Tuesday, September 27, 2016

Thunderstorms At Sunrise

Yesterday was mostly sprinkle showers and strong east winds, although a few spots in metro may have had a hundredth or two. We had a Trace here, along with quite strong winds. During the afternoon and evening, 3:30 pm MST until after dark, winds gusted intermittently here to at least 35 to 50 mph, with a few small branches down in the yard. I actually feared for the rest of our large desert willow a couple of times.

First thing I saw when I got up and was walking through the dark house was a lightning flash. Before I could get out to get the paper it had started raining. So thunderstorms at sunrise here with about 0.08" of rain so far. Composite radar charts here are for 06:12 am above and 06:47 am below. Activity appears to be increasing to southeast of metero area. Second graphic below shows detected CG flashes for 24-hours ending at 06:00 am - white to purple are flashes during past 3 hours or so.

The ALERT rainfall for 3-hours ending at 6;45 am is shown above - measurable rain already widespread across the metro area, but amounts are light with only a few sites having over a tenth of an inch.

The morning sounding plot (skewT below from SPC) for TWC indicates elevated CAPE from about 800 to 650 mb, with steering flow from the southeast.

Although forecast high today is 86 F for the airport, the morning rains have produced cool temperatures in the upper 50s to low 60s F. Will probably be very hard to realize the temperatures forecast - below is 06 UTC WRF-NAM forecast of surface conditions valid at 02:00 pm this afternoon.

Mike Leuthold cautioned yesterday, in his special WRF Discussion:

All model runs allow full heating tomorrow and as past history has shown, the model does have issues with insufficient clouds so if we wake up to clouds tomorrow, there may be much less activity than predicted. 

The 06Z WRF forecasts did not forecast our sunrise storms, so I have not looked at the details. 

1 comment:

  1. Bob,
    By the way, that was Will who suggested I put in that 'disclaimer'. Smart guy that Will!