644
FXUS65 KMSO 190927
AFDMSO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
227 AM MST THU DEC 19 2024
DISCUSSION
HIGH PRESSURE WILL BEGIN TO BUILD TODAY OVER THE
NORTHWESTERN U.S. AND LAST INTO THE COMING WEEKEND. WATER VAPOR
SATELLITE IMAGERY THIS MORNING INDICATES MOST AVAILABLE PACIFIC
MOISTURE IS RIDING THE RIDGE TO THE NORTH OF THE NORTHERN
ROCKIES. ONE EXCEPTION WILL BE LIGHT, TERRAIN-DRIVEN SNOW OVER THE
NORTHERN CONTINENTAL DIVIDE THROUGH THIS MORNING. MORNING FOG
WILL BE THE PRIMARY IMPACT ASSOCIATED WITH THIS PERIOD OF HIGH
PRESSURE. EXPECT DECREASED VISIBILITY FOR THE MORNING COMMUTES IN
THE PRONOUNCED VALLEYS OF WESTERN MONTANA SUCH AS THE MISSOULA,
BITTERROOT, MISSION, AND FLATHEAD VALLEYS. ON FRIDAY MORNING, AN
EMBEDDED SHORTWAVE TROUGH WILL BRING INCREASING CLOUDS AND CHANCES
FOR RAIN OR LIGHT SNOW TO NORTHWEST MONTANA.
LOOKING OUT A LITTLE FARTHER, ENSEMBLE AND DETERMINISTIC MODELS
INDICATE A DEEPER TROUGH ARRIVING SATURDAY NIGHT INTO SUNDAY. AS
HAS BEEN THE THEME LATELY, PACIFIC MOISTURE ASSOCIATED WITH THIS
SYSTEM ARRIVES UNDER SOUTHWESTERLY FLOW ALOFT, SO TEMPERATURES
NECESSARY FOR SNOW WILL LIKELY REMAIN ABOVE THE VALLEY FLOORS.
DEPENDING ON THE STRENGTH OF VALLEY TEMPERATURE INVERSIONS THAT
SET UP UNDER THE CURRENT HIGH PRESSURE REGIME, FREEZING RAIN MAY BE
A POSSIBILITY FOR SUNDAY MORNING.
AVIATION
HIGH PRESSURE WILL BUILD OVER THE NORTHERN ROCKIES
AIRSPACE TODAY. MORNING FOG AT KGPI AND KMSO WILL BE A
POSSIBILITY GIVEN THE DECREASING CLOUDS AND RECENT PRECIPITATION,
SO WILL KEEP A MENTION OF FOG IN TAFS THIS MORNING. ELSEWHERE,
EXPECT DECREASING CLOUDS WITH LIGHT AND VARIABLE WINDS UNDER HIGH
PRESSURE.
MSO WATCHES/WARNINGS/ADVISORIES
MT...NONE.
ID...NONE.
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