169
FXUS65 KPSR 151700
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1000 AM MST FRI MAY 15 2026
UPDATE
UPDATED AVIATION
KEY MESSAGES
- BREEZY TO LOCALLY WINDY CONDITIONS RETURN OVER THE WEEKEND WITH
THE STRONGEST GUSTS ACROSS SOUTHEAST CALIFORNIA AND THE ARIZONA HIGH
TERRAIN.
- CRITICAL FIRE WEATHER CONDITIONS WILL BE POSSIBLE THIS WEEKEND,
PARTICULARLY ON SUNDAY FOR THE EASTERN ARIZONA HIGHER TERRAIN.
- AFTERNOON HIGH TEMPERATURES 4 TO 8 DEGREES ABOVE NORMAL THROUGH
SATURDAY WILL DROP INTO A NEAR TO BELOW NORMAL RANGE SUNDAY AND
EARLY NEXT WEEK.
SHORT TERM /TODAY THROUGH SUNDAY/
CLEAR SKIES ARE OBSERVED ACROSS MUCH OF THE REGION, AS A WEAK
DISTURBANCE SLOWLY TRACKS EASTWARD ACROSS AZ EARLY THIS MORNING.
WITH GENERALLY WEAK REGIONAL PRESSURE/TEMPERATURE GRADIENTS AND H5
HEIGHTS BEING MAINTAINED AROUND 582 DAM, ANTICIPATE ONLY MODEST
AFTERNOON BREEZINESS AND A NEAR PERSISTENCE TEMPERATURE FORECAST
WITH LOWER DESERT HIGHS COMMONLY REACHING THE MIDDLE TO UPPER 90S
AND NEAR 100F FOR SOME SPOTS.
A QUICK-MOVING, RELATIVELY LOW-AMPLITUDE TROUGH IS CURRENTLY SEEN
OFF THE PACIFIC NORTHWEST COAST. ENSEMBLES REMAIN IN EXCELLENT
AGREEMENT THAT THIS FEATURE WILL MOVE ONSHORE TONIGHT INTO EARLY
SATURDAY FOLLOWED BY A PERIOD OF AMPLIFICATION ONCE IT REACHES THE
INTERIOR WEST (APPROXIMATELY OVER THE GREAT BASIN). THERE WILL BE A
FEW SHORTWAVES THAT ROTATE THROUGH AS THE LARGER SYSTEM DEEPENS, ONE
LIKELY ON SATURDAY JUST AHEAD OF THE MORE PRONOUNCED HEIGHT FALLS
OVER THE GREAT BASIN, AND THE SECOND MORE POTENT PIECE OF ENERGY
LATE SUNDAY INTO MONDAY. HOWEVER, THERE ARE STILL SOME NOTABLE
DISCREPANCIES BETWEEN THE ENSEMBLES ON THE STRENGTH OF THE TROUGH
AND HOW CLOSE IT WILL DRAW TO THE AREA, AND SO THE TIMING AND PEAK
MAGNITUDE OF WINDS HAS CONTINUED TO SHIFT OVER THE LAST FEW FORECAST
UPDATES. FOR EXAMPLE, THE LATEST 00Z GEFS FAVORS A DEEPER, MORE
SOUTHERN SOLUTION FOR THIS SYSTEM THAN THE ECMWF ENS OR GEPS, AND SO
THERE IS MORE PRONOUNCED HEIGHT PACKING OVER NORTHERN/CENTRAL AZ IN
THE GEFS SOLUTIONS. THE RESULT OF SOME OF THE LATEST GUIDANCE SHIFTS
HAS BEEN A LATER TIMING OF PEAK WINDS ALOFT (NOW SUNDAY NIGHT) AND
THUS PEAK GUSTS ON SUNDAY ACROSS THE AZ HIGH TERRAIN. ADDITIONALLY,
AFTERNOON MINRHS HAVE COME UP A FEW PERCENTAGE POINTS, LEADING TO
MARGINAL AND SHORTER DURATION OF CRITICAL (15% OR LESS) THRESHOLDS
BEING MET. REGARDLESS, BREEZY TO LOCALLY WINDY CONDITIONS WILL
DEVELOP THIS WEEKEND, LEADING TO WIDESPREAD ELEVATED AND LOCALLY
NEAR CRITICAL FIRE DANGER. A WIND ADVISORY WILL BE IN EFFECT FOR THE
TYPICALLY PRONE SW CORNER OF IMPERIAL COUNTY SATURDAY LATE AFTERNOON
THROUGH SUNDAY EVENING. FIRE WEATHER HEADLINES MAY BE POSTED LATER
TODAY FOR THE EASTERN AZ HIGH TERRAIN ON SUNDAY IF THE FORECAST
HOLDS.
ASIDE FROM WINDS AND FIRE WEATHER CONCERNS, THE PATTERN THIS WEEKEND
WILL PROMOTE COOLER TEMPERATURES BY SUNDAY. LOWER LEVEL THERMAL
PROFILES WILL NOT HAVE HAD TIME TO MODIFY BY SATURDAY, AND SO
AFTERNOON HIGHS WILL BE SIMILAR, OR ONLY 1F-2F COOLER ACROSS THE
AREA. NEGATIVE H5 HEIGHT ANOMALIES AROUND THE 20TH-25TH PERCENTILE
OF CLIMATOLOGY WILL ESTABLISH OVER THE FORECAST AREA SUNDAY INTO
EARLY NEXT WEEK, WITH VALUES BOTTOMING OUT AROUND 571-574 DAM. AS A
RESULT, ANTICIPATE LOWER DESERT HIGHS TO FALL INTO A 90F-95F RANGE
BY SUNDAY.
