Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
280 FXUS65 KTWC 050924 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 224 AM MST Fri Jul 5 2024 .SYNOPSIS...Shower and thunderstorm chances will mainly be confined south and east of Tucson into early next week as drier air overspreads Arizona from the north. With high pressure building in from the northwest, daytime temperatures will be trending hotter into next week. Temperatures are expected to approach record levels in some locations. && .DISCUSSION...A strong ridge of high pressure currently centered over the northern California coast will move slowly southeast through early next week, when it will be centered along the AZ/CA/NV borders. The models then show the high lifting northeast into Utah mid to late next week. This pattern will result in hot daytime temperatures and a low grade monsoon through early next week, with deeper moisture moving back into the region mid to late next week. The main story through early next week will be the EXCESSIVE HEAT and HOT temperatures across southeast Arizona, with near record to record high temperatures. Heights and thicknesses support extending the Excessive Heat (EH) Warning out through Monday from Tucson into the lower deserts and also adding Zones 506 and 509 (southeast Pinal and the lower elevations of Graham County, namely the upper Gila River valley and the city of Safford). During this time frame monsoon activity will be limited to south/southeast of Tucson, mainly across Santa Cruz and Cochise counties as the deeper moisture gets pushed south into northern Mexico and high pressure builds in from the northwest. Precipitable water values are currently around 1 inch in Tucson, with 1.2-1.4 inches along the International Border and a paltry 0.40 inches in the White Mountains. The ensemble models indicate PW values will continue to lower through the weekend into early next week, when PW values will range from around 0.30 inches in the White Mountains to 0.6-0.8 inches across the rest of southeast Arizona and even much of northern Mexico. As the high shifts north and then northeast of the region mid to late next week, a more favorable moisture pattern returns to southeast Arizona and expect shower and thunderstorm chances to increase, as well as high temperatures to slowly decrease (but still remaining above normal levels). && .AVIATION...Valid through 06/12Z. FEW-SCT clouds at 13k-15K ft AGL and BKN-OVC clouds AOA 20k ft AGL southeast of a KTUS to KSAD line thru 05/15Z, then diminishing cloud cover. Clear skies elsewhere. Between 05/18Z and 06/05Z, SCT-BKN clouds at 7k-10k ft AGL and ISOLD-SCT TSRA/SHRA mainly south and east of KTUS. MVFR conditions near TSRA, with mountain obscurations, VSBY restrictions and gusts to 40+ kts. Aft 06/05Z, gradual clearing thru the remainder of the forecast period. Outside of TSRA outflows, SFC wind less than 12 kts 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...There will be the daily chance for isolated to scattered showers and thunderstorms mainly from Tucson south and east into early next week. High pressure aloft will build to our northwest through the weekend into early next week, which will result in hot conditions. With the hotter temperatures and some of the deeper moisture getting pushed to the south and east of the region, min RH values will lower into the 10-18% range across the lower elevations and 15-30% in the higher elevations into the middle of next week. Hot high temperature are expected through early next week, with highs 106-113 degrees from Tucson westward and in the Gila River Valley, and in the upper 90s to 105 degrees across Santa Cruz and Cochise counties. Excessive Heat will be an issue during this time frame. Outside of any thunderstorm outflow winds, 20-foot winds will generally be 15 mph or less each afternoon with occasional gusts to 20-25 mph through the weekend. Early next week there will be the potential for more elevated wind speeds in the 15- 20 mph range, especially east of Tucson. && .CLIMATE... Near record to record high temperatures today, Saturday and Sunday. Date Jul 05 Jul 06 Jul 07 FCST RCD/YR FCST RCD/YR FCST RCD/YR Tucson Intl Airport 108 111/2018 108 110/2023 107 111/2017 Organ Pipe Cactus 108 115/1983 108 113/2018 106 116/2017 Picacho Peak 110 113/2007 110 113/2005 109 114/2017 Safford Ag Station 108 109/2007 105 109/2023 106 107/1964 && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning from 11 AM today to 8 PM MST Monday for AZZ501-502-504>506-509. && $$ Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson