Area Forecast Discussion
Issued by NWS Tucson, AZ
Issued by NWS Tucson, AZ
684 FXUS65 KTWC 272117 AFDTWC Area Forecast Discussion National Weather Service Tucson AZ 217 PM MST Sat Apr 27 2024 .SYNOPSIS... Cooler temperatures today with afternoon breeziness is expected as a weather system continues to cross the region. There will be a chance of showers and thunderstorms north of Safford through the White Mountains this afternoon and evening. A warming trend is expected to begin Sunday with temperatures rising above normal by early next week. && .DISCUSSION... A deep upper level trough will continue to slowly push east today, with the center crossing the Four Corners by mid- day. A modest moisture profile along with cooler temperatures aloft is observed towards the center of the low, meaning weak instability should produce isolated shower and thunderstorm activity in the vicinity of the White Mountains today. Better chances will be further north but precipitation probabilities range from 20 to 35 percent in the northern areas of Graham and Greenlee counties. Today will be less windy, but still breezy thanks to a lingering pressure gradient and unidirectional flow through the mid-levels. With the trough axis centered aloft, cooler surface temperatures are expected today around 8 to 12 degrees below normal forecast. As the upper level trough exits east by Sunday, highs will rise about 6 to 8 degrees from today. Then a rapid increase in mid- level heights will bring a quick warm-up early next week with highs back to around 5 to 10 degrees above average by Tuesday. Ensembles continue to favor western CONUS troughing late next week, however ensemble 500mb height trends keep southern Arizona on the warmer and drier side. && .AVIATION... Valid through 29/00Z. FEW-SCT cumulus clouds AOA 7-10k ft AGL south of the White Mountains and SCT-BKN cumulus clouds 7-10k ft AGL over the White Mountains. 20-40 percent chance of scattered, light showers may develop along the White Mountains this evening. By 29/03Z clouds will have dissipated and SKC conditions will prevail south of the White Mountains. By 29/10Z clouds will have moved out of the White Mountains and SKC conditions will prevail. SFC winds this afternoon are breezy around 13-18 kts from the northwest with gusts to 25 kts. Overnight winds light and variable. Tomorrow afternoon surface winds around 5-10 kts from the northwest with gusts up to 20 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Winds will be breezy this afternoon, though lighter than Friday and below critical levels. Temperatures will also be around 8 degrees cooler than yesterday. With the cooler temperatures minimum relative humidity will be a bit higher across the board, with the driest spots falling to around 15 percent in southeastern Cochise and areas of central to western Pima county. There will be a chance of showers north of Safford this afternoon, which may produce a few lightning strikes. Temperatures quickly warm up by early next week. Minimum relative humidity values in the valleys drop from the 10 to 15 percent range Sunday to the single digits next week while values in the mountains lower from 15 to 30 percent Sunday to 12 to 20 percent next week. && && .TWC WATCHES/WARNINGS/ADVISORIES... None. && $$ Public...Malarkey Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson