149
FXUS65 KFGZ 210500
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1000 PM MST WED AUG 20 2025
SYNOPSIS
CHANCES FOR SHOWERS AND THUNDERSTORMS RISE OVER THE
COMING DAYS AS MONSOONAL MOISTURE BEGINS TO INCREASE OVER NORTHERN
ARIZONA. SCATTERED TO WIDESPREAD STORMS, SOME WITH HEAVY RAIN AND
LOCALIZED FLASH FLOODING, ARE EXPECTED TO DEVELOP BY WEEKS END
AND CONTINUE INTO NEXT WEEK. HOT TEMPERATURES WILL REMAIN THROUGH
FRIDAY, BEFORE COOLER TEMPERATURES RETURN FOR THE WEEKEND.
DISCUSSION
STRONG HIGH PRESSURE (500 MB HEIGHTS NEAR 598 DAM)
WILL BE CENTERED NEAR THE FOUR CORNERS THROUGH FRIDAY BEFORE
GRADUALLY WEAKENING AND SLIDING SOUTHWARD INTO NEW MEXICO LATE
THIS WEEKEND/EARLY NEXT WEEK. THIS IS A MUCH MORE FAVORABLE SETUP
FOR TRANSPORTING MONSOON MOISTURE INTO OUR REGION THAN WE HAVE
SEEN LATELY, AND SHOULD SET THE STAGE FOR AN ACTIVE PERIOD OF
SHOWERS AND THUNDERSTORMS. WITH SUCH A STRONG HIGH PRESSURE
SYSTEM, HEAT WILL ALSO BE AN ISSUE THROUGH AROUND FRIDAY. AN
EXTREME HEAT WARNING IS IN EFFECT THROUGH FRIDAY FOR THE LOWER
ELEVATIONS OF GRAND CANYON. THE LOWER ELEVATIONS OF YAVAPAI COUNTY
WILL ALSO BE QUITE HOT THROUGH FRIDAY (VERDE VALLEY NEAR 105F),
THOUGH CLOUD COVER/PRECIP MAY IMPACT THESE AREAS EACH DAY BY
EARLY/MID AFTERNOON AND KEEP TEMPERATURES DOWN A BIT. FOR TODAY,
THE MAIN AREA OF MOISTURE INCREASE HAS BEEN EASTERN AND PARTS OF
CENTRAL ARIZONA, WITH ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM DEVELOPMENT. THIS ACTIVITY WILL CONTINUE TO PUSH
TOWARD THE WEST-SOUTHWEST THROUGH EARLY TO MID EVENING BEFORE
DISSIPATING.
THURSDAY - A CONTINUED WESTWARD PUSH OF MOISTURE IS FORECAST AS
THE LARGE SCALE FLOW AS WELL AS OUTFLOW BOUNDARIES ARE FAVORABLE
FOR MOISTENING UP AREAS AS FAR WEST AS YAVAPAI COUNTY. STORM
CHANCES GO UP TO 50-60% ALONG THE MOGOLLON RIM/WHITE MTNS INTO
EASTERN YAVAPAI AND NORTHERN GILA COUNTIES. MOISTURE SHOULD
INCREASE ENOUGH FOR SOME HIGH-BASED ACTIVITY ALL THE WAY TO THE
AZ/UT STATE LINE FOR THURSDAY AS WELL. MAIN THREATS WITH STORMS
WILL BE GUSTY OUTFLOW WINDS TO 50 MPH ALONG WITH SOME POCKETS OF
HEAVY RAIN SOUTH OF I-40 - THOUGH STORM MOTIONS OF 10-15 MPH
SHOULD KEEP THE LOCALIZED FLOODING RISK FAIRLY LOW.
