Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 200255
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
755 PM MST FRI DEC 19 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SUNDAY...
UPDATE...
MAIN UPDATE TONIGHT WAS TO BETTER TRACE THE CLOUD COVER ASSOCIATED
WITH THE STRATUS DECK ALONG THE BORDERS OF NORTH
DAKOTA/MONTANA/SASKATCHEWAN AND ADJUST TEMPERATURES ACCORDINGLY.
OTHERWISE THE FORECAST IS IN OVER ALL GOOD SHAPE. THE UPPER RIDGE
WILL MOVE THROUGH THIS EVENING AND OVERNIGHT FOLLOWED BY AN UPPER
LEVEL DISTURBANCE WHICH IS EXPECTED TO BRING A MIXED BAG OF VERY
LIGHT PRECIPITATION TO THE REGION. WILL NOT ISSUE ANY HIGHLIGHTS
AS OF NOW WITH THE GENERALLY VERY LIGHT NATURE OF THE
PRECIPITATION.   PROTON

PREVIOUS DISCUSSION...
A SHORTWAVE RIDGE WILL CONTINUE TO BRING DRY WEATHER AND LIGHT
WINDS ACROSS NORTHEAST MONTANA THIS EVENING. A SHORTWAVE
APPROACHING FROM THE WEST WILL BRING A WINTRY MIX OF PRECIPITATION
TOWARD MORNING. WHILE QPF AMOUNTS LOOK LIGHT...PLACES THAT SEE
EITHER FREEZING RAIN OR FREEZING DRIZZLE MAY EXPERIENCE HAZARDOUS
TRAVEL CONDITIONS.

LATEST NAM FORECAST BUFKIT SOUNDINGS MAINTAIN A NICE WARM NOSE
ACROSS NORTHEAST MONTANA THROUGH THE WEEKEND WHICH SUGGEST THAT
THE NEXT SHORTWAVE WILL ALSO BE ASSOCIATED WITH COMPLEX WEATHER
TYPES. PRECIPITATION FOR ROUND TWO WILL BEGIN SATURDAY NIGHT AS A
WINTRY MIX BUT AS WARMER AIR RUSHES IN...A CHANGE TO RAIN SHOULD
ENSUE. NORTHERN TIER ZONES MAY CONTINUE WITH A WINTRY MIX THROUGH
THE AFTERNOON HOURS. KEEP IN MIND THAT EVEN WITH TEMPERATURES A
FEW DEGREES ABOVE FREEZING SUNDAY MORNING...THE GROUND MAY STILL
BE FROZEN. THUS...ICY CONDITIONS ARE A CONCERN ESPECIALLY SUNDAY
MORNING. THIS SYSTEM ALSO HAS SOMEWHAT HIGHER QPF SO THE STAKES
ARE A BIT HIGHER IF IT ENDS UP BEING ON THE COLDER SIDE OF
EXPECTATIONS. RIGHT NOW EXPECT BRIEF FREEZING RAIN AND/OR A MIX
WITH A GRADUAL CHANGE TO RAIN DURING THE DAY...BUT THIS BEARS
MONITORING. CONSIDERING THAT THE NAM/GFS/ECMWF ARE ALL IN
EXCELLENT AGREEMENT ON TIMING/PLACEMENT/AMOUNT OF QPF...CONFIDENCE
IS RATHER HIGH ON THIS SECOND EVENT. HOWEVER...CONFIDENCE IS NOT
YET THERE WHEN IT COMES TO EXACT PRECIPITATION TYPE. MALIAWCO


.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
THE NEW ECMWF AND GFS HAVE TRENDED CLOSER TOGETHER FAVORING A
POSSIBLE SNOW EVENT FOR PORTIONS OF NORTHEAST MONTANA ON
CHRISTMAS DAY. THUS THE ONLY TWEAK WAS TO CONSERVATIVELY TREND UP
POPS FOR THE 25TH. GILCHRIST

PREVIOUS LONG TERM DISCUSSION...NORTHWEST FLOW ALOFT WILL PREVAIL
DURING THE EARLY PART OF THE WEEK WITH UPPER RIDGE TO THE WEST
AND DEEPENING UPPER TROUGH TO THE EAST. A SHORTWAVE SUNDAY NIGHT
AND MONDAY WILL BRING A CHANCE OF PRECIP TO THE AREA.

SUNDAY EVENING STILL LOOK LIKE IT HAS A MIXED PRECIPITATION
POTENTIAL AS FORECAST TEMPERATURE PROFILES INDICATE WARM ENOUGH
AIR ALOFT FOR EITHER RAIN OR FREEZING RAIN OVER THE SOUTHWEST PART
OF THE FORECAST AREA. TEMPERATURES ARE EXPECTED TO COOL OVERNIGHT
SO THAT PRECIP TYPE WILL LIKELY BE ALL SNOW AFTER MIDNIGHT.
TEMPERATURES ALOFT WILL LIKELY BE COLD ENOUGH FOR MOSTLY SNOW
SHOWERS ON MONDAY ALTHOUGH THE SOUTHWEST ZONES COULD HAVE WARM
ENOUGH TEMPERATURES FOR A MIX OF RAIN.

THE MODELS HAVE A SHORTWAVE RIDGE IN THE NW FLOW ALOFT MONDAY
NIGHT AND TUESDAY WITH WARM FRONT MOVING EAST. LIMITED MOISTURE
WITH THE SYSTEM AT THIS POINT WILL KEEP FORECAST DRY.

COLD FRONT MOVES SOUTH TUESDAY NIGHT AND WEDNESDAY. ONCE AGAIN...
LIMITED MOISTURE IS EXPECTED. WILL MENTION A SLIGHT CHANCE OF SNOW
SHOWERS MAINLY TUESDAY NIGHT.

MODELS BRING AN UPPER TROUGH INLAND FROM THE PACIFIC ON WEDNESDAY
AND TAKE IT TO THE SOUTH OF THE FORECAST AREA ON THURSDAY. WHILE
THE GFS CURRENTLY KEEPS THE MOISTURE SOUTH OF THE FORECAST AREA...
THE ECMWF WANTS TO BRING IT AS FAR NORTH AS THE MISSOURI RIVER.
WILL MAINTAIN A SLIGHT CHANCE OF SNOW FOR NOW. TEMPERATURES WILL
BE SOMEWHAT COLDER.

WILL MAINTAIN A SLIGHT CHANCE OF SNOW INTO FRIDAY AS MODELS
INDICATE A MOIST CYCLONIC FLOW ALOFT. FORRESTER


&&

.AVIATION...

AN UPPER LEVEL RIDGE WILL MOVE ACROSS NORTHEAST MONTANA TONIGHT
QUICKLY FOLLOWED BY A SHORT-WAVE DISTURBANCE EARLY SATURDAY
MORNING THROUGH AFTERNOON. THE DISTURBANCE WILL GENERATE LIGHT
MIXED PRECIPITATION...INCLUDING RAIN...FREEZING RAIN...SLEET AND
SNOW. EXPECT SHORT PERIODS OF MVFR/IFR CEILINGS AND VISIBILITIES.

EXPECT MOSTLY VFR THIS EVENING. SATELLITE IMAGERY REVEALS A
WIDESPREAD DECK OF FREEZING FOG AND LOW LEVEL STRATUS IN NORTHERN
NORTH DAKOTA AND SOUTHEASTERN SASKATCHEWAN THAT MIGHT BACK INTO
PORTIONS OF NORTHEAST MONTANA TONIGHT. THIS WILL BE MONITORED AND
TAFS WILL BE AMENDED IF THE DECK APPROACHES CLOSER.

THE DISTURBANCE WILL CREATE WESTERLY WINDS TONIGHT OF 10KT-20KT
TO CONTINUE THROUGH SATURDAY AFTERNOON. LATE SATURDAY AFTERNOON
AND EVENING EXPECT WIND TO BACK AROUND TO THE SOUTHWEST AND BECOME
LIGHT. SCT


&&

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

&&

$$

WEATHER.GOV/GLASGOW





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