983  
FXUS65 KTFX 162352  
AFDTFX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREAT FALLS MT  
452 PM MST SUN FEB 16 2025  
 
AVIATION SECTION UPDATED.  
   
KEY MESSAGES
 
 
- A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW WILL OCCUR ACROSS  
PORTIONS OF NORTH CENTRAL AND SOUTHWEST MONTANA THROUGH  
TUESDAY, WITH THE HEAVIEST SNOW FALLING ACROSS CENTRAL MONTANA  
ALONG AND SOUTHWEST OF A BROWNING TO LEWISTOWN LINE AND  
NORTHEAST OF BUTTE TO BOZEMAN LINE.  
 
- BITTER COLD TEMPERATURES WILL OCCUR THROUGH THE MIDDLE OF THE  
UPCOMING WORK WEEK, WITH THE COLDEST READINGS BEING FELT OVER  
THE PLAINS OF CENTRAL AND NORTH CENTRAL MONTANA, ESPECIALLY  
ALONG THE HI-LINE.  
 
- TEMPERATURES WILL BEGIN TO MODERATE TOWARDS THE END OF THE  
UPCOMING WORK WEEK, BUT WITH THE MODERATING TEMPERATURES WILL  
COME INCREASING SOUTHWEST TO WEST WINDS AND THE POTENTIAL FOR  
BLOWING AND DRIFTING SNOW.  
 

 
   
DISCUSSION
 
 
/ISSUED 251 PM MST SUN FEB 16 2025/  
 
NOT MUCH HAS CHANGED WITH THIS AFTERNOON'S FORECAST PACKAGE, BUT  
THERE ARE A FEW BUT NOTABLE DIFFERENCES THAT I WANT TO HIGHLIGHT  
FROM THE PREVIOUS SHIFT'S DISCUSSION, WHICH IS BELOW.  
 
FIRST AND FOREMOST, THIS SNOWFALL BAND ALONG A LINE FROM  
GENERALLY CUT BANK TO GREAT FALLS TO LEWISTOWN HAS BEEN A BIT  
WEAKER THAN ORIGINALLY FORECAST, LIKELY DUE TO SOME DRY AIR  
UNDERCUTTING IT FROM THE NORTH. THIS DRY AIR (EVIDENCED BY A 5  
DEGREE DEW POINT DEPRESSION EARLIER THIS MORNING AT GREAT FALLS  
INTERNATIONAL AIRPORT) SEEMS TO HAVE RESULTED IN LESS SNOW  
GENERATION FOR ONE, BUT ALSO LIKELY RESULTED IN SOME SUBLIMATION  
OF THE SNOW AS IT FELL TO THE GROUND. RADAR HAS BEEN FILLING IN A  
BIT OVER THE PAST FEW HOURS, AND THIS DRY AIR NEAR THE GROUND HAS  
BEEN SLOWLY SATURATING, SO I SUSPECT THAT SNOWFALL RATES SHOULD  
GRADUALLY PICK BACK UP TO FORECAST LEVELS BY THIS EVENING.  
NEVERTHELESS, SNOWFALL TOTALS DID TREND SLIGHTLY DOWNWARD FOR THE  
EVENT WITH THE ABSENCE OF THIS MORNING'S SNOW, BUT THE EXISTING  
WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES CONTINUE TO  
LOOK GOOD, SO I DID NOT MAKE ANY ADJUSTMENTS TO WHAT I INHERITED  
EARLIER THIS MORNING.  
 
WHERE I DID MAKE SOME ADJUSTMENTS WERE TO THE COLD WEATHER  
PRODUCTS, AS I UPGRADED THE EXTREME COLD WATCH TO A WARNING AND  
ISSUED COLD WEATHER ADVISORIES ALONG THE EDGE OF THE WARNING.  
WHILE SOME AREAS MIGHT NOT EXACTLY HIT CRITERIA OVERNIGHT TONIGHT  
FOR THE WARNING AREA, THE MESSAGE IS THE SAME WHETHER IT IS -35  
OR -40 AT THIS POINT, SO I WANTED TO MAKE THE HIGHLIGHTS  
CONSISTENT AS WELL. LUDWIG  
 
PREV DISCUSSION...  
/ISSUED 1047 AM MST SUN FEB 16 2025/  
 
- METEOROLOGICAL OVERVIEW:  
 
NORTHWESTERLY FLOW ALOFT WAS IN PLACE OVER THE NORTHERN ROCKIES  
EARLY THIS MORNING, WITH TRANSIENT RIDGING OVER THE PACIFIC  
NORTHWEST BEING FLATTENED BY A DIGGING SHORTWAVE OVER THE GULF OF  
ALASKA. STRONG MID- TO UPPER LEVEL WARM AIR ADVECTION AHEAD OF  
THE FLATTENING RIDGE WILL CONTINUE TO OVERSPREAD THE NORTHERN  
ROCKIES THROUGH TUESDAY AS LONGWAVE TROUGHING OVER THE EASTERN  
2/3RDS OF THE CONUS AND CANADA REMAINS FIRMLY ENTRENCHED; WITH  
LOBES OF VERY COLD LOW TO UPPER LEVEL AIR PIVOTING SOUTH ALONG  
THE CANADIAN ROCKIES AND INTO NORTH CENTRAL AND PORTIONS OF  
SOUTHWEST MONTANA. THIS SETUP WILL LEAD TO A VERY STRONG  
BAROCLINIC ZONE ORIENTATED FROM NORTHWEST TO SOUTHEAST FROM THE  
GLACIER NATIONAL PARK REGION TO THE BOZEMAN AREA THROUGH TUESDAY,  
WITH PACIFIC MOISTURE OVERRUNNING THE DEEP ARCTIC AIRMASS AT THE  
SURFACE. STRONG MID- LEVEL FRONTOGENESIS WILL REMAIN NEARLY  
STATIONARY ACROSS AN AREA FROM SOUTHWEST OF A BROWNING TO  
LEWISTOWN LINE AND NORTHEAST OF A BUTTE TO BOZEMAN LINE OVER THIS  
PERIOD, WHICH COMBINED WITH THE OVERRUNNING PACIFIC MOISTURE WILL  
SET THE STAGE FOR A PROLONGED PERIOD OF LIGHT TO MODERATE  
SNOWFALL (RATES) THROUGH THE DAY ON TUESDAY. PERIODS OF MODERATE  
SNOW ARE LIKELY TO LEAD ACCUMULATIONS OF 0.25" TO 0.75" PER HOUR  
ACROSS CENTRAL MONTANA THROUGH MONDAY AFTERNOON. THESE RATES AND  
THE OVERALL LONG DURATION OF THE EVENT WILL LEAD TO SIGNIFICANT  
SNOWFALL ACCUMULATIONS ACROSS ALL ELEVATIONS SOUTHWEST OF THE  
BROWNING TO LEWISTOWN LINE AND NORTHEAST OF THE BUTTE TO BOZEMAN  
LINE.  
 
IN ADDITION TO THE THREAT FOR ACCUMULATING SNOW THROUGH THE  
MIDDLE OF THE UPCOMING WORK WEEK A VERY STRONG SURFACE HIGH OF  
~1050MB TO 1055MB WILL SLOWLY DRIFT SOUTHEAST FROM THE CANADIAN  
PRAIRIE PROVINCES TO THE NORTHERN HIGH PLAINS. BITTERLY COLD  
TEMPERATURES WILL ACCOMPANY THIS SURFACE HIGH SOUTH AND INTO  
NORTH CENTRAL AND PORTIONS OF SOUTHWEST MONTANA THROUGH  
WEDNESDAY, WITH THE COLDEST TEMPERATURES AND SUBSEQUENT WIND  
CHILLS RESIDING OVER THE PLAINS OF CENTRAL AND NORTH CENTRAL  
MONTANA.  
 
