Wednesday, July 28, 2021

Scattered Thunderstorms Yesterday



Wispy clouds over the Catalinas before sunrise this morning.

There was considerable thunderstorm activity over southeast Arizona yesterday afternoon and evening - as per above plot of detected CG flashes for 24 hours ending at 7:53 UTC (from Atmo and Vaisala).

Precipitation reports from the ALERT network (above and below) show heaviest rain amounts along I-10 from downtown off toward Tortolita, and in the the Catalinas. Reports from observations: TUS 1.29" along with gusts to 54 mph; Atmo 0.35"; DM 0.03"; and here at house 0.01". Looks like areal coverage across the network was a bit over 50%.


Plot of TPW this morning at 6:00 am MST (above) shows most moist air now pushed out to far southwestern corner of Arizona. The morning sounding from TWC/TUS (below) is down to PW of 1.25 inches, with Td decreasing rapidly up to 700 mb. No matter how I estimate the evolution of this sounding during the day, I come up with a double BL structure, that has at most a sliver of CAPE - so probably much less activity than yesterday.


At 300 mb this morning the low near Brownsville, Texas, appears to be elongating east-to-west. Current forecasts now take this feature into New Mexico this weekend, and weaken it markedly.

Finally, a look at the 06 UTC WRF-GFS forecast of precipitation through midnight tonight (below). The model forecasts only a bit of rainfall over the Rincons, which fits with the fairly pathetic morning sounding shown above.


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