Another Rain Event For September

Yesterday evening brought a widespread (nearly 100% coverage) rain event to southeast Arizona. Here at house we had morning thunder with a very light shower (this early event was heavier to east and northeast). Then about 6 pm MST the rain began again as thick anvil overspread the area from convection to the southwest. We had several hours of anvil rain, with some embedded convection - heard one rumble of thunder here at house. We ended up with 0.38". All of the ALERT gauges measured rainfall, with 20 sites having more than half an inch, and 2 sites with more than an inch. Saw that Yuma had a thunderstorm in the afternoon with gusts to 49 mph, visibility down to 1/2 a mile, and 0.10" of rain. There were also a number of reports of 1 inch diameter hail around Flagstaff - so storms and rain over much of the entire state. A continuing and nice start to Fall.

This morning storms are active over southern California and the lower Colorado River Basin, as the 500 mb cutoff begins to move ashore from the Pacific (see reional radar from NCAR above). The eastern Pacific PW (see image below) product indicates that the cutoff has tapped moisture inflow from low latitudes out around 120 W.

This morning's Tucson sounding is quite interesting. Even though there is a fairly deep layer of cool air at the surface, there appears to be CAPE in the old BL above. Middle-level temperatures remain cool with -10C at 500 mb, and PW has inched up a bit and is over 30 mm. Winds aloft are a bit more westerly today, with a strong 70 kt jet over southern Arizona. The hodograph (upper right) indicates a nearly linear shear vector, from the southwest, with a magnitude of nearly 60 kts - quite impressive.

The NAM and the Atmo early WRF-GFS both forecast widespread storms and rain again for Arizona. The WRF-GFS total rainfall through midnight tonight is shown above. The WRF has forecast heaviest rains in south-central Arizona. The new NAM forecast keeps heavier storms out in the western part of the state. Note that the WRF-GFS forecast early convection that was ot there at sunrise, so I'll take a look at the morning runs, since the entire forecast may have been affected. Regardless, looks like another interesting weather day.