Chance Of Showers As December Begins

View of clear skies over the Catalinas at 7:30 am MST this morning.

Complicated situation this morning. The morning sounding for TWC/TUS (above) is dry and stable, with moderate westerly winds aloft. At 500 mb several, weak short waves will be crossing Arizona during next couple of days. The GFS forecast below shows 500 mb analysis valid at 06 UTC on December 1st.

The 06 UTC GEFS plumes for QPF at the airport (above) indicate several periods with chances for showers, with best chances centered on Friday. Current NWS graphic (below) calls for showers tonight. The morning forecast for the airport (second below) has 40 percent POPs for tonight and then again Thursday night and Friday.

The 12 UTC WRF-RR forecast from Atmo (above) shows dry conditions for all of southwestern Arizona through noon tomorrow - quite different than NWS forecast (second above). The 09 UTC WRF-HRRR forecast for precipitation through 2:00 am on Saturday the second of December (below) indicates light amounts across portions of eastern Pima County. Will be interesting to watch how all this evolves, as we head toward first weekend of December.