340
FXUS65 KPSR 042324
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
424 PM MST THU JUN 4 2026
UPDATE
00Z AVIATION DISCUSSION.
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES WITH WIDESPREAD MODERATE HEATRISK
WILL PREVAIL THROUGH THE REMAINDER OF THE WEEK BEFORE READINGS
RETREAT CLOSER TO NORMAL BY THE END OF THE WEEKEND.
- OTHER THAN A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM THIS
AFTERNOON OVER EASTERN ARIZONA, DRY CONDITIONS UNDER MOSTLY
SUNNY SKIES WILL PREVAIL THROUGH AT LEAST THE MIDDLE PART OF
NEXT WEEK.
- LOCALLY BREEZY CONDITIONS WILL DEVELOP FOR THE END OF THE WEEK
AND INTO THE WEEKEND, PARTICULARLY ACROSS THE LOWER COLORADO
RIVER VALLEY AND HIGHER TERRAIN COMMUNITIES OF ARIZONA.
SHORT TERM /TODAY THROUGH SATURDAY/
THE WEAK LOW PRESSURE SYSTEM TO THE SOUTH IN NORTHERN MEXICO
CONTINUES TO SLOWLY MEANDER EASTWARD THIS AFTERNOON. THE POSITION
HAS SHIFTED FAR ENOUGH EASTWARD TO THE POINT WHERE ANTICYCLONIC
FLOW HAS BECOME MORE DOMINANT OVER SOCAL TO CENTRAL AZ WITH MORE
SUBSIDENCE OVER THE AREA. THIS INCREASED SUBSIDENCE AND LOWER
INSTABILITY THAN YESTERDAY ACROSS SOUTHEASTERN AZ SHOULD MAKE
TERRAIN CONVECTION MORE LIMITED AND LESS ROBUST THAN YESTERDAY
THROUGH THE REST OF THIS AFTERNOON AND EVENING. THIS IS ALREADY
EVIDENT BASED ON THE MORE LIMITED CONVECTIVE CUMULUS COVERAGE SO
FAR THIS AFTERNOON. FOR THE LOCAL CWA, MAYBE A SHOWER OR STORM
CLIPS THROUGH SOUTHEAST GILA COUNTY THIS AFTERNOON WITH SOME
GUSTY WINDS AND A LIGHTNING RISK.
TEMPERATURES AT 1300MST THIS AFTERNOON WERE RUNNING AROUND 1-2
DEGREES WARMER THAN THE SAME TIME YESTERDAY AND SHOULD TOP OUT A
TOUCH WARMER THAN YESTERDAY AS WELL. HIGH TEMPERATURES ARE
FORECAST TO REACH 106-109F ACROSS THE LOWER DESERTS THIS
AFTERNOON. THE LATEST NBM DOES HAVE LOW ODDS (10-20%) OF REACHING
110F THIS AFTERNOON IN A FEW LOWER DESERT COMMUNITIES, INCLUDING
THE PHOENIX AREA AND THE IMPERIAL VALLEY. THE HIGHS TODAY, WHILE
6-8 DEGREES ABOVE NORMAL, WILL STILL BE WELL SHY OF DAILY RECORDS
WHICH ARE AROUND 112-116F. THROUGH FRIDAY AND SATURDAY HIGH
TEMPERATURES WILL COOL, BUT ONLY BY A DEGREE OR TWO EACH DAY AS
THE PATTERN ACROSS THE WESTERN CONUS SLOWLY TRANSITIONS TO
NEGATIVE HEIGHT ANOMALIES WITH LONGWAVE TROUGHING ACROSS THE
REGION. THIS PATTERN SHIFT WILL LOWER H5 HEIGHTS SLIGHTLY OVER THE
DESERT SOUTHWEST AND INDUCE A DEEPER SOUTHWEST FLOW ACROSS THE
REGION.
THE PATTERN SHIFT HEADING INTO THE WEEKEND WILL ALSO SUPPORT DRIER
MORE STABLE CONDITIONS ACROSS THE AREA, CLEARING OUT THE MOISTURE
THAT CREPT INTO THE SOUTHEASTERN AZ. THE PRESSURE GRADIENT WILL
ALSO INCREASE ACROSS THE AREA, LEADING TO AN INCREASE IN WINDS
ACROSS THE REGION. STRONGEST SOUTHWESTERLY WIND GUSTS WILL
APPROACH 25-30 MPH, AND LOCALLY UP TO 35 MPH, ALONG THE LOWER
COLORADO RIVER AND THE HIGH TERRAIN EAST OF PHOENIX BOTH FRIDAY
AND SATURDAY, BUT WILL BE STRONGEST ON SATURDAY. WITH AFTERNOON
HUMIDITY VALUES ONLY HOVERING AROUND 5-10% THE NEXT SEVERAL
AFTERNOONS, ANY ENHANCED GUSTS WILL RESULT IN WIDESPREAD ELEVATED
FIRE WEATHER CONDITIONS AND AREAS OF CRITICAL CONDITIONS,
ESPECIALLY IN THE AREAS WITH THE STRONGEST WINDS.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
IT APPEARS THAT ENSEMBLES HAVE COME INTO BETTER AGREEMENT IN
TERMS OF THE EVOLUTION OF THE PREVIOUSLY MENTIONED GULF OF ALASKA
LOW. SOME FRICTION REMAINS, BUT TRENDS POINT TOWARDS A WEAKER
SOLUTION THAT WAS BEING FAVORED BY THE GEFS AT THIS TIME
YESTERDAY. BOTH THE GEFS AND ECMWF ENS SHOW THIS CLOSED LOW
BECOMING AN OPEN WAVE AND EXTENDING FROM THE BRITISH COLUMBIA DOWN
THE LENGTH OF THE PACIFIC COAST, SO THERE WILL LIKELY BE AT LEAST
SOME INFLUENCE FROM THIS DISTURBANCE ON THE DESERT SOUTHWEST.
