771
FXUS65 KPSR 161754
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1054 AM MST SAT MAY 16 2026
UPDATE
18Z AVIATION DISCUSSION.
KEY MESSAGES
- BREEZY TO LOCALLY WINDY CONDITIONS RETURN OVER THE WEEKEND WITH
THE STRONGEST GUSTS ACROSS SOUTHEAST CALIFORNIA AND THE ARIZONA
HIGH TERRAIN.
- ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS THIS WEEKEND,
PARTICULARLY ON SUNDAY FOR THE EASTERN ARIZONA HIGHER TERRAIN,
WHERE A RED FLAG WARNING WILL BE IN EFFECT.
- AFTERNOON HIGH TEMPERATURES 4 TO 6 DEGREES ABOVE NORMAL THROUGH
SATURDAY WILL DROP INTO A NEAR NORMAL RANGE SUNDAY AND BELOW
NORMAL MONDAY, FOLLOWED BY A WARMING TREND THROUGH THE REST OF
NEXT WEEK.
SHORT TERM /TODAY THROUGH MONDAY/
BROAD CYCLONIC FLOW WILL BECOME ESTABLISHED OVER THE WESTERN US
THIS WEEKEND AS AN UPPER LEVEL TROUGH CURRENTLY MOVING INLAND OVER
THE PACIFIC NORTHWEST ENTERS AN AMPLIFICATION PHASE. ENSEMBLE
GUIDANCE HAS BEEN PICKING UP ON THE IMPACTS OF TWO DISTINCT
SHORTWAVES THAT WILL SWING THROUGH THE DESERT SOUTHWEST AS A
RESULT OF THIS PATTERN EVOLUTION, THE FIRST OF WHICH CAN BE SEEN
IN MIDLEVEL WATER VAPOR IMAGERY OVER CENTRAL CA, AND A SECOND,
MORE POTENT SYSTEM ASSOCIATED WITH A STRONGER CORE OF VORTICITY
AND NEGATIVE MIDLEVEL HEIGHT ANOMALIES WHICH WILL DIVE SOUTHWARD
AND SWING JUST NORTH OF THE AREA SUNDAY NIGHT INTO MONDAY. THE
FIRST SHORTWAVE WILL QUICKLY PROGRESS THROUGH THE REGION LATER
TODAY, BRINGING A QUICK-MOVING AXIS OF HIGHER MOMENTUM AIR ALOFT
WITH NAEFS MEAN 700 MB FLOW AROUND 25 KTS. UNDER CLEAR SKIES AND
PEAK SURFACE HEATING THIS AFTERNOON INTO THE EARLY EVENING, IT
WOULD NOT BE SURPRISING FOR MUCH OF THE AREA TO EXPERIENCE A
PERIOD WITH GUSTS UP TO AROUND 20-25 KTS, AS MIXING HEIGHTS
COMMONLY STRETCH UP TO 700 MB OR HIGHER THIS TIME OF YEAR. AS THIS
FIRST SHORTWAVE QUICKLY EJECTS NORTHEAST OF THE AREA, GLOBAL
GUIDANCE DEPICTS A CONSIDERABLE DECREASE IN SURFACE PRESSURE OVER
THE COLORADO RIVER VALLEY AND LATER OVER THE FOUR CORNERS,
CREATING A STRONG MSLP E-W GRADIENT ACROSS THE SAN DIEGO MOUNTAINS
THAT CAN SUPPORT STRONG GAP FLOW AND MOUNTAIN ROTOR ACTIVITY
DOWNSTREAM OVER WESTERN IMPERIAL COUNTY. AS A RESULT, A WIND
ADVISORY WILL GO IN EFFECT MID-LATE AFTERNOON FOR THE TYPICALLY
PRONE SW CORNER OF IMPERIAL COUNTY. THIS STRONG E-W MSLP GRADIENT
ACROSS THE SAN DIEGO MTNS WILL BE SUSTAINED AS THE SECOND SYSTEM
DIVES SOUTH SUNDAY AND DEEPENS THE SURFACE LOW PRESSURE ACROSS THE
REGION, RESULTING IN A PROLONGED WINDY PERIOD FOR THAT AREA
THROUGH THE REST OF THE WEEKEND BUT ESPECIALLY DURING THE
EVENINGS.
