904  
FXUS65 KPSR 280024  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
524 PM MST SAT MAY 27 2023  
   
UPDATE  
UPDATED AVIATION DISCUSSION.  
 
 
   
SYNOPSIS  
 
DRY AND NEAR TO BELOW NORMAL TEMPERATURES WILL PERSIST THROUGH  
NEXT WEEKEND. BREEZY TO LOCALLY WINDY CONDITIONS DURING THE  
AFTERNOON/EVENINGS WILL ALSO CONTINUE FOR THE SEVERAL DAYS. A  
SLIGHT COOLING TREND IS EXPECTED DURING THE MIDDLE AND LATTER  
PORTIONS OF NEXT WEEK AS A WEAK DISTURBANCE SLIDES THROUGH THE  
REGION.  
 
 
   
DISCUSSION  
 
CLEAR SKIES PREVAIL THIS AFTERNOON ACROSS THE DESERT SOUTHWEST.  
FURTHER NORTH ACROSS THE SOUTHERN ROCKIES, THUNDERSTORMS HAVE  
DEVELOPED AHEAD OF A SHORT-WAVE TROUGH MOVING EASTWARD THROUGH  
UTAH AND COLORADO. HOT/DRY/BREEZY CONDITIONS AHEAD OF THIS SYSTEM  
WILL MAINLY AFFECT EASTERN ARIZONA THIS AFTERNOON, INCLUDING  
SOUTHERN GILA COUNTY, HOWEVER LIGHTER WINDS PREDOMINATE ACROSS THE  
LOWER DESERTS.  
 
LATEST MODEL ENSEMBLES INDICATE A WEAK SHORT-WAVE RIDGE IN THE  
EASTERN PACIFIC WILL SLIDE EASTWARD TOWARDS THE ARIZONA/NEW MEXICO  
BORDER THROUGH MONDAY, RESULTING IN INCREASED THICKNESSES AND A  
GRADUAL WARMING TREND. LATEST DETERMINISTIC NBM INDICATES THE  
HOTTEST DAY THIS WEEK ACROSS CENTRAL ARIZONA WILL BE MONDAY, WHEN  
HIGH TEMPERATURES AGAIN APPROACH THE 100 DEGREE MARK IN PHOENIX.  
MEANWHILE, A COMPACT, CLOSED LOW WILL DROP SOUTHWARD DOWN THE  
CALIFORNIA COAST GRADUALLY TIGHTENING THE PRESSURE GRADIENT EARLY  
NEXT WEEK. THIS WILL TRANSLATE INTO WIDESPREAD BREEZINESS EACH  
AFTERNOON, THOUGH ECWMF EFIS BELOW 50 PERCENT PERSIST THROUGH THE  
WEEK, SUGGESTING THE LACK OF ANY ANOMALOUS EVENTS ACROSS MUCH OF  
THE AREA. NEVERTHELESS, SOME ECMWF MEMBERS INDICATE PEAK GUSTS  
COULD REACH 40-45 MPH ACROSS THE IMPERIAL VALLEY WEDNESDAY  
AFTERNOON AND EVENING.  
 
THE AFOREMENTIONED LOW WILL LIKELY MEANDER AND EVEN RETROGRADE  
OFF THE CALIFORNIA COAST BEFORE ULTIMATELY MOVING EASTWARD AND  
MOVING THROUGH THE AREA MID TO LATE WEEK. ALTHOUGH THE OVERALL  
EVOLUTION OF THE LOW IS A BIT UNCERTAIN, THIS SYSTEM IS EXPECTED  
TO USHER IN NOTICEABLY COOLER CONDITIONS AND A RETURN TO BELOW  
NORMAL TEMPERATURES, PARTICULARLY ACROSS SOUTHERN ARIZONA AND  
CALIFORNIA, WHERE THE NEGATIVE HEIGHT ANOMALIES WILL BE MOST  
PRONOUNCED. THE ENSEMBLES ALSO SUGGEST A SLIGHT UPTICK IN MOISTURE  
LATE IN THE WEEK, THOUGH POPS WILL REMAIN NEAR ZERO FOR THE  
FORESEEABLE FUTURE.  
 
 
   
AVIATION  
UPDATED AT 0024Z.  
 
SOUTH-CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, KDVT:  
NO MAJOR AVIATION WEATHER CONCERNS ARE EXPECTED THROUGH THE TAF  
PERIOD. LIGHT WINDS, WITH SOME AFTERNOON BREEZINESS, WILL PERSIST  
WITH DIRECTIONS GENERALLY FOLLOWING DIURNAL TENDENCIES. A PERIOD  
OF SOUTHERLY WINDS WILL BE POSSIBLE BY LATE SUNDAY MORNING BEFORE  
VEERING TOWARD A W/SW COMPONENT GOING THROUGH THE AFTERNOON. CLEAR  
SKIES WILL PERSIST.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
LIGHT WINDS AT KIPL WILL GIVE WAY TO INCREASING WESTERLY WINDS,  
WITH A FEW GUSTS TO AROUND 20 KTS, EARLY THIS EVENING BEFORE  
SUBSIDING TONIGHT. AT KBLH, SOUTHERLY WINDS WILL CONTINUE WITH  
PERIODS OF VARIABILITY. CLEAR SKIES WILL CONTINUE THROUGH THE  
PERIOD.  
 
