876  
FXUS65 KPSR 021141 AAA  
AFDPSR  
 
AREA FORECAST DISCUSSION...UPDATED  
NATIONAL WEATHER SERVICE PHOENIX AZ  
440 AM MST THU JUL 2 2020  
   
UPDATE
 
UPDATED AVIATION DISCUSSION.  
 

 
   
SYNOPSIS
 
 
AS HIGH PRESSURE BUILDS INTO THE REGION, TEMPERATURES WILL STEADILY  
WARM THROUGH THE WEEK WITH HIGHS CLIMBING BACK ABOVE NORMAL BY THE  
WEEKEND. THIS AREA OF HIGH PRESSURE WILL ALSO ALLOW MOISTURE LEVELS  
TO RISE RESULTING IN A VERY SLIGHT CHANCE OF THUNDERSTORMS FOR PARTS  
OF SOUTH-CENTRAL ARIZONA. MUCH OF THE AREA LIKELY WILL NOT  
EXPERIENCE STORMS DIRECTLY, BUT WIND AND DUST MORE COMMON EARLY IN  
THIS SEASON, PARTICULARLY THIS AFTERNOON AND EVENING. A GRADUAL  
DRYING TREND BEGINNING THIS WEEKEND WILL NOT FAVOR STORM  
DEVELOPMENT FOR SOUTH-CENTRAL AZ FOR THE HOLIDAY WEEKEND AND EARLY  
NEXT WEEK.  
 

 
   
DISCUSSION
 
 
CURRENT SATELLITE IMAGERY SHOWS A FEW CLOUDS STRETCHING ACROSS  
SOUTHERN MARICOPA AND PINAL COUNTIES AS SOME MIDLEVEL MOISTURE  
FROM YESTERDAY'S SOUTHERN ARIZONA CONVECTION ADVANCES NORTHWARD.  
MEANWHILE, INCREASING SOUTHERLY FLOW MAY ENHANCE A GULF MOISTURE  
SURGE INTO THE FORECAST AREA LATER THIS MORNING. SO FAR, SURFACE  
OBSERVATIONS SHOW ONLY A FRAGMENTED SURGE OF 50-55 DEW POINTS  
INTO SOUTHWESTERN YUMA COUNTY AND WITHIN A NARROW CORRIDOR FROM  
ROCKY POINT NORTHWARD INTO AJO. LATEST TRENDS IN HI-RES GUIDANCE  
SHOW THE GULF SURGE FINALLY EXPANDING AND REACHING THE SOUTH-  
CENTRAL AND WESTERN ARIZONA DESERTS AROUND SUNRISE.  
 
THE BEST CHANCES FOR PRECIPITATION TODAY ARE CONFINED TO  
SOUTHEASTERN ARIZONA AND ALONG THE MOGOLLON RIM. A FEW ELEVATED  
SHOWERS AND/OR THUNDERSTORMS ASSOCIATED WITH THE AFOREMENTIONED  
MOISTURE SURGE CANNOT BE RULED OUT FOR THIS MORNING. BY THIS  
AFTERNOON, THUNDERSTORM CHANCES IMPROVE, ALBEIT VERY SLIGHTLY, AS  
DEEPER MOISTURE AND DAYTIME HEATING INCREASE INSTABILITY. STILL,  
STRONG CONVECTIVE INHIBITION WILL LIMIT STORM DEVELOPMENT OVER THE  
LOWER DESERT RESULTING IN POPS MOSTLY AT OR BELOW 10 PCT. MOST  
PLACES WILL NOT SEE ANY STORMS, AND ANY THAT DO, ARE NOT LIKELY TO  
SEE MUCH RAINFALL. NONETHELESS, A CLASSIC INVERTED-V ATMOSPHERIC  
PROFILE WILL SUPPORT STRONG GUSTY WINDS FROM ANY STORMS THAT DO  
DEVELOP. LONG TRAVELING OUTFLOWS ARE ALSO IN THE MIX, AS THE MOST  
AGGRESSIVE HI-RES MODELS SUGGEST, WHICH MEANS THAT EVEN IF  
CONVECTION IS NEARLY NON-EXISTENT OVER THE FORECAST AREA THIS  
AFTERNOON, STORMS THAT DO FORM FARTHER SOUTH IN PIMA COUNTY COULD  
POTENTIALLY TRAVEL NORTHWARD INTO SOUTHERN MARICOPA AND PINAL  
COUNTIES WHERE BLOWING DUST IS FAVORABLE.  
 
AFTER TOMORROW, ENSEMBLE GUIDANCE SHOWS THE RIDGE REMAINING OVER  
THE SOUTHWEST FOR NEXT SEVERAL DAYS WITH MEAN H5 HEIGHTS OF 594DM  
SLICING THROUGH ARIZONA. MOISTURE LEVELS, WHICH ARE NOT CURRENTLY  
SPECTACULAR, DRY THROUGH THE WEEKEND WHICH WILL KEEP ANY POPS  
MINIMAL AND FOCUSED OVER THE HIGHER TERRAIN NORTH AND EAST OF  
PHOENIX. MEANWHILE, AFTERNOON TEMPERATURES WILL CONTINUE WARMING  
INTO THE 110 DEGREE NEIGHBORHOOD BY SATURDAY AND THEN PERSIST  
THROUGH MOST OF NEXT WEEK.  
 

