Catalina Foothills, AZ Weather

Synopsis

Dry conditions are expected across southeast Arizona into Thursday. Showers and thunderstorms will return to the region late Thursday through the weekend. Afternoon high temperatures will be near normal today, warming to a couple of degrees above normal Tuesday through Thursday, then lowering back below normal Friday through the weekend.

Discussion

Near zonal flow currently in place across Arizona, with shortwave ridging just upstream. PW values were in the 0.25- 0.40 inch range across the forecast area, with dewpoints in the upper 30s to lower 40s. High cirrus level clouds were noted across much of southeast Arizona, but will shift northeast of the area by the late morning hours. Otherwise, high pressure aloft will build in across the desert southwest through Wednesday, with the upper flow pattern turning increasingly southwest toward midweek. This will result in dry conditions and warmer temperatures across southeast Arizona into Thursday.

Late this week into the upcoming weekend the models show an active pattern, with west coast troughing and southern stream moisture moving into the southern half of the west coast and across the Intermountain West. There continues to be timing/track differences, with the ECMWF now focusing more on the northern half of Arizona into the Great Basin, while the GFS is focused further south across the desert southwest. The GFS/ECMWF solutions have flipped over the last 24 hours. Cluster Analysis is in good agreement with the west coast troughing late this week/weekend, although most solutions keep the largest height anomalies to our north/northwest. The EMC GEFS plumes across southeast Arizona have mean storm rainfall totals of 0.45-0.65 inches, with a couple of solutions indicating 1.0+ inches. The 24-hour Tucson rainfall NBM probabilities currently have a 38% probability for 1+ inch and a 10% probability for 2+ inches. The current NWS forecast for Tucson has 0.18 inches spanning Friday and Saturday, with 0.82 inches during the Sunday/Monday time frame and higher totals in the mountains. This seems reasonable given the model differences at this time. Overall, the weather turns unsettled late in the day Thursday, with a chance of showers and thunderstorms Friday and Saturday across southeast Arizona and then the potential for subtropical moisture plume influence late Saturday into Monday.

High temperatures will be near normal today, warming to 2-4 degrees above normal Tuesday through Thursday, then lowering to 4-6 degrees below normal Friday and Saturday.

Aviation

Valid through 27/12Z. SCT-BKN clouds AOA 20k ft AGL mainly from KTUS eastward thru 26/18Z, then clear skies areawide thru the remainder of the forecast period. SFC wind 10 kts or less thru the forecast period, favoring a WLY/NWLY direction during the afternoon/early evening hours and variable in direction at other times. Aviation discussion not updated for TAF amendments.

Fire Weather

Dry conditions are expected across southeast Arizona into Thursday. Showers and thunderstorms will return to the region late Thursday through the weekend. High temperatures will be near normal today, warming to a couple of degrees above normal Tuesday through Thursday, then lowering back below normal Friday through the weekend. 20-foot winds will generally be 15 mph or less through Friday. Minimum RH values will be in the 18-30 percent range in the valleys today (higher in the mountains) and in the 15-25 percent range Tuesday and Wednesday. Minimum RH levels will increase late in the week and over the weekend, with values at 40+ percent.