16 PM.  Heavy Altostratus with scary anvil-like feature and VIRGA just to SW of Catalina about 50 miles.
5:16 PM. Heavy Altostratus with scary anvil-like feature and VIRGA just to SW of Catalina about 50 miles.

Finally, this sunset shot of the same band 30 minutes later, making the same points as above again to better imprint them on you:

5:36 PM.  Same band of Altostratus with anvil-like feature and virga (to right) at sunset.
5:36 PM. Same band of Altostratus with anvil-like feature and virga (to right) at sunset.

The above has been, in effect, a burst of altruism.  Let’s say I am hiking on the trails, I’ve missed a forecast, and you’re heading in my direction.  At about 100 yards you will want to exit right or left and bushwhack it for awhile until I have passed to avoid an extended “in hindsight…”, hike-delaying conversation in which you have no real interest. Its gonna happen.  It would be kinda like this blog-blab right now….

Now, feeling better, some REALLY pretty Cirrus uncinus from last evening:

5:17 PM.  Pretty Cirrus uncinus along with some other varieties/species.
5:17 PM. Pretty Cirrus uncinus along with some other varieties/species.


Now that I have gotten yesterday’s burr-under-my-saddle dispensed with, can ahead now, not stuck anymore, clouds moving away, can have new thoughts…

Will look at model outputs and see which one has the most rain/snow in it for us on the 11th-12-13th, with that Arctic blast, and think about the onset of that new “zonal” pattern after that, that pattern that will mild us1 quite a bit after the Arctic blast.  Beginning look at mods now….

WHAT?!!!  Its back!   That “trough bowl” collecting area for storms in AZ and the Southwest, after only short respite from cold storms.  What happened to theThis is remarkable, check this prog for January 22nd at 5 PM AST.  If it looks familiar, its almost the same as the map for yesterday afternoon, the 7th, but 15 days later!  I repeat myself in the gif for emphasis now that I see I have repeated myself.

Valid for 5 PM AST, January 22nd.
Valid for 5 PM AST, January 22nd.

What’s the gut check here?  “Spaghetti”, which seems appropriate for a “gut check.”  Yesterday we saw that the NOAA spaghetti plots varied wildly 15 days out, making ANY model forecast that popped beyond about a week out pretty unreliable.

But what aspect of the atmosphere do we know about that makes a prog 14 days out that looks like weather we had yesterday look that bit more credible:  the mantra, “the atmosphere remembers.”

Persistence, a forecast based on weather you’ve already had for the past week or three, and projecting it into the future is one of our more reliable forecasting techniques.  Sounds silly, but its true.  The pattern eventually changes, but its hard to catch that tipping point when it does.  Yesterday, the mods had that pattern change and it was some support for that in the NOAA spaghetti plots.  That support has weakened, though not gone, seen here if you dare.

——————Module on conversational meteorology——–making the past the future

Imagine, that on January 1st last, a neighbor asked you, knowing that you were a cloud maven junior, maybe have Asberger’s Syndrome, and in your case, focus on itty-bitty weather details and data:

“What kind of weather do you think we’ll have in January?”  Without divulging details of your forecasting methodology, hindsight, and then trying to remember, if you could, what the weather had been like in the two weeks leading your neighbor’s question, i.e., the time when the new flow pattern began here, you could have furrowed your brow and said, with at least feigned authority:

“I see below normal temperatures, perhaps much below, with a good chance of above normal precip. “‘Hey'”, and then going a bit too far, you might have ventured into, “…and I think there’s a good chance of a real snow here in Catalina this month with all that cold air we’ll have.”

Today, with a severe cold spell ahead, you would be the forecasting guru of the block, icon of the next block party,  and all you had to do was remember, which can be hard sometimes.

In weather, it really is true:  the past is often the future.

—————-End of conversational meteorology module———————————————————–

So what to think?

Its not a bad idea to hedge your forecast longer term forecast with “persistence”; continuing below normal temperatures, maybe not as severely cold as what’s immediately ahead on the 12-14th, precip on the 11th.  Amounts, due to the speed of this thing, still 0.10 inches at the bottom, but I’d reduce the max potential to 0.40 from 0.50 inches, median then 0.30, about the same as the last prediction.   The flow pattern with this will be like the last front on the 31st, and so we’ll do better than most of areas around us in amount because the clouds will bank up against our side of the Catalinas more than elsewhere.  Still expecting rain to change to snow at the end of the FROPA on Friday morning, the 11th, but amounts likely to be an inch or less now.  Dang, again.

Because it will be so cold aloft, and here, and there are minor disturbances that blow on through for the two days after the 11th, a passing flurry is likely (that from, as you KNOW, from “heavily glaciated clouds”, at least at times.

A bit much  today, so will gift you by quitting here.

The end.


1Using “mild” as a verb here; might be first time ever such use–William Safire, language-maven, where are you now that we need you?  Remember when we made fun of Alexander Haig, the Nixon admin Chief of Staff, about the way he used nouns as verbs, i.e.,  “gifted him.”  Now he can be considered a language pioneer since we hear that usage all the time.  Don’t forget to use “mild” as a verb today at least once:  “the weather pattern is going to mild us for awhile before the big freeze hits.”  That would be great!  Thanks.

By Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa.