940  
FXUS65 KGJT 131135  
AFDGJT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
535 AM MDT TUE APR 13 2021  
   
SHORT TERM
 
(TODAY THROUGH WEDNESDAY NIGHT)  
ISSUED AT 348 AM MDT TUE APR 13 2021  
 
PLENTY OF HIGH- AND EVEN SOME MID-LEVEL CLOUDS HAVE INFILTRATED  
EASTERN UTAH AND WESTERN COLORADO OVERNIGHT IN RESPONSE TO THE  
APPROACHING PACIFIC SYSTEM. THE FEW LIGHT RETURNS ON RADAR DO NOT  
AMOUNT TO ANYTHING AT THE SURFACE AT THE MOMENT AS THE LOWER  
LEVELS OF THE ATMOSPHERE REMAIN DRY EARLY THIS MORNING. THE  
INCREASE IN CLOUD COVER HAS LED TO A MILD NIGHT ACROSS THE REGION  
WITH CURRENT TEMPERATURES SITTING SEVERAL DEGREES WARMER THAN THIS  
TIME LAST NIGHT. THE PREVIOUSLY MENTIONED MIDLEVEL TROUGH WILL  
DROP SOUTH FROM THE NORTHERN ROCKIES AND INTO THE GREAT BASIN  
THROUGHOUT THE DAY TODAY AS ANOTHER CLOSED LOW REMAINS FIRMLY  
PLANTED OVER THE GREAT LAKES REGION. THE APPROACH OF THE PACIFIC  
LOW WILL SEE UPPER LEVEL FLOW SHIFT TO THE SOUTHWEST ACROSS OUR  
FORECAST AREA THIS AFTERNOON, RESULTING IN CONTINUED MOSTLY CLOUDY  
SKIES. A WEAK SHORTWAVE WILL EJECT OUT AHEAD OF THIS SYSTEM THIS  
AFTERNOON, LIFTING FROM THE FOUR CORNERS AREA TO THE WEST-CENTRAL  
COLORADO MOUNTAINS ALONG THE DIVIDE. THIS WILL SEE PRECIPITABLE  
WATER VALUES INCREASE TO 0.30 TO 0.40 INCHES ACROSS THIS REGION,  
WHICH IS RIGHT AT OR UP TO 130% OF THE CLIMATOLOGICAL NORMAL FOR  
MID APRIL. AS A RESULT WE CAN EXPECT LIGHT SHOWERS TO DEVELOP AND  
INCREASE IN COVERAGE DURING THE AFTERNOON, THOUGH ACTIVITY WILL  
CONTINUE TO FAVOR THE HIGHER ELEVATIONS ALONG THE DIVIDE. BUFKIT  
SOUNDINGS SHOW DECENT SATURATION IN THE MIDLEVELS OF THE  
ATMOSPHERE WITH A CONTINUED DRY LAYER AT THE SURFACE INTO THE LATE  
AFTERNOON HOURS BEFORE THE LOWER LEVELS FINALLY BECOME SATURATED  
IN THE EVENING. THIS IS ALSO WHEN THE VALLEYS WILL SEE THEIR BEST  
CHANCE FOR WETTING RAIN WHEN THE MOST FAVORABLE COMBINATION OF  
LIFT AND SATURATION THROUGH THE COLUMN PASSES THROUGH.  
 
OVERNIGHT AND INTO WEDNESDAY MORNING WILL SEE GENERALLY 2 TO 5  
INCHES OF SNOW FALL IN THE WESTERN COLORADO MOUNTAINS WITH AN  
ISOLATED 6 OR MORE INCHES POSSIBLE AT THE HIGHEST PEAKS OF THE  
CENTRAL RANGES. HOWEVER, RATES WILL GENERALLY BE LIGHT AND ROAD  
TEMPERATURES LOOK TO REMAIN IN THE UPPER 30S THROUGHOUT THE NIGHT  
WHICH, AS MENTIONED PREVIOUSLY, WILL NOT BE ENOUGH TO WARRANT ANY  
WINTER HIGHLIGHTS AT THIS TIME. AS ALWAYS THOUGH, ANYONE PLANNING  
TO TRAVEL IN THE HIGHER ELEVATIONS SHOULD CHECK THE LATEST  
FORECAST AND ROAD CONDITIONS BEFORE HEADING OUT. A FEW HUNDREDTHS  
TO TWO TENTHS OF AN INCH OF LIQUID LOOK LIKELY FOR MANY VALLEY  
LOCATIONS OVERNIGHT WITH EVEN A RAIN/SNOW MIX POSSIBLE FOR THE  
NORTHERN CITIES LIKE CRAIG AND RANGELY.  
 
