Area Forecast Discussion
Issued by NWS Phoenix, AZ
Issued by NWS Phoenix, AZ
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316 FXUS65 KPSR 012310 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 410 PM MST Sat Jun 1 2024 .UPDATE... Updated Aviation && .SYNOPSIS... Seasonably hot and dry weather conditions will persist through early next week with temperatures running 3 to 5 degrees above normal. By the middle through latter half of next week, high pressure is forecast to strengthen across much of the western United States, resulting in hotter temperatures as highs get closer to 110 degrees across much of the lower deserts. && .DISCUSSION... A quasi-zonal flow pattern continues to persist across the Desert Southwest with subtropical ridging across central Mexico and troughing across the northern tier of the western United States. This overall flow pattern will persist through at least Monday with temperatures remaining steady state with highs topping out between 100-105 degrees across the lower deserts. A very weak shortwave extending from base of the trough over the Pacific Northwest will skirt the region through Sunday, however, no discernible sensible weather impacts are expected from it other than just slightly enhancing the afternoon and early evening breeziness. The weather pattern starts to shift heading into the Tuesday- Wednesday timeframe as an upper-level ridge of high pressure begins to amplify across much of the western United States. At the same time, a weak cutoff low will develop and sit just off the central Baja Peninsula. With the developing ridge, the upper-level height fields are likely to rise to between 589-593dm, resulting in hotter temperatures during the middle to latter half of the week. Temperatures on Wednesday are likely to range between 105-110 degrees across most of the lower desert communities and likely be a touch warmer on Thursday with highs ranging between 106-111 degrees. These hotter temperatures will certainly will elevate the HeatRisk to moderate areawide with areas of major HeatRisk materializing on Thursday as temperatures approach 110 degrees. Heading into Friday and next weekend, guidance has come into better agreement in showing the cutoff low over the Baja Peninsula moving northward through southern CA/western AZ, which will lower the upper- level height fields and result in a slight cooling trend with temperatures closer to 105 degrees. Ensembles also hint that potentially another larger scale trough from the Pacific may move into the west coast later next weekend, however, differences are noted in the overall strength and positioning and thus what impacts if any it will have in our region is unknown at this time. With the cutoff low near the Baja Peninsula late next week, the south to southeast flow on the east side will likely advect some moisture into AZ with a slight chance of isolated afternoon convection across the higher terrain areas of eastern AZ. && .AVIATION...Updated at 2310Z. South-Central Arizona including KPHX, KIWA, KSDL, KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH: No significant weather issues will exist through Sunday afternoon under clear skies. Wind trends will again follow a near persistence forecast around the Phoenix metro, albeit with more frequent westerly gusts up to 20 kt through early evening. Periods of variable directions will be common during directional shifts. For SE California terminals, sundowner gusts at KIPL should be more pronounced than previous days with occasional daytime gusts around 20 kt at KBLH. && .FIRE WEATHER... Little to no change in the weather pattern will keep seasonably dry and hot conditions in place through early next week. Expect lower desert highs between 100 and 105 degrees, or 3-5 degrees above average each day. Hotter temperatures are expected by the middle to latter half of the week as readings close in at 110 degrees. MinRH values will continue to run between 5-15% across the majority of the area each day, while overnight recoveries will continue to range from poor to fair at around 25-40%. Winds will overall be fairly light following diurnal tendencies with periodic afternoon gusts of 15-20 mph. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Lojero AVIATION...18 FIRE WEATHER...Kuhlman/Lojero