Area Forecast Discussion
Issued by NWS Great Falls, MT

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FXUS65 KTFX 130557
AFDTFX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1050 PM MST FRI FEB 12 2016

AVIATION SECTION UPDATED.

.UPDATE...
NO SIGNIFICANT WEATHER EXPECTED TONIGHT ACROSS CENTRAL AND
SOUTHWEST MT. RESIDUAL LIGHT SNOW SHOWERS MOVING THROUGH
HILL/BLAINE COUNTIES EARLIER THIS EVENING HAVE CLEARED OUT OF THE
AREA AND WEAK HIGH PRESSURE RIDGING OVER THE MIDDLE PART OF THE
STATE WILL KEEP CONDITIONS DRY OVER MOST OF OUR REGION THROUGH THE
OVERNIGHT HOURS. EXCEPTIONS WILL BE CONTINUED SCATTERED SNOW
SHOWERS ALONG THE ROCKY MTN FRONT AND ISOLATED SHOWERS DEVELOPING
AROUND 3AM TO 6AM FROM HELENA TO THE BIG HOLE VALLEY AS LEADING
EDGE OF MOISTURE FROM TOMORROW`S WEATHER SYSTEM COMES EAST OF THE
CONTINENTAL DIVIDE.

MAIN FORECAST ADJUSTMENTS THIS EVENING WERE TO REMOVE MENTION OF
ANY PRECIPITATION FOR HILL/BLAINE COUNTIES THROUGH TONIGHT AND
ADD IN A SLIGHT CHANCE OF SHOWERS OVERNIGHT IN SOUTHWEST MT. ALSO
MADE SOME MINOR TWEAKS TO LOW TEMPS ALONG THE HILINE TO BETTER
MATCH COOLER OBSERVED TEMPS.
WARANAUSKAS

&&

.AVIATION...
UPDATED 0550Z.

A PASSING PACIFIC WEATHER SYSTEM SATURDAY WILL BRING TEMPORARY
MVFR/IFR CONDITIONS IN WIDESPREAD RAIN OR SNOW SHOWERS ACROSS
CENTRAL AND SOUTHWEST MONTANA. CONDITIONS WILL IMPROVE AFTER 17Z AS
THE DISTURBANCE STARTS TO EXIT THE AREA, BUT SHOWERS WILL LINGER IN
THE MOUNTAIN AREAS. WESTERLY WINDS WILL ALSO INCREASE SIGNIFICANTLY
AFTER 17Z. THE SOUTHWEST MONTANA VALLEYS WILL LIKELY HAVE WINDS OF
15 TO 25 KT, WHILE THE NORTH CENTRAL MONTANA PLAINS WILL HAVE WINDS
OF 20 TO 30 KT, WITH GUSTS POSSIBLY EXCEEDING 45 KT AT TIMES ALONG
THE ROCKY MOUNTAIN FRONT. PN

&&

.PREV DISCUSSION...
/ISSUED 440 PM MST FRI FEB 12 2016/

TONIGHT THROUGH SUNDAY...AN UPPER LEVEL LOW PRESSURE TROF OVER
THE EASTERN PACIFIC WILL MOVE OVER THE WEST COAST TONIGHT.
MOISTURE AHEAD OF THIS TROF WILL KEEP CLOUDS ACROSS THE MOST OF
THE AREA AND KEEP OVERNIGHT TEMPS MODERATE. THE TROF WILL
APPROACH THE ROCKIES TONIGHT AND THE CHANCE OF PRECIPITATION WILL
INCREASE AFTER MIDNIGHT. BEST CHANCES FOR PRECIPITATION THROUGH
SATURDAY WILL BE OVER THE NORTHERN ROCKIES AND SOUTHWEST MONTANA.
A COLD FRONT ASSOCIATED WITH THE TROF WILL HELP BOOST SURFACE
WINDS ACROSS THE ROCKIES AND ADJACENT PLAINS EARLY SATURDAY. A
JET OF STRONGER WINDS ALOFT AHEAD OF THIS TROF WILL CROSS THE
ROCKIES TONIGHT, STRENGTHEN, AND VEER NORTHWEST LATE SATURDAY
AFTER THE TROF PASSES. THIS STRONG NORTHWEST FLOW WILL REMAIN
OVER THE ZONES SUNDAY. A SERIES OF DISTURBANCES MOVING THROUGH
THIS FLOW WILL INCREASE THE CHANCE OF PRECIPITATION AGAIN OVER
MAINLY THE NORTHERN ROCKIES AND SOUTHWEST MONTANA. SNOW
ACCUMULATIONS OF 2 TO 4 INCHES WILL MAINLY BE OVER HIGHER
TERRAIN. THE AIRMASS WILL BE COOLER AFTER COLD FRONT PASSAGE
SATURDAY AND TEMPERATURES WILL REMAIN COOLER THROUGH SUNDAY...BUT
REMAIN WELL ABOVE SEASONAL NORMALS. ZELZER

SUNDAY NIGHT THROUGH FRIDAY...A SOMEWHAT ACTIVE WEATHER PATTERN
IS IN STORE FOR THE MEDIUM RANGE PERIOD. WITH AN UPPER RIDGE
ALONG THE WEST COAST, THE PERIOD BEGINS WITH RATHER UNSETTLED
NORTHWEST FLOW ALOFT OVER THE AREA. SHORT WAVE ENERGY MOVING
WITHIN THIS FLOW ALOFT WILL BRING SCATTERED MOUNTAIN SNOW AND
ISOLATED RAIN SHOWERS TO THE PLAINS MONDAY AND TUESDAY.
PRECIPITATION AMOUNTS OVER THE PLAINS WILL BE LIGHT AS A LEE SIDE
TROF THAT DEVELOPS MONDAY WILL RESULT IN INCREASING DOWNSLOPE
WINDS. HIGH WINDS MAY DEVELOP ALONG THE ROCKY MOUNTAIN FRONT AND
ADJACENT PLAINS BUT MODEL DIFFERENCES DEPICTING THE LEE SIDE TROF
RESULT IN LOW CONFIDENCE AT THIS TIME REGARDING ANY POSSIBLE
HIGHLIGHTS THAT MAY BE NEEDED. ISOLATED SHOWERS DECREASE ON
WEDNESDAY AS A SOMEWHAT FLATTENED RIDGE MOVES TO THE CONTINENTAL
DIVIDE. MODELS DIVERGE WITH THEIR SOLUTIONS THURSDAY WITH THE GFS
BRINGING AN UPPER TROF ACROSS THE AREA RESULTING IN RAIN AND/OR
SNOW SHOWERS OVER THE WESTERN MOUNTAINS AND SOUTHWEST MONTANA.
MODEL DIFFERENCES CONTINUE FRIDAY WITH THE GFS REBUILDING THE
UPPER RIDGE WHILE THE ECMWF SPINS SHORT WAVE ENERGY OUT OF AN
UPPER TROF APPROACHING WESTERN MONTANA. HAVE LEANED TOWARD A
WETTER EUROPEAN SOLUTION. TEMPERATURES WILL CONTINUE ABOVE
SEASONAL AVERAGES THROUGH THE PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  38  51  34  51 /  10  20  10  30
CTB  35  49  32  49 /  10  10  10  10
HLN  33  45  31  46 /  20  20  20  30
BZN  26  41  25  41 /  10  50  30  50
WEY  22  34  22  34 /  10  50  50  60
DLN  32  41  29  42 /  20  30  20  30
HVR  27  50  30  50 /  10  30  20  10
LWT  34  44  29  44 /  10  30  10  30

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

WEATHER.GOV/GREATFALLS


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