Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
721 FXUS65 KTWC 132206 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 306 PM MST Sat Jul 13 2024 .SYNOPSIS...Temperatures will fall back closer to seasonal averages as high pressure weakens and deeper moisture returns to the area. Fewer storms this weekend, then thunderstorm coverage will ramp back up early in the new week. Damaging thunderstorm winds will continue to be a threat with some storms, along with heavy rain threats gradually increasing through the week. && .DISCUSSION...Today looks similar to yesterday in that we are seeing drier air from New Mexico impact much of our corner of the state. The 12Z KTWC sounding came in with precipitable water under 3/4 of an inch which is consistent with satellite estimates. Around .6 from Tucson eastward, to around 1.2 inches in western areas. Surface dewpoints have cratered into 30s and 40s from Tucson eastward this afternoon. As expected, our best convective potential is south through west of Tucson (primarily central to southern portions of the T.O. Moisture will slosh back into the picture with a deeper moisture surge into the lower deserts that will circulate back through our area and bring increasing thunderstorm chances early in the new week. Eventually this will combine with a weak easterly wave bringing moisture back into mid level upstream locations for eastern areas. With the high center meandering around the 4 corners area, we`ll continue to vulnerable to strong organized outflow off the Mogollon Rim on days where there is enough moisture in eastern areas. However, ensemble means suggest that positive height anomalies may sag far enough south for the flow to veer around to the southeast on some days during the coming week. At any rate, watch for H7 theta-e values to increase through central and northern Mexico this week, which will provide a solid foundation for deeper moisture into SE AZ. && .AVIATION...Valid through 15/00Z. SCT-BKN clouds at 8k-12k ft AGL thru 14/04Z and again aft 14/18Z. Diminishing cloud cover aft 14/04Z and generally clear skies/SKC conditions between 14/07Z and 14/18Z. Isold/SCT TSRA/SHRA thru 14/04Z and again aft 14/19Z, mainly along the International Border from KALK westward across Santa Cruz and central/western Pima counties and also in the White Mountains. MVFR conditions in TSRA, with mountain obscurations, vsby reductions and wind gusts to 40+ knots. Outside of TSRA, SFC wind less than 12 knots and variable in direction thru 14/18Z, then WLY/NWLY at 8-15 kts with occasional gusts to 22 kts between 14/18Z and 15/00Z. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Through this evening, the best chances for storms will be in central/western Pima County and in the White Mountains with the main threats being strong winds and locally heavy rainfall. Moisture increases Sunday through next week, leading to an increase in storm coverage and the potential for more widespread rainfall. Minimum relative humidity values increase Sunday through next week, with values in most lower elevation locations in the 20-30 percent range and 25-45 percent in mountain areas. Away from thunderstorms, 20-foot winds will generally be 15 mph or less, with afternoon/early evening gusts to 20-25 mph and light winds overnight. Wind direction will be west-northwest Sunday through the middle of next week. Winds then switch to an easterly direction late next week. && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson