469
FXUS65 KMSO 231904
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
1204 PM MST FRI JAN 23 2026
DISCUSSION
KEY MESSAGES:
- COLD TEMPERATURES THROUGH THE WEEKEND, WITH BELOW ZERO WIND
CHILLS ALONG THE DIVIDE.
- LIGHT SNOW EVENT ALONG THE DIVIDE AND IN SOUTHWEST MONTANA
SATURDAY INTO SUNDAY.
- STAGNANT AND DRY WEATHER PATTERN NEXT WEEK (JANUARY 26-30).
ARCTIC AIR CONTINUES TO MOVE WESTWARD ACROSS THE NORTHERN ROCKIES
THIS AFTERNOON, DRIVEN BY A MODEST PRESSURE GRADIENT AND AN
1044MB SURFACE HIGH POSITIONED OVER GREAT FALLS. BELOW ZERO WIND
CHILLS HAVE BEEN OBSERVED ALONG THE DIVIDE, ESPECIALLY OVER THE
HIGHER TERRAIN. GOES SATELLITE IMAGERY HIGHLIGHTS STRATUS CLOUDS
ACROSS WEST-CENTRAL MT AND NORTH-CENTRAL ID. RECENT TRENDS SUGGEST
THIS CLOUD DECK WILL CONTINUE TO ERODE THIS EVENING INTO THE
OVERNIGHT HOURS, WITH CLEARING SKIES ALLOWING FOR COLD TEMPERATURES
INTO SATURDAY MORNING.
THE NEXT WEATHER SYSTEM ARRIVES SATURDAY INTO SUNDAY MORNING.
MODEL GUIDANCE HIGHLIGHTS A SHORTWAVE TROUGH MOVING SOUTHWARD FROM
CANADA ALONG THE DIVIDE. AS DISCUSSED PREVIOUSLY, THE TRACK AND
DEPTH OF MOISTURE WITH THIS SYSTEM REMAINS A CHALLENGE WITHIN
FORECAST GUIDANCE. THE LATEST FORECAST POINTS TOWARDS HIGHER
POPS, QPF, AND SNOW AMOUNTS ALONG THE DIVIDE INTO SOUTHWEST
MONTANA. LIGHT SNOW WILL GENERALLY DEVELOP ACROSS THE GLACIER PARK
REGION SATURDAY MORNING/AFTERNOON, BEFORE SPREADING INTO
SOUTHWEST MONTANA BY THE EVENING INTO SUNDAY MORNING. OVERALL,
SNOW ACCUMULATIONS WILL BE LIGHT WITH MOST AREAS SEEING A TRACE TO
1 INCH, WITH LOCALIZED AREAS OF 2-4 INCHES. A SECOND PUSH OF
ARCTIC AIR WILL IMPACT THE DIVIDE SUNDAY MORNING, WITH ANOTHER
ROUND OF BELOW ZERO WIND CHILLS FOR HIGHER ELEVATION AREAS SUCH AS
MACDONALD, HOMESTAKE, AND MARIAS PASSES AND GEORGETOWN LAKE AND
VICINITY. SNOW AS FAR WEST AS THE US-93 CORRIDOR CAN NOT BE RULED
OUT SATURDAY NIGHT INTO SUNDAY MORNING, WITH A 15-20% CHANCE OF
MEASURABLE SNOWFALL.
DRIER CONDITIONS WILL RETURN SUNDAY NIGHT INTO MONDAY AS THE
WEEKEND SYSTEM EXITS. THE LATEST MODEL GUIDANCE SUGGESTS CLEARING
SKIES SUNDAY NIGHT INTO MONDAY MORNING, ALLOWING FOR EFFICIENT
RADITIONAL COOLING. LOWS COULD PLUNGE WELL INTO THE SINGLE DIGITS
OR BELOW ZERO IN THE COLDER VALLEYS.
NEXT WEEK (JANUARY 26-30): THE MAIN STORY NEXT WEEK WILL BE THE
RETURN OF A STRONG RIDGE OF HIGH PRESSURE ACROSS THE WESTERN US.
GLOBAL ENSEMBLES SUGGEST A SPLIT FLOW WEATHER PATTERN OFF THE
WESTERN US COAST, WITH THE PACIFIC JET AIMED WELL NORTH, IN CANADA
AND ALASKA. THIS LEAVES THE NORTHERN ROCKIES UNDER STABLE AND
STAGNANT CONDITIONS LEADING TO THE DEVELOPMENT OF VALLEY
INVERSIONS. PREVIOUS DISCUSSIONS MENTIONED A LOW RISK FOR
OVERRUNNING LIGHT SNOW AND FREEZING RAIN BY MID-WEEK; HOWEVER,
RECENT GUIDANCE HAS TRENDED FURTHER AWAY FROM THIS SOLUTION, WITH
ENSEMBLES NOW SHOWING LESS THAN A 5 PERCENT CHANCE FOR THIS
SCENARIO.
AVIATION
EAST WINDS FROM ACROSS THE CONTINENTAL DIVIDE ARE
BRINGING A COLD, DRY AIR MASS INTO THE REGION. THE RESULT HAS
BEEN A SLOW EROSION OF THE STRATUS OVER THE REGION. WITH THE DRY
AIR MASS OVER THE REGION, IT WILL GET VERY COLD TONIGHT AND
SATURDAY MORNING WITH SINGLE DIGIT TEMPERATURES AT MOST TERMINALS.
A RIDGE OF HIGH PRESSURE BUILDING OVER THE REGION THROUGH EARLY
NEXT WEEK MEANS THAT THE FOG AND STRATUS WILL EVENTUALLY BECOME
REESTABLISHED OVER THE REGION, BUT THAT WILL TAKE TIME, PROBABLY
AT LEAST A COUPLE OF DAYS.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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