Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
501 FXUS65 KTWC 070959 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 259 AM MST Sun Jul 7 2024 .SYNOPSIS... Excessive heat continues through early this coming week with high temperatures expected to approach record levels in some locations. Drier air moving in from the north has reduced thunderstorm chances, but returning moisture should begin to increase chances again by the middle of the week. && .DISCUSSION... In the upper levels, an impressive ridge remains anchored over the west coast, while southeastern Arizona sits on the southeastern periphery of the anomalous mid to upper level heights. With this ridge axis position, climate sites in southeastern Arizona should tease record highs over the next several days. In Tucson, NBM probabilities for reaching 110 degrees rise from 25 percent today to 50-60 percent Monday through Wednesday, an example of the period of elevated Heat Risk across the region. The current Excessive Heat Warning remains in good standing. There is a possibility it may need to be extended into Wednesday at some point, however questions on the moisture return`s impact on high temperatures lead to enough uncertainty for now. The atmospheric column this morning is about as dry as it`s been since the monsoon season started, with the 00Z sounding measuring 0.74 inches of precipitable water. This, combined with warming aloft, will keep the forecast today nearly dry outside of a very low chance of a thunderstorm near the International Border. A weak impulse running through the northwest flow aloft will tighten the pressure gradient today, creating breezy conditions this afternoon. The Safford area should see the strongest winds with gusts up to 35 mph as the Gila River valley orientation will be favorably aligned for the northwest flow setup. Through the upcoming week, the center of the upper high will slowly migrate east and gradually turn mean flow easterly by the weekend. This process will bring moisture and thunderstorm probabilities back into southeastern Arizona as early as Tuesday, with ensemble probabilities for precipitable water exceeding one inch becoming more widespread by Saturday. && .AVIATION...Valid through 08/12Z. Generally SKC across southeastern Arizona with FEW-SCT ceilings 10k-12k ft this afternoon. An isolated shower or thunderstorm near KOLS-KDUG can`t be ruled out this afternoon. West to northwest winds increase after 07/17Z with gusts up to 25 kts. Wind gusts to around 30 kts possible at KSAD. Winds decrease after 08/02Z, but may remain breezy in areas exposed to northwest winds. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Excessive heat continues through early this coming 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. As moisture has pushed south of the region, minimum relative humidities will lower into the 10-17% range across the lower elevations and 14-25% range in the higher elevations into the middle of the week. Monday should see the driest conditions with the lowest relative humidity values falling into the single digits. Winds today will be highest in the upper Gila River valley near Safford where northwest winds of 20 to 25 mph and gusts to around 35 mph are expected. Otherwise, 20-foot winds will generally be 15 mph or less each afternoon with occasional gusts to 20-25 mph. Moisture begins to return Tuesday onwards as well as chances for thunderstorms. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM MST Tuesday for AZZ501-502- 504>506-509. && $$ Public...Edwards Aviation...Edwards Fire Weather....Edwards Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson