Wednesday, January 20, 2021

First Precip Event Of 2021

Another great sunrise here in Tucson.  Our first precipitation event of 2021 is imminent and much anticipated, since there has only been 0.01" of rain here at house since December 11th.

Happened to catch a view of a BurlingtonNorthernSantaFe train clipping through Flagstaff this morning (bottom).

Time series of TUS observations above shows dewpoint temperature rising slowly, but steadily since the strange blip yesterday (reasons for that not clear). The east-southeast winds have been quite gusty all night at the airport, with a max of 40 mph a bit before midnight.

Yuma has had a thunderstorm during the night and now has about 0.40" of rainfall. Plot of detected CG flashes for about the last 6 hours (below, from Atmo and Vaisala) shows quite a bit of activity north end GoC into southwest Arizona, and also with the closed low west of Baja.

The 500 mb low (above) has moved about as forecast yesterday and is currently well southwest of San Diego. The 1430 UTC GeoColor image below (from CIRA at Colorado State) shows considerable middle and high clouds (gray shades) from the low across Baja and into western Arizona and California deserts. The blue shades are low clouds and the orange areas are the city lights of Arizona and California.

Model forecasts from the GEFS (above) continue to call for a significant rain event to begin at the airport later today and extend into tomorrow morning. Forecast amounts today are a bit lower than they were yesterday. The morning forecast for the airport - below from NWS - indicates 100 percent POPS, as well as heavy rain amounts, tonight into tomorrow morning.

Second below is forecast rain amounts from the 12 UTC WRF-RR run this morning - WRF amounts are down by around an inch relative to yesterday. Note that the WRF picks up the ominous Tucson donut hole, probably due to downslope, low-level winds. 

Regardless, I look forward to seeing what the gauge out in our yard catches!

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