BEYOND THE MIDDLE OF THE UPCOMING WORK WEEK UPPER LEVEL RIDGING  
OVER THE EASTERN PACIFIC WILL SLOWLY BEGIN TO BUILD EAST TOWARDS  
THE NORTHERN ROCKIES, WHICH WILL HELP TO START A MODERATION TREND  
WITH RESPECT TO TEMPERATURES ACROSS SOUTHWEST THROUGH NORTH  
CENTRAL MONTANA. THE FEW EXCEPTION TO THIS WILL BE THE COLD PRONE  
VALLEYS OF SOUTHWEST AND CENTRAL MONTANA WHERE STRONG INVERSIONS  
ARE LIKELY TO INHIBIT ANY DRASTIC WARMING, ALONG WITH THE  
STUBBORN MILK RIVER VALLEY IN NORTH CENTRAL MONTANA WHERE  
GUIDANCE TENDS TO ERODE ARCTIC AIRMASSES SEVERAL DAYS TOO SOON.  
AS IS THE CASE WITH ANY WARM-UPS DURING THE WINTER SEASON ACROSS  
SOUTHWEST THROUGH NORTH CENTRAL MONTANA, MOST NOTABLY OVER THE  
PLAINS, WILL COME THE PRICE OF INCREASING SOUTHWEST TO WEST WINDS.  
THESE SOUTHWEST TO WEST WINDS WILL BE ESPECIALLY STRONG AND GUSTY  
ALONG THE ROCKY MOUNTAIN FRONT AND MONTANA HWY 200/US HWY 87  
CORRIDOR ACROSS CENTRAL MONTANA.  
 
- FORECAST CONFIDENCE & SCENARIOS:  
 
ACCUMULATING SNOW THROUGH TUESDAY :  
 
CONFIDENCE REMAINS VERY HIGH THAT SIGNIFICANT SNOWFALL  
ACCUMULATIONS WILL OCCUR SOUTHWEST OF A BROWNING TO LEWISTOWN  
LINE AND NORTHEAST OF A BUTTE TO BOZEMAN LINE. OVERALL RUN-TO-  
RUN GUIDANCE HAS CHANGED VERY LITTLE OVER THE PAST 48HRS ACROSS  
THIS REGION, WITH THE ONLY NOTICEABLE CHANGE BEING AN INCREASE IN  
THE 6" SNOWFALL CONTOUR SOUTH BY APPROXIMATELY 25-50 MILES.  
CLIMATE ANOMALY INDICATORS LIKE THE ECMWF EFIS CONTINUE TO  
SUPPORT A CLIMATOLOGICALLY EXTREME SNOWFALL EVENT ACROSS THE  
AFOREMENTIONED AREAS, WITH EFI VALUES NOW RANGING FROM 0.8 TO  
0.9. BUFKIT SOUNDINGS SUPPORT BOTH SATURATED AND DEEP DGZS OVER  
THE TIMEFRAME, ESPECIALLY IN THE GREAT FALLS AREA; WHICH COMBINED  
WITH THE STRONG MID-LEVEL FRONTOGENESIS AND OVERALL LIGHT WIND  
SPEEDS SHOULD FAVOR HIGH SNOWFALL RATIOS OF NEARLY 20:1. ONLY  
CONCERN WITH THE ON-GOING FORECAST IS THE POTENTIAL NEED TO  
EXPAND THE CURRENT WINTER STORM WARNING INTO THE LEWISTOWN AND  
BOZEMAN AREAS GIVEN AN UPTICK IN SNOWFALL AMOUNTS HERE, BUT FOR  
NOW I HAVE KEPT THESE AREAS OUT WHILE ADDING THE BOULDER AND  
ELKHORN MOUNTAINS AND CANYON FERRY AREA. WHILE SNOWFALL AMOUNTS  
HAVE INCREASED ACROSS THE CANYON FERRY AREA THE BIGGEST CONCERN  
THROUGHOUT THE PERIOD WILL BE STRONG AND GUSTY NORTH WINDS ON  
MONDAY AS THE ARCTIC AIRMASS SURGES SOUTH THROUGH THE CONSTRICTED  
VALLEY. THESE STRONG AND GUSTY NORTH WINDS HERE WILL LEAD TO THE  
POTENTIAL FOR SIGNIFICANT BLOWING AND DRIFTING OF THE  
FALLING/FALLEN SNOW.  
 