WEDNESDAY MORNING WILL SEE THE MIDLEVEL LOW CENTERED OVER THE  
GREAT BASIN BEFORE IT SLOWLY SHIFTS EAST TOWARDS WESTERN UTAH  
THROUGHOUT THE DAY. UNFORTUNATELY FOR US, THIS MEANS WE WILL GET  
DRY-SLOTTED WITH SHOWERS AND CLOUDY SKIES DISSIPATING ACROSS THE  
SOUTHERN TIER OF THE FORECAST AREA. THE GRADIENT WILL TIGHTEN  
ALOFT AS AN 80 TO 90KT JETSTREAK SETTLES OVER THE FOUR CORNERS  
REGION, RESULTING IN BREEZY CONDITIONS WEDNESDAY AFTERNOON.  
SOUTHWEST GUSTS OF 30 TO 40 MPH ARE LIKELY ACROSS SOUTHEAST UTAH  
AND SOUTHWEST COLORADO WHICH, WHEN COMBINED WITH THE RETURN OF  
SINGLE DIGIT TO MID-TEEN HUMIDITIES, WILL LEAD TO INCREASED  
POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS. A FIRE WEATHER  
WATCH REMAINS IN EFFECT FOR WEDNESDAY AFTERNOON AND EARLY EVENING  
AND WAS EXPANDED TO INCLUDE THE NORTH FORK REGION BELOW 8000 FEET.  
LOCALIZED CRITICAL CONDITIONS ARE LIKELY ELSEWHERE, AND THE WATCH  
AREA MAY CONTINUE TO EXPAND DEPENDING ON HOW THE MODELS PROGRESS.  
FURTHER NORTH, SPOTTY VALLEY RAIN AND HIGH ELEVATION SNOW SHOWERS  
WILL CONTINUE ON WEDNESDAY, THOUGH THE HIGH SUN ANGLE WILL RESULT  
IN LITTLE TO NO IMPACT. THIS TREND OF SPOTTY SHOWER ACTIVITY  
ACROSS THE NORTH AND NEAR THE CONTINENTAL DIVIDE CONTINUES INTO  
WEDNESDAY NIGHT WITH LARGELY DRY CONDITIONS ELSEWHERE.  
   
LONG TERM
 
(THURSDAY THROUGH MONDAY)  
ISSUED AT 348 AM MDT TUE APR 13 2021  
 
ON THURSDAY, OUR SLOW AND STUBBORN CLOSED MID-LEVEL LOW FINALLY  
GAINS SOME FORWARD SPEED AND BEGINS TO KICK EASTWARD INTO THE  
INTERMOUNTAIN WEST. THIS WILL LIKELY SPARK ANOTHER ROUND OF MORE  
WIDESPREAD SHOWERS AS DYNAMICAL FORCING RETURNS, STRENGTHENS AND  
ACTS UPON A RENEWED PUSH OF 700-400MB MOISTURE. AS IS THE CASE ON  
WEDNESDAY, SOUTH OF I-70 WON'T SEE MUCH MOISTURE RETURN AT ALL SO  
AGAIN EXPECTING MOST PRECIPITATION TO FALL ACROSS THE NORTH AND IN  
THE HIGHER TERRAIN. SIMILAR TO WEDNESDAY, EXPECTING ANOTHER DAY  
OF FIRE WEATHER CONCERNS ACROSS THE FAR SOUTH AS HUMIDITIES REMAIN  
IN THE LOW TO MID TEENS.  
 
FORECAST CONFIDENCE REMAINS LOW FRIDAY AND BEYOND AS MODELS  
CONTINUE TO STRUGGLE TO RESOLVE THE EVOLUTION OF THE CLOSED MID-  
LEVEL LOW. AS OF THE 00Z CYCLE, IT APPEARS THAT THE PARENT  
CIRCULATION WILL MAINTAIN ITS MOMENTUM AND EJECT EASTWARD INTO THE  
CENTRAL/NORTHERN PLAINS. HOWEVER, THERE ARE HINTS WITHIN THE  
DETERMINISTIC GUIDANCE THAT A SECONDARY TROUGH WILL BREAK OFF TO  
THE WEST AND DIG SOUTHWARD INTO THE NORTHERN FOUR CORNERS FRIDAY  
INTO SATURDAY. TAKING A LOOK AT THE LATEST WPC ENSEMBLE CLUSTERS,  
MORE THAN 50% OF THE MEMBERS THAT MAKE UP THE CANADIAN, GFS AND  
ECMWF ENSEMBLES DEPICT THIS PIECE OF ENERGY BREAKING OFF AND BEING  
HELD BACK OVER OUR REGION WITH THE REST EITHER MUCH WEAKER OR  
MORE PROGRESSIVE. GIVEN THE ABOVE, I'M INCLINED TO PUT MORE WEIGHT  
INTO THIS SOLUTION AND THINK UNSETTLED WEATHER IS LIKELY TO  
PERSIST ACROSS OUR MOUNTAIN RANGES THROUGH SATURDAY AND POSSIBLY  
SUNDAY AS WELL. STILL A LOT OF TIME TO WATCH THE TRENDS BUT THIS  
COULD BE AT LEAST SOME MARGINALLY GOOD NEWS FOR OUR MOUNTAINS  
WHERE OUR YEARLY SNOWPACK IS BELOW OR MUCH BELOW AVERAGE.  
UNFORTUNATELY FOR THE DROUGHT-STRICKEN LOWER ELEVATIONS OF  
EASTERN UTAH AND WESTERN COLORADO, NOT MUCH PRECIPITATION IS  
LIKELY TO COME FROM THIS DEVELOPMENT WITH MAINLY DRY WEATHER  
HOLDING COURSE THROUGH THE WEEKEND.  
 
