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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