052  
FXUS65 KFGZ 131623  
AFDFGZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE FLAGSTAFF AZ  
923 AM MST THU AUG 13 2020  
   
SYNOPSIS
 
THERE WILL BE AN INCREASE IN MONSOON ACTIVITY THIS  
AFTERNOON AND EARLY EVENING. STRENGTHENING HIGH PRESSURE WILL  
BUILD OVER THE REGION LATER THIS WEEK AND LASTING INTO NEXT WEEK.  
THIS MEANS MORE HOT AND DRY CONDITIONS, WITH SOME RECORD HIGH  
TEMPERATURES POSSIBLE. DANGEROUS HEAT IS LIKELY AT LOWER  
ELEVATIONS.  
 

 
   
UPDATE
 
MOISTURE HAS INCREASED A BIT THIS MORNING COMPARED TO  
WEDNESDAY, MAINLY IN THE MID LEVELS. THE SOUNDING AT BELLEMONT  
INDICATED THAT PRECIPITABLE WATER VALUES HAD RISEN FROM 0.49"  
WEDNESDAY MORNING TO 0.68" THIS MORNING. STILL BELOW NORMAL  
MONSOON LEVELS, BUT SUFFICIENT FOR AN INCREASE IN SHOWER AND STORM  
COVERAGE TODAY. WE ARE STILL EXPECTING ONLY ISOLATED COVERAGE,  
EXCEPT ALONG THE MOGOLLON RIM INTO THE WHITE MOUNTAINS WHERE  
SCATTERED STORMS ARE FORECAST. MULTIPLE HIGH RESOLUTION MODELS ARE  
ALSO SHOWING SCATTERED ACTIVITY IN WESTERN COCONINO AND FAR NW  
YAVAPAI COUNTIES INCLUDING THE WILLIAMS AND SELIGMAN AREAS, SO  
STORM CHANCES WERE BUMPED UP WITH A FORECAST UPDATE A SHORT TIME  
AGO. REST OF THE FORECAST IS ON TRACK. WILL ADDRESS ANY CHANGES OR  
ADDITIONS TO THE HEAT PRODUCTS WITH THE AFTERNOON PACKAGE.  
 

 
   
PREV DISCUSSION /419 AM MST/
 
INCREASING MOISTURE AND GREATER  
CHANCES FOR SHOWERS ARE EXPECTED TODAY. THE PRIMARY THUNDERSTORM  
HAZARDS ARE EXPECTED TO BE GUSTY OUTFLOW WINDS, BRIEF PERIODS OF  
MODERATE RAINFALL, AND LIGHTNING.  
 
HOWEVER, HIGH PRESSURE STRENGTHENS FOR MORE DRY AND HOT WEATHER  
FOR FRIDAY AND THE WEEKEND. ALREADY WARM TEMPERATURES WILL  
INCREASE AS CHANCES FOR SHOWERS AND STORMS DECREASE. THESE HOT  
TEMPERATURES WILL CONTINUE AT LEAST THROUGH MONDAY. DUE TO THESE  
TEMPERATURES, AN EXCESSIVE HEAT WARNING IS IN EFFECT FROM 11 AM  
MST FRIDAY UNTIL 8 PM MST MONDAY FOR THE LOWER ELEVATIONS OF  
YAVPAI COUNTY AND IN THE GRAND CANYON. THERE IS A CHANCE THIS  
PRODUCT WILL BE EXTENDED BEYOND THE CURRENT TIME PERIOD AND  
EXPANDED INTO OTHER VALLEY LOCATIONS.  
 

 
   
AVIATION...FOR THE 18Z PACKAGE
 
PRIMARILY VFR CONDITIONS OVER  
THE NEXT 24 HOURS. ISOLD-SCT SHRA/-TSRA ONCE AGAIN ALONG AND SOUTH  
OF THE MOGOLLON RIM/WHITE MTNS FROM 19Z-01Z THURSDAY, WITH ONLY  
ISOLD COVERAGE NORTH OF THE MOGOLLON RIM. SOME CELLS MAY PRODUCE  
BRIEF MVFR AND WIND GUSTS TO 40KTS. SFC WINDS MAINLY W-SW5-15KTS  
DURING THE DAYTIME HOURS. AVIATION DISCUSSION NOT UPDATED FOR  
AMENDMENTS.  
 

 
   
FIRE WEATHER
 
EXPECT ISOLATED TO SCATTERED THUNDERSTORMS WITH  
GUSTY OUTFLOW THURSDAY ALONG AND SOUTH OF THE MOGOLLON RIM AND IN  
THE WHITE MOUNTAINS. HOT TEMPERATURES TO RETURN ON FRIDAY.  
THUNDERSTORM CHANCES WILL BE MAINLY IN THE WHITE MOUNTAINS WITH  
ISOLATED CHANCES ELSEWHERE.  
 
SATURDAY THROUGH MONDAY...EXPECT DRY AND HOT WEATHER WITH HAINES  
INDICES AT 5 OR 6. SLIGHT CHANCE OF STORMS FOR THE WHITE MOUNTAINS.  
 

 
   
FGZ WATCHES/WARNINGS/ADVISORIES
 
EXCESSIVE HEAT WARNING FROM  
11 AM FRIDAY TO 8 PM MST MONDAY FOR AZZ006-037-038.  
 

 
 

 
 
PUBLIC...JJ/KD  
AVIATION...JJ  
FIRE WEATHER...JJ  
 
FOR NORTHERN ARIZONA WEATHER INFORMATION VISIT  
WEATHER.GOV/FLAGSTAFF  
 
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