603 FXUS65 KPSR 280537 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 1037 PM MST Sat Sep 27 2025 .UPDATE...06Z Aviation Discussion. && .KEY MESSAGES... - Shower and thunderstorm activity will continue to affect portions of southwest Arizona and southeast California with more isolated activity across south-central Arizona through this evening. - A drier and much quieter weather pattern will settle across the region beginning on Sunday. - Below normal temperatures will prevail through the weekend before gradually warming up to near normal by the middle of next week. && .SHORT TERM /TODAY THROUGH SUNDAY/... The upper-level low pressure system that has been causing impactful weather during the last couple of days remains situated near southeast CA as of early this afternoon. Along the eastern flank of the low, shower and thunderstorm activity have erupted across portions of southeast CA and southwest AZ, with activity expected to continue across these through this evening before eventually dissipating completely. With MLCAPE values ranging between 500-1000 J/KG along with PWATs between 1.2-1.5", the environment will remain favorable for some stronger storms capable of producing heavy rainfall amounts in excess of 1-2" in a short amount of time. Thus, the flash flood potential will remain elevated with a Flood Watch in effect through early this evening. Farther east, across south- central AZ, the shower and thunderstorm activity will remain more isolated in coverage and thus not nearly as impactful as yesterday's activity where widespread flash flooding was observed. Nevertheless, any storms that do move across will be capable of producing brief heavy downpours but the quick residence time should limit rainfall amounts. Heading into Sunday, the upper-level low will finally weaken and move eastward through central AZ and thus most of the region will remain on the subsident side. Therefore, thunderstorm activity will be much more limited in coverage with chances mainly across the AZ high terrain and any terrain escarpments through the afternoon before rain chances end completely by the evening hours. && .LONG TERM /MONDAY THROUGH FRIDAY/... By Sunday night into Monday, our region will transition more into zonal flow to weak ridging as a deep Pacific low moves southward to off the Pacific Northwest coast. Temperatures will remain 5-8 degrees below normal areawide this weekend with the help of the cutoff low over SoCal. Once we start to see weak ridging back into our region early next week, daily highs will gradually warm, attaining near normal values for the time of year (middle 90s for the lower deserts) during the middle of the upcoming work week. && .AVIATION...Updated at 0532Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation concerns through the TAF period. Activity has since moved out of the region and the terminals have had some time to relax. Going forward winds will be light and VRB until ~08-10Z, where an easterly component will then prevail through the morning hours. Wind speeds will be aob 10kts. FEW-SCT low to mid level clouds will persist through most of the TAF period. Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation concerns through the TAF period. Winds at KIPL will be light and VRB, where as at KBLH winds will mostly be light and VRB with a period of westerly winds tomorrow afternoon. Wind speeds will be aoa 10kts. Mostly clear skies for the TAF period. && .FIRE WEATHER... As a low pressure system meanders over Southern California, chances for wetting rainfall and isolated to scattered thunderstorms remain today, mainly focused over the high terrain of the eastern districts (20-50% CWR) and fairly widespread across the western districts (30-60% CWR). Rain chances will end across the area by Sunday evening, with only lingering chances over the AZ high terrain Sunday during the day. MinRHs will continue in the 30-45% range and temperatures in a 5-8 degrees below normal range areawide today and Sunday, with humidity gradually decreasing and temperatures gradually warming early next week. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ SHORT TERM...Lojero LONG TERM...Whittock AVIATION...Ryan FIRE WEATHER...Whittock