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

Author: Art Rangno

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