501  
FXUS65 KPSR 011923  
AFDPSR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PHOENIX AZ  
1223 PM MST MON JUN 1 2026  
   
KEY MESSAGES
 
 
- SLIGHTLY ABOVE NORMAL TEMPERATURES WILL PREVAIL THROUGHOUT THE  
WEEK BEFORE RETREATING CLOSER TO NORMAL OVER THE WEEKEND.  
 
- OTHER THAN A SLIGHT CHANCE OF A THUNDERSTORM IN EASTERN AZ  
DURING THE MIDDLE OF THE WEEK, DRY CONDITIONS UNDER MOSTLY SUNNY  
SKIES WILL PREVAIL THROUGH THE NEXT SEVERAL DAYS.  
 

 
   
SHORT TERM /TODAY THROUGH WEDNESDAY/
 
 
LATEST WATER VAPOR SATELLITE IMAGERY AS WELL AS STREAMLINE ANALYSIS  
SHOW AN OMEGA BLOCKING PATTERN CENTERED OVER CENTRAL CANADA WITH  
TROUGHING ALONG THE NORTHEASTERN CONUS AND OVER THE NORTHERN  
ROCKIES. MEANWHILE, OVER THE DESERT SOUTHWEST, SOUTHWESTERLY FLOW  
ALOFT PREVAILS WITH WEAK TROUGHING NOTED JUST OFF THE SOUTHERN CA  
COAST. THIS WEAK TROUGHING FEATURE WILL CONTINUE TO SLOWLY  
PROGRESS EAST-SOUTHEASTWARD INTO NORTHERN MEXICO THROUGH MIDWEEK  
AND THUS WILL NOT HAVE ANY SIGNIFICANT SENSIBLE WEATHER IMPACTS  
FOR OUR REGION. THUNDERSTORM ACTIVITY MATERIALIZING ACROSS NEW  
MEXICO THROUGH THE MIDDLE OF THE WEEK WILL LIKELY SEND A WESTWARD  
PROPAGATING OUTFLOW BOUNDARY INTO FAR EASTERN ARIZONA, INCREASING  
LOW-LEVEL MOISTURE SOMEWHAT. THUS, ISOLATED THUNDERSTORMS ARE  
LIKELY TO MATERIALIZE NEAR THE WHITE MOUNTAINS WEDNESDAY  
AFTERNOON, POTENTIALLY IMPACTING FAR EASTERN GILA COUNTY.  
OTHERWISE, FAIRLY TRANQUIL WEATHER UNDER MOSTLY CLEAR SKIES WILL  
PREVAIL THROUGHOUT THE MAJORITY OF THE REGION.  
 
WITH 500 MB HEIGHT FIELDS RANGING 582-585DM, LOWER DESERT HIGHS  
TODAY AND TOMORROW WILL GENERALLY BE IN THE LOW 100S AND WILL RISE A  
COUPLE OF MORE DEGREES TO AROUND 105 DEGREES BY MIDWEEK AS 500 MB  
HEIGHTS RISE CLOSER TO 585-587DM. THESE TEMPERATURES WILL BE AROUND  
3-5 DEGREES ABOVE NORMAL FOR EARLY JUNE. THE OVERALL HEATRISK  
THROUGH TUESDAY WILL REMAIN IN THE MINOR CATEGORY BEFORE  
INCREASING INTO THE MODERATE CATEGORY MIDWEEK AS TEMPERATURES RISE  
INTO THE MID 100S. THEREFORE, IF PLANNING IN ANY OUTDOOR  
ACTIVITIES, MAKE SURE TO TAKE THE NECESSARY HEAT PRECAUTIONS TO  
AVOID ANY HEAT-RELATED ILLNESSES.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
DURING THE LATTER HALF OF THE WEEK, NAEFS MEMBERS ARE IN FAIR  
AGREEMENT SHOWING WEAK SOUTHERN STREAM TROUGHING SLOWLY TRANSLATING  
INTO THE SOUTHERN PLAINS AS DEEP NEGATIVE HEIGHT ANOMALIES APPROACH  
THE WESTERN CONUS. THE PRIMARY UNCERTAINTY IS THE FORWARD SPEED AT  
WHICH THIS OCCURS, AND HOW QUICKLY THE FORECAST AREA FALLS UNDER  
ANTI-CYCLONIC SUBSIDENCE. THE PREPONDERANCE OF ENSEMBLE OUTPUT  
SUGGESTS THE TROUGH AXIS NOT PASSING INTO THE SOUTHERN ROCKIES UNTIL  
FRIDAY, THUS KEEPING MODEST ASCENT MECHANISMS INTO EASTERN ARIZONA  
THURSDAY WITH A CONTINUED SLIGHT CHANCE OF STORMS OVER MOUNTAINOUS  
AREAS. REGARDLESS, THE PATTERN EVOLUTION LATE IN THE WEEK WILL  
PROMOTE HEIGHT FALLS AND DRY WESTERLY FLOW WITH H5 READINGS  
RETREATING CLOSER TO 580-582DM BY THE WEEKEND (AND POSSIBLY MUCH  
LOWER EARLY NEXT WEEK). WHILE NUMERICAL GUIDANCE SPREAD WIDENS  
DURING THE EVOLUTION, AN INCREASING NUMBER OF ENSEMBLE MEMBERS  
INDICATE DEEPER TROUGHING AND MORE ROBUST COOLING ARRIVING OVER THE  
WEEKEND SUCH THAT TEMPERATURES SHOULD RETURN TO NEAR NORMAL, OR  
EVEN INTO A SLIGHTLY BELOW NORMAL CATEGORY.  
 

