Friday, December 23, 2016
Yesterday's Event Brought Heavy Thunderstorms To Northwest Side
A strong line of thunderstorms plowed into the northwest metro and west side of the Catalinas around 01:00 pm MST yesterday afternoon. The storms were visually spectacular and also dropped rain amounts of a half inch and more in less than an hour. Although there seem to be continuing problems with the ALERT network, the plot below (24-hour rainfall ending at 07:00 am this morning) gives a feel for the line of storms in the reports of more than half an inch from I-10 north-northeastward to Oracle. Here at house the entire 36-hour event produced only 0.32".
I may try to do a separate post on the thunderstorms later today.
The event for tomorrow is rapidly approaching - Christmas Eve evening will not be the time to be touring the Winterhaven festival of lights. The GEFS plumes for rainfall at the airport are shown above - note that the operational run at 06 UTC was the wettest version of the model.
The SREF plumes from SPC are shown below, and they provide a bit higher time resolution wrt the possiblities of onset and ending times. The plot is scaled at 0.10" and only two of the members forecast a bit over half an inch, with the average being drier than the GEFS forecasts.
The hourly grid point forecasts for the airport (above) indicate an abrupt frontal passage during the early afternoon, with temperatures dropping into the 40s, along with strong winds, during the late afternoon. The 10-m wind forecast below is from the 06 UTC WRF-GFS, showing very strong per-frontal winds, as well as the abrupt wind shift line.
Last minute errands tomorrow would go most comfortably if done in the morning and midday hours, before things deteriorate into a nasty afternoon.
With the snow level dropping very low, there could be some nice opportunities for "snow in the desert" photography early on Christmas morning.
Posted by Bob Maddox at 6:23 AM