108
FXUS65 KFGZ 311838
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1138 AM MST FRI JUL 31 2026
SYNOPSIS
VISIBLE SATELLITE IMAGERY SHOWS CUMULUS CLOUDS ARE
DEVELOPING OVER THE HIGHER TERRAIN OF THE RIM AND WHITE MOUNTAINS,
WERE DEWPOINT TEMPERATURES REMAIN IN THE LOW TO MID 50S. 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 SOMETIME NEXT WEEK
AS THE HIGH BEGINS TO WEEKEND AND SHIFTS 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...FRIDAY 31/18Z THROUGH SATURDAY 01/18Z
VFR
CONDITIONS, ISOLATED SHOWERS/STORMS FROM 18Z-03Z ALONG RIM AND
WHITE MOUNTAINS. WINDS LIGHT AND VARIABLE 5-15KTS DAY AND NIGHT.
GUSTY ERRATIC WINDS POSSIBLE NEAR STORMS.
OUTLOOK...SATURDAY 01/18Z THROUGH MONDAY 03/18Z...VFR CONDITIONS,
ISOLATED SHOWERS/STORMS FROM 18Z-03Z NEAR THE WHITE MOUNTAINS.
WINDS LIGHT AND VARIABLE 5-15KTS DAY AND NIGHT. GUSTY ERRATIC
WINDS POSSIBLE NEAR STORMS.
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...BERNHART
FIRE WEATHER...BERNHART
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
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