671  
FXUS65 KGJT 240019  
AFDGJT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
619 PM MDT WED SEP 23 2020  
   
UPDATE
 
 
ISSUED AT 619 PM MDT WED SEP 23 2020  
 
FRIDAY'S FIRE WEATHER WATCH HAS BEEN EXPANDED INTO THE STEAMBOAT  
SPRINGS BASIN AND ITS SURROUNDING MOUNTAINS. RELATIVE HUMIDITY  
APPEARED BORDERLINE, HOWEVER THE STRONG AND GUSTY WESTERLY WINDS  
WILL NEGATIVELY IMPACT THE MIDDLE FORK FIRE. LATER SHIFTS WILL  
NEED TO CONSIDER ADDING THE I-70 CORRIDOR TO THE WATCH AS WINDS  
AND RELATIVE HUMIDITY APPEARED TO BE APPROACHING CRITICAL VALUES.  
 

 
   
SHORT TERM
 
(TONIGHT THROUGH THURSDAY NIGHT)  
ISSUED AT 141 PM MDT WED SEP 23 2020  
 
HIGH PRESSURE CENTERED OFF THE SOUTHERN CALIFORNIA COAST HAS  
BUILT IN TODAY WITH RADAR AND SATELLITE SHOWING A BIT OF  
CONVECTION GOING OVER THE HIGHEST TERRAIN. DO NOT ANTICIPATE ANY  
PRECIP HITTING THE GROUND WITH ONLY SOME VIRGA TO CONTEND WITH, IF  
THAT EVEN FORMS. TEMPERATURES REMAIN ON THE WARM SIDE OF THINGS  
WITH DRY CONDITIONS STILL IN PLACE THOUGH NOT 'AS' DRY AS WE'VE  
SEEN LATELY. A VERY TRANQUIL DAY IN STORE WITH A FEW, TERRAIN-  
DRIVEN WINDS EXPECTED.  
 
AN APPROACHING TROUGH WILL START DROPPING DOWN FROM THE NORTHWEST  
TOMORROW AND THIS WILL CAUSE AN UPTICK IN WIND SPEEDS THANKS TO  
UPPER LEVEL SUPPORT MIXING DOWN AS WELL AS A TIGHTENING PRESSURE  
GRADIENT. DRIER AIR WILL ALSO MOVE IN AS WEST TO NORTHWESTERLY  
FLOW SETS UP OVER THE AREA SO CRITICAL FIRE WEATHER CONDITIONS SET  
UP ONCE AGAIN FOR OUR FAR NORTHERN COLORADO VALLEYS. MORE ON THAT  
BELOW. THE REST OF THE CWA WILL SEE PLENTY OF SUNNY SKIES WITH  
CONTINUED WARM CONDITIONS IN PLACE.  
   
LONG TERM
 
(THURSDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 415 AM MDT WED SEP 23 2020  
 
A BROAD TROUGH WILL SWING BY TO OUR NORTH ON FRIDAY, TIGHTENING UP  
THE PRESSURE GRADIENT OVER NORTHERN PORTIONS OF OUR CWA WHICH, WHEN  
COMBINED WITH THE DEEP MIXING ALLOWED BY THE EXPECTED WARM AND DRY  
CONDITIONS, WILL RESULT IN STRONG, GUSTY WINDS. BECAUSE OF THIS, AND  
THE EXPECTED LOW RHS, A FIRE WEATHER WATCH HAS BEEN ISSUED FOR  
FRIDAY AFTERNOON.  
 
FIRE WEATHER CONCERNS DROP OFF FROM SATURDAY ONWARD, ALTHOUGH SOME  
GUSTINESS MAY LINGER FOR THE WEEKEND. AFTER THAT, HIGH PRESSURE WILL  
BE IN CONTROL FOR THE REST OF THE PERIOD. EXPECT TEMPERATURES TO BE  
AT OR ABOVE SEASONAL NORMS, AND LITTLE CHANCE OF PRECIPITATION.  
SUMMER IS TRYING VERY HARD TO HANG ON JUST A LITTLE LONGER.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)  
ISSUED AT 619 PM MDT WED SEP 23 2020  
 
EXPECT VFR CONDITIONS TO PERSIST THROUGH THE NEXT 24 HOURS. SKIES  
WILL BE CLEARING THIS EVENING WITH FEW CLOUDS DEVELOPING OVER THE  
AREA ON THURSDAY. WINDS WILL SHIFT TO REGULAR DRAINAGE FLOWS IN  
THE NEXT COUPLE OF HOURS WHICH WILL CONTINUE THROUGH MIDMORNING  
THURSDAY. EXPECT BREEZY SOUTHWEST WINDS TO DEVELOP ACROSS  
NORTHWEST COLORADO THURSDAY AFTERNOON AS A DISTURBANCES PASSES TO  
THE NORTH.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 619 PM MDT WED SEP 23 2020  
 
A MID-LEVEL SHORT WAVE TROUGH MOVING OVER THE NORTHERN ROCKIES  
WILL TIGHTEN THE SURFACE PRESSURE GRADIENT ON THURSDAY RESULTING  
IN BREEZY SOUTHWEST WINDS ACROSS NORTHWEST COLORADO. LOW RELATIVE  
HUMIDITY AND DRY FUELS PERSIST ACROSS THE REGION WHICH, WHEN  
COMBINED WITH FREQUENT GUSTS ABOVE 25 MPH ARE EXPECTED TO RESULT  
IN CRITICAL FIRE WEATHER CONDITIONS ACROSS FIRE WEATHER ZONE 200.  
THEREFORE, A RED FLAG WARNING REMAINS IN EFFECT FOR THIS AREA FROM  
NOON TO 8 PM THURSDAY.  
 
A SECOND, MORE VIGOROUS SHORT WAVE TROUGH SWEEPS EASTWARD TO THE  
NORTH OF THE FORECAST AREA ON FRIDAY. IN RESPONSE, GUSTY WINDS  
WILL REDEVELOP DURING THE AFTERNOON WHILE SPREADING FARTHER  
SOUTH. THE AIRMASS AND FUELS REMAIN DRY SO THERE IS THE POTENTIAL  
FOR MORE WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS FRIDAY  
AFTERNOON THROUGH EARLY FRIDAY EVENING. A FIRE WEATHER WATCH HAS  
BEEN ISSUED AND HAS BEEN EXPANDED TO ENCOMPASS ALL OF NORTHWEST  
COLORADO ALONG WITH NORTHEAST AND EAST-CENTRAL UTAH. LATER SHIFTS  
WILL NEED TO ASSESS WHETHER TO INCLUDE THE I-70 CORRIDOR AND  
PORTIONS OF SOUTHEAST UTAH AS WIND AND RELATIVE HUMIDITY APPEARED  
TO BE APPROACHING CRITICAL LEVELS.  
 

 
   
GJT WATCHES/WARNINGS/ADVISORIES
 
 
CO...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING  
FOR COZ200>202.  
 
RED FLAG WARNING FROM NOON TO 8 PM MDT THURSDAY FOR COZ200.  
 
UT...FIRE WEATHER WATCH FROM FRIDAY AFTERNOON THROUGH FRIDAY EVENING  
FOR UTZ486-487-490.  
 

 
 

 
 
UPDATE...NL  
SHORT TERM...TGR  
LONG TERM...ERW  
AVIATION...NL  
FIRE WEATHER...NL  
 
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