FXUS65 KPSR 180937 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 237 AM MST Mon May 18 2026 .KEY MESSAGES... - A Wind Advisory remains in effect through 11 AM for portions of Southeast California for strong northerly post-frontal winds. - Coolest temperatures over the next week and beyond are expected today, with high temperatures 4 to 7 degrees below normal, before slowly warming back up and nearing 100 degree highs again this weekend. - Daily dry conditions, with no threat of rain, and seasonal afternoon breeziness are expected through the next 7 days. && .SHORT TERM /TODAY THROUGH TUESDAY/... A potent shortwave trough was seen moving eastward through UT early this morning with a southward and southeastward moving cold front through AZ and SoCal. Strong northerly winds and widespread lofted dust were observed post-front in San Bernardino County. The cold front will continue dropping south through southeast CA and southwest AZ early this morning, with strong northerly post- frontal winds expected through mid-morning. A Wind Advisory is in effect for eastern Riverside and northeast Imperial Counties through 11 AM PDT/MST this morning with northerly gusts up to 35-50 mph expected. Latest HREF shows strongest 850mb winds (>40 mph) occurring through around 3-5 AM PDT/MST this morning. During this time is when the greatest impacts - primarily northerly crosswinds across I-10 and localized blowing dust - are anticipated. While the gradient wind is expected to weaken around the sunrise hours, some areas may see northerly wind gusts pick back up for a few hours after sunrise due to mixing. Otherwise, winds should gradually subside across southeast CA and southwest AZ heading into late-morning and the afternoon. Hazy skies should become evident after sunrise this morning, with all the lofted dust across CA and NV, especially across southeast CA and southwest AZ. Hi-res models depict the cold front stalling out across south- central AZ toward sunrise and mid-morning. So, south-central AZ is not expected to experience any of the strong northerly and northwesterly post-frontal winds. There will still be some breezy southwest winds though late morning and this afternoon, mostly gusting up to 15-30 mph. A narrow band of low level moisture and forcing along and ahead of the front will lead to some lower clouds this morning across south-central AZ, including the Phoenix area, and a few hi-res models still support a brief sprinkle shower. So, a few drops falling in the morning, after sunrise cannot be ruled out, but do not expect any measurable rain. The dip in 500mb heights over the area and push of cooler air from the north will result in cooler surface temperatures today, with below normal high temperatures expected across the region. Highs this afternoon are forecast to mostly be in the 80s across the lower deserts, with only 10-20% chances of reaching 90F in places like Phoenix and Yuma. Heading into tomorrow, the potent trough will have left the region, ejecting through the Plains, but another trailing weak shortwave will follow and keep a large-scale trough pattern in place across the Desert Southwest. This will keep temperatures from rapidly warming back up and while they will warm up from today, highs tomorrow are still forecast to come up shy of daily normals. Most lower deserts will top out with highs in the lower 90s. Winds tomorrow will be even lighter than today for most areas. Although, with the trailing shortwave there will be another enhancement to northerly winds down the Colorado River and southeast CA, with peak wind gusts as high as 20-30 mph in the morning through midday. The lagging shortwave will also help draw scattered high clouds into the Desert Southwest through the day. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Through the rest of the week, global ensembles depict a lasting weak longwave trough pattern across the Desert South, with neutral height anomalies and no significant shortwaves rolling through the region. This will translate to rather seasonal weather conditions, but with a slow day-to-day warming trend. High temperatures are forecast to be near normal through the end of the work week - highs in the middle to upper 90s. Meanwhile morning lows are expected to be near to slightly below normal, largely due to dry air/low humidity and limited cloud cover. It is not until the weekend when odds of high temperatures reaching the 100 degree mark spikes back up to around 30-60%, as the longwave trough across the Desert Southwest breaks down. Conditions will remain dry through this weekend, with no threat of rain, and seasonal wind patterns are expected, with light winds through the overnight and morning hours and afternoon upslope breezes up to 15-25 mph. && .AVIATION...Updated at 0540Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: The main aviation concerns will be a brief period of lower clouds (04-05 kft AGL) tomorrow morning. SW winds with around 8-13 kt will continue into the overnight hours. There is still low confidence in winds going SE during the overnight hours and may be more southerly. This shift is expected between 09-11Z. A early shift to SW winds is expected by 14-15Z, with winds picking up speed into the teens during the afternoon. Some occasional gusts into the upper teens are possible during the afternoon and early evening hours. FEW high clouds will gradually move out overnight, with FEW- SCT CU as low as 4-5 kft AGL expected to develop around sunrise, but are only expected to last for a few hours. Then mostly clear skies are expected for the remainder of the TAF period. Southeast California/Southwest Arizona including KIPL and KBLH: Periods of gusty winds will be the main aviation weather concerns throughout the TAF period. At KIPL, wind gusts of 20-25 kts will continue over the next couple hours before decreasing to around 10-15 kt. At KBLH, SW winds with speeds of 10-15 kt will continue for the next couple hours. A cold front will enter the area from the N-NW and switch winds abruptly at KBLH overnight (around 08-09Z) and at KIPL (around 13Z) early tomorrow morning. Brief visibility restrictions, due to blowing/lofted dust, will be possible initially at KBLH as the cold front moves through the area. Winds at both terminals will then remain out of the N-NW for the remainder of the TAF period. Gusts of 20-25 kt are expected at KBLH from the early morning through the early evening. FEW high clouds will clear out overnight with mostly clear skies expected the rest of the TAF period. && .FIRE WEATHER... Elevated and marginally critical fire weather conditions are expected early this morning across portions of southeast CA as a result of strong northerly winds and dry air following a frontal passage. Conditions will improve by late-morning/early-afternoon as northerly winds subside. Elsewhere today, winds will be lighter, but still with peak southwesterly gusts up to 15-30 mph across south-central AZ. Minimum RH values today will be around 5-10% across western districts to 15-25% across eastern districts. Temperatures will be coolest, and below normal, today, which will result lower max mixing heights (up to 6-8K ft above ground level). Temperatures will slowly warm through the end of the week, but remain near seasonal level, and conditions will remain dry. Daily minimum RH values will be around 5-15% each day after today with poor to fair overnight recoveries at 25-50%. After today seasonal wind patterns are expected through the rest of the week, with afternoon upslope breezes up to 15-25 mph and the only exception being another brief enhanced northerly wind down the Colorado River tomorrow morning. There is no rain in the forecast through this weekend. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...Wind Advisory until 11 AM PDT Monday for CAZ560-561-564-568>570. && $$ SHORT TERM...Benedict LONG TERM...Benedict AVIATION...Berislavich FIRE WEATHER...Benedict