THIS INFLUENCE WILL MORE THAN CERTAINLY COME IN THE FORM OF
CONTINUED BREEZY TO LOCALLY WINDY CONDITIONS THROUGH THE END OF
THE WEEKEND AND INTO THE WEEKEND. THE ASSOCIATED NEGATIVE HEIGHT
ANOMALIES WILL PROMOTE SOME SLIGHT COOLING, BUT THE VAST MAJORITY
OF LOWER DESERT HIGHS WILL REMAIN IN TRIPLE DIGIT REGARDLESS. THIS
TROUGH WILL NOT PROVIDE ANYTHING IN TERMS OF MOISTURE FLUX, SO
WITH CONTINUED BREEZINESS FORECASTED, DAILY ELEVATED FIRE WEATHER
RISK IS EXPECTED TO EXTEND AT LEAST INTO NEXT MONDAY FOR PARTS OF
THE FORECAST AREA.
THERE APPEARS TO BE BETTER AGREEMENT, COMPARED TO 24 HOURS AGO,
REGARDING THE PATTERN TOWARD THE MIDDLE OF NEXT WEEK. CLUSTERS
HAVE HONED IN ON THE CONTINUED PRESENCE OF TROUGHING ACROSS THE
GREAT BASIN, BUT WHERE THEY DIFFER IS HOW STRONG THIS FEATURE
MIGHT BE. SOME CLUSTERS EVEN SUGGEST CYCLONIC CURVATURE COLLOCATED
WITH POSITIVE HEIGHT ANOMALIES OVER THE DESERT SOUTHWEST, PERHAPS
KEEPING BREEZY CONDITIONS IN THE FORECAST AS WELL AS TRIPLE DIGIT
TEMPERATURES. THERE IS STILL SOME WIGGLE ROOM SO THINGS ARE
LIKELY TO CHANGE OVER THE NEXT FEW DAYS. ONE THING THAT DOES
APPEAR CERTAIN IS CONTINUED DRY CONDITIONS THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK.
AVIATION
UPDATED AT 2324Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT;
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
NO MAJOR AVIATION CONCERNS ARE EXPECTED THROUGH THE TAF PERIOD.
WINDS IN THE PHOENIX METRO WILL EXHIBIT TYPICAL DIURNAL TENDENCIES
WITH PERIODS OF ELEVATED SPEEDS AND GUSTS UP TO 20KTS POSSIBLE
THROUGH SUNSET AND AGAIN TOMORROW AFTERNOON. OUT WEST, KIPL WILL
MAINTAIN A SE'RLY COMPONENT THROUGHOUT THE PERIOD, WITH WIND SPEEDS
AROUND 8-12 KTS OVERNIGHT, THEN RELAXING DURING THE MORNING HOURS,
BEFORE INCREASING AGAIN TOMORROW AFTERNOON. KBLH WILL MAINTAIN A
S/SSW COMPONENT WITH SPEEDS GENERALLY AROUND 10 KTS, INCREASING
TOMORROW AFTERNOON TO 10-15 KTS WITH GUSTS 20-25 KTS POSSIBLE. SKIES
WILL BE CLEAR FOR MOST OF THE PERIOD WITH FEW MID LEVEL CLOUDS
PASSING TOMORROW AFTERNOON.
FIRE WEATHER
THE THREAT FOR AN ISOLATED DRY THUNDERSTORM OVER SOUTHERN GILA
COUNTY THIS AFTERNOON IS THE MAIN FIRE WEATHER HAZARD IN THE SHORT
TERM. WINDS THROUGH THIS AFTERNOON WILL FOLLOW TYPICAL DIURNAL
TENDENCIES WITH TYPICAL AFTERNOON UPSLOPE BREEZINESS. GUSTS PICK
UP FRIDAY AND INTO THE WEEKEND, MAINLY ACROSS THE LOWER COLORADO
RIVER VALLEY AND HIGH TERRAIN AREAS OF THE EASTERN DISTRICTS WITH
READINGS REACH UPWARDS OF 25-30 MPH. WITH DAILY MINRHS HOVERING
CLOSE TO 5- 10% FOR THE MAJORITY OF THE REGION, EVEN MARGINAL
BREEZES WILL RESULT IN PERIODS OF ELEVATED FIRE WEATHER
CONDITIONS. ISOLATED INSTANCES OF NEAR CRITICAL TO CRITICAL
CONDITIONS CAN BE EXPECTED WITH LOCALIZED HIGHER GUSTS. OVERNIGHT
RECOVERY WILL OFFER VERY LITTLE IN TERMS OF RELIEF AS MAXRHS RUN
ONLY BETWEEN 15-45% FOR MOST LOCATIONS. BREEZY CONDITIONS ARE
LIKELY TO CONTINUE INTO THE WEEKEND, PERHAPS EVEN LINGERING INTO
NEXT WEEK, POTENTIALLY RESULTING IN A PROLONGED PERIOD OF DAILY
OCCURRENCES OF ELEVATED TO NEAR CRITICAL FIRE WEATHER CONDITIONS
STARTING FRIDAY.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...NONE.
SHORT TERM...BENEDICT
LONG TERM...RW
AVIATION...HUMPHREYS (FGZ)
FIRE WEATHER...RW
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