 
   
AVIATION
 
UPDATED AT 1140Z.  
 
SOUTH-CENTRAL ARIZONA INCLUDING KPHX, KIWA, KSDL, AND KDVT:  
 
A WEAK DISTURBANCE APPROACHING FROM THE SOUTH, AND EMBEDDED IN  
SOUTHWEST FLOW ALOFT, WILL SPREAD INCREASING MAINLY MID CLOUD INTO  
THE PHOENIX AREA THIS MORNING. EXPECT FEW-SCT DECKS AROUND 10K FEET  
BY 14Z, WITH CIGS DEVELOPING DOWN TO AROUND 9K FEET THRU EARLY  
AFTERNOON. CLOUDS SHOULD DIMINISH SOMEWHAT DURING THE AFTERNOON, BUT  
MORE MID LEVEL DEBRIS CLOUD WILL LIKELY SPREAD INTO THE AREA THIS  
EVENING WITH SCT DECKS AROUND 10K AND MID DECKS IN THE 15K BALLPARK.  
 
CANNOT RULE OUT SOME SHOWERS WITHIN THE MID CLOUD STARTING AFTER 15Z  
AND PERSISTING PAST NOON, BUT CONFIDENCE TOO LOW AT THIS TIME TO  
MENTION THIS IN THE TAFS. ALSO, CANNOT RULE OUT ISOLATED  
THUNDERSTORMS DEVELOPING THIS AFTERNOON TO THE SOUTH/SOUTHEAST OF  
PHOENIX; MOST LIKELY THEY WOULD NOT DIRECTLY IMPACT THE TERMINALS  
BUT COULD SEND SOME SOUTHERLY OUTFLOW INTO THE METRO MOST LIKELY  
LATER IN THE AFTERNOON OR EARLY EVENING. AGAIN, THERE IS NO CLEAR  
SIGNAL FROM OUR LOCAL/MESOSCALE MODELS ON ANY OUTFLOW WIND SO AT THIS  
TIME WILL NOT ALTER THE TYPICAL DIURNAL WIND PATTERNS TO ACCOUNT FOR  
THIS. WE WILL CONTINUE TO MONITOR AND ADJUST THE TAFS ACCORDINGLY  
WHEN CONFIDENCE IN OUTFLOW WIND INCREASES. FOR NOW WILL CONTINUE TO  
GO WITH TYPICAL DIURNAL WIND PATTERNS AT THE TAF SITES OVER THE NEXT  
24 HOURS.  
 
SOUTHEAST CALIFORNIA/SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH:  
 
DRY SOUTHWEST WINDS ALOFT WILL CONTINUE OVER THE WESTERN DESERTS  
OVER THE NEXT 24 HOURS. SKIES TO BE GENLY CLEAR TODAY WITH MAYBE A  
FEW MID OR HIGHER LEVEL DECKS APPROACHING FROM THE WEST DURING THE  
EVENING. WINDS WILL FAVOR THE SOUTH NEXT 24 HOURS AT KBLH BECOMING  
BREEZY DURING THE AFTERNOON WITH GUSTS OVER 25KT POSSIBLE AT TIMES  
AFTER 18Z. WINDS TO TAPER OFF BY 03Z. WINDS WILL FAVOR SOUTHEAST  
MUCH OF THE DAY AT KIPL, BECOMING MORE SOUTHWEST AFTER 03Z THIS  
EVENING. DO NOT EXPECT AS MUCH WIND AT KIPL AS COMPARED TO KBLH.  
 

 
   
FIRE WEATHER
 
 
SATURDAY THROUGH WEDNESDAY:  
NO CHANGES TO THE FIRE WEATHER OUTLOOK...A WARMING TREND WILL  
CONTINUE THROUGH SUNDAY OR MONDAY WITH ABOVE NORMAL HIGHS EXPECTED  
THROUGH THE PERIOD. A GRADUAL DRYING TREND IS ALSO UNDERWAY BY  
SATURDAY AND CONTINUES THROUGH THE END OF THE PERIOD. HOWEVER,  
THERE IS STILL A VERY SLIGHT LINGERING CHANCE OF A FEW ISOLATED  
STORMS FOCUSED OVER HIGHER TERRAIN AREAS OF THE EASTERN DISTRICTS  
THOUGH RAINFALL MAY NOT BE VERY WIDESPREAD OR HEAVY WITH ANY  
ISOLATED STORMS. AFTERNOON MINIMUM HUMIDITY VALUES WILL GENERALLY  
FALL BETWEEN THE SINGLE DIGITS IN THE FAR WEST AND THE LOW TO MID  
TEENS ELSEWHERE, WHILE OVERNIGHT MAXIMUM RHS LOOK TO VARY BETWEEN  
25-40%. TYPICAL AFTERNOON BREEZES WITH GUSTS UP TO 20 MPH WILL BE  
LIKELY WITH SOME LOCALIZED STRONGER OUTFLOW WINDS POSSIBLE NEAR  
ANY RENEGADE STORMS.  
 

 
   
SPOTTER INFORMATION STATEMENT
 
 
SPOTTERS SHOULD FOLLOW STANDARD REPORTING PROCEDURES.  
 

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

 
 

 
 
DISCUSSION...AD  
AVIATION...CB  
FIRE WEATHER...SAWTELLE/SMITH  
 
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