Monday, March 20, 2017

Showers Possible Wednesday Night In Metro Area

Models forecast the possiblity of a moisture-starved event on Wednesday night as a rapidly weakening AR affects southern Arizona. The 00 UTC 20 March QPF plumes for TUS are shown above (from the GEFS). The operational GFS (blue) was one of the wettest forecasts at 00 UTC. The GEFS forecasts 100 % POPs for the airport Wednesday night into Thursday morning - current NWS forecast bit more conservative at 40%. Remember that the grid point forecasts used to extrapolate the GEFS to TUS are a fair ways off and all at higher elevations than the airport. For comparison the plumes from about the same lead time for the February 28th "event" are shown down at the bottom.

The 00 UTC WRF-GFS forecast from Atmo for total precipitation through 05:00 pm MST on Thursday (above) avoids the airport. However, the forecast sounding for TUS below is valid at 02:00 am on Thursday and shows some threat of showers or thunder during the night. The 06 UTC runs have become somewhat drier than were the 00 UTC forecasts.

So another iffy situation for us to watch.

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