863
FXUS65 KFGZ 191720
AFDFGZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
1021 AM MST SAT JUL 19 2025
SYNOPSIS
FOR TODAY, THE BEST CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL BE EAST OF INTERSTATE 17 AND SOUTH OF
INTERSTATE 40, WITH MORE ISOLATED STORM ACTIVITY FORECAST
ELSEWHERE. LOW GRADE MONSOON CONDITIONS ARE FORECAST TO PERSIST
INTO NEXT WEEK, WITH THE GREATEST STORM CHANCES OVER THE HIGHER
TERRAIN FROM FLAGSTAFF EASTWARD.
DISCUSSION
NORTHERN ARIZONA REMAINS SANDWICHED BETWEEN A 500 MB
LOW CENTERED OVER SOUTHERN CALIFORNIA AND A BROAD 500 MB HIGH
CENTERED OVER TEXAS. SOUTHERLY FLOW BETWEEN THESE FEATURES
CONTINUES TO ADVECT TROPICAL MOISTURE INTO THE STATE, BUT WITH A
NOTICEABLE MOIST-EAST TO DRY-WEST ORIENTED GRADIENT THAT WILL
LARGELY DICTATE THE CHANCES FOR SHOWERS AND THUNDERSTORMS THIS
AFTERNOON.
FOR TODAY, THE BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE
EAST OF INTERSTATE 17 AND SOUTH OF INTERSTATE 40, WITH MORE
ISOLATED STORM ACTIVITY FORECAST ELSEWHERE. WHERE THE GREATEST
MOISTURE EXISTS, MARGINAL CAPE BETWEEN 100-500 J/KG IS FORECAST.
ESPECIALLY IN THIS AREA, STORMS WILL BE SLOW MOVING, SO FLASH
FLOODING WILL BE THE PRIMARY THREAT. HOWEVER, BETWEEN 25-35 KTS OF
DEEP LAYER SHEAR IS ALSO FORECAST. THIS IMBALANCE WILL MAKE IT
DIFFICULT FOR BUILDING STORMS TO REMAIN INTACT, BUT FOR THOSE THAT
DO SURVIVE, A FEW MORE POWERFUL ROTATING STORMS ARE POSSIBLE
TODAY AS WELL. SO, ISOLATED, SEVERE STORMS CANNOT BE COMPLETELY
RULED OUT.
ACTIVE, BUT LOW GRADE MONSOON CONDITIONS ARE FORECAST TO CONTINUE
INTO EARLY NEXT WEEK, WITH THE GREATEST STORM CHANCES OVER THE
HIGHER TERRAIN FROM FLAGSTAFF EASTWARD. AROUND THE MIDDLE OF NEXT
WEEK, THE GENERAL MODEL CONSENSUS SHOWS THAT A DEEP LOW WILL
BECOME ESTABLISHED OFF THE WEST COAST, FORCING THE SUBTROPICAL
HIGH AND TROPICAL MOISTURE PLUME EASTWARD, LEADING TO A DOWNTREND
IN STORM ACTIVITY. THAT SAID, CONSIDERABLE SPREAD EXISTS, AND SOME
MODEL SOLUTIONS KEEP THE STATE ENTRENCHED IN ENOUGH MOISTURE FOR
A CONTINUATION OF LOW GRADE MONSOON ACTIVITY THROUGH THE WEEK.
AVIATION...SATURDAY 19/18Z THROUGH SUNDAY 20/18Z
MAINLY VFR
CONDITIONS, OUTSIDE OF STORMS. ISOLD-SCT -SHRA/-TSRA BETWEEN 19Z-
03Z, MAINLY ALONG AND NORTH OF THE MOGOLLON RIM AND WHITE MOUNTAINS.
BRIEF MVFR AND GUSTY WINDS POSSIBLE NEAR THUNDERSTORMS. DAYTIME SFC
WINDS SW-W5-10G25-20KTS.
OUTLOOK...SUNDAY 20/18Z THROUGH TUESDAY 22/18Z...EXPECT ISOLD-SCT
-SHRA/-TSRA BETWEEN 19Z-03Z EACH DAY. MVFR AND GUSTY WINDS POSSIBLE
NEAR THUNDERSTORMS. DAYTIME SFC WINDS SW-W5-10G25-20KTS.
FIRE WEATHER...SATURDAY AND SUNDAY
ISOLATED/SCATTERED SHOWERS
AND THUNDERSTORMS ARE EXPECTED EACH AFTERNOON AND EVENING, MOST
NUMEROUS OVER THE EASTERN MOGOLLON RIM/WHITE MOUNTAINS. LOCALIZED
WETTING RAINS AND GUSTY/ERRATIC OUTFLOW WINDS ARE LIKELY IN THE
VICINITY OF STORMS. AWAY FROM STORMS, DAYTIME WINDS FROM THE
WEST/SOUTHWEST AT 5-10 MPH WITH GUSTS TO 10-20 MPH. EXPECT
TEMPERATURES NEAR NORMAL AND DAILY MINIMUM RH 15-30%.
MONDAY THROUGH WEDNESDAY...EXPECT ISOLATED/SCATTERED SHOWERS AND
THUNDERSTORMS EACH AFTERNOON AND EVENING, WITH THE BEST CHANCES OVER
THE EASTERN MOGOLLON RIM/WHITE MOUNTAINS. DAYTIME WINDS FROM THE
WEST/SOUTHWEST AT 5-10 MPH WITH GUSTS TO 10-20 MPH. EXPECT
TEMPERATURES NEAR NORMAL AND DAILY MINIMUM RH 15-30%.
FGZ WATCHES/WARNINGS/ADVISORIES
NONE.
PUBLIC...RR
AVIATION...PETERSON
FIRE WEATHER...RR
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT
WEATHER.GOV/FLAGSTAFF
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