LONG TERM /MONDAY THROUGH THURSDAY/
THE AFOREMENTIONED SECOND, MORE POTENT PIECE OF ENERGY WILL ROTATE
THROUGH JUST NORTH OF THE AREA SUNDAY NIGHT INTO MONDAY, WITH
SEVERAL GLOBAL MODELS DEPICTING AN ASSOCIATED FRONT BEING SENT DOWN
THE LOWER CO RIVER VALLEY, RESULTING IN LOCALLY WINDY CONDITIONS FOR
PORTIONS OF SOUTHEAST CA MONDAY MORNING. THIS IS THE FINAL
ANTICIPATED IMPACT FROM THE SYSTEM THAT DEEPENS OVER THE WESTERN US
THIS WEEKEND, AS NEGATIVE HEIGHT ANOMALIES RETREAT TO THE NORTH AND
EAST HEADING INTO THE MIDDLE OF THE UPCOMING WORKWEEK. MONDAY IS
ALSO SHAPING UP TO BE THE "COOLEST" OF THE NEXT 7 DAYS, WITH
AFTERNOON HIGHS POTENTIALLY STRUGGLING TO REACH 90F ACROSS THE LOWER
DESERTS, AROUND 5F BELOW DAILY NORMALS. FORECAST UNCERTAINTY REMAINS
MODERATE TO HIGH MONDAY ONWARD, HOWEVER, 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 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.
AVIATION
UPDATED AT 1700Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:
NO MAJOR WEATHER ISSUES WILL EXIST THROUGH SATURDAY AFTERNOON UNDER
CLEAR SKIES. A BRIEF PERIOD OF VARIABLE WINDS (140V230) MAY EXIST
DURING THE SWITCH TO WESTERLY TODAY, HOWEVER SPEEDS SHOULD BE
LIMITED UNDER 10KT. ANY STRONGER WIND GUSTS EARLY THIS EVENING
SHOULD BE RATHER WEAK WITH GOOD CONFIDENCE OF THE NOCTURNAL SWITCH
BACK TO EASTERLY OCCURRING AFTER MIDNIGHT. HEIGHTENED WIND SPEEDS
AND INCREASED GUSTINESS WILL RETURN SATURDAY AFTERNOON.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
SOME OCCASIONAL STRONGER WIND GUSTS WILL BE THE ONLY WEATHER ISSUE
THROUGH SATURDAY AFTERNOON UNDER CLEAR SKIES. WHILE SOME WIND
VARIABILITY WILL BE COMMON DURING THE MORNING, CONFIDENCE IS GOOD
THAT SOUTH WINDS WILL BE PREFERRED AT KBLH WHILE WEST WINDS BECOME
MORE COMMON AT KIPL. LATE AFTERNOON/EVENING GUSTS 20-25KT WILL
AFFECT THE AREA WITH MORE PRONOUNCED GUSTS LIKELY AT KIPL.
FIRE WEATHER
SLIGHTLY ABOVE NORMAL TEMPERATURES AND GENERALLY LIGHT WINDS WITH
TYPICAL AFTERNOON UPSLOPE/UPVALLEY BREEZINESS WILL PREVAIL TODAY.
A WEATHER SYSTEM WILL MOVE ONSHORE ALONG THE PACIFIC NORTHWEST EARLY
SATURDAY AND DEEPEN OVER THE WESTERN US RESULTING IN INCREASED WINDS
ACROSS THE AREA THIS WEEKEND. AFTERNOON/EARLY EVENING WIND GUSTS
WILL COMMONLY PEAK BETWEEN 20-35 MPH SATURDAY, WITH LOCALLY STRONGER
GUSTS IN SOUTHEAST CA. THE STRONGEST GUSTS BY SUNDAY WILL LIKELY BE
CONFINED TO EASTERN AZ HIGHER TERRAIN. THIS WILL LIKELY RESULT IN
ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS ACROSS THE
REGION BOTH DAYS. AFTERNOON MINRHS MOSTLY BETWEEN 8-12% TODAY WILL
INCREASE BY SEVERAL POINTS THIS WEEKEND, WITH VALUES 7-15% AREAWIDE
SATURDAY, THEN 10-20% SUNDAY. OVERNIGHT RECOVERIES RANGING FROM 25-
45% ACROSS THE AREA AND IMPROVING ONLY SLIGHTLY FROM THERE ON
SATURDAY AND SUNDAY NIGHTS.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...NONE.
CA...WIND ADVISORY FROM 2 PM SATURDAY TO 11 PM PDT SUNDAY FOR CAZ562.
WIND ADVISORY FROM 4 PM TO 11 PM PDT SATURDAY FOR CAZ566.
SHORT TERM...WHITTOCK
LONG TERM...WHITTOCK
AVIATION...18
FIRE WEATHER...WHITTOCK
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