147  
FXUS65 KTFX 060237  
AFDTFX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREAT FALLS MT  
837 PM MDT MON MAY 5 2025  
   
KEY MESSAGES  
 
- RAIN/SNOW WILL GRADUALLY END OVERNIGHT.  
 
- IT WILL GRADUALLY WARM UP THROUGH THE MIDDLE OF THIS WEEK WITH  
MOSTLY DRY WEATHER.  
 
- SHOWERS/THUNDERSTORMS ARE POSSIBLE THURSDAY AFTERNOON/EVENING  
WITH WINDY CONDITIONS IN NORTH-CENTRAL MONTANA.  
 
 
   
UPDATE  
 
UPDATED FORECAST IS OUT. MAIN CHANGE WAS TO ADD WINTER WEATHER  
ADVISORY FOR THE ENNIS AND BOZEMAN VALLEYS, AND CHANGE THE  
ADVISORY TO A WINTER STORM WARNING FOR THE BIG SKY, WEST  
YELLOWSTONE AND BOZEMAN PASS AREAS. SNOWFALL WAS HEAVY AT TIMES  
EARLIER THIS EVENING. THERE IS STILL ONE MORE BAND OF HEAVIER  
PRECIPITATION JUST SOUTH OF THE BORDER IN IDAHO, AND IT IS MOVING  
NORTHWARD. SO AT LEAST THE POTENTIAL IS THERE FOR A FEW MORE HOURS  
OF HEAVY SNOW IN THE WEST YELLOWSTONE, ENNIS, BIG SKY AND BOZEMAN  
AREAS. OTHERWISE, THE SNOW HAS PRETTY MUCH ENDED AROUND ELK PARK  
AND BOULDER, THUS THE ADVISORY WAS CANCELLED FOR THAT AREA.  
ELSEWHERE CLEARING SKIES ARE OCCURRING OVER NORTH CENTRAL MT, AS  
DRY AIR MOVES IN FROM THE NORTH. SOME PATCHY FOG COULD DEVELOP  
OVERNIGHT, ESPECIALLY IN AREAS THAT HAVE SOME CLEARING. OVERNIGHT  
LOWS ON TRACK, JUST TRENDED TOWARDS CURRENT TRENDS. BRUSDA  
 
 
   
DISCUSSION  
 
/ISSUED 546 PM MDT MON MAY 5 2025/  
 
- METEOROLOGICAL OVERVIEW:  
 
THIS AFTERNOON AN UPPER-LEVEL RIDGE WILL BEGIN TO MOVE IN OVER NORTH-  
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL ALLOW  
PRECIPITATION TO CONTINUE DIMINISHING FROM NORTHWEST TO SOUTHEAST  
THROUGH EARLY TOMORROW MORNING. DUE TO THE UPPER-LEVEL RIDGE SKIES  
WILL CLEAR ACROSS NORTH-CENTRAL MONTANA TONIGHT INTO TOMORROW  
MORNING. THIS WILL LEAD TO A LOW RISK FOR FOG TO FORM ACROSS NORTH-  
CENTRAL MONTANA TOMORROW MORNING. THE UPPER-LEVEL RIDGE WILL REMAIN  
OVER THE AREA THROUGH THURSDAY WITH WEAK FLOW ALOFT. THIS WILL BRING  
MOSTLY DRY CONDITIONS TO THE AREA WITH TEMPERATURES GRADUALLY  
WARMING UP. THURSDAY AFTERNOON AND EVENING A QUICK MOVING SHORTWAVE  
WILL MOVE OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA.  
THIS WILL BRING WINDY CONDITIONS TO NORTH-CENTRAL MONTANA WITH THE  
STRONGEST WINDS ALONG THE ROCKY MOUNTAIN FRONT. THERE IS ALSO A  
CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS NORTH-CENTRAL, CENTRAL,  
AND SOUTHWESTERN MONTANA THURSDAY AFTERNOON AND EVENING. SEE THE  
FORECAST CONFIDENCE AND SCENARIOS SECTION FOR DETAILS.  
 
