Marine Weather and Tide Forecast for South Tucson, AZ

DISCUSSION
The large scale picture has the upper low currently centered in southern Sonora Mexico moving east of the region on Sunday, with shortwave ridging across the desert southwest Monday through Wednesday. Baggy troughiness slides across the area Thursday and Friday, followed by ridging next weekend.

The latest satellite/radar imagery shows overcast skies across the eastern half of southeast Arizona, with scattered showers east of Tucson. Expect periods of valley rain and mountain snow to develop this afternoon/early evening and then persist through early Sunday morning as the upper low moves northeast across Sonora Mexico. The highest PoPs through this period will be east of a Safford to Tucson to Nogales line. In addition, a shortwave trough approaching from the north/northwest will bring colder air aloft and increased forcing/instability, resulting in a slight chance of thunder this afternoon and evening across the eastern half of southeast Arizona.
Snow levels currently around 8000 feet will lower to 7000 feet by midnight tonight and then to around 5500 feet early Sunday morning.
A Winter Weather Advisory remains in effect above 7000 feet through 5 AM MST Sunday for the Catalina Mountains, Mt.Graham, the White Mountains and the Chiricahua Mountains. For more information on the Winter Weather Advisory refer to the PHXWSWTWC product. The precipitation will end from west to east early Sunday morning across southeast Arizona, shifting completely east of the forecast area into New Mexico by the late morning hours on Sunday. High temperatures through Sunday will be 6 to 10 degrees below normal.

Dry conditions areawide return on Monday and continue through at least Wednesday of next week as shortwave ridging works into the area from the west. High temperatures will still be 3-6 degrees below normal on Monday, warming to around normal on Tuesday and then 2-4 degrees above normal Wednesday. Breezy east winds of 10-20 mph are expected Monday in those locations prone to easterly winds.

Model differences exist in the Thursday and Friday time frame on the extent of troughiness across the area. Cluster Analysis highlights these differences and given this uncertainty a couple of degrees of cooling and slight chance PoPs (10-20 percent) seem reasonable attm.
Ridging returns across the desert southwest next weekend.

AVIATION
Valid through 26/00Z.
BKN-OVC clouds at 4K-8K ft AGL east of Sells, with FEW-SCT clouds at 6k-10k ft AGL west of Sells thru 25/12Z. Aft 25/12Z, clearing skies from west to east, with FEW-SCT clouds at 6K-10K ft AGL and SCT clouds AOA 25k ft AGL after 25/18Z. Periods of -SHRA/SHRA and ISOLD -TSRA thru 25/12Z, with the precipitation ending by 25/15Z. MVFR conditions possible during periods of SHRA activity. SFC wind thru 25/03Z, generally SWLY thru NWLY at 8-14 kts, between 25/03Z-25/18Z, variable wind at 10 kts or less, and aft 25/18Z WLY/NWLY at 7-12 kts. The exception will be at KALK, with SWLY SFC wind at 10-20 kts between 25/01Z and 25/14Z. Aviation discussion not updated for TAF amendments.

FIRE WEATHER
An area of low pressure will bring valley rain and mountain snow into early Sunday morning, along with below normal temperatures and high humidity levels. Dry and warmer conditions return next week, with highs near seasonal averages. 20-foot winds will be less than 15 mph through Sunday, with gusty easterly winds at 10-20 mph on Monday. 20-foot winds will generally be less than 15 mph Tuesday through Friday of next week. Min RH levels will lower into the 18-28 percent range by Wednesday of next week.

TWC WATCHES/WARNINGS/ADVISORIES
Winter Weather Advisory until 5 AM MST Sunday for AZZ510>512-514.