882  
FXUS65 KBOU 122124  
AFDBOU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DENVER/BOULDER CO  
324 PM MDT MON APR 12 2021  
   
SHORT TERM
 
(THIS EVENING THROUGH TUESDAY)  
ISSUED AT 323 PM MDT MON APR 12 2021  
 
SATELLITE PICTURES ARE SHOWING THE STRATOCUMULUS DECK OVER MOST  
OF THE PLAINS IS THINNING OUT A BIT. HOWEVER, IT HAS EXPANDED TO  
COVER MOST OF THE PLAINS OVER THE CWA. MOST OF THE PLAINS HAVE A  
NORTH-NORTHWEST TO NORTHEASTERLY WIND FIELD IN PLACE. THE  
SOUTHEASTERN CWA HAS SOUTHEASTERLY WINDS.  
 
MODELS HAVE WEST-SOUTHWESTERLY FLOW ALOFT FOR THE CWA TONIGHT AND  
TUESDAY. MODELS KEEP THE LOW LEVEL FLOW ALL UPSLOPE FOR THE FIRST  
TWO PERIODS; NORTHEASTERLY TO THE DIVIDE THIS EVENING/TONIGHT, THEN  
MORE EASTERLY AND SOUTHEASTERLY ON TUESDAY. THERE IS WEAK UPWARD  
VERTICAL MOTION PROGGED FOR MOST OF THE CWA ON THE QG FIELDS TONIGHT  
AND TUESDAY. DOWNWARD MOTION IS PLACE OVER THE FAR NORTHEAST. FOR  
MOISTURE, THERE ISN'T A BUNCH AROUND UNTIL AFTER 06Z TONIGHT. MOISTURE  
GETS PRETTY DEEP LATE TONIGHT AND CONTINUES ON TUESDAY. IN THE MOUNTAINS,  
WILL GET THE POPS UP TO "LIKELY'S AFTER 09Z TUESDAY MORNING. THE SNOW  
LOOKS LIGHT UP THERE MOST OF THE DAY, WITH AN INCREASE BY MID/LATE  
AFTERNOON. OVER THE WESTERN HALF OF THE PLAINS, POPS OF 10-30%S LOOK  
GOOD FROM LATE TONIGHT THROUGH MID/LATE TUESDAY AFTERNOON, THEN AN  
INCREASE. SNOW IS A GOOD BET FO THE PLAINS THROUGH EARLY TUESDAY  
AFTERNOON, THEN IS COULD BE RAIN. EITHER WAY, THE PRECIPITATION WILL  
BE LIGHT. FOR TEMPERATURES, TUESDAY'S HIGHS SHOULD BE CLOSE TO  
THIS AFTERNOON'S READINGS.  
   
LONG TERM
 
(TUESDAY NIGHT THROUGH MONDAY)  
ISSUED AT 323 PM MDT MON APR 12 2021  
 
TUESDAY NIGHT INTO WEDNESDAY, SNOW SHOWERS WILL BE ONGOING IN THE  
MOUNTAINS AND FOOTHILLS WITH SCATTERED, LIGHT SHOWERS ON THE  
PLAINS. EXPECT MIXED PRECIPITATION FOR MUCH OF THE LOWER  
ELEVATIONS DURING THE EVENING, CHANGING TO ALL SNOW AS  
TEMPERATURES FALL OVERNIGHT. A WINTER WEATHER ADVISORY FOR THE  
MOUNTAINS, AND MAYBE FOOTHILLS, IS BECOMING MORE PROBABLE WITH A  
TREND OF INCREASING FORECAST QPF AND RESULTANT SNOWFALL. TOTAL  
SNOW ACCUMULATIONS OF 6 TO 12 INCHES ARE POSSIBLE IN THE NORTHERN  
MOUNTAINS AND FOOTHILLS, 1 TO 3 INCHES OVER THE URBAN CORRIDOR AND  
STILL LESS THAN AN INCH FOR THE EASTERN PLAINS. UNCERTAINTY  
REMAINS REGARDING AFTERNOON ROAD TEMPERATURES AND THEIR AFFECT ON  
PAVEMENT ACCUMULATION, BUT TRAVEL IMPACTS DUE TO SLUSHY OR SNOWY  
ROADS ARE SEEMING MORE LIKELY FOR THE MOUNTAINS. WE WILL BE  
CLOSELY MONITORING THIS SITUATION.  
 
SCATTERED, LIGHT SHOWERS SHOULD PERSIST WEDNESDAY INTO THURSDAY  
AS THE UPPER TROUGH CONTINUES TO SLOWLY ADVANCE TOWARD COLORADO.  
MODEL AGREEMENT HAS ON THE TIMING OF THE TROUGH HAS IMPROVED,  
BRINGING IT OVER COLORADO PROBABLY THURSDAY AFTERNOON, AND THE  
BEST LIFT SHOULD OCCUR THURSDAY EVENING INTO FRIDAY MORNING. THE  
GFS IS STILL BRINGING THE SURFACE LOW FURTHER SOUTH THAN THE  
ECMWF, RESULTING IN GREATER UPSLOPE FLOW AND PRECIPITATION ACROSS  
THE AREA. I REDUCED FORECAST QPF TO REFLECT THIS UNCERTAINTY, BUT  
WIDESPREAD SHOWERS ARE LIKELY LATE THURSDAY THROUGH FRIDAY.  
 
CONFIDENCE IN FORECAST DETAILS FOR THE WEEKEND AND EARLY NEXT  
WEEK REMAIN LOW, BUT IT LOOKS LIKE SCATTERED TO ISOLATED SHOWERS  
MIGHT PERSIST SATURDAY WITH THE TROUGH LINGERING OVER THE ROCKY  
MOUNTAINS AND GREAT PLAINS. THERE SHOULD BE SOME BRIEF CLEARING  
SUNDAY BEFORE ANOTHER TROUGH APPROACHES EARLY NEXT WEEK. MODELS  
ARE NOW SHOWING NORTHERLY TO NORTHWESTERLY FLOW ALOFT AND ANOTHER  
TROUGH APPROACHING FROM THE NORTH, MAYBE JUST CLIPPING NORTHEAST  
COLORADO.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)  
ISSUED AT 323 PM MDT MON APR 12 2021  
 
MODELS NOW HAVE EASTERLY WINDS AT DIA MOST OF THE TONIGHT, THEN  
SOUTHEASTERLY ON TUESDAY. BEST GUESS FROM SATELLITE PICTURES  
INDICATED THAT THE BKN050-060 CEILING SHOULD STICK AROUND FOR A  
FEW MORE HOURS. NOT SURE IF IT WILL BE IN PLACE FROM MID EVENING  
THROUGH ABOUT 09Z? AFTER THAT CEILINGS SHOULD GET DOWN INTO THE  
BKN-OVC 010-020 RANGE. THE TEMPO GROUP FOR 2SM -SN STILL LOOKS  
GOOD FOR TUESDAY MORNING.  
 

 
   
BOU WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...RJK  
LONG TERM....DIRENZO  
AVIATION.....RJK  
 
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