FRIDAY AND SATURDAY AN UPPER-LEVEL RIDGE BUILDS BACK IN OVER NORTH-  
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. THIS WILL ALLOW  
TEMPERATURES TO WARM UP MORE WITH DRY WEATHER. ON SUNDAY THE UPPER-  
LEVEL RIDGE REMAINS OVER NORTH-CENTRAL, CENTRAL, AND SOUTHWESTERN  
MONTANA UNTIL SUNDAY AFTERNOON/EVENING WHEN A SURFACE COLD FRONT  
ASSOCIATED WITH AN UPPER-LEVEL TROUGH WILL MOVE THROUGH. DUE TO WARM  
TEMPERATURES PRIOR TO THE COLD FRONTAL PASSAGE THERE WILL BE  
INSTABILITY THAT IS GENERATED. THIS WILL LEAD TO SHOWERS AND  
THUNDERSTORMS SUNDAY AFTERNOON AND EVENING. SEE THE FORECAST  
CONFIDENCE AND SCENARIOS SECTION FOR DETAILS.  
 
- FORECAST CONFIDENCE & SCENARIOS:  
 
THERE IS HIGH UNCERTAINTY IN WHEN IT WILL STOP SNOWING IN LEWISTOWN.  
DUE TO REDUCED VISIBILITY CURRENTLY, A SPECIAL WEATHER STATEMENT WAS  
ISSUED THROUGH 5 PM TODAY FOR THE LOWER-ELEVATION OF FERGUS  
COUNTY. THERE IS HIGH UNCERTAINTY ON IF IT WILL CLEAR ENOUGH  
TONIGHT INTO TOMORROW MORNING FOR FOG TO FORM ACROSS NORTH-CENTRAL  
MONTANA.  
 
FOR THUNDER ON THURSDAY THERE IS A 10 - 30% CHANCE ACROSS CENTRAL  
AND SOUTHWESTERN MONTANA. ON SUNDAY CLUSTERS AND DETERMINISTIC  
MODELS DIFFER ON THE TIMING AND PROGRESSION OF THE TROUGH THAT WILL  
MOVE THROUGH. IF IT MOVES THROUGH EARLY IN THE DAY ON SUNDAY THAT  
WILL REDUCE THE RISK FOR ANY THUNDERSTORMS. A THIS TIME, ON  
SUNDAY THERE IS A 10 - 30% CHANCE FOR THUNDERSTORMS ACROSS NORTH-  
CENTRAL, CENTRAL, AND SOUTHWESTERN MONTANA. -IG  
 
 
   
AVIATION  
 
06/00Z TAF PERIOD  
 
RAIN/SNOW CONTINUE TO AFFECT CENTRAL AND SOUTHWEST MT THIS  
AFTERNOON. HEAVY SNOWFALL IS POSSIBLE AT TIMES, MOSTLY FOR AREAS  
EAST AND SOUTH OF BOZEMAN, BUT THIS DOES INCLUDE AREAS NEAR ENNIS  
AND WEST YELLOWSTONE. THE HEAVIEST PRECIPITATION SHOULD START TO  
DIMINISH AFTER 06Z TUE. THE MAIN CONCERN LATER TONIGHT WILL BE THE  
POTENTIAL FOR FOG. SOME AREAS OVER NORTH CENTRAL MT COULD GET  
SOME PERIODS OF DENSE FOG, AS SKIES ARE PROGGED TO CLEAR OUT THE  
MOST IN THAT REGION. HOWEVER, CONFIDENCE IS LOW AT THIS TIME FOR  
FOG DEVELOPMENT. MOUNTAINS WILL BE OBSCURED OVER CENTRAL/SOUTHWEST  
MT THROUGH ABOUT 15Z TUE. BRUSDA  
 
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED  
REGIONAL AVIATION WEATHER AND HAZARD INFORMATION.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
GTF 32 59 38 74 / 10 10 0 0  
CTB 29 61 34 74 / 0 0 0 0  
HLN 33 60 37 75 / 30 10 0 0  
BZN 31 53 31 72 / 100 10 0 0  
WYS 27 59 28 65 / 100 10 0 10  
DLN 31 53 33 70 / 70 10 0 0  
HVR 31 65 36 77 / 0 0 0 0  
LWT 30 52 33 70 / 50 20 0 0  
 
 
   
TFX WATCHES/WARNINGS/ADVISORIES  
 
WINTER STORM WARNING UNTIL 6 AM MDT TUESDAY FOR BIG BELT,  
BRIDGER AND CASTLE MOUNTAINS-GALLATIN AND MADISON COUNTY  
MOUNTAINS AND CENTENNIAL MOUNTAINS.  
 
WINTER WEATHER ADVISORY UNTIL 6 AM MDT TUESDAY FOR GALLATIN  
VALLEY-MADISON RIVER VALLEY.  
 
 
 
 
HTTP://WWW.WEATHER.GOV/GREATFALLS  
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