Thursday, July 01, 2021

Storms On Last Day Of June



Showers and thunderstorms did come off the Catalinas into the metro area fairly early yesterday - above image from 1:58 pm MST. Image below shows some residual cloudiness over the Catalinas a bit before 7:00 am this morning.


Plot above is of detected CG flashes (from Atmo and Vaisala) for 24-hours ending at midnight last night. there was considerable storm activity over much of Arizona, but with a very large donut hole centered on Maricopa County and almost no activity over Cochise County.

Precipitation amounts from ALERT (above north and below south) - note fairly large number of sites reported more than half an inch accumulations. While we had rain here, amount in gauge this morning was only 0.09" - making June precipitation total here 0.11".


The 500 mb chart this morning (above) is very chaotic and the winds are very light over the Southwest and northern Mexico. Note that heights are about 30 m too low at Chihuahua, Mexico, as they have been for many months. Very little in the way of forcing for vertical motion - so evolution of storms today will depend upon local heating and storm outflows. 

The TWC sounding (below) has increased moisture (PW of 1.57"), but a bit cooler temperatures below 500 mb. CAPE has also decreased relative to yesterday. These changes are reflected in the 12 UTC WRF-RR forecast of rainfall through noon tomorrow (second below), which indicates light, scattered amounts over eastern Pima County this afternoon and evening.

 




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