Bit Of Rain To Start September

Category 5 hurricane Dorian (above at 13 UTC this morning) is nearly stationary over northern Bahamas. The NHC forecasts Dorian to move slowly toward Florida and then move northward just offshore. 

There were more widespread showers and thunderstorms over the metro yesterday afternoon, but with generally light rainfall amounts (ALERT plot of 24-hour rainfall above ending at 7:00 am MST). There were only 7 sites recording over half an inch of rain - there was a gauge near Picture Rocks with more than an inch. Here at house we had 0.10" to start the month. There was no thunder here just light showers after dark; DM and TUS both reported thunderstorms but only 0.02".

Plot of detected CG flashes above (from Atmo and Vaisala) is for 24-hours ending at a bit after midnight last night, showing fairly widespread thunderstorm activity across much of the state. Severe thunderstorm reports (all strong winds, shown below from SPC) were numerous for Arizona. Nearest severe storms to Tucson metro were up in Mesa and near Ajo (note black indicates gusts of 65 mph and higher).

The 500 mb pattern this morning (chart above from SPC) shows the anticyclone elongated west-to-east with center somewhere over southern Colorado. The sounding plot for TWC at 12 UTC this morning (below, also from SPC) shows a sort-of onion profile with easterly winds through most of troposphere - the surface analyzed CAPE is a considerable over-estimate for this afternoon. 

The forecast skew-T (above from 06 UTC WRF-GFS)  shows a well-mixed surface BL reaching only 800 mb, with an old BL above. Not a very favorable sounding for storms our area, but storms from mountains may move into parts of the metro. The composite radar forecast from same model run keeps strong storms from south to west of the metro area.

After today, a slow drying continues through much of the week - forecast below of PW (from same model run and valid at midnight of the 4rth) indicates values dropping to less than an inch over southeastern Arizona. If this verifies, much of the week will have little activity this part of state.