TEMPERATURES THROUGH THE LONG TERM PERIOD WILL VARY QUITE A BIT, BUT  
WILL LIKELY AVERAGE OUT TO BE NEAR SEASONABLE IN THE END. PLACES  
THAT SEE A GOOD DEAL OF CLOUDS AND SHOWERS WILL END UP COOLER THAN  
AVERAGE DURING THE DAY, BUT LIKELY A BIT WARMER THAN AVERAGE AT  
NIGHT. THE OPPOSITE CAN BE SAID FOR LOCATIONS THAT CAN STAY MAINLY  
DRY AND BREAK OUT INTO SOME SUNSHINE.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 535 AM MDT TUE APR 13 2021  
 
BROKEN TO OVERCAST MID AND HIGH-CLOUDS PERSIST ACROSS MUCH OF  
EASTERN UTAH AND WESTERN COLORADO THIS MORNING, THOUGH CIGS REMAIN  
ABOVE ILS BREAKPOINTS AT THE MOMENT. SHOWERS WILL SPREAD ACROSS  
THE AREA THROUGHOUT THE DAY AS A DISTURBANCE APPROACHES THE REGION,  
FAVORING THE HIGHER ELEVATIONS ALONG THE DIVIDE. LOWER ELEVATIONS  
ARE LIKELY TO SEE MORE WIND THAN RAIN WITH BREEZY CONDITIONS  
TUESDAY AFTERNOON AS DRY AIR AT LOW LEVELS WILL BE TOUGH TO  
OVERCOME. EXPECT VFR CONDITIONS FOR MOST AREAS, WITH LOWER CIGS  
IN ANY SHOWERS FOR BRIEF MVFR/IFR POSSIBLE, MORE FAVORED FOR THE  
HIGHER TERRAIN TAF SITES. SHOWER COVERAGE AND BETTER CHANCES FOR  
WETTING RAINS WILL OCCUR IN THE VALLEYS OVERNIGHT AND INTO EARLY  
WEDNESDAY MORNING.  
 

 
   
FIRE WEATHER
 
 
ISSUED AT 348 AM MDT TUE APR 13 2021  
 
COMPLICATED SYSTEM COMING IN FOR THE REMAINDER OF THE WEEK WITH  
GOOD CHANCES OF WETTING PRECIPITATION IN THE HIGHER ELEVATIONS BUT  
DRY AND WINDY IN THE LOWEST ELEVATIONS. THE WIND LOOKS THE  
STRONGEST ON WEDNESDAY AS THE UPSTREAM SYSTEM BEGINS TO MOVE OUR  
WAY. THURSDAY INTO FRIDAY COULD BE THE WETTEST DAYS THOUGH THE  
FIRST ROUND OF PRECIPITATION TUESDAY AFTERNOON INTO WEDNESDAY WILL  
BE BENEFICIAL TO SOME AREAS. FOR NOW MAIN CONCERN WILL BE CRITICAL  
FIRE WEATHER CONDITIONS IN SOUTHEAST UTAH AND PORTIONS OF SOUTHWEST  
AND WEST-CENTRAL COLORADO WHERE A FIRE WEATHER WATCH IS IN PLACE.  
EXPANDED THE HIGHLIGHT TO INCLUDE ZONE 292 BELOW 8000 FEET WITH  
THIS MORNING'S PACKAGE. CONSIDERED ADDING ZONE 295 BELOW 8000 FEET  
AS WELL BUT, FOR NOW, RED FLAG CRITERIA DOES NOT LOOK TO BE MET  
FOR A LONG ENOUGH DURATION. SIMILAR TO WEDNESDAY, ANOTHER DAY OF  
FIRE WEATHER CONCERNS LOOKS LIKELY ON THURSDAY ACROSS THE FAR  
SOUTH AS HUMIDITIES REMAIN IN THE LOW TO MID TEENS.  
 

 
   
GJT WATCHES/WARNINGS/ADVISORIES
 
 
CO...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY  
EVENING FOR COZ203-207-290-292.  
 
UT...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY  
EVENING FOR UTZ490-491.  
 

 
 

 
 
SHORT TERM...MMS  
LONG TERM...MDM/MMS  
AVIATION...TGJT  
FIRE WEATHER...TGJT  
 
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