438
FXUS65 KPSR 121705
AFDPSR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PHOENIX AZ
1005 AM MST MON MAY 12 2025
UPDATE
UPDATED AVIATION
SYNOPSIS
A DRY WEATHER SYSTEM WILL MOVE THROUGH THE REGION EARLY THIS WEEK
WHICH WILL ALLOW TEMPERATURES TO COOL THROUGH WEDNESDAY. IN ADDITION
TO COOLER TEMPERATURES THIS WEATHER SYSTEM WILL ALSO BRING BREEZY TO
LOCALLY WINDY CONDITIONS TO THE REGION OVER THE NEXT COUPLE OF DAYS.
THESE INCREASED WINDS IN COMBINATION WITH VERY LOW HUMIDITY WILL
LEAD TO ELEVATED FIRE WEATHER CONDITIONS. TEMPERATURES WILL RETURN
TO NEAR NORMAL LEVELS FOR THE SECOND HALF OF THE WEEK.
DISCUSSION
UPPER LEVEL WATER VAPOR SATELLITE IMAGERY AND OBJECTIVE ANALYSIS
DEPICT QUASI-ZONAL FLOW OVER ARIZONA WITH THE CENTER OF A LOW
PRESSURE SYSTEM JUST OFF THE COAST OF OREGON. THIS LOW WILL MOVE ON
SHORE THROUGHOUT THE MORNING AND CONTINUE TO PUSH EASTWARD INTO OUR
AREA OVER THE NEXT COUPLE OF DAYS. AS A RESULT TEMPERATURES WILL
COOL THROUGH THE MIDDLE OF THE WEEK. ALTHOUGH TEMPERATURES TODAY
WILL BE COOLER THAN THEY HAVE BEEN THE PAST COUPLE OF DAYS THEY WILL
STILL BE ABOVE NORMAL. WITH AFTERNOON HIGH TEMPERATURES IN THE UPPER
90S TO LOW 100S ACROSS THE LOWER DESERTS AND IN THE 90S IN THE
HIGHER TERRAIN AREAS. THERE WILL STILL BE AREAS OF MODERATE HEATRISK
ACROSS PORTIONS OF SOUTH-CENTRAL AZ, SO MAKE SURE TO KEEP PRACTICING
SMART HEAT SAFETY. THE REAL COOL DOWN WILL BE FELT TOMORROW WITH
AFTERNOON HIGH TEMPERATURES FORECASTED TO BE 10-15 DEGREES COOLER
THAN TODAY. THE BASE OF THE TROUGH WILL MOVE THROUGH OUR FORECAST
AREA DURING THE TUESDAY-WEDNESDAY TIMEFRAME, WHICH WILL BE THE
COOLEST DAYS OF THE WEEK WITH TEMPERATURES FALLING BELOW NORMAL.
AFTERNOON HIGH TEMPERATURES TUESDAY AND WEDNESDAY ARE FORECASTED TO
BE IN THE 80S TO NEAR 90 DEGREES ACROSS THE LOWER DESERTS AND IN
UPPER 70S TO MID 80S IN THE HIGHER TERRAIN AREAS.
WHILE THIS WEATHER SYSTEM WILL MOVE THROUGH DRY, IT WILL CAUSE SOME
WEATHER IMPACTS. IT WILL BRING BREEZY TO LOCALLY WINDY CONDITIONS TO
THE REGION. WIND GUSTS OF 25-40 MPH ARE EXPECTED ACROSS THE AREA,
MAINLY DURING THE AFTERNOONS AND EVENING. THE HIGHEST WIND GUSTS
WILL OCCUR ACROSS SOUTHEASTERN CA AND THE HIGHER TERRAIN IN EASTERN
AZ. A WIND ADVISORY REMAINS IN EFFECT FOR THE FAR SW CORNER OF
IMPERIAL COUNTY FROM SUNRISE THIS MORNING THROUGH SUNRISE WEDNESDAY
MORNING WHERE WIND GUSTS UP TO 55 MPH WILL BE POSSIBLE. HREF AND
ECMWF SHOW GOOD CONFIDENCE (>70%) OF WINDS IN EXCESS OF 40 MPH
REACHING INTO IMPERIAL VALLEY. DUE TO THIS, THE WIND ADVISORY HAS
BEEN EXPANDED AND NOW INCLUDES THE REST OF WESTERN IMPERIAL COUNTY
(INCLUDING IMPERIAL VALLEY AND THE SALTON SEA). THIS WIND ADVISORY
IS IN EFFECT FROM THIS AFTERNOON THROUGH THE EARLY MORNING HOURS ON
WEDNESDAY FOR GUSTS UP TO 45 MPH. THESE GUSTY WINDS IN COMBINATION
WITH THE DRY CONDITIONS (RELATIVE HUMIDITY OF 8-15%) AND DRY FUELS
WILL LEAD TO ELEVATED FIRE WEATHER CONDITIONS. DUE TO THIS
COMBINATION A RED FLAG WARNING HAS BEEN ISSUED FOR SOUTHERN GILA
COUNTY AND THE HIGHER ELEVATIONS OF NORTHEASTERN PINAL AND EASTERN
MARICOPA COUNTIES FOR THIS AFTERNOON AND EARLY EVENING AND AGAIN
TOMORROW FROM THE LATE MORNING THROUGH EARLY EVENING.
THE LOW PRESSURE SYSTEM WILL ADVECT INTO THE NORTHERN PLAINS DURING
THE LATTER HALF OF THE WEEK LEAVING QUASI-ZONAL FLOW IN ITS WAKE. H5
HEIGHTS WILL RISE OVER OUR AREA (TO A 576-579 DM RANGE) LEADING TO
SOME WARMING. THIS WILL ALLOW TEMPERATURES TO WARM BACK TO NEAR
NORMAL READINGS FOR THIS TIME OF YEAR WITH AFTERNOON HIGH
TEMPERATURES IN THE MID 90S ACROSS THE LOWER DESERTS AND IN THE 80S
IN THE HIGHER TERRAIN AREAS. THE QUASI-ZONAL FLOW WILL REMAIN
OVERHEAD HEADING INTO THE WEEKEND KEEPING TEMPERATURES STEADY FOR
THE END OF THE WEEK. GLOBAL ENSEMBLES START TO DIFFER BY THE END OF
THE FORECAST PERIOD, ALTHOUGH THEY HAVE COME INTO SLIGHTLY BETTER
AGREEMENT THAN YESTERDAY. OVERALL THE ENSEMBLES LEAN IN FAVOR
ANOTHER TROUGH MOVING INTO WESTERN CONUS BY THE END OF THE WEEKEND.
HOWEVER, THEY DIFFER ON THE EXACT STRENGTH AND TIMING OF THIS
TROUGH. WHETHER IT'S A STRONGER/DEEPER TROUGH OR WEAKER/SHALLOWER
TROUGH TEMPERATURES ARE EXPECTED TO COOL AT LEAST A LITTLE BIT. DRY
CONDITIONS WILL PERSIST THROUGH THE WEEKEND.
AVIATION
UPDATED AT 1705Z.
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:
A PERIOD OF SOUTHERLY CROSS RUNWAY WINDS FOLLOWED BY VEERING
DIRECTIONS AND INCREASING AFTERNOON/EARLY EVENING GUSTS WILL BE THE
MAIN WEATHER ISSUES THROUGH TUESDAY MORNING UNDER PERIODS OF
MID/HIGH CIGS. CONFIDENCE IS GOOD THAT A FEW HOURS OF 150V210 WINDS
WILL BE COMMON EARLY THIS AFTERNOON BEFORE COMPLETING THE W/SW
SWITCH. GUSTS AROUND 25KT SHOULD AFFECT ALL TERMINALS INTO THE MID
EVENING BEFORE RELAXING. CONFIDENCE IN WIND TRENDS OVERNIGHT IS LOW
WITH THE TRADITIONAL EASTERLY SWITCH EITHER FAILING TO OCCUR, OR
ONLY OCCURRING FOR A FEW HOURS BEFORE QUICKLY REVERTING BACK TO A SW
DIRECTION.
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:
GUSTY WINDS AND THE POTENTIAL FOR LOCALIZED BLOWING DUST WILL BE THE
PRIMARY WEATHER ISSUES UNDER MID/HIGH CLOUD DECKS. GUSTS WILL
INCREASE THROUGH THE AFTERNOON WITH DIRECTIONS GENERALLY VEERING
FROM SOUTHERLY TO SW. GUSTS MAY EXCEED 30KT AT KIPL THROUGH THE
EVENING HOURS WITH SPEEDS PEAKING 25-30KT AT KBLH DURING THE EARLY
EVENING BEFORE PARTIALLY RELAXING OVERNIGHT. THESE STRONG GUSTS MAY
RESULT IN LOCAL SURFACE AND SLANTWISE VISIBILITY RESTRICTIONS DUE TO
BLOWING DUST.
FIRE WEATHER
ELEVATED FIRE DANGER WILL EXIST TODAY AND TOMORROW AS WARM
TEMPERATURES, LOW HUMIDITY LEVELS, AND GUSTY WINDS BECOME JUXTAPOSED
WITH RECEPTIVE, DRY FINE FUELS. MINRHS OF 8-15% WILL BE COMMON
THROUGHOUT THE WEEK FOLLOWING POOR TO FAIR OVERNIGHT RECOVERY OF 20-
50%. WINDS WILL BE STRONGEST TODAY AND TOMORROW WITH GUSTS 25-40 MPH
DURING THE AFTERNOON AND EARLY EVENING, SOME HIGHER GUSTS ARE
POSSIBLE IN WESTERN IMPERIAL COUNTY. GUSTS WILL LIKELY BE MOST
PRONOUNCED ACROSS RIDGE TOPS AND IN THE TYPICAL DOWNSLOPING AREAS.
SPEEDS SHOULD WEAKEN DURING THE LATTER HALF OF THE WEEK, THOUGH
STILL WILL RETAIN THE USUAL AFTERNOON UPSLOPE GUSTINESS.
TEMPERATURES WILL ALSO COOL DURING THE FIRST HALF OF THE WEEK AS THE
WEATHER SYSTEM MOVES INTO THE REGION, HOWEVER SHOULD REBOUND CLOSER
TO SEASONAL NORMALS BY THE END OF THE WEEK.
PSR WATCHES/WARNINGS/ADVISORIES
AZ...RED FLAG WARNING FROM NOON TODAY TO 7 PM MST THIS EVENING FOR
AZZ133.
RED FLAG WARNING FROM 10 AM TO 8 PM MST TUESDAY FOR AZZ133.
CA...WIND ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR CAZ562.
WIND ADVISORY FROM 2 PM THIS AFTERNOON TO 2 AM PDT WEDNESDAY FOR
CAZ563-566-567.
DISCUSSION...BERISLAVICH
AVIATION...18
FIRE WEATHER...BERISLAVICH/18
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