928 FXUS65 KPSR 261107 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 407 AM MST Sat Jul 26 2025 .UPDATE...Updated 12Z Aviation Discussion. && .KEY MESSAGES... - Near normal temperatures will warm to slightly above normal by the beginning of next week, resulting in widespread Moderate HeatRisk. - Very dry conditions will greatly inhibit any rain chances through the weekend. - Monsoonal activity should increase again across portions of Arizona region by the middle of next week. && .SHORT TERM /Today through Sunday/... The unusual weather pattern with a near persistent upper level trough along and just off the West Coast is likely to continue influencing our weather through the upcoming week. The main trough is still situated off the coast of southwest Canada, but a secondary trough remains over California where H5 heights are currently below the 10th percentile of climatology. These lower heights aloft have provided the Desert Southwest with cooler than normal temperatures much of time over the past week and a half, but the close proximity is also a big negative for our monsoonal pattern. The last few days have seen very dry air from the southwest spread over our region, cutting off any monsoon activity and this is forecast to last through Sunday. However, we will start to see the subtropical ridge, which is positioned over the Southeastern U.S., to begin to shift westward by Sunday. This will in turn raise our heights aloft and boost temperatures a few degrees. Forecast highs for today will be very similar to the last couple of days with highs right around normals and lows a few degrees below normal. By Sunday, daytime highs are expected to reach near the 110 degree mark in the Phoenix area to 105-108 degrees across the western lower deserts. && .LONG TERM /Monday through Friday/... The first part of next week will see the trough to our northwest gradually weaken and likely lift a bit more to the north. As we begin to somewhat lose the dry westerly flow influence from this trough, the subtropical ridge is forecast to continue to retrograde westward. Previous guidance was fairly confident in a meaningful inverted trough moving out of northern Mexico and reaching southeast Arizona later Monday into Tuesday. This is still somewhat the case in the latest model runs, but the inverted trough looks weaker and now is likely to get held up, not reaching past southeast Arizona. The slight shift in the flow pattern should still allow for a period of southeast semi-moist flow into much of Arizona starting Monday, but the recent model shift now mostly keeps the better quality moisture across eastern Arizona through Tuesday. Very limited shower and thunderstorm chances will be possible across the eastern Arizona high terrain on Monday with slightly better chances on Tuesday, but still mostly relegated to the higher terrain. The flow pattern is not likely to change much going through the middle of next week and this should provide for daily chances for higher terrain convection and eventually increasing moisture into the south-central Arizona lower deserts via outflows. Guidance does try to indicate just enough moisture working as far west as the Phoenix area to provide for some very limited (10-15%) chances by next Wednesday. These daily low end rain chances may very well continue through the rest of next week as ensemble output shows little change in the positioning of the subtropical high to our east and the broad troughing to our northwest. Temperatures next week look quite stable with H5 heights mostly hovering within the higher end of the normal range. This should keep daily highs right around or maybe 2-3 degrees above normal throughout the entire week. The increased moisture and clouds should also lead to higher overnight lows across south-central and eastern Arizona with readings within the Phoenix metro mostly between 83-88 degrees each night. Lower humidities and generally clear skies across the western deserts should provide for overnight lows mostly in the mid 70s to lower 80s. && .AVIATION...Updated at 1105Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation weather concerns under some passing high level clouds are expected throughout the TAF period. The overall wind pattern will continue to exhibit the typical diurnal tendencies with speeds generally aob 10 kts along with some occasional afternoon/early evening gusts into the mid to upper teens. Southeast California/Southwest Arizona including KIPL and KBLH: No major weather issues under some passing high level clouds are expected throughout the TAF period. Winds at KIPL will stay out of the west while at KBLH winds will generally be out of the south to southwest. Wind gusts upwards of 20-25 kts are expected at both terminals this afternoon and evening. KIPL could potentially see temporary gusts near 30 kts during the evening hours. && .FIRE WEATHER... Very dry conditions with zero rain chances and near to slightly above normal temperatures will continue through the weekend. Some lower desert location may reach 110 degrees starting Sunday before moisture increases gradually across the eastern districts next week. MinRHs through Monday will be in the 5-10% range across the lower deserts with poor overnight recoveries of only 15-35%. Winds will tend to follow their typical diurnal tendencies with some afternoon upslope gustiness. With the increase in moisture next week there will also be increasing shower and storm chances across the eastern districts, especially later in the week. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ SHORT TERM...Kuhlman LONG TERM...Kuhlman AVIATION...Berislavich/Lojero FIRE WEATHER...Kuhlman