 
   
AVIATION
 
UPDATED AT 1750Z.  
 
SOUTH CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:  
 
NO AVIATION WEATHER IMPACTS ARE EXPECTED THROUGH TUESDAY. WINDS  
WILL FOLLOW TYPICAL DIURNAL TENDENCIES, WITH A PERIOD OF LIGHT  
SOUTHERLY CROSS WINDS THROUGH EARLY AFTERNOON AT KPHX AND KDVT,  
BEFORE SHIFTING WESTERLY LATER THIS AFTERNOON. WIND SPEEDS WILL  
MOSTLY STAY AOB 10KTS WITH OCCASIONAL GUSTS INTO THE TEENS.  
FEW TO SCT PASSING HIGH CLOUDS WILL BE COMMON THIS AFTERNOON AND  
TONIGHT.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
 
NO AVIATION WEATHER IMPACTS EXPECTED THROUGH TUESDAY MORNING UNDER  
MOSTLY CLEAR SKIES. WINDS AT KIPL WILL FAVOR A SE COMPONENT  
THROUGH THIS AFTERNOON AND SHIFT W-SW THIS EVENING, WITH SPEEDS  
MOSTLY AOB 10 KTS AND A FEW GUSTS UP TO 15-20 KTS THIS EVENING.  
AT KBLH WINDS WILL FAVOR A SSW-SSE COMPONENT THROUGH THE PERIOD.  
WIND SPEEDS WILL ALSO MOSTLY BE AOB 10 KTS, WITH THE EXCEPTION OF  
SOME BREEZINESS THIS AFTERNOON WITH GUSTS UP TO 15-20 KTS.  
 

 
   
FIRE WEATHER
 
 
THE THREAT FOR A FEW LIGHTNING STRIKES WITH LITTLE RAINFALL IN FAR  
EASTERN GILA COUNTY WEDNESDAY AND THURSDAY IS THE MAIN FIRE WEATHER  
HAZARD THIS WEEK. WITH TEMPERATURES HOVERING SLIGHTLY ABOVE NORMAL,  
WINDS WILL MAINTAIN A DIURNAL UPSLOPE/NOCTURNAL DRAINAGE PATTERN.  
GUSTS WILL BE LIMITED THE FIRST HALF OF THE WEEK, THEN INCREASE  
LATER IN THE WEEK, PARTICULARLY ACROSS THE LOWER COLORADO RIVER  
VALLEY AND OVER MOUNTAINOUS LOCATIONS. MINIMUM AFTERNOON HUMIDITY  
LEVELS WILL GENERALLY FALL IN A 5-15% RANGE FOLLOWING A WIDELY  
RANGING POOR TO FAIR OVERNIGHT RECOVERY OF 15-45%.  
 

 
   
PSR WATCHES/WARNINGS/ADVISORIES
 
 
AZ...NONE.  
CA...NONE.  

 
 

 
 
SHORT TERM...LOJERO  
LONG TERM...18  
AVIATION...BENEDICT  
FIRE WEATHER...18  
 
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