116  
FXUS65 KFGZ 010522  
AFDFGZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FLAGSTAFF AZ  
1022 PM MST FRI JUL 31 2026  
   
SYNOPSIS  
ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON OVER  
THE HIGHER TERRAIN, ESPECIALLY OVER THE WHITE MOUNTAINS. OTHERWISE,  
AS HIGH PRESSURE BUILDS OVER ARIZONA TODAY, HOT DAYTIME TEMPERATURES  
ARE EXPECTED THROUGH THE WEEKEND, AND ARE EXPECTED TO REACH THE  
WARMEST READINGS SO FAR THIS YEAR. MONSOON MOISTURE IS THEN EXPECTED  
TO START MOVING BACK INTO THE REGION DURING THE SECOND-HALF OF NEXT  
WEEK AS THE HIGH BEGINS TO WEAKEN AND SHIFT INTO A MORE FAVORABLE  
POSITION.  
 
 
   
DISCUSSION  
HIGH PRESSURE IS BUILDING OVER ARIZONA TODAY AND  
WILL HELP TO DIMINISH MONSOON ACTIVITY AS SUBSIDENCE INCREASES  
UNDER THE RIDGE AND DRIER AIR GRADUALLY WORKS ITS WAY INTO THE  
REGION. OBSERVATIONS FROM THIS MORNING STILL SHOW DEWPOINTS IN THE  
LOW TO MID 50S ACROSS THE HIGHER TERRAIN, ESPECIALLY FROM  
FLAGSTAFF SOUTHWARD TO THE WHITE MOUNTAINS. THIS LINGERING  
MOISTURE MAY STILL SUPPORT ISOLATED THUNDERSTORMS OVER THE HIGHER  
TERRAIN THIS AFTERNOON. STORM MOTION IS EXPECTED TO BE EAST-  
NORTHEAST AROUND 5 MPH, WHILE OUTFLOW FROM THUNDERSTORMS MAY  
INTRODUCED A SLIGHT SOUTHWARD DRIFT. THE SLOW STORM MOTION WILL  
WILL KEEP A LOW-END FLASH FLOOD THREAT IN PLACE, ESPECIALLY OVER  
BURNS SCARS IF THUNDERSTORMS DEVELOP OVERHEAD. THIS SOMEWHAT  
SUPPRESSED PERIOD OF MONSOONAL ACTIVITY IS FORECAST TO CONTINUE  
THROUGH AT LEAST THE WEEKEND. SHOWERS AND THUNDERSTORMS WILL NOT  
FULLY SHUT OFF EACH DAY, BUT REMAIN ISOLATED WITH THE BEST  
COVERAGE IN THE WHITE MOUNTAINS.  
 
THE PRIMARY HAZARD OVER THE NEXT FEW DAYS WILL BE HEAT. WITH THE  
DECREASE IN MOISTURE AND ABOVE NORMAL HEIGHTS AT 500MB,  
TEMPERATURES WILL BE THE WARMEST OF THE YEAR SO FAR FOR ALL OF  
NORTHERN AZ. AS A RESULT, A VARIETY OF HEAT HEADLINES WILL BE IN  
EFFECT. AN EXTREME HEAT WARNING FOR THE GRAND CANYON BELOW 4000 FT  
WILL REMAIN IN EFFECT UNTIL SUNDAY WITH DAYTIME TEMPERATURES UP  
TO 110-117 F. ADDITIONAL EXTREME HEAT WARNINGS WILL BE IN EFFECT  
TODAY THROUGH SUNDAY FOR GLEN/MARBLE CANYON AND LOW ELEVATION  
AREAS SOUTH OF THE MOGOLLON RIM, WHERE TEMPERATURES WILL APPROACH  
OR EXCEED 110 F. LOWER ELEVATIONS OF NORTHEASTERN ARIZONA WILL  
HAVE A HEAT ADVISORY ON SATURDAY AND SUNDAY, WITH DAYTIME  
TEMPERATURES UP TO 100-105 F.  
 
BY THE EARLY TO MIDDLE PART OF NEXT WEEK, ENSEMBLE GUIDANCE IS  
LEANING TOWARDS THE HIGH WEAKENING AND SHIFTING EAST. THIS WOULD  
ALLOW MONSOONAL ACTIVITY TO INCREASE AGAIN. THERE IS STILL SOME  
UNCERTAINTY ON THE EXACT TIMING AND NATURE OF THIS TRANSITION, AND  
THERE IS POTENTIAL THAT HEAT HEADLINES WILL BE EXTENDED PAST  
SUNDAY. RIGHT NOW THE FORECAST IS LEANING TOWARD HOT TEMPERATURES  
WITH DIMINISHED MONSOONAL ACTIVITY CONTINUING INTO MONDAY AND  
POTENTIALLY TUESDAY, BEFORE MONSOON MOISTURE STARTS TO MAKE A MORE  
NOTICEABLE RETURN AROUND WEDNESDAY.  
 
 
   
AVIATION...SATURDAY 01/06Z THROUGH SUNDAY 02/06Z  
VFR CONDITIONS.  
ISO -SHRA/-TSRA INVOF A KFLG-KSOW-KJTC 19Z TO 03Z. GUSTY OUTFLOW  
WINDS POSSIBLE IN AND AROUND TS. OTHERWISE, WINDS VRB 5-10 KTS.  
 
OUTLOOK...SUNDAY 02/06Z THROUGH TUESDAY 04/06Z...VFR CONDITIONS. ISO  
-SHRA/-TSRA EACH AFTERNOON INVOF KSOW/KJTC. GUSTY OUTFLOW WINDS  
POSSIBLE IN AND AROUND TS. OTHERWISE, WINDS VRB 5-10 KTS.  
 
 
   
FIRE WEATHER...SATURDAY AND SUNDAY  
HOT WITH TEMPERATURES 10-15  
DEGREES ABOVE AVERAGE ALL WEEKEND. ISOLATED SHOWERS AND  
THUNDERSTORMS EACH AFTERNOON/EVENING OVER THE WHITE MOUNTAINS. WINDS  
LIGHT AND VARIABLE 5-15 MPH. MINIMUM RH VALUES AS LOW AS 7-15% IN  
THE DESERTS, 15-25% MOUNTAINS.  
 
MONDAY THROUGH WEDNESDAY...A SLIGHT COOLING TREND BUT STILL 5-10  
DEGREES ABOVE AVERAGE. ISOLATED SHOWERS AND STORMS OVER THE WHITE  
MOUNTAINS MONDAY, WITH COVERAGE INCREASING AND EXPANDING WESTWARD ON  
TUESDAY AND WEDNESDAY. DAYTIME WINDS GENERALLY SW-W AT 5-15 MPH EACH  
DAY. MINIMUM RH VALUES 10-25% MONDAY AND TUESDAY, 10-30% WEDNESDAY.  
 
 
   
FGZ WATCHES/WARNINGS/ADVISORIES  
 
EXTREME HEAT WARNING UNTIL 8 PM MST /9 PM MDT/ SUNDAY FOR AZZ005-  
006-018-037-038.  
 
HEAT ADVISORY FROM 10 AM MST /11 AM MDT/ SATURDAY TO 8 PM MST /9  
PM MDT/ SUNDAY FOR AZZ009-010-012>014-040.  
 
 
 
 
 
PUBLIC...SCHANK  
AVIATION...HUMPHREYS  
FIRE WEATHER...BERNHART  
 
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT  
WEATHER.GOV/FLAGSTAFF  
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