502  
FXUS65 KBOU 101106  
AFDBOU  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DENVER/BOULDER CO  
506 AM MDT THU SEP 10 2026  
   
KEY MESSAGES  
 
- MAINLY DRY THROUGH FRIDAY WITH WARMER TEMPERATURES.  
 
- RETURN TO MORE UNSETTLED PATTERN THIS WEEKEND WITH A CHANCE OF  
THUNDERSTORMS ESPECIALLY ON SUNDAY. COOLER SATURDAY, THEN WARMER  
ON SUNDAY.  
 
- ANOTHER COLD FRONT MOVES INTO THE AREA NEXT MONDAY OR TUESDAY  
WITH A CHANCE OF SHOWERS AND THUNDERSTORMS.  
 
 
   
DISCUSSION /THROUGH WEDNESDAY/  
 
ISSUED AT 240 AM MDT THU SEP 10 2026  
 
THE FLOW ALOFT WILL REMAIN WNW TODAY AS SOUTHERLY LEVEL FLOW IS  
ACROSS THE PLAINS. MLCAPE WILL RISE UP TO 1000 J/KG OVER PORTIONS  
OF THE FAR ERN PLAINS BY AFTN. CHANCES FOR TSTMS STILL LOOK ON THE  
LOW SIDE AS I CAN'T FIND A FOCUS FOR ACTIVITY. HOWEVER, CAN'T RULE  
OUT AN ISOLD STORM OR TWO MAINLY ACROSS LINCOLN COUNTY WHERE A WEAK  
CONVERGENCE ZONE WILL EXIST THIS AFTN. MEANWHILE, TEMPS WILL BEGIN  
TO WARM AS READINGS REACH THE UPPER 80'S TO LOWER 90'S OVER NERN CO.  
 
ON FRI, ZONAL FLOW ALOFT WILL BE OVER THE AREA AS A SFC LEE TROUGH  
DEVELOPS OVER THE PLAINS. THIS WILL LEAD TO ANOTHER WARM DAY AS  
HIGHS RISE INTO THE UPPER 80'S TO MID 90'S OVER THE PLAINS.  
MEANWHILE, MODELS HAVE SOME MID LEVEL MOISTURE EMBEDDED IN THE FLOW,  
WHICH MAY LEAD TO ISOLD HIGH BASED SHOWERS/TSTMS OVER THE HIGHER  
TERRAIN IN THE AFTN. ACROSS THE PLAINS, MLCAPE IS UNDER 500 J/KG SO  
ANY THREAT OF SHOWERS/TSTMS WILL BE ON THE LOW SIDE.  
 
FOR FRI NIGHT INTO SAT, ZONAL FLOW ALOFT WILL CONTINUE. MEANWHILE,  
A COLD FRONT WILL MOVE ACROSS FRI NIGHT INTO SAT MORNING. THIS  
FRONT WILL DROP TEMPS BACK TO MORE SEASONAL LEVELS ACROSS NERN CO.  
MLCAPE IS FCST TO BE IN THE 500-800 J/KG ACROSS THE PLAINS WITH  
LOWER VALUES ACROSS THE HIGHER TERRAIN. FOR NOW, HAVE KEPT IN A  
SLIGHT CHC FOR SHOWERS/TSTMS ACROSS THE HIGHER TERRAIN AND ALONG THE  
I-25 CORRIDOR FOR THE AFTN/EVENING HOURS. HIGHS OVER NERN CO WILL  
BE IN THE UPPER 70'S TO MID 80'S.  
 
BY SUN, AN UPPER LEVEL TROUGH WILL MOVE INTO THE NRN ROCKIES WITH  
INCREASING WSW FLOW ALOFT ACROSS THE AREA. AT THE SFC, A LEE TROUGH  
WILL INTENSIFY EAST OF THE MTNS WITH SSE LOW LEVEL FLOW ACROSS THE  
PLAINS. MLCAPE IS FCST TO INCREASE TO 1000-1500 J/KG OVER PORTIONS  
OF THE PLAINS EAST OF A PSEUDO DRYLINE. THUS MAY SEE A FEW  
STRONG/SVR STORMS BY LATE AFTN THRU THE EVENING HOURS. HIGHS ON  
SUN, WILL LIKELY RISE BACK TO ABOVE NORMAL LEVELS.  
 
LOOKING AHEAD TO MON, WSW FLOW ALOFT WILL REMAIN OVER THE AREA.  
MODELS HAVE BACKED OFF ON THE TIMING OF ANOTHER COLD FRONT MOVING  
ACROSS AS THEY NOW SHOW IT MOVING IN MON NIGHT INTO TUE MORNING. IF  
THIS FRONT DOES HOLD OFF UNTIL MON NIGHT, THEN ANOTHER DAY OF ABOVE  
NORMAL TEMPS WOULD OCCUR OVER THE PLAINS. MEANWHILE, MAY HAVE A  
BETTER CHC OF SHOWERS/TSTMS ACROSS THE PLAINS MON NIGHT INTO TUE  
MORNING AS POSITION OF UPPER LEVEL JET COMBINES WITH UPSLOPE FLOW  
BEHIND THE FRONT.  
 
FOR TUE, DIFFERENCES EXIST BETWEEN THE ECMWF AND GFS WITH RESPECT TO  
TIMING OF ADDITIONAL PRECIP AND TEMPS. THE ECMWF HAS A COOL AND  
STABLE AIRMASS, OVER THE PLAINS, WITH HIGHS ONLY IN THE MID 60'S TO  
LOWER 70S. MEANWHILE, THE GFS ISN'T AS COOL AND HAS FAR MORE  
PRECIP.  
 
 
   
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/  
 
ISSUED AT 504 AM MDT THU SEP 10 2026  
 
LIGHT DRAINAGE WINDS WILL BECOME LIGHT AND VARIABLE BY 16Z. BY 18Z  
WINDS WILL GO ESE AND THEN MORE SE BY 23Z. FOR THIS EVENING WINDS  
WILL GRADUALLY BECOME SOUTH BY 03Z AND THE SSW BY 06Z. OTHERWISE  
VFR CONDITIONS WILL CONTINUE THRU THE PERIOD.  
 
 
   
BOU WATCHES/WARNINGS/ADVISORIES  
 
NONE.  
 
 
 
 
 
DISCUSSION...RPK  
AVIATION...RPK  
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