Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 170855
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
255 AM MDT THU APR 17 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
THE FORECAST AREA WILL HAVE NORTHWEST FLOW ALOFT TODAY BETWEEN
UPPER TROUGH TO THE EAST AND INCOMING RIDGE FROM THE WEST. WEAK
SHORTWAVES IN THE NW FLOW ALOFT TODAY WILL BRING CHANCES FOR RAIN
AND SNOW SHOWERS (DEPENDING ON TEMPS) ACROSS NORTHEAST MONTANA. A
QUASI-STATIONARY FRONT IN CENTRAL MONTANA WILL START MOVING EAST
AS A WARM FRONT. THIS WILL KEEP EASTERLY TO SOUTHEAST WINDS GOING
OVER MOST OF THE AREA. AT THE SAME TIME...THE SOUTHWEST PART OF
THE FORECAST AREA WILL HAVE MUCH WARMER TEMPERATURES THIS
AFTERNOON.

WHILE THE UPPER RIDGE MOVES THROUGH EASTERN MONTANA TONIGHT...THE
WARM FRONT IS FORECASTED TO BECOME QUASI-STATIONARY OVER EASTERN
MONTANA AS STARTS OCCLUDING WITH A COLD FRONT APPROACHING THE AREA
FROM THE WEST. THIS OCCLUDED FRONT WILL PUSH THROUGH THE FORECAST
AREA FRIDAY AFTERNOON AND EVENING WITH A STRONG UPPER TROUGH.
THERE WILL BE ENOUGH MOISTURE WITH THIS SYSTEM THAT MOST AREAS
SHOULD HAVE SOME RAIN SHOWERS ESPECIALLY FRIDAY AFTERNOON. WILL
MENTION SHOWERS LIKELY IN THE NORTH WHICH WILL BE CLOSER TO THE
LOW PRESSURE TRACK.

THE SYSTEM MOVES TO THE EAST BY SATURDAY MORNING WITH DRIER
AIRMASS MOVING INTO THE AREA. ALTHOUGH THE AIR MASS WILL BE
SOMEWHAT COOLER...GOOD MIXING WILL ALLOW FOR TEMPERATURES SIMILAR
TO FRIDAY`S HIGHS. FORRESTER


.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...

SYNOPTIC SET UP...A SHORTWAVE TROUGH IS EXITING THE AREA OVER THE
UPPER MISSISSIPPI VALLEY AND MANITOBA. A LARGE RIDGE RUNS UP HIGH
PLAINS OF MONTANA AND ALBERTA AND THEN TIPS OVER WEST ACROSS
NORTHERN BRITISH COLUMBIA AND THE GULF OF ALASKA. A SHORTWAVE EXIST
S OVER THE PACIFIC NORTHWEST WHILE AN EVEN LARGE TROUGH OF COLD
AIR IS JUST SOUTH OF THE GULF OF ALASKA RIDGE RUNNING UP INTO THE
BEARING SEA.

SATURDAY NIGHT THROUGH SUNDAY... THE RIDGE WILL FLATTEN AND THE WEAK
SHORTWAVE WILL PASS JUST NORTH OF THE CWA SKIRTING THE
INTERNATIONAL BORDER. A SLIGHT CHANCE FOR SPILL OVER PRECIP IS
POSSIBLE IF THE SHORTWAVE MOVES SLIGHTLY FARTHER SOUTH.

SUNDAY NIGHT THROUGH TUESDAY... RIDGE WILL RE-AMPLIFY ACROSS THE
REGION WITH THE EXITING SHORTWAVE. EXPECT DRY CONDITIONS OUT WITH
A WEAK DOWN-SLOPING EFFECT ON MONDAY. HIGH TEMPERATURES WILL RISE
INTO THE 60S AND 70S HELPING TO DESTABILIZE THE SURFACE LAYER A
BIT MORE.

TUESDAY NIGHT ONWARD...SURPRISINGLY...MODELS STILL 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 FULLY RESOLVED THE BASE/SOUTHERN COMPONENT OF THIS
TROUGH...HOWEVER THEY DO APPEAR TO BREAK THE NORTHERN HALF INTO A
WIND UP LOW OVER EASTERN MONTANA AND SOUTHERN SASKATCHEWAN. A
STRONG JET LADDENED WITH PACIFIC MOISTURE WILL PUMP INTO THIS LOW 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: HIGH MVFR TO VFR.

SYNOPSIS: A LINE OF HIGH MVFR CLOUDS ABOVE 2KFT HAS OVERSPREAD
ACROSS THE TERMINALS FROM SOUTHERN SASKATCHEWAN INTO NORTH DAKOTA.
THIS CLOUD DECK IS ANTICIPATED TO REMAIN ALMOST IN PLACE WITH A
SLOW CREEP TO BACK TO THE EAST THROUGH AROUND 18Z. AT WHICH POINT
CLEARING IS ANTICIPATED TO ACCELERATE.

SNOW SHOWERS: A SLIGHT CHANCE FOR SNOW SHOWERS EXISTS AT ALL
TERMINALS BUT CHANCES ARE TOO LOW TO INCLUDE DIRECTLY IN THE
TAFS. IF SNOW DOES OCCUR IT COULD BRING CEILINGS INTO FUEL
LOADING CONDITIONS BELOW 2KFT BUT WOULD BE VERY BRIEF. MVFR
VISIBILITIES WOULD ALSO BE POSSIBLE WITH SNOW SHOWERS.

AREA WINDS: OUT OF THE EAST AROUND 10 TO 15 KTS THROUGH 18Z...
THEN VEERING SLIGHTLY TO SOUTHEAST AND INCREASING TO 15 TO 20 KTS.

GAH

&&

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

&&

$$

WEATHER.GOV/GLASGOW





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