444  
FXUS65 KGJT 211734  
AFDGJT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
1134 AM MDT SAT SEP 21 2019  
   
SHORT TERM
 
(TODAY THROUGH SUNDAY)  
ISSUED AT 407 AM MDT SAT SEP 21 2019  
 
DRY AND COOLER CONDITIONS WILL OCCUR TODAY AS THE TROUGH CONTINUES  
TO DEPART THE REGION. THE GRADIENT WILL BE MUCH MORE RELAXED,  
ALLOWING WINDS TO LESSEN CONSIDERABLY COMPARED TO YESTERDAY. SOME  
ISOLATED STORMS ARE POSSIBLE OVER THE EASTERN UINTAS THIS  
AFTERNOON, BUT ASIDE FROM THAT, THE DRY AND COOL AIR MASS WITH  
LESS WIND WILL BE A WELCOME CHANGE. LATEST GUIDANCE CAME UP A BIT  
WITH THE LOW TEMPERATURES TONIGHT INTO SUNDAY MORNING ACROSS THE  
NORTHERN YAMPA RIVER VALLEY. THIS PUTS LOW TEMPS HOVERING AROUND  
THE FREEZING MARK IN CRAIG AND STEAMBOAT WHILE THE MAJORITY OF  
THOSE ZONES DOWN TOWARDS MEEKER REMAIN IN THE MID 30S. DECIDED TO  
HOLD OFF ON ISSUING ANY FREEZE WATCH TONIGHT DUE TO LIMITED  
SPATIAL COVERAGE AS THE COLDEST TEMPS LOOK TO BE LOCALIZED ALONG  
THE YAMPA RIVER. ALSO, TEMPERATURES THIS MORNING ARE IN THE LOW TO  
MID 30S IN CRAIG, MEEKER AND STEAMBOAT WHERE A FREEZE WARNING  
REMAINS IN EFFECT THROUGH 9 AM. WOULD LIKE TO WAIT AND SEE HOW THE  
CURRENT FREEZE WARNING PANS OUT AND SEE HOW MODEL GUIDANCE TRENDS  
IN THE NEXT RUN OR TWO. THERE MAY BE ENOUGH MIXING OVERNIGHT TO  
KEEP TEMPS NEAR TO SLIGHTLY ABOVE FREEZING DUE TO THE UPPER LEVEL  
JET OVERHEAD. A TRANSITORY RIDGE OF HIGH PRESSURE SLIDES OVER THE  
REGION SUNDAY, PROVIDING FOR A SLIGHT BUMP UP IN TEMPERATURES AND  
ANOTHER DRY AND SUNNY AFTERNOON.  
   
LONG TERM
 
(SUNDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 407 AM MDT SAT SEP 21 2019  
 
SOUTHWEST FLOW WILL INCREASE SUNDAY NIGHT INTO MONDAY AS A TROUGH  
OF LOW PRESSURE DROPS FROM THE PACIFIC NORTHWEST INTO THE SOUTHERN  
GREAT BASIN. MODELS ARE COMING INTO BETTER AGREEMENT ON THE TIMING  
AND PLACEMENT OF THIS SYSTEM, SHOWING THE LOW DROPPING FURTHER  
SOUTH AND WEST, SETTLING SOUTHWEST OF THE FOUR CORNERS OVER  
ARIZONA LATE MONDAY THROUGH MID-WEEK. THIS KEEPS THE MAJORITY OF  
THE PRECIPITATION OUT OF OUR CWA. REDUCED THE POPS IN COORDINATION  
WITH NEIGHBORING OFFICES FOR THE MONDAY AFTERNOON THROUGH TUESDAY  
MORNING PERIOD DUE TO THIS TREND. DECIDED TO STILL KEEP ISOLATED  
TO SCATTERED SHOWERS AND STORMS FOCUSED MORE ACROSS SOUTHEAST UTAH  
AND SOUTHWEST COLORADO LATE MONDAY AS THIS LOW DROPS SOUTHWARD.  
THE LOW TRIES TO CLOSE ITSELF OFF OVER ARIZONA MONDAY NIGHT INTO  
TUESDAY AND EVEN DIVES FURTHER SOUTH TOWARDS SOUTHERN ARIZONA AND  
THE NORTHERN BAJA IN MEXICO. THIS KEEPS AREAS NORTH OF THE FOUR  
CORNERS (SO BASICALLY OUR ENTIRE CWA) IN THE DEFORMATION AREA WITH  
DRY CONDITIONS AND TEMPERATURES NEAR NORMAL. THE LOW THEN LIFTS  
NORTHEAST AS AN OPEN TROUGH ACROSS THE FOUR CORNERS INTO SOUTHWEST  
COLORADO AND TO THE FRONT RANGE ON THURSDAY, BRINGING US OUR BEST  
CHANCE OF PRECIPITATION. THIS SYSTEM IS MUCH WARMER THOUGH THAN  
PREVIOUS RUNS SO SNOW LEVELS WILL BE FAIRLY HIGH. DID RAISE THE  
POPS A BIT FROM THE BLENDED SOLUTION ON THURSDAY DUE TO THIS  
TROUGH PASSAGE, BUT STILL REMAIN AT SLIGHT CHANCE DUE TO THE MODEL  
DISPARITY AS THE ECMWF IS NOT QUITE AS ROBUST AS THE GFS. ALSO,  
AS WE'VE SEEN THE LAST FEW DAYS, MODEL SOLUTIONS CAN CHANGE AS WE  
GET CLOSER TO THAT TIME.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)  
ISSUED AT 1134 AM MDT SAT SEP 21 2019  
 
WINDS BECOME MILDLY BREEZY AT MOST TAF SITES ACROSS EASTERN UTAH  
AND WESTERN COLORADO AGAIN THIS AFTERNOON BUT WINDS WILL  
DEFINITELY BE LESS STRONG THAN ON FRIDAY. CLOUDS WILL BE MID TO  
HIGH BASED WITH NO PRECIPITATION EXPECTED, EXCEPT OVER THE EASTERN  
UINTA MOUNTAINS DURING THE AFTERNOON AND EARLY EVENING.  
THEREFORE, EXPECT VFR CONDITIONS WITH CIGS ABOVE ILS BREAKPOINTS  
AT ALL TAF SITES ACROSS THE REGION THROUGH THE NEXT 24 HOURS.  
 

 
   
GJT WATCHES/WARNINGS/ADVISORIES
 
 
CO...NONE.  
UT...NONE.  
 

 
 

 
 
SHORT TERM...MDA  
LONG TERM...MDA  
AVIATION...NL  
 
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