494 FXUS65 KPSR 221132 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 432 AM MST Sun Jun 22 2025 .UPDATE...Updated Aviation Discussion && .KEY MESSAGES... - Below normal temperatures today through at least the first half of next week, followed by a return to above normal as early as Thursday and lower desert highs back around 110 degrees next weekend. - Dry conditions will prevail, under mostly clear skies, and with afternoon and evening breeziness (15 to 25 mile per hour gusts). - Slight chances (10 to 20 percent) for afternoon storms in parts of Southern Gila County beginning Tuesday. && .DISCUSSION... Widespread heat alerts are seen from the Midwest through the Northeast, while there are winter weather and freeze alerts in parts of the Northwest. The yin and the yang, with a large area of high pressure across much of the eastern CONUS and an anomalously cool trough across the western CONUS. This trough across the West will lead below normal temperatures today through at least Tuesday, with today expected to be the coolest day in the forecast. Most lower desert locations will come up short of 100 degrees this afternoon, which is rare for late-June. Phoenix has only observed a sub-100 degree high 7 times between June 20th-30th during the 2000s (Yuma 11 times & El Centro 13 times). The morning low temperatures will also be more pleasantly in the upper-60s to middle-70s through mid-week. Unfortunately, the sub-seasonal temperatures will not last as global models continue to show the trough in the West gradually weakening and negative height anomalies disappearing by Thursday. The negative height anomalies will not be immediately be replaced by positive anomalies and strong high pressure, as the blocking high/heat dome in the East is expected to persist through most of the week. H5 heights are still expected to slowly rise across the Desert Southwest, however, and so will surface temperatures as a result. Latest NBM forecast has a return to above normal as early as Thursday and then 110 degree highs by next weekend. With the trough still in the West, daily breezy conditions will continue across the region, though winds will not be as strong as the past couple of days. Winds are actually still quite breezy (25-35 mph gusts) across Southeast CA early this morning, with westerly downsloping winds in Imperial County and northwesterly winds behind a dry cold front that has dropped down into eastern Riverside County, but these winds will subside through the morning and become light by this afternoon. Afternoon 15-25 mph gusts will be common through the next several days. So, when will monsoon storms get going here? Well, while the western trough lingers across the area through early week it will maintain dry southwest flow across Southeast CA and most of AZ and keep a deeper moisture axis off to the east and southeast in New Mexico and northern Mexico. As the trough weakens by midweek moisture levels are expected to start rising across southeast and south-central AZ, more to seasonal levels (lower desert PWATs of 0.7-0.9"). This looks like it will lead to at least some isolated storms developing in parts of southeast AZ beginning around Tuesday, including as far north as the White Mountains and into Gila County. Grand ensemble probabilities >50% for MUCAPE >200 J/kg suggests afternoon and evening storms will mostly stay east of a line from Tucson through Globe Tuesday through Friday. The MUCAPE probabilities then drop heading into next weekend, suggesting a decrease in activity. NBM PoPs in southern Gila County only peak around 10-20% Tuesday-Friday. Looking a little further ahead, long-range models are not indicating any strong signals for anymore negative height anomalies across the West and there is consensus for the monsoon high becoming established in the Desert Southwest around or just after July 4th. Overall, it is looking like we will slowly ease our way into the monsoon stormy season with moisture levels slowly creeping up. && .AVIATION...Updated at 1130Z. South Central Arizona including KPHX, KIWA, KSDL, KDVT: No major aviation concerns under clear skies can be expected throughout the TAF period. Winds will follow familiar diurnal trends, with a longer than usual window of S`rly crosswinds at KPHX and KDVT. Gusts in the mid-teens to near 20 kts will develop this afternoon before then diminishing after sunset. Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation concerns under clear skies can be expected throughout the TAF period. Winds should generally contain a W`rly component at both terminals through much of the forecast, with some variability during the afternoon hours. Cannot rule out the potential for some windows of reduced visibility at KIPL due to wildfire smoke, but confidence surrounding any surface reductions remains too low to warrant inclusion in the TAF at this time. && .FIRE WEATHER... There are no considerable fire weather concerns through the next 7 days, aside from perhaps some isolated dry thunderstorm impacts in parts of southern Gila County (toward the White Mountains) beginning Tuesday. Winds will be lighter than the previous couple of days, but still breezy in the afternoons and evenings with daily peak gusts up to 15-25 mph. Conditions overall will remain dry with daily minimum RH values down to 5-15% and overnight recoveries only to 20-40%. Near to below normal temperatures are expected through the first half of the week, but will warm through the end of the week and lower desert highs will push back to around the 110 degree mark by next weekend. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Benedict AVIATION...RW FIRE WEATHER...Benedict