049  
FXUS65 KFGZ 190742  
AFDFGZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FLAGSTAFF AZ  
1242 AM MST TUE AUG 19 2025  
   
SYNOPSIS
 
ISOLATED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE  
THIS AFTERNOON OVER EASTERN ARIZONA, WITH HOT AND DRY CONDITIONS  
EXPECTED ELSEWHERE. MONSOONAL MOISTURE LOOKS TO INCREASE OVER THE  
COMING DAYS, WITH SCATTERED TO WIDESPREAD STORMS DEVELOPING BY  
WEEKS END. OTHERWISE, HOT TEMPERATURES AND LIGHT WINDS LOOK TO  
PREVAIL.  
 

 
   
DISCUSSION...TODAY
 
HOT AND MAINLY DRY CONDITIONS AND EXPECTED  
TODAY ACROSS NORTHERN ARIZONA AS A STRONG AREA OF HIGH PRESSURE  
BEGINS TO BUILD INTO THE FOUR CORNERS REGION. GIVEN THE MORE  
FAVORABLE POSITION OF THE HIGH, MOISTURE DOES LOOK TO GRADUALLY  
INCREASE STARTING TODAY. HOWEVER, MUCH OF THE ACTIVITY WILL LOOKS  
TO BE LIMITED TO THE EASTERN PORTIONS OF ARIZONA AND POTENTIALLY  
EXTENDED UP THE MOGOLLON RIM. EVEN SO, GIVEN THE 596-598 DAM  
RIDGE, STRONG SUBSIDENCE ALOFT WILL ACT TO SUPPRESS ANY STORMS  
THAT DO DEVELOP, THUS MAINLY ISOLATED ACTIVITY IS EXPECTED AT  
BEST.  
 
WEDNESDAY AND THURSDAY...HEIGHTS CONTINUE TO RISE AS THE RIDGE  
CONTINUES TO STRENGTHEN OVER FOUR CORNERS. AS A RESULT, HIGH  
TEMPERATURES LOOK TO REMAIN HOT FOR MOST OF THE AREA, WITH HIGHS  
AROUND 5-10F ABOVE NORMAL FOR THIS TIME OF YEAR. AN EXTREME HEAT  
WARNING REMAIN THROUGH WEDNESDAY FOR THE LOWER ELEVATIONS OF THE  
GRAND CANYON, WITH A WATCH THEN FOLLOWING. ADDITIONAL HEADLINES MAY  
BE NEED FOR SOME OF THE LOWER ELEVATIONS OF YAVAPAI FOR THURSDAY,  
BUT TO WHAT EXTENT INCREASED MOISTURE (AND THUS INCREASED CLOUD  
COVER) MAY AFFECT THE TEMPERATURES IS STILL NOT CERTAIN.  
 
WHILE MONSOONAL MOISTURE DOES LOOK TO CONTINUE TO INCREASE, THE  
STRENGTH OF THE HIGH LOOKS TO CONTINUE TO BE THE LIMITING FACTOR.  
MODEL SOUNDINGS DO SOME TO INDICATE A SLIGHTLY WEAKER CAP BY  
THURSDAY AS THE RIDGE STARTS TO WEAKEN AND BEGIN TO RETROGRADE.  
HOWEVER, SOME UNCERTAINTY STILL REMAINS HERE. ADDITIONALLY, DECAYING  
STORMS OVER NORTHERN MEXICO MAY BECOME A FAVOR IN LEADING TO  
INCREASED STORM CHANCES. AS OF NOW, COVERAGE LOOKS TO BE MAINLY  
FOCUSED OVER THE HIGHER TERRAIN WITH SOME ISOLATED STORMS  
POTENTIALLY MOVING INTO THE LOWER ELEVATIONS IN THE LATE AFTERNOON  
AND EVENING HOURS.  
 
FRIDAY THROUGH MONDAY...AS HEIGHTS BEGIN TO FALL WITH THE WEAKENING  
RIDGE, THE ODDS FOR SHOWERS AND THUNDERSTORMS LOOK TO INCREASE BY  
THE END OF THE WEEK AND INTO NEXT WEEK. ENSEMBLE GUIDANCE FROM THE  
EPS, GEFS, AND CMCE ALL CONTINUE TO SIGNAL A NOTABLE INCREASE IN  
PWATS THROUGH THE WEEKEND. THUS, A PERIOD OF ACTIVE MONSOONAL  
ACTIVITY, WITH A THREAT FOR FLASH FLOODING, LOOKS PROBABLE.  
 

 
   
AVIATION...TUESDAY 19/06Z THROUGH WEDNESDAY 20/06Z
 
VFR  
CONDITIONS EXPECTED TO PERSIST THROUGH THE TAF PERIOD. ISOLATED  
-SHRA POSSIBLE THROUGH 06Z PRIMARILY ACROSS APACHE COUNTY. LIGHT  
AND VARIABLE WINDS EXPECTED THROUGH 18Z, BEFORE WINDS INCREASE TO  
~ 10KTS BUT REMAIN VARIABLE IN DIRECTION. ADDITIONAL  
-SHRA/TSRA POSSIBLE AFTER 18Z ALONG AND SOUTH OF A KPAN-KRQE  
 
OUTLOOK...WEDNESDAY 20/06Z THROUGH FRIDAY 22/06Z...VFR CONDITIONS  
WILL PERSIST OUTSIDE BRIEF MVFR CONDITIONS IN HEAVIER SHRA/TSRA.  
DAILY CHANCES FOR SHOWERS/STORMS POSSIBLE BETWEEN 18Z-03Z, WITH  
GREATEST ACTIVITY LIKELY ACROSS THE HIGHER TERRAIN. OUTSIDE OF  
STORM DRIVEN GUSTY WINDS, LOOK FOR VARIABLE WINDS 5-10 KTS.  
 

 
   
FIRE WEATHER...TODAY AND WEDNESDAY
 
HOT AND MAINLY DRY CONDITIONS  
CONTINUE. ISOLATED SHOWERS AND THUNDERSTORMS TODAY, MAINLY ACROSS  
EASTERN ARIZONA THEN SPREADING FURTHER WESTWARD ON WEDNESDAY. WINDS  
GENERALLY VARIABLE 5-10 MPH. GUSTY AND ERRATIC WINDS POSSIBLE IN AND  
AROUND THUNDERSTORMS. MINIMUM AFTERNOON RH VALUES 10-30%, HIGHEST  
ACROSS THE WHITE MOUNTAINS.  
 
THURSDAY THROUGH SATURDAY...CHANCES FOR SHOWERS AND THUNDERSTORMS  
INCREASE EACH DAY, WITH WETTING RAIN POSSIBLE BY THE WEEKEND. WINDS  
WILL PRIMARILY BE VARIABLE 5-10 MPH. GUSTY AND ERRATIC WINDS  
POSSIBLE IN AND AROUND THUNDERSTORMS. MINIMUM AFTERNOON RH VALUES 10-  
30%, HIGHEST VALUES ACROSS THE WHITE MOUNTAINS AND MOGOLLON RIM.  
 

 
   
FGZ WATCHES/WARNINGS/ADVISORIES
 
 
EXTREME HEAT WARNING FROM 10 AM THIS MORNING TO 8 PM MST  
WEDNESDAY FOR AZZ006.  
 
EXTREME HEAT WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY EVENING  
FOR AZZ006.  
 

 
 

 
 
PUBLIC...HUMPHREYS  
AVIATION...KONIECZNY  
FIRE WEATHER...HUMPHREYS  
 
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT  
WEATHER.GOV/FLAGSTAFF  
 
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