BITTER COLD THROUGH THE MIDDLE OF THE WORK WEEK :  
 
CONFIDENCE ALSO REMAINS VERY HIGH WITH RESPECT TO WELL, WELL  
BELOW NORMAL TEMPERATURES THROUGH THE MIDDLE OF THE UPCOMING WORK  
WEEK, MOST NOTABLY OVER THE PLAINS OF CENTRAL AND NORTH CENTRAL  
MONTANA. CLIMATE ANOMALY INDICATORS LIKE THE ECMWF EFIS FOR HIGH  
AND LOW TEMPERATURES CONTINUE TO RANGE FROM -0.7 TO NEARLY -1.0  
OVER THE PLAINS OF CENTRAL AND NORTH CENTRAL MONTANA, WITH EVEN  
SOME VALLEYS OF CENTRAL AND SOUTHWEST MONTANA SEEING THE  
POTENTIAL FOR A CLIMATOLOGICALLY EXTREME COLD EVENT. LATEST  
DETERMINISTIC FORECAST IS CALLING FOR HIGH TEMPERATURES OVER THE  
PLAINS OF CENTRAL AND NORTH CENTRAL MONTANA ON MONDAY,  
TUESDAY,AND WEDNESDAY TO ONLY WARM INTO INTO THE TEENS BELOW ZERO  
TO NEAR ZERO DEGREES, WITH OVERNIGHT LOWS MONDAY NIGHT AND  
TUESDAY NIGHT PLUNGING TO 20 DEGREES BELOW ZERO TO NEARLY 40  
DEGREES BELOW ZERO. AT THIS TIME TUESDAY NIGHT/WEDNESDAY MORNING  
LOOKS TO BE COLDEST NIGHT AS SKIES SLOWLY CLEAR, WITH AREAS ALONG  
THE HI- LINE HAVING THE HIGHEST PROBABILITIES OF REACHING OR  
EXCEEDING 40 DEGREES BELOW ZERO. - MOLDAN  
 

 
   
AVIATION
 
 
17/00Z TAF PERIOD  
 
MAIN CONCERN WILL BE THE STEADY LIGHT SNOW THAT WILL AFFECT MUCH  
OF THE CWA THROUGH THE ENTIRE PERIOD. OVERALL THE SNOWFALL SHOULD  
BE LIGHT. AT THIS TIME, I KEPT THE MODERATE SNOWFALL OUT OF THE  
TERMINALS, BUT THERE IS A 20 PERCENT CHANCE OF THIS HAPPENING  
OVERNIGHT TONIGHT. I REALLY DON'T EXPECT MUCH BREAK IN THE  
SNOWFALL FROM WHERE IT IS OCCURRING RIGHT NOW. OVERALL, THE  
SNOWFALL WILL SLOWLY BEGIN TO END FROM NORTH TO SOUTH STARTING  
EARLY TUESDAY MORNING. MOUNTAINS/PASSES WILL BE OBSCURED ACROSS  
THE CWA THROUGH THE PERIOD. BRUSDA  
 
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION  
WEATHER AND HAZARD INFORMATION.  
 