 
   
FIRE WEATHER  
 
SEASONABLY DRY AND BREEZY CONDITIONS WILL CONTINUE THIS WEEKEND ALONG  
WITH A GRADUAL WARMING TREND. MINIMUM HUMIDITY IN THE AFTERNOONS  
WILL BE AROUND 5-15% MOST AREAS, WITH AN OVERNIGHT RECOVERY AROUND  
20-30% ACROSS EASTERN DISTRICTS AND 40-60% FOR THE WESTERN AREAS.  
SOUTHWEST WIND GUSTS UP TO 25-30 MPH IN SOUTHERN GILA COUNTY THIS  
AFTERNOON COULD CREATE LOCALLY ELEVATED FIRE WEATHER CONDITIONS.  
OTHERWISE, MOST LOWER DESERT LOCATIONS WILL SEE WEST-SOUTHWEST  
WIND GUSTS AROUND 15-20 MPH IN THE AFTERNOON, WHILE WESTERLY  
SUNDOWNER WIND GUSTS IN PARTS OF IMPERIAL COUNTY REACH 25-35 MPH.  
THE LOWER DESERTS WILL BE A LITTLE BREEZIER SUNDAY, WITH GUSTS UP  
TO 20-25 MPH. IMPERIAL COUNTY WILL SEE SIMILAR SUNDOWNER WINDS  
AGAIN. SLIGHTLY COOLER CONDITIONS ARE ANTICIPATED ACROSS  
SOUTHEASTERN CALIFORNIA MONDAY AS A LOW PRESSURE SYSTEM APPROACHES  
THE REGION.  
 
BREEZY CONDITIONS WILL BE COMMON EACH DAY, ESPECIALLY DURING  
THE AFTERNOON AND EVENING HOURS WHEN WESTERLY TO SOUTHWESTERLY WINDS  
COULD GUST UPWARDS OF 20-25 MPH ACROSS THE LOWER DESERTS, UP TO 25  
TO 35 MPH ACROSS IMPERIAL COUNTY, AND LOCALLY HIGHER IN WESTERN  
PORTIONS OF IMPERIAL COUNTY. WIND DIRECTIONAL TENDENCIES WILL MOSTLY  
FOLLOW TYPICAL DIURNAL AND TERRAIN INFLUENCES. OTHERWISE, NEAR  
NORMAL TEMPERATURES ARE ANTICIPATED EARLY IN THE WEEK FOLLOWED BY  
SOMEWHAT COOLER CONDITIONS MID TO LATE WEEK AS A LOW PRESSURE  
SYSTEM MOVES THROUGH THE INTERMOUNTAIN WEST.  
 
 
   
HYDROLOGY  
UPDATED 150 AM MST 5/27/2023  
 
GILA: ONGOING RELEASES FROM PAINTED ROCK DAM CONTINUE TO TRAVEL DOWN  
THE GILA RIVER THROUGH YUMA COUNTY. THESE RELEASES WILL CONTINUE TO  
IMPACT UNBRIDGED CROSSINGS WITH MULTIPLE ROADS REMAINING CLOSED DUE  
TO FLOODING. THE LATEST USGS GAUGE OBSERVATION ALONG THE GILA RIVER  
NEAR DATELAND HAS FALLEN MORE THAN 1.5 FT BELOW ACTION STAGE OVER  
THE LAST FEW DAYS, WITH THE MOST RECENT READING BEING 6.46 FT.  
FURTHER DOWNSTREAM, THE USGS GAUGE NEAR DOME/YUMA IS VERY SLOWLY  
DECLINING, BUT REMAINS ABOVE ACTION STAGE (20 FT) WITH THE LATEST  
READING OF 20.45 FT. DESPITE THE DECLINES, AND ONE GAUGE FALLING  
BELOW ACTION STAGE, WILL MAINTAIN THE CURRENT FLOOD WARNINGS  
DOWNSTREAM FROM PAINTED ROCK DAM UNTIL IMPROVEMENT OF IMPACTS CAN BE  
CONFIRMED WITH OFFICIALS. THE FLOOD WARNINGS REMAIN IN EFFECT  
THROUGH MAY 30TH.  
 
 
   
PSR WATCHES/WARNINGS/ADVISORIES  
 
AZ...NONE.  
CA...NONE.  
 
 
 
 
DISCUSSION...HIRSCH  
AVIATION...SMITH  
FIRE WEATHER...BENEDICT/HIRSCH  
HYDROLOGY...BENEDICT  
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