Tracy day; OK sunset, too

BTW, finally got a “submission” in late yesterday about our neat storm after what was deemed a power outage of some type affecting the hosting service yesterday.  After re-reading it, perhaps I had too much time to think about it… Oh, well, onward.

First, from yesterday, a day with occasional sprinkles, dessert:

6:48 PM.  Residual Stratocumulus and Cirrus from our nice storm provide a finishing touch to an unusually cool day.
6:48 PM. Residual Stratocumulus and Altostratus translucidus from a cloudy, unusually cool April day.

 

 

 

 

 

 

 

 

 

 

 

 

The remarkable thing about yesterday, and you might have thought it was fog, was the amount of dust in the air after the rain and after the winds calmed down from those 50-60 mph blasts from yesterday. Well, it was plenty windy in the deserts behind the rainy frontal band and that dust-laden air moved in right after the front went by. At first glance, and since it had rained, I thought it might be fog! But a quick check of my senses and the relative humidity, which needs to be near 100%, showed that it was only around 60%, the measurement that demonstrated it could not POSSIBLY be fog. There you have it. Problem solving for you by C-M.
Here’s an example of that dust:

7:12 AM.  The unusual sight of thick dust below Stratocumulus clouds and only hours after a substantial rain.
7:12 AM. The unusual sight of thick dust below Stratocumulus clouds and only hours after a substantial rain.

With cloud tops yesterday only having to reach to 11,000 feet above sea level to surpass the magical -10 C (14 F) temperature level, hardly much above Ms. Lemmon, ice and virga from these clouds was virtually guaranteed. And, if you were watching, there was plenty, including from those clouds we couldn’t really see so well due to dust, ones that produced those several morning and early afternoon sprinkles (“its not drizzle”, a continuing theme here. Only a meteorological ignoramus would call a fall of isolated drops, “drizzle” (or snow and rain mixed together “sleet”). Perhaps I am too strong here, but it is important to get it right since REAL drizzle and sleet (raindrops that freeze on their way down through a shallow cold layer) tell you important things about the clouds and layering of the air overhead. Here are some of yesterday’s clouds as the dust thinned (both due to mixing upward into a greater depth, and due to clearer air moving in):

9:09 AM.  The dust remains, but the Stratocu is mostly gone.  Twin Peaks still not visible from Catalina.
9:09 AM. The dust remains, but the Stratocu is mostly gone. Twin Peaks still not visible from Catalina.
10:13 AM.  Dust lifts as Cumulus arise on the Catalina Mountains.  Nice view of "Catalina Heights" manufactured home country, too.
10:13 AM. Dust lifts as Cumulus arise on the Catalina Mountains. Nice view of “Catalina Heights” manufactured home country, too, where C-M lives.
12:20 PM.   By mid-day, quite a few of the highest tops of the Cumulus-Stratocumulus complexes had likely surpassed the -10 C level, probably much lower, to -15 C or lower temperatures, and scattered virga and snowshowers were aplenty in the afternoon.
12:20 PM. By mid-day, quite a few of the highest tops of the Cumulus-Stratocumulus complexes had likely surpassed the -10 C level, probably much lower, to -15 C or lower temperatures, and scattered virga and snowshowers were aplenty in the afternoon.
3:20 PM.  By this time cloud tops had descended, weren't so cold, and those Cumulus and Stratocumulus clouds just kind of sat around not doing much but making pretty shadows on the Catalinas.
3:20 PM. By this time cloud tops had descended, weren’t so cold, and those Cumulus and Stratocumulus clouds just kind of sat around not doing much but making pretty shadows on the Catalinas.

By mid-afternoon, most of the deeper clouds with substantial virga were gone. You can see what happened in the mid-afternoon here in the U of AZ time lapse movie (as well as the thinning of the dust haze we had yesterday) here.

 

The weather ahead

No rain has popped now in the mods for some time regarding the passage of a trough on the 17th, just some wind with it, though not anywhere like what we just had. In the drought relief department, it was another great day yesterday for portions of KS and NE as shown in the WSI Intellicast radar-derived precip map:

The 24 h precip totals for the US ending at 5 AM AST this morning.
The 24 h precip totals for the US ending at 5 AM AST this morning.

The End

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.