 
   
HYDROLOGY
 
 
THE FLOOD ADVISORY CONTINUES FOR THE MADISON RIVER IN ENNIS  
BECAUSE OF AN ICE JAM. OVER THE PAST FEW DAYS, EMERGENCY MANAGER  
IN ENNIS REPORTED THE ICE JAM IS NOT GETTING BETTER, WITH  
FLOODING CONTINUING IN ENNIS LIONS CLUB PARK. THE MINOR FLOODING  
IS CONTINUES TO AFFECT AREAS EASTWARD TOWARDS ODELL CREEK, ALONG  
WITH SOUTHWARD TOWARDS HIGHWAY 287. THERE IS SOME POTENTIAL THAT  
THE ICE JAM COULD RESULT IN WATER GOING OVER HIGHWAY 287 IF THE  
ICE JAM CONTINUES TO GROW. THUS THE FLOOD ADVISORY WILL CONTINUE  
UNTIL THE ICE JAM BREAKS AND THE WATER RECEDES. BRUSDA  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
GTF -5 -2 -15 -4 / 80 90 70 20  
CTB -11 -4 -21 -4 / 80 70 20 0  
HLN -1 6 -8 7 / 90 90 90 30  
BZN 3 17 -6 12 / 90 80 90 50  
WYS 16 30 11 27 / 90 80 90 70  
DLN 18 33 10 25 / 60 30 50 30  
HVR -18 -7 -27 -7 / 10 20 10 0  
LWT -7 0 -15 0 / 80 90 80 20  
 

 
   
TFX WATCHES/WARNINGS/ADVISORIES
 
 
WINTER STORM WARNING UNTIL 11 PM MST MONDAY FOR BIG BELT,  
BRIDGER AND CASTLE MOUNTAINS-CANYON FERRY AREA-CASCADE COUNTY  
BELOW 5000FT-EAST GLACIER PARK REGION-EASTERN GLACIER, WESTERN  
TOOLE, AND CENTRAL PONDERA-EASTERN PONDERA AND EASTERN TETON-  
ELKHORN AND BOULDER MOUNTAINS-GATES OF THE MOUNTAINS-HELENA  
VALLEY-JUDITH BASIN COUNTY AND JUDITH GAP-LITTLE BELT AND  
HIGHWOOD MOUNTAINS-MEAGHER COUNTY VALLEYS-NORTHERN HIGH PLAINS-  
SNOWY AND JUDITH MOUNTAINS-SOUTHERN HIGH PLAINS-SOUTHERN ROCKY  
MOUNTAIN FRONT-UPPER BLACKFOOT AND MACDONALD PASS.  
 
WINTER WEATHER ADVISORY UNTIL 11 PM MST MONDAY FOR EASTERN TOOLE  
AND LIBERTY-FERGUS COUNTY BELOW 4500FT-GALLATIN VALLEY-GALLATIN  
AND MADISON COUNTY MOUNTAINS AND CENTENNIAL MOUNTAINS-MISSOURI  
HEADWATERS-NORTHWEST BEAVERHEAD COUNTY-WESTERN AND CENTRAL  
CHOUTEAU COUNTY.  
 
COLD WEATHER ADVISORY UNTIL NOON MST WEDNESDAY FOR CASCADE  
COUNTY BELOW 5000FT-JUDITH BASIN COUNTY AND JUDITH GAP-NORTHERN  
HIGH PLAINS-SOUTHERN HIGH PLAINS.  
 
EXTREME COLD WARNING UNTIL NOON MST WEDNESDAY FOR BEARS PAW  
MOUNTAINS AND SOUTHERN BLAINE-EASTERN GLACIER, WESTERN TOOLE,  
AND CENTRAL PONDERA-EASTERN PONDERA AND EASTERN TETON-EASTERN  
TOOLE AND LIBERTY-FERGUS COUNTY BELOW 4500FT-HILL COUNTY-  
NORTHERN BLAINE COUNTY-WESTERN AND CENTRAL CHOUTEAU COUNTY.  
 

 
 

 
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