Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 112147
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
247 PM MST THU FEB 11 2016

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
PROGRESSIVE NORTHWEST FLOW ALOFT LOOKS TO CONTINUE ACROSS THE
REGION THROUGH THE SHORT TERM PERIOD WITH QUICK MOVING WEAK
SHORTWAVES PRODUCING OCCASIONAL PRECIPITATION CHANCES.

CANADIAN RADAR CONTINUES TO PRODUCE HEALTHY LOOKING ECHOES
UPSTREAM...ALTHOUGH GRADUALLY DIMINISHING IN INTENSITY AS THEY
APPROACH THE CWA FROM THE NORTH. THE 12Z NAM/GFS/ECMWF ALL AGREE
ON A LIGHT QPF EVENT IN THE NORTHERN AND EASTERN ZONES OVERNIGHT.
A QUICK LOOK AT THE 18Z NAM FURTHER SUPPORTS THIS THESIS. IF
ANYTHING THE BAND PUSHING SOUTHEAST COULD RETROGRADE A LITTLE
FURTHER WEST...AND SO THE CENTRAL PORTIONS OF THE CWA MAY SEE SOME
SNOW SHOWER ACTIVITY TONIGHT AS WELL. GIVEN THAT THE EVENT LAST
NIGHT WAS MORE BULLISH THAN INITIAL EXPECTATIONS...DECIDED TO PLAY
THE PERSISTENCE FORECAST CARD IN COMBINATION WITH CANADIAN RADAR
OBSERVATIONS TO PRODUCE A SCENARIO SLIGHTLY ABOVE GUIDANCE
EXPECTATIONS. THUS...HAVE CHANCE POPS IN GRIDS WITH QPF ON ORDER
OF A FEW HUNDREDTHS. THEREFORE EXPECT A DUSTING OF SNOW TO UP TO A
HALF INCH IN ISOLATED STEADIER SNOW SHOWERS TONIGHT.

A BRIEF LULL IN ACTIVITY IS IN THE CARDS FRIDAY BEFORE THE NEXT
SYSTEM APPROACHES FROM THE WEST FRIDAY EVENING AND NIGHT WITH A
WINTRY MIX OF PRECIPITATION. THIS ACTIVITY IS EXPECTED TO LINGER
INTO SATURDAY MORNING...WHICH COULD TRANSITION TO PLAIN RAIN
BEFORE ENDING AS THERMAL PROFILES WARM. AS THE SYSTEM DEPARTS FROM
THE WEST EXPECT HIGHER TEMPERATURES...HIGHS RANGING NEAR 40 TO THE
MID 50S IN THE FAR SOUTHWEST. MALIAWCO

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
THE EXTENDED CONTINUES TO ADVERTISE A EXTENDED FORECAST PERIOD FOR
NORTHEAST MONTANA. NORTHWEST TO WEST FLOW WILL CONTINUE THROUGH
THE PERIOD WITH EMBEDDED WAVES FOR STORM SYSTEMS TO DEVELOP ON.
THIS WILL PROVIDE AN EXTENDED FORECAST WITH LOTS OF SLIGHT CHANCE
POPS FOR THE REGION.

THE MODELS FOR THE 12Z RUN THIS MORNING CONTINUE WITH THE SAME
IDEA ON THE SYNOPTIC AND HEMISPHERIC SCALE HOWEVER THE GFS IS A
BIT LESS ACTIVE ON PRECIPITATION FOR NORTHEAST MONTANA OVER THE
OTHER SOLUTIONS. WILL KEEP WITH THE CURRENT FORECAST CONCEPT OF
KEEPING THE POPS LOWER THROUGH THE EXTENDED STAYING IN LINE WITH
THE GFS WAY OF THINKING.

VERY LITTLE CHANGE IN THE GOING EXTENDED FORECAST WITH ONLY
COSMETIC UPDATES AROUND THE EDGES FOR THIS AFTERNOON/S REFRESH.
PROTON

PREVIOUS DISCUSSION...
SATURDAY NIGHT AND SUNDAY...LOOK FOR NORTHWEST FLOW ALOFT WITH
UPPER TROUGH TO THE EAST AND RIDGE TO THE WEST. WILL SEE MAINLY
DRY WEATHER WITH THE FORECAST AREA BETWEEN SYSTEMS.

THE UPPER RIDGE MOVES INLAND FROM THE PACIFIC SUNDAY NIGHT AND
MONDAY. THIS WILL BRING A WARM FRONT EAST ACROSS CENTRAL AND
EASTERN MONTANA. AT THIS POINT...THE ECMWF IS MUCH WETTER AND
SOMEWHAT SLOWER THAN THE GFS WITH THIS FRONT. THERE IS A POTENTIAL
FOR A WINTRY MIX OF PRECIP TYPES WITH THIS SYSTEM BETWEEN SUNDAY
NIGHT AND MONDAY NIGHT.

MODELS DIFFER ON TUESDAY IN THAT THE ECMWF BRINGS A COLD FRONT
SOUTH WHILE THE GFS KEEPS IT TO THE NORTH OF THE FORECAST AREA.
WILL MAINTAIN A SLIGHT CHANCE OF RAIN OR SNOW DEPENDING ON
TEMPERATURