601
FXUS65 KTFX 261747
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1047 AM MST SUN JAN 26 2025
AVIATION SECTION UPDATED.
KEY MESSAGES
- DENSE FOG AND COLD TEMPERATURES THROUGH THIS MORNING.
- GENERALLY QUIET WEATHER CONDITIONS WITH A SLOW WARMING TREND
EXPECTED FOR MUCH OF NEXT WEEK.
- POTENTIAL FOR LIGHT SNOW NEXT WEEKEND.
UPDATE
/ISSUED 931 AM MST SUN JAN 26 2025/
930 AM UPDATE: SATELLITE AND WEBCAMS SHOW FOG HAS DIMINISHED
SIGNIFICANTLY OUTSIDE OF THE HELENA VALLEY OVER THE PAST 45
MINUTES OR SO. HENCE, THE DENSE FOG ADVISORY HAS BEEN CANCELED
FOR THESE AREAS. NO OTHER CHANGES WERE NECESSARY AT THIS TIME.
845AM UPDATE: THE COMBINATION OF CLEAR SKIES AND LIGHT WINDS
OVERNIGHT IN CENTRAL AND SOUTHWEST MONTANA VALLEYS HAS RESULTED IN
A COLD MORNING. THE COLDEST TEMPERATURES ARE CONFINED TO TYPICAL
COLD- PRONE HIGH ELEVATION VALLEYS SUCH AS WEST YELLOWSTONE AND
THE BIG HOLE VALLEY (-30S F AMBIENT TEMPERATURES). ELSEWHERE
TEMPERATURES ARE LARGELY IN THE SINGLE DIGITS TO TEENS BELOW ZERO.
THE GOING COLD WEATHER ADVISORY IS IN GOOD SHAPE, WHICH IS IN
EFFECT THROUGH 11 AM THIS MORNING.
THE OTHER CONCERN ACROSS CENTRAL AND SOUTHWEST MONTANA VALLEYS THIS
MORNING IS FOG, WHICH IS MOST DENSE/WIDESPREAD IN THE HELENA
VALLEY. ALONG THE CORRIDOR BETWEEN HELENA AND BOZEMAN, WEBCAMS AND
SATELLITE SHOW THE FOG IS MORE PATCHY IN NATURE. ALTHOUGH FOG IS
MORE PATCHY IN NATURE OUTSIDE OF THE HELENA VALLEY, THE DENSE FOG
ADVISORY WILL REMAIN IN EFFECT AT THIS TIME. GIVEN THAT THE FOG
APPEARS TO BE MORE PERSISTENT IN HELENA THIS MORNING, DAYTIME
HIGHS WERE LOWERED A BIT FOR TODAY.
BREEZY WINDS ACROSS THE PLAINS MAY BRING ABOUT A LOCALIZED
DRIFTING SNOW CONCERN. OTHERWISE, TODAY APPEARS TO BE BENIGN
ACROSS THE REGION AS UPPER LEVEL RIDGING OFF TO THE WEST EXERTS
ITS INFLUENCE OVER THE NORTHERN ROCKIES. -AM
DISCUSSION
/ISSUED 931 AM MST SUN JAN 26 2025/
- METEOROLOGICAL OVERVIEW:
CLEAR SKIES OVER SOUTHWEST MT THIS MORNING IS ALLOWING FOR A VERY
COLD MORNING, ALONG WITH SOME PATCHY DENSE FOG IN THE VALLEYS.
MOST OF THE FOG WILL DIMINISH BY LATE MORNING, AND WITH WARMING
TEMPERATURES BY LATE MORNING AS WELL, THE COLD AIR PRODUCTS
SHOULD BE ALLOWED TO EXPIRE BY THEN. OTHERWISE EXPECT INCREASING
CLOUDS THIS MORNING FROM THE NORTH, AS HIGH CLOUDS MOVE SOUTHWARD
FROM CANADA.
FOR MUCH OF THE WORK WEEK, EXPECT QUIET WEATHER CONDITIONS, AS AN
UPPER LEVEL RIDGE BUILDS ALONG THE WEST COAST. THIS WILL RESULT
IN SLOWLY WARMING TEMPERATURES OVER THE CWA THROUGH THE WEEK. THE
ONE EXCEPTION WILL BE THE VALLEYS OF SOUTHWEST MT. WITH MOSTLY
CLEAR SKIES AT NIGHT AND LIGHT WINDS DURING THE DAY, SOME VALLEY
LOCATIONS MIGHT NOT WARM AS QUICKLY AS PROGGED. THUS SOME
ADJUSTMENTS MIGHT NEED TO MADE TO HIGH TEMPERATURES OVER THE
SOUTHWEST MT THIS WEEK TO LOWER THEM A BIT.
THE NEXT CHANCE FOR SNOW LOOKS TO ARRIVE LATE ON FRIDAY, BUT MOST
LIKELY OVER THE WEEKEND. THE GFS/EC WERE IN PRETTY GOOD AGREEMENT
A FEW DAYS AGO, BUT NOW HAVE DIVERGED A BIT, WITH THE GFS
BECOMING A BIT WARMER AND SLOWER WITH THE INCREASED CHANCES FOR
SNOW. SO SOME ADJUSTMENTS TO SNOWFALL/TEMPERATURES MIGHT OCCUR
OVER THE NEXT FEW DAYS BECAUSE OF THE DIFFERENCE.
- FORECAST CONFIDENCE & SCENARIOS:
THE MAIN CONCERN OVER THE NEXT SEVERAL DAYS WILL BE DAYTIME HIGH
TEMPERATURES IN THE VALLEYS OF SOUTHWEST MT. WITH A COLD START
AND LIGHT WINDS, THE VALLEYS OF SOUTHWEST MT WILL BE SLOW TO
WARM, AND HIGH TEMPERATURES MIGHT BE A FEW DEGREES COOLER THAN
CURRENTLY FORECASTED.
FOR NEXT WEEKEND, SNOW AMOUNTS LOOK TO BE ON THE LIGHT SIDE, WITH
A GENERAL 1 TO 3 INCHES AT LOWER ELEVATIONS AND 4 TO 8 INCHES IN
THE MOUNTAINS, EXPECT GLACIER PARK WHERE SNOW AMOUNTS COULD
EXCEED A FOOT. HOWEVER, PROBABILITIES ARE LOW NOW, BECAUSE OF
MODEL DIFFERENCES, THUS THE LOW CONFIDENCE IN THESE SNOW AMOUNTS.
BRUSDA
AVIATION
26/18Z TAF PERIOD
PATCHY FOG NEAR KHLN SHOULD GRADUALLY IMPROVE THROUGH EARLY THIS
AFTERNOON, HOWEVER A LINGERING POOL OF COLD AIR AT THE SURFACE
FROM THE HELENA VALLEY SOUTH THROUGH THE GALLATIN VALLEY COULD
LEAD TO SOME PATCHY FOG DEVELOPMENT AGAIN TONIGHT AT KHLN AND
KBZN. OTHERWISE, VFR CONDITIONS PREVAIL ACROSS THE AREA BENEATH A
DRY/STABLE NORTHERLY FLOW ALOFT WITH JUST SOME THIN HIGH CLOUDS AT
TIMES. WEST TO SOUTHWEST SURFACE WINDS INCREASE ACROSS THE NORTH-
CENTRAL MT PLAINS TODAY WITH LIGHT WINDS PREVAILING ACROSS
SOUTHWEST MT VALLEYS. HOENISCH
REFER TO WEATHER.GOV/ZLC FOR MORE DETAILED REGIONAL AVIATION
WEATHER AND HAZARD INFORMATION.
PRELIMINARY POINT TEMPS/POPS
GTF 29 18 37 18 / 0 0 0 0
CTB 33 21 37 20 / 0 0 0 0
HLN 18 4 31 10 / 0 0 0 0
BZN 18 -4 30 7 / 0 0 0 0
WYS 22 -19 32 -6 / 0 0 0 0
DLN 18 3 29 9 / 0 0 0 0
HVR 30 18 37 18 / 0 0 0 0
LWT 32 19 40 20 / 0 0 0 0
TFX WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY UNTIL 11 AM MST THIS MORNING FOR
BEAVERHEAD AND WESTERN MADISON BELOW 6000FT-ELKHORN AND BOULDER
MOUNTAINS-GALLATIN VALLEY-GALLATIN AND MADISON COUNTY MOUNTAINS
AND CENTENNIAL MOUNTAINS-MADISON RIVER VALLEY-MEAGHER COUNTY
VALLEYS-MISSOURI HEADWATERS-NORTHWEST BEAVERHEAD COUNTY-RUBY
MOUNTAINS AND SOUTHERN BEAVERHEAD MOUNTAINS-UPPER BLACKFOOT AND
MACDONALD PASS.
DENSE FOG ADVISORY UNTIL NOON MST FOR HELENA VALLEY.
HTTP://WWW.WEATHER.GOV/GREATFALLS
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