Definitions

Rain begins to fall in Catalina; more on way!

The obvious often makes a good headline:  “National debt HUGE;  more on way!”

With Simon’s decrepit, but juicy remnants on the way, and swept in our direction due to a little upper trough of the southern Cal and Baja coasts, significant rain is likely here.  The heaviest reported amounts from the USGS and the Pima County ALERT sites (as of 4 AM) are already a little over an inch in the Green Valley area and near Bisbee.  Likely more has fallen in the data sparse SW part of AZ.  Will have to depend of radar-derived amounts there, but some of those will surely be over an inch as well.

Oddly, the Yuma radar doesn’t see much to the east of them, which is quite incorrect, but the PHX radar does see something akin to what was predicted the evening before last;  a narrow band of heavy rain starting near the border near the Organ Pipe Cactus NM.

Overdoing the radar discussion but continuing anyway, the PHX radar is too far away to really see what fell at the ground down there by the SW border, but it did have that band of heavier rain shown in their storm total loop near Organ Pipe.

Our own TUS radar is also too far away to catch what’s going on that far to the west of us.  However, it does show several hot rain accumulation spots already over an inch at of 4 AM AST to the SE-SW of us, validated by those larger totals around Bisbee and Green Valley mentioned above.

Radar-derived rain totals through 4 AM AST October 8th. Yellow areas denote those where the radar believes more than an inch has already fallen.
Radar-derived rain totals through 4 AM AST October 8th. Yellow areas denote those where the radar believes more than an inch has already fallen.

Today

Now here’s the excitement plan for today:  Check this out from OUR very own University of Washington Huskies’ Weather Department, one of the highest ranked publicly-funded universities, not at all like Stanford U. which gets huge amounts of funding from big billionaires:

A forecast of the locations of curly air (red areas) at 5 PM AST today.
A forecast of the locations of curly air (red areas) at 5 PM AST today.  The model run was based on global data taken at 5 PM AST last evening.

 

Red curly air, always in low pressure troughs, can organize storms.  Looking at this, one would expect that as the red curly air moves toward Arizona in the trough that was off southern Cal but passes over us tonight, that storms will get organized and move through our area later today as it approaches!  Because they’re organized, one tends to think,  if its me, that there will be a nice line of thunder rain, and the rain duration would be several hours, heaviest at first, then tapering off to steady rain that gradually decreases, much  like in our winter cold fronts.

The use of “curly” here, BTW,  means those locations aloft where the air has relatively high vorticity, or rotation, as in around a center, as in the inside of a low; check out the “red curly air” in that low south of the Aleutians on this map).   The approach and passage of “red curly air” (as it is shown in this color scheme) over you is associated with upgliding air motions that assist in the formation of large cloud shields; helps organize rainbands.  So, a depiction like this, showing that southern Cal trough passing over us, combined with all the tropical air that has come into the State ahead of it during the past 24, portends some heavy rains in the State today with the cores of the heaviest cells.  That’s, of course, what the models are anticipating, too, though going “blind” at this point, haven’t checked ’em, which is kind of silly.  OK, checking now as a rational weatherperson would do….  OK, here goes:

Accumulated rain between now and 4 PM AST tomorrow afternoon.
Accumulated rain between now and 4 PM AST tomorrow afternoon from the 11 PM AST U of AZ Beowulf Cluster model run by the U of AZ.  Now this is pretty exciting since it shows that twixt later today and tomorrow that something around an inch will fall here, and an inch and a half to two in the Catalina Mountains!

 Yesterday’s clouds

Not a really exciting day, though a great sunrise due to Altocumulus, just more Altostratus and Altocumulus clouds as we had the day before.   By mid-afternoon, some exciting towering Cu began to appear over the Rincon Mountains and to over the Santa Rita Mountains indicating the lower level moistening of the air approaching us.

6:15 AM. Under lit Altocumulus perlucidus with a higher CIrrostratus layer above.
6:15 AM. Under lit Altocumulus with a higher vale of Cirrostratus above.  TUS sounding suggests the Ac was about 19,000 feet above the ground as seen from Catalina.  BTW, during our (U of WA) research, we found that Altocumulus clouds,  via pilot reports obtained directly from the local ATC Center1 and in our own flights were often higher than usually thought of as “middle level” clouds).

 

7:49 AM. More Altocumulus with Cs above.
7:49 AM. Band of Altocumulus with Cs above.  No virga here.
11:40 AM. Virga to the west from an Altocumulus castellanus buildup, but in this case some of the virga was reaching the ground as a sprinkle-not-drizzle, a great sight because that showed how moist the air was all the way to the ground.
11:40 AM. Virga to the west from an Altocumulus castellanus buildup, but in this case some of the virga was reaching the ground as a sprinkle-not-drizzle, a great sight because that showed how moist the air was all the way to the ground.
4:36 PM. Dense Altocumulus clouds with considerable virga spread over the sky late yesterday. By this time, sounding data indicated that they had lowered from 19,000 feet above the ground to 13,000 feet.
4:36 PM. Dense Altocumulus clouds with considerable virga spread over the sky late yesterday. By this time, sounding data indicated that they had lowered from 19,000 feet above the ground to 13,000 feet.

 

Hoping to report at least half an inch by this time tomorrow morning.

The End.

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1 In those days of the 1980s and 1990s, it was possible to call the ATC Center in Auburn, WA, and ask if they had an aircraft taking off from or landing at  Sea-Tac, and get the height of an Altocumulus layer when it was intercepted by that aircraft!  Imagine, being able to call some guy working the planes and getting that info (for our research on aircraft-produced ice)?  It seems totally amazing now.