Snow Advisory 14, NWS Missoula, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
747 AM MST MON FEB 4 2008

.UPDATE...FORECAST FOR NORTHERN BITTERROOT...MISSOULA VALLEY
SOUTHEASTWARD TO BUTTE UPDATED FOR MORNING SNOW.

&&

.DISCUSSION...A WEATHER DISTURBANCE AND SURGE OF MOISTURE IS
MOVING ACROSS WEST-CENTRAL MONTANA THIS MORNING. AS THIS MOISTURE
AND ENERGY FROM THIS DISTURBANCE INTERACTS WITH A STATIONARY
SURFACE FRONT OVER WEST-CENTRAL MONTANA...SNOW SHOWERS HAVE BEEN
ENHANCING. ALREADY RECEIVED REPORTS UP TO 2 INCHES IN THE NORTHERN
BITTERROOT VALLEY. BIG QUESTION IS HOW MUCH MORE AND WHETHER AREAS
LIKE DEER LODGE...ANACONDA...AND BUTTE MAY SEE SIMILAR
ACCUMULATION. SINCE THE TRANSLATION OF THE MOISTURE AND ENERGY IS
TOWARDS THE SOUTHEAST AND THE FRONT ALSO SEEMS TO AT LEAST
PARTIALLY EXIST IN THE BUTTE AREA...BELIEVE SOME SNOW ACCUMULATION
LIKELY THESE AREAS AS WELL. FORECASTS HAVE BEEN UPDATED...ALTHOUGH
MAY FURTHER UPDATE DEER LODGE TO BUTTE TO ADD IN A BIT MORE SNOW
ACCUMULATION THIS MORNING. OVERALL...THE SURFACE FRONT RAPIDLY
WEAKENS AND SHIFTS EASTWARD MID DAY AND AFTERNOON. SO...THE
CURRENT ENHANCEMENT OF THE SNOW SHOULD DECREASE.

&&

.AVIATION...WIDESPREAD MOUNTAIN OBSCURATIONS AND AREAS OF LOW
VISIBILITIES WILL CONTINUE THIS MORNING...ESPECIALLY ACROSS
WEST-CENTRAL MONTANA. CONDITIONS SHOULD GRADUALLY IMPROVE MID DAY
AND THIS AFTERNOON AS THE CURRENT WEATHER DISTURBANCE SHIFTS TO
THE SOUTHEAST.

&&

.PREV DISCUSSION... /ISSUED 637 AM MST MON FEB 4 2008/

UPDATE...ISSUED AN UPDATE TO INCREASE CHANCES OF SNOW TO ACCOUNT
FOR CURRENT SNOWFALL OVER NORTHWEST MONTANA AND NORTHERN IDAHO.

DISCUSSION...AN UNSTABLE ATMOSPHERE OVER NORTHWEST MONTANA AND
NORTHERN IDAHO HAS ALLOWED SNOW SHOWERS TO DEVELOP THIS MORNING. A BREAK
IN THE SNOWFALL CAN BE EXPECTED THIS MORNING BEFORE ANOTHER ROUND
OF SNOW IS POSSIBLE WITH A WEAK SYSTEM MOVING IN FROM WASHINGTON.

AVIATION...SNOW SHOWERS THIS MORNING WILL REDUCE VISIBILITIES AND
LOWER CEILINGS NEAR THE MSO AND BTM TERMINALS. MOUNTAIN AND PASS
OBSCURATIONS ARE EXPECTED TO CONTINUE IN PLACES TODAY AND TONIGHT
AS UNSETTLED WEATHER CONTINUES OVER THE NORTHERN ROCKIES.
OBSCURATIONS WILL MORE PREVALENT NEAR THE IDAHO/MONTANA BORDER.

PREV DISCUSSION... /ISSUED 308 AM MST MON FEB 4 2008/

DISCUSSION...AN UNSTABLE AIRMASS WILL ALLOW SNOW SHOWERS TO
CONTINUE OVER NORTHERN IDAHO AND NORTHWEST MONTANA THROUGH THIS
MORNING. A SHORTWAVE CURRENTLY MOVING OVER EASTERN WASHINGTON
WILL MOVE ACROSS THE NORTHERN ROCKIES LATER THIS MORNING AND THIS
AFTERNOON. WITH THE LACK OF GROUND REPORTS OF SNOWFALL FROM THIS
SYSTEM AS IT MOVES OVER EASTERN WASHINGTON IT IS LIKELY THE SNOW
WILL BE CONFINED TO THE HIGHER TERRAIN. THE ATMOSPHERE WILL STAY
UNSTABLE IN THE LOWER LEVELS KEEPING THE POTENTIAL FOR SNOW
SHOWERS IN THE FORECAST THROUGH TONIGHT.

THE NEXT FRONTAL SYSTEM WILL BEGIN TO IMPACT THE REGION TUESDAY
AFTERNOON. THE HEAVIEST PRECIPITATION IS EXPECTED OVER NORTHWEST
MONTANA AND NORTHERN IDAHO. THIS WILL BE A FAIRLY FAST MOVING
SYSTEM...LEAVING COLDER AIR IN ITS WAKE. SYNOPTIC SCALE LIFT IS
EXPECTED TO SET UP OVER NORTHWEST MONTANA AND CENTRAL IDAHO
WEDNESDAY NIGHT INTO THURSDAY. THIS SHOULD BRING STEADY SNOW TO
THIS REGION. IT IS POSSIBLE ACCUMULATIONS WITH THIS STEADY SNOW
WILL BE HIGHER THAN WITH TUESDAYS COLD FRONT...ESPECIALLY FOR
VALLEY LOCATIONS.

SWIFT NORTHWESTERLY FLOW WILL BRING CONTINUED UNSETTLED WEATHER WITH
MAINLY MOUNTAIN SNOW SHOWERS TO THE NORTHERN ROCKIES FRIDAY INTO
THE WEEKEND. TEMPERATURES ARE EXPECTED TO RAISE TO ABOUT 5
DEGREES ABOVE NORMAL BY THE END OF THE WEEK AS HIGH PRESSURE
BUILDS OVER THE WESTERN US.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
     MORNING FOR KOOTENAI/CABINET REGION-LOWER CLARK FORK REGION.

ID...WINTER STORM WATCH FROM TUESDAY AFTERNOON THROUGH WEDNESDAY
     MORNING FOR NORTHERN CLEARWATER MOUNTAINS.

&&

SHORT TERM...BAUCK
LONG TERM....LOEFFELBEIN
AVIATION...BAUCK