377  
FXUS65 KBYZ 210635  
AFDBYZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BILLINGS MT  
1235 AM MDT MON SEP 21 2026  
   
KEY MESSAGES
 
 
- AREAS OF FOG THROUGH THE MORNING COMMUTE.  
 
- WARMER AND DRIER FOR THE WORK WEEK. 80S RETURN MIDWEEK.  
 
- SCATTERED SHOWERS AND STORMS LATE TUESDAY INTO WEDNESDAY.  
 

 
   
DISCUSSION
 
 
NEXT 7 DAYS...  
 
AS THE SLOW MOVING UPPER LEVEL LOW FINALLY MAKES ITS EXIT TO OUR  
EAST, WE WILL SEE CLEARING SKIES AND TEMPS RETURN TO AVERAGE.  
WHILE THE NEXT SYSTEM TO IMPACT THE REGION WILL ZIP THROUGH  
TUESDAY AND WEDNESDAY, THE NEXT LARGE WEATHER MAKER COULD IMPACT  
US THIS WEEKEND, HOWEVER A LOT OF UNCERTAINTY REMAINS.  
 
WHILE SOME SCATTERED SHOWERS WILL LINGER ACROSS FAE SE MONTANA  
AND NORTHERN WYOMING THROUGH THE NIGHT, THESE WILL BE LIGHT WITH  
MINIMAL ACCUMULATIONS. AS THE SHOWERS AND CLOUDS EXIT EASTWARDS  
AND THIN OUT THROUGH THE MORNING, FOG AND LOW STRATUS WILL TAKE  
THEIR PLACE. THE OVERALL EXTENT AND DENSITY OF THIS FOG REMAINS A  
QUESTION AS A LITTLE WIND SHIFT COULD MEAN THE DIFFERENCE BETWEEN  
SLIGHT VISIBILITY REDUCTIONS AND DENSE FOG. THE SHORT RANGE  
MODELS ARE REALLY HITTING THE LOCATIONS THAT SAW THE MOST  
RAINFALL OVER THE WEEKEND WITH HARLOWTON, BILLINGS, AND HARDIN IN  
THE BULLSEYE OF THE LATEST HRRR RUNS. PREVIOUSLY THE SHORT RANGE  
MODELS BROUGHT DENSE FOG ALL THE WAY UP TO THE BEARTOOTH/ABSAROKA  
FOOTHILLS BUT HAVE SINCE BACKED OFF. THIS SEEMS TO BE DUE TO A  
SURFACE HIGH OVER YNP THAT HAS PRODUCED SOME WEAK DOWNSLOPE WINDS  
THAT ARE FIGHTING OFF THE EASTERLIES. THAT BEING SAID, THE ENTIRE  
FORECAST AREA HAS THE CHANCE OF SEEING FOG AND LOW CLOUDS THROUGH  
DAYBREAK TODAY. USE EXTRA CAUTION ON YOUR COMMUTE AS VISIBILITY  
CAN CHANGE RAPIDLY OVER SHORT DISTANCES.  
 
IN THE WAKE OF OUR WEEKEND LOW, THE RIDGE THAT WAS DOMINATING THE  
SOUTHERN PLAINS BUILDS NORTHWESTWARDS TOWARDS OUR AREA. THIS WILL  
ALLOW FOR TEMPERATURES TO QUICKLY REBOUND TO NEAR AVERAGE TODAY  
AND THEN PUSH ABOVE AVERAGE FOR THE REST OF THE WORK WEEK.  
READINGS IN THE 80S ARE POSSIBLE FOR MANY LOCATIONS TUESDAY  
THROUGH FRIDAY SO DO NOT PUT AWAY THE T-SHIRTS JUST YET, EVEN WITH  
TUESDAY BEING THE START OF ASTRONOMICAL AUTUMN.  
 
LATE TUESDAY INTO WEDNESDAY, REMNANT ENERGY WILL RIDE ALONG THE  
JET OUT OF THE DESERT SW THROUGH OUR AREA. THIS WILL PROVIDE A  
CHANCE FOR SOME QUICK HITTING SHOWERS AND THUNDERSTORMS. THERE IS  
A POTENTIAL THAT A STORM OR TWO IN FAR EASTERN PARTS OF THE CWA  
COULD PRODUCE SOME GUSTY WINDS OR HAIL BUT WE ARE SIMPLY STILL TOO  
FAR OUT TO GET A GOOD LOOK AT THE EVENT. DO NOTE THOUGH THAT ANY  
SEVERE WEATHER WILL BE VERY HARD TO COME BY WITH THIS SETUP.  
 
THIS UPCOMING WEEKEND IS OUR NEXT SHOT AT A POTENTIALLY IMPACTFUL  
WEATHER SYSTEM. AS OF RIGHT NOW THERE IS STILL A LOT OF SPREAD  
AMONGST MODELS AND ENSEMBLE MEMBERS TOO. RIGHT NOW THE MEAN  
SOLUTIONS TAKE THE LOW JUST TO OUR NORTH WHICH WOULD RESULT IN  
MINIMAL PRECIP AND A POTENTIAL STRONG WIND EVENT SATURDAY. DO NOT  
ALTER ANY PLANS YET THOUGH AS THIS FORECAST WILL ALMOST CERTAINLY  
CHANGE AS WE GET CLOSER TO THE EVENT AND START TO SEE MORE  
AGREEMENT AMONGST MODELS. WMR  
   
AVIATION
 
 
06Z DISCUSSION.  
 
EXPECT WIDESPREAD LOW STRATUS AND FOG (IFR AND LOWER) ACROSS THE  
REGION EARLY THIS MORNING. FOG COULD BE LOCALLY DENSE AND PRODUCE  
VISIBILITIES TO 1/4SM OR LESS. ALL TAF SITES ARE AT RISK OF SEEING  
SEVERAL HOURS OF FOG/STRATUS. CONDITIONS SEEM IDEAL FOR  
SIGNIFICANT REDUCTIONS DUE TO FOG AT KBIL, POTENTIALLY IMPACTING  
EARLY MORNING OPERATIONS, AND THIS WILL BE MONITORED. LOOK FOR  
FOG/STRATUS TO DISSIPATE IN THE 15-18Z TIME FRAME. OTHERWISE, A  
FEW LIGHT SHOWERS MAY LINGER OVER FAR SOUTHEAST MT UNTIL SUNRISE.  
BUILDING HIGH PRESSURE ALOFT WILL BRING DRY CONDITIONS TODAY AND  
TONIGHT. FOG IS POSSIBLE AGAIN LATE TONIGHT, BUT WITH LESS  
COVERAGE THAN EARLY THIS MORNING. JKL  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
TDY TUE WED THU FRI SAT SUN  
-------------------------------------------------------  
BIL 071 047/077 053/079 052/081 053/083 053/071 046/068  
0/B 00/B 31/B 00/U 00/U 21/B 12/W  
LVM 073 042/077 046/078 046/081 048/081 045/069 039/068  
0/U 00/B 20/U 00/U 00/U 21/B 22/W  
HDN 072 043/078 049/079 047/085 050/085 049/074 043/071  
0/B 00/B 43/W 00/U 00/U 11/U 11/B  
MLS 068 047/076 051/078 050/084 055/084 053/073 047/071  
2/B 00/U 25/T 00/U 00/U 11/U 11/B  
4BQ 066 047/076 052/077 050/082 054/084 054/075 048/072  
3/W 20/B 43/T 00/U 00/U 10/U 12/W  
BHK 066 043/071 048/078 048/083 051/083 051/076 044/071  
2/W 00/N 46/T 10/U 00/N 00/U 22/W  
SHR 068 040/076 047/076 044/081 048/083 048/075 042/072  
2/W 00/U 23/W 00/U 00/U 01/U 12/W  
 

 
   
BYZ WATCHES/WARNINGS/ADVISORIES
 
 
MT...NONE.  
WY...NONE.  
 

 
 

 
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