Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
599 FXUS65 KTWC 252049 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 149 PM MST Wed Sep 25 2024 .SYNOPSIS... Well above normal temperatures are expected through the coming weekend. The hottest days are expected to be Friday and Saturday when an Excessive Heat Warning is in effect from Tucson westward. && .DISCUSSION... An amplified ridge currently centered from north-central Mexico through New Mexico and Colorado will back westward and become more centered over the southwest CONUS and southeastern Arizona Friday and Saturday. Sunday into early next week the ridge will flatten somewhat with the center moving northward. However it`s looking likely that strong height anomalies aloft remain in place through the foreseeable future, looking in place a climatologically warm pattern. High temperatures over southeastern Arizona are forecast to tease or break daily records through the weekend and potentially into early next week as the thermal and height profile of the atmosphere aloft touches climatological maximums, especially Friday and Saturday. NAEFS 850/700mb temperatures exceed the 99.5th percentile for climatology this time of year, while the EFI (Extreme Forecast Index) from the ECMWF near maxes out with high temperatures Friday and Saturday. All this to say that it`s looking very likely very anomalous temperatures for this time of year will be experienced through the weekend. Major HeatRisk will arrive with the hottest period Friday and Saturday from Tucson westward, including western Pima, the Tohono O`odham Nation, and south central to southwest Pinal county. An Excessive Heat Warning remains in effect Friday and Saturday for these areas. Temperatures will nudge down Sunday onwards, but remain above normal next week. If you`re looking for a significant cool down you will likely have to wait. Extended ensemble height anomalies point to a warmer than average October across the region. In other weather, a pressure gradient will drive breezy southeasterly winds today, then winds diminish following today with the ridge moving overhead. The southeasterly flow will drive some weak moisture into the area, however impacts should mainly be kept to cumulus cloud build-ups given the warm subsident air aloft. && .AVIATION... SCT clouds 9k-12k feet through 26/04Z. Southeast surface winds 12 to 17 kts with gusts to 25 kts through 26/00Z. Locations susceptible to southeast flow will see breezy conditions late tonight, otherwise winds diminish this evening. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Dry conditions and hot temperatures this week. Temperatures will be 7 to 14 degrees above normal through Thursday, peaking at 10 to 15 degrees above normal Friday and Saturday. 20- foot winds east to southeast around 15 mph today from Tucson eastward with a few higher gusts. Otherwise, 20-foot winds generally less than 15 mph with an easterly component through the weekend. Min relative humidities will be in the teens for the lower elevations and the middle 20s for the higher elevations. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning from 10 AM Friday to 7 PM MST Saturday for AZZ501-502-504-505. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson