Saturday, December 12, 2015

Last Night's Weather Event

First, I should say that the GFS plume forecasts from the ensembles did an excellent job for this particular event - beginning back at the start of the week. For past several days 100% of the ensemble members forecast measurable rainfall at the airport (TUS), and yesterday's WRF forecasts for last night were also very good - last several posts illustrate all this. The official NWS forecast for TUS POPs went up to 80% yesterday afternoon. However, the model forecasts were a bit low on the amounts of precipitation forecast. 

The airport measured 0.39"; DM had 0.59"; Atmo had 0.38"; and here at house we had 0.34". The amount here at house is a bit more than fell during all of November. Across the ALERT network 100% of the sites had measurable precipitation, although low amounts at high elevations indicate that the rain changed very quickly over to snow - amounts unknown right now, but should have been fairly substantial. There were 33 sites that measured over 0.50" and max rain amount was 1.18" at Italian Trap on Redington Pass. The metro West and East sectors of the network are shown above and below for amounts ending at 6:00 am MST this morning.

Other notable observations include: thunderstorms, wind and snow. Graphics above and below use data from Vaisala - above from Atmo shows detected CG flashes during the night over southeast Arizona. There were quite a few flashes in eastern Pima County and in southeastern Cochise County. Below from shows CG flash density for 24-hours ending at 6:00 am this morning. Douglas did report a thunderstorm early this morning. Yesterday afternoon David Blanchard reported thunder-snow in the Flagstaff area.

As for winds here in southeast Arizona, gusts over 40 mph were recorded at Sierra Vista, Pioneer Airfield (G to 48), and at the RAWS stations at Mt. Hopkins and Guthrie. Up north Winslow came in with gusts to 53 mph, Here in the southeast there was a considerable period of early morning snowfall in Sierra Vista and at Pioneer Airfield (both sites just over 4700 ft MSL).

So a wide diversity of weather with this system, which will be quickly followed by another possible event on Monday. Could this be the start of our El Nino winter?

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