FRIDAY INTO EARLY/MID NEXT WEEK - SHOWER AND THUNDERSTORM
COVERAGE IS FORECAST TO REMAIN HIGH (50-80%) EACH DAY WITH SOME
FLUCTUATION RELATED TO OUTFLOWS AND DEBRIS CLOUDINESS THOUGH THESE
ARE NOT REALLY PREDICTABLE MUCH MORE THAN 24 HOURS OUT. WITH
ELEVATED PRECIPITABLE WATER VALUES ACROSS THE REGION, THE THREAT
OF LOCALLY HEAVY RAIN AND FLASH FLOODING WILL INCREASE, ESPECIALLY
SATURDAY AND SUNDAY. IN ADDITION, EASTERLY STEERING FLOW FRIDAY
AND SATURDAY WILL BE FAVORABLE FOR PUSHING STORMS OFF THE HIGH
TERRAIN WESTWARD INTO YAVAPAI COUNTY AND NORTHERN GILA COUNTY
WHERE MOISTURE AND INSTABILITY WILL BE HIGHEST EACH AFTERNOON.
THIS PATTERN CAN PRODUCE STRONG TO LOCALLY SEVERE THUNDERSTORMS
WITH STRONG WINDS AND HAIL IN THIS AREA. AS THE HIGH GRADUALLY
WEAKENS AND SHIFTS SOUTHWARD, HIGH TEMPERATURES SHOULD FALL BACK
CLOSER TO NORMAL BY THE WEEKEND AND EARLY NEXT WEEK. THE HIGH
SHIFTING SOUTHWARD WILL ALSO TURN OUR STEERING FLOW MORE SOUTHERLY
TO SOUTHWESTERLY SUNDAY THROUGH MID WEEK, GIVING AREAS NORTH OF
THE MOGOLLON RIM A BETTER SHOT AT RAINFALL.
AVIATION...THURSDAY 21/06Z THROUGH FRIDAY 22/06Z
MAINLY VFR
CONDITIONS EXPECTED THROUGH THE TAF PERIOD. BRIEF MVFR CONDITIONS
POSSIBLE NEAR SHRA/TSRA, BUT ONLY VERY ISOLATED ACTIVITY REMAINS
OVERNIGHT. OUTSIDE OF STORM DRIVEN OUTFLOW WINDS, LOOK FOR LIGHT
AND VARIABLE WINDS. ADDITIONAL SHRA/TSRA EXPECTED AFTER 18Z
THURSDAY, MOSTLY ALONG AND SOUTH OF A KPGA-KRQE LINE.
OUTLOOK...FRIDAY 22/06Z THROUGH SUNDAY 24/06Z...DAILY CHANCES FOR
SHOWERS/STORMS WILL CONTINUE EACH AFTERNOON/EVENING. MAIN HAZARDS
WILL BE HEAVY RAIN, SMALL HAIL, GUSTY/ERRATIC WINDS, AND
LIGHTNING. OUTSIDE OF STORM DEVELOPMENT, LOOK FOR VFR CONDITIONS
AND WINDS 10 KTS OR LESS VARYING IN DIRECTION.
FIRE WEATHER...THIS EVENING THROUGH FRIDAY
HOT CONDITIONS
CONTINUE. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS INTO THIS
EVENING, MOST NUMEROUS ACROSS EASTERN AZ. MORE WIDESPREAD SHOWERS
AND THUNDERSTORMS EXPECTED ON THURSDAY AND FRIDAY, ALONG WITH
INCREASING RH VALUES. WINDS GENERALLY VARIABLE 5-10 MPH. GUSTY AND
ERRATIC WINDS POSSIBLE IN AND AROUND THUNDERSTORMS.
SATURDAY THROUGH MONDAY...INCREASING CHANCES FOR NUMEROUS TO
WIDESPREAD SHOWERS AND THUNDERSTORMS WITH WETTING RAINS EACH DAY.
WINDS WILL PRIMARILY BE VARIABLE 5-10 MPH. GUSTY AND ERRATIC WINDS
POSSIBLE IN AND AROUND THUNDERSTORMS.
FGZ WATCHES/WARNINGS/ADVISORIES
EXTREME HEAT WARNING UNTIL 8 PM MST FRIDAY FOR AZZ006.
PUBLIC...JJ
AVIATION...KONIECZNY
FIRE WEATHER...JJ
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page