Monday, August 19, 2013

Stagnant Pattern Persists


Storms mostly avoided both the Tucson and Phoenix metro areas yesterday. The early WRF from Atmo forecast the broad trends quite well with storm activity mostly to west and scant rainfall at low elevations in eastern Pima County. Above is TUS radar at 3 pm MST yesterday afternoon (the 18th) indicating distant storms in all directions. Below shows CG lightning strikes for 24-hours ending at 5 am this morning. Southeasten Arizona had storms mostly at higher elevations, with much more activity to the west. Heaviest storm activity occurred from the mountains of western Arizona, across the Las Vegas area, and into California. Unusual early morning thunderstorms today in the California Sierra Nevada Mountains. There was a Trace of rain here at house yesterday when outflow from a small cell to the west blew in some rain drops. There were 16 ALERT sites with light rain - mostly at high elevations and around edges of network.

Biggest weather story is the run of 100+F days that now exceeds a week, with the highs last three days (108F, 108F, and 107F) tying or breaking the daily records for Tucson.



The early WRF-NAM forecasts rainfall through midnight (above) tonight to be similar to what occurred yesterday. The GFS version has much less activity in its forecast. Things are stagnant and yesterday's discussion can just be carried over for today.

The global models continue to forecast a tropical storm in the eastern Pacific around next weekend - below is from last evening's ECMWF valid at 5 pm next Saturday the 24th. Most of the GFS ensemble members also forecast this storm to develop, although its position is forecast a bit further west. Regardless, if all this comes about, then there would be a chance for a return of low-level mT air to southern Arizona, after an unduly  long abscence


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