Area Forecast Discussion
Issued by NWS Glasgow, MT

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000
FXUS65 KGGW 160904
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
304 AM MDT WED APR 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
SHORTWAVES ON NORTHWEST FLOW ALOFT AND A QUASI-STATIONARY FRONT TO
THE WEST WILL BRING CHANCES FOR RAIN AND SNOW SHOWERS TO NORTHEAST
MONTANA TODAY AND TONIGHT ALONG WITH COLDER THAN NORMAL TEMPERATURES.
HOWEVER...A DRY SLOT BETWEEN THE WAVES MAY PROVIDE DRY WEATHER FOR
PART OF THE DAY.

AN UPPER RIDGE MOVES INLAND FROM THE PACIFIC TONIGHT AND INTO
MONTANA ON THURSDAY. THIS WILL BRING THE FRONT BACK EAST AS A WARM
FRONT. A SHORTWAVE IN NW FLOW ALOFT AHEAD OF THE RIDGE WILL BRING
A CHANCE OF RAIN AND SNOW SHOWERS TO THE AREA ON THURSDAY.

THE RIDGE QUICKLY MOVES THROUGH EASTERN MONTANA THURSDAY NIGHT AND
A SHORTWAVE TROUGH AND COLD FRONT FOLLOWS ON FRIDAY WITH A CHANCE
OF RAIN SHOWERS. FORRESTER


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
SYNOPTIC SET UP... A WEAK RIDGE EXTENDS FROM THE SOUTHERN US HIGH
PLAINS UP THROUGH THE DAKOTAS WHILE A SECOND RIDGE RUNS UP THE
COAST OF CALIFORNIA... THE PACIFIC NORTHWEST... AND BRITISH COLUMBIA. A
WEAK TROUGH LIES BETWEEN THESE TWO FEATURES OVER MONTANA AND THE
HIGH PLAINS OF ALBERTA. FARTHER WEST... A LARGE TROUGH EXISTS OVER
THE BEARING SEA AND IS EJECTING INTO THE GULF OF ALASKA.

FRIDAY NIGHT... THE TROUGH ALOFT WILL FORM A SURFACE LOW OVER
ALBERTA AND MOVE IT EAST INTO SASKATCHEWAN. A COLD FRONT
EXTENDING DOWN WITH PACIFIC MOISTURE WILL QUICKLY EXIT THE AREA
BUT NOT BEFORE LEAVING RAIN SHOWERS BEHIND THAT EVENING.

SATURDAY THROUGH MONDAY NIGHT... COASTAL RIDGE WILL MOVE INTO THE
AREA AND DRY CONDITIONS OUT WITH WEAK DOWNSLOPING EFFECT IN THE
SURFACE LAYER THROUGH SATURDAY. THEN THE RIDGE WILL FLATTEN
SLIGHTLY ALLOWING FOR THE WARMER SIDE OF ZONAL FLOW AND SLIGHTLY
UNSTABLE AFTERNOONS. HIGH TEMPERATURES WILL RISE INTO THE 60S AND
70S HELPING TO DESTABILIZE THE SURFACE LAYER A BIT MORE.

TUESDAY ONWARD... SURPRISINGLY... MODELS SEEM TO BE HOLDING TOGETHER
DURING THESE PERIODS WITH FAIRLY WELL MATCHED SYNOPTIC FEATURES FROM
RUN TO RUN AND MODEL TO MODEL. THE MAIN PLAYER IS THE LARGE TROUGH
OVER THE BEARING SEA AND GULF OF ALASKA DROPPING DOWN OVER THE
WESTERN THIRD OF THE CONUS. MODELS HAVE NOT RESOLVED THE
BASE/SOUTHERN COMPONENT OF THIS TROUGH... HOWEVER THEY DO APPEAR
TO BREAK THE TROUGH INTO A NORTHERN AND SOUTHERN COMPONENT WITH THE
NORTHERN COMPONENT BRINGING INCREASED CHANCES FOR PRECIPITATION TO
NORTHEAST MONTANA IN MULTIPLE MODELS. FOR THIS REASON... RAISED POPS
CONSIDERABLY ABOVE THE NORMAL CLIMO OF 15 TO 20 PERCENT DURING
THESE PERIODS. GAH

&&

.AVIATION...
FLIGHT CATEGORY: VFR TO HIGH MVFR WITHOUT FUEL LOADING.

SYNOPSIS: SURFACE LOW PRESSURE HAS DRIFTED OVER SOUTH DAKOTA
LEAVING A COLD FRONT BEHIND PRESSING TO THE SOUTHWEST. CEILINGS
WILL BEGIN TO LOWER TO HIGH MVFR AROUND 09Z THROUGH 18Z THEN SLOWLY
INCREASE BACK TO VFR AFTER NOON. FUEL LOADING CONDITIONS BELOW 2
KFT MAY BE BRIEFLY POSSIBLE BUT ARE NOT EXPECTED TO BE
PREDOMINATE.

SNOW SHOWERS: WILL BE POSSIBLE ACROSS THE AREA BUT WILL BE TOO
LOW OF A CHANCE NEAR THE TERMINALS TO BE PLACED DIRECTLY IN THE
TAFS. THESE SHOWERS COULD BRIEFLY REDUCE VISIBILITIES DOWN TO NEAR
5SM. SLIGHT CHANCES FOR SNOW SHOWERS SHOULD BRIEFLY SUBSIDE
BETWEEN 00Z AND 06Z BUT THEN RETURN AFTER MIDNIGHT.

AREA WINDS: NORTHEASTERLY AROUND 10 TO 15 KTS THIS MORNING...
SLOWLY VEERING TO THE EAST DURING THE LATE AFTERNOON.

GAH

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

WEATHER.GOV/GLASGOW




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