THE PRIMARY HAZARD THIS WEEKEND WILL BE ELEVATED AND LOCALLY
CRITICAL FIRE WEATHER CONDITIONS, ESPECIALLY SUNDAY PM, HOWEVER,
MIDLEVEL HEIGHT PACKING OVER NORTHERN/CENTRAL AZ WILL NOT BE
MAXIMIZED UNTIL THE OVERNIGHT HOURS. THUS, PEAK FLOW ALOFT WILL
OCCUR OVERNIGHT AND STRONGER WINDS WILL PRIMARILY BE CONFINED TO
NORTHERN/EASTERN AZ HIGHER TERRAIN. NAEFS MEAN 700 MB WIND SPEEDS
WILL PEAK UPWARDS OF 30-35 KTS, ABOVE THE 90TH PERCENTILE ACROSS
MUCH OF THE STATE. THERE WILL BE A WINDOW WHERE RELATIVE
HUMIDITIES DROP BELOW 15% AS WIND GUSTS INCREASE THROUGH SUNDAY
AFTERNOON INTO THE EVENING, LEADING TO CRITICAL FIRE WEATHER
PRIMARILY OVER THE EASTERN AZ HIGH TERRAIN. AS A RESULT, A RED
FLAG WARNING WILL BE IN EFFECT SUNDAY AFTERNOON THROUGH MUCH OF
THE EVENING.
ON THE BACKSIDE OF THE SECOND SYSTEM, A FRONT WILL BE SENT DOWN
THE LOWER CO RIVER VALLEY RESULTING IN WINDY CONDITIONS ACROSS
PORTIONS OF SOUTHEAST CA MONDAY MORNING. GUSTS WILL PEAK MID-
MORNING, THEN DECREASE THROUGH THE REST OF THE DAY AS REGIONAL
PRESSURE GRADIENTS RELAX. WIND HEADLINES MAY BE NEEDED FOR THIS IN
FUTURE UPDATES. AN ADDITIONAL IMPACT OF THIS TANDEM OF SYSTEMS
THIS WEEKEND WILL BE COOLING TEMPERATURES THROUGH MONDAY. BY
MONDAY MORNING, ENSEMBLE GUIDANCE INDICATES A MUCH COOLER AIRMASS
OVER THE FORECAST AREA, WITH MEAN 850 MB TEMPERATURES BOTTOMING
OUT AROUND 9C-12C, AROUND THE 10TH PERCENTILE OF CLIMATOLOGY.
MONDAY WILL LIKELY BE THE COOLEST OF THE NEXT 7 DAYS, WITH
AFTERNOON HIGHS ONLY REACHING THE MIDDLE TO UPPER 80S FOR THE
TYPICALLY WARMER SPOTS ACROSS THE LOWER DESERTS, BETWEEN 5F-10F
BELOW THE DAILY NORMALS.
LONG TERM /TUESDAY THROUGH FRIDAY/
AS THE CORE OF THE WEEKEND SYSTEM DEPARTS NORTHEASTWARD, SOME
MEASURE OF BROAD CYCLONIC FLOW OVER THE WESTERN US WILL REMAIN AND
LIKELY EVOLVE INTO QUASI-ZONAL FLOW THROUGH THE MIDDLE OF THE
UPCOMING WORK WEEK. HEIGHTS ALOFT WILL REBOUND CLOSER TO SEASONAL
AVERAGES AND SO TEMPERATURES ARE EXPECTED TO WARM THROUGH THE
MIDDLE OF THE WEEK, WITH DRY CONDITIONS CONTINUING. MEANWHILE, A
STRONG MIDLEVEL RIDGE WILL REMAIN NEARLY STATIONARY OFF THE
PACIFIC NORTHWEST COAST THROUGH MUCH OF NEXT WEEK, WITH MOST
GLOBAL GUIDANCE SHOWING A SUBTROPICAL JET FORMING UNDER THE RIDGE
AND DEVELOPING A FEW WEAK DISTURBANCES, A FEW OF WHICH MAY BE SENT
DOWNSTREAM AND NEAR/OVER THE SOUTHWEST US. REGARDLESS OF THE
DETAILS AND HOW WEAK TROUGHING OVER THE WEST-CENTRAL CONUS
EVENTUALLY RESOLVES, ESSENTIALLY ALL SOLUTIONS CURRENTLY SHOW THE
REGION REMAINING COMPLETELY DRY, WITH PERIODS OF MID-HIGH LEVEL
CLOUDS AND GRADUALLY WARMING TEMPERATURES THROUGH THE WORK WEEK.
AVIATION
UPDATED AT 1750Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
THE MAIN AVIATION CONCERNS WILL CONTINUE TO BE A PERIOD OF
ELEVATED CROSS-RUNWAY WINDS AT KPHX FOLLOWED BY GUSTY W-SW WINDS
THIS AFTERNOON. LATEST SFC OBS SHOW SUSTAINED S-SE WINDS AROUND
10-11 KTS. WINDS WILL GRADUALLY SHIFT AROUND TO THE SW THROUGH
THIS AFTERNOON WITH GUSTS INCREASING TO AROUND 20-22 KTS AT ALL
TERMINALS. EXPECTED WESTERLY FLOW TO PREVAIL THROUGH THIS EVENING
WITH GUSTS SUBSIDING AFTER SUNSET. THE TYPICAL DIURNAL EASTERLY
SHIFT IS EXPECTED TO OCCUR AT KIWA AND KPHX LATE TONIGHT. BY EARLY
SUNDAY MORNING, WINDS WILL BEGIN TO SHIFT BACK OUT OF THE SOUTH
AND BECOME ELEVATED UP TO 10-11 KTS WITH GUSTS DEVELOPING AGAIN BY
THE AFTERNOON. SKIES WILL REMAIN MOSTLY CLEAR OVER THE REGION.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
PERIODS OF GUSTY WINDS WILL BE THE MAIN AVIATION WEATHER ISSUE
THROUGHOUT THE TAF PERIOD. AT KIPL, WINDS WILL MAINTAIN A WESTERLY
COMPONENT WHILE AT KBLH WINDS WILL FLUCTUATE FROM THE SOUTH TO
SOUTHWEST. WINDS WILL INCREASE AT BOTH TERMINALS BY THIS AFTERNOON
WITH GUSTS REACHING 20-25 KTS AT TIMES. AT KIPL, A PERIOD OF
STRONGER GUSTS CAN BE EXPECTED DURING THE EARLY EVENING HOURS AND
MAY EXCEED 30 KTS, WITH AROUND 70% CHANCE FOR PEAK GUSTS >35 KTS
BETWEEN 00Z-04Z. WIND DIRECTIONS OF STRONGEST WINDS WILL NOT BE
IDEAL TO BRING DUST PLUMES THROUGH KIPL, BUT SOME HAZY EVENING
SKIES MAY STILL DEVELOP. WINDS WILL RELAX AT KBLH AFTER SUNSET,
BUT WILL REMAIN ELEVATED AT KIPL OVERNIGHT. MOSTLY CLEAR SKIES
WILL PREVAIL OVER SE CALIFORNIA.
FIRE WEATHER
A WEATHER SYSTEM HAS MOVED ONSHORE ALONG THE PACIFIC NORTHWEST
AND WILL DEEPEN OVER THE GREAT BASIN RESULTING IN INCREASED WINDS
AND ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS ACROSS
THE AREA THIS WEEKEND. AFTERNOON/EARLY EVENING WIND GUSTS WILL
COMMONLY PEAK BETWEEN 20-35 MPH TODAY, WITH LOCALLY STRONGER
GUSTS IN SOUTHEAST CA. THE STRONGEST GUSTS BY SUNDAY WILL LIKELY
BE CONFINED TO EASTERN AZ HIGHER TERRAIN, WHERE GUSTS BETWEEN
25-40 MPH WILL BE COMMON. A RED FLAG WARNING WILL BE IN EFFECT
STARTING SUNDAY 11 AM MST FOR SOUTHERN GILA COUNTY AND TONTO NF
FOOTHILLS. AFTERNOON MINRHS MOSTLY BETWEEN 8-15% TODAY WILL
INCREASE TO 10-20% AREAWIDE SUNDAY. OVERNIGHT RECOVERIES BETWEEN
30-50% TONIGHT WILL IMPROVE PRIMARILY FOR THE EASTERN DISTRICTS
SUNDAY NIGHT TO AROUND 40-60%.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...RED FLAG WARNING FROM 11 AM TO 11 PM MST SUNDAY FOR AZZ133.
CA...WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM PDT SUNDAY FOR
CAZ562.
WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING
FOR CAZ566.
SHORT TERM...WHITTOCK
LONG TERM...WHITTOCK
AVIATION...SALERNO
FIRE WEATHER...WHITTOCK
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