The many rains, maybe floods, to come

The last time we met I had fallen in love with a weather map, one I thought I had waited for all my life.  Today, I have to inform you that I have a new love, a map that came out yesterday around mid-day.  I love this new map so much!

I know this news is shocking to you, maybe your even disappointed in me since I was so sure before, but let us put this development in the perspective of the legendary fickleness of men, as demonstrated below:

Cropped Ed and Robin:Loretta
Fluctuating love. Love is dynamic, ever changing, here seen in Robin becoming Loretta. But we know how truly “Ed” did love “Robin” at one time, enough to paint a billboard, a sign of the truest love. Ed was careful enough to post the exact date that he loved Robin.

Below, my new love:

2015020818_WST_GFS_500_HGT_WINDS_300
Valid on date night, Friday, February 20th, at 11 PM AST.

Of course, I truly believed I loved that prior map more than anything, but then this one  came in, so full of a potentially wonderful, if stormy,  relationship.   See how the powerful flow curls so gently southeastward in the eastern Pacific off Baja1!   It would then be moving over the warmer-than-normal waters of the “California Niño”2 still in progress, gaining warmth and a wet personality, as she goes.

See, too,  how the strongest winds in her are not yet at the bottom of the curl, but are still behind her to the west, indicating that she will migrate that bit farther southward over still warmer waters before she arrives to meet us here in Catalina.

Look, too,  how a high pressure, that entity that blocks storms and causes pain and drought,  has been recused to the Gulf of Alaska, allowing this regal,  “queen of storms”,  to flood in to us, arms open in a welcoming grasp!  I am so happy today!

How much rain can we expect from a loveable pattern like this?

Oh, a few inches in the mountains, maybe an inch or two here, too.  A “broad” trough like this would take a couple of days to travel through, too, so the duration of storminess will be exceptional.   More on this situation farther below….

In the meantime, just ahead, a true rain dance

The computer models have been equally fickle in what’s more immediately ahead, first having some for a couple of days, then taking it away, and now those rains are back in the Feb 12-14th time slot.  A small, dry  system passes over us, produces a good Santa Ana wind situation in southern Cal, gets stuck southwest of us, wobbling , spinning dizzily around down over the waters of the Gulf of Cal and eastern Pac,  and from there then comes back over us again (!) with a treasure of clouds and water for our wildflowers and other biota.  Here’s the sequence, which includes a famous weather dance, called, “The Fujiwhara”, you remember, “EEE-yah, round and around and up and down….”, in this case, a REAL rain dance for Arizona!  One of the “partners” in this dance is a sensuous, humid and warm, no,  “hot” low twirled north out of the deep Tropics.  See below, with modifications, from IPS MeteoStar:

Valid on Wednesday, 11 PM AST.
Valid on Wednesday, 11 PM AST.
Valid at
Valid at 11 AM, February 14th, Valentine’s Day.  How appropriate to have dancing lows on that day.

The rain from this rain dance arrives here overnight on the 14th 15th.  Amounts are likely to be between 0.25 and 0.75 inches, ending on the evening of the 16th.  Snow levels will be real high again due to the sensuous nature of this storm, much of its moisture having come all the way from off Acapulco.

After a little clearing spell, the beautiful one comes in to give Arizona a real water treat!  See below these predictions based on the 5 PM AST global data ingestion:

Valid at 5 AM on February 19th.  The colored regions are those in which the model has calculated amounts for the prior 12 h.
Valid at 5 AM on Thursday, February 19th. The colored regions are those in which the model has calculated amounts for the prior 12 h.  This will be a cold blow, with normal snow levels, not above the top of Mt. Lemmon as we saw at the end of January.
Valid 12 h later, 5 PM AST, Thursday, Feb. 19th.  Wow!
Valid 12 h later, 5 PM AST, Thursday, Feb. 19th. Wow!

 

 

5 AM AST, Friday Feb. 20th, even more substantial rain has fallen here!
5 AM AST, Friday Feb. 20th, even more substantial rain has fallen here!

 

Its still been raining substantially by 5 PM ASTon the 20th!
Its still been raining substantially in the 12 h prior to 5 PM AST on the 20th!  Washes would be flowing, for sure.

Clouds discussion:  on the formation of Cirrus; an example:

4:09 PM.
4:04 PM, Feb. 6th. Patch of Cirrus spissatus with a flocculent mass has suddenly appeared in the midst of it, one that could be taken as a much lower cloud since it looks initially like Altocumulus.
4:09 PM.
4:09 PM.
formed flocculent mass, one that could be taken as a much lower cloud since it looks initially like Altocumulus.
4:28 PM.  Now fading over the horizon, that original flocculent mass has all the attributes of CIrrus, with crystals falling out to produce a tail leaning back due to lower wind speeds below the level where it formed.

The End,  quite enough really!

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1Of course, we men are inexorably drawn to gentle curves; it can’t be helped.  There’s no way around them.

2Not to be confused with “The New Niño” (“Region 3.4”) or the “Classic Niño” (the original one off Peru) both of which have died out for the most part. The California Niño is when there are warmer than normal waters off, you guessed, the Californias! (There are a lot of Niñoes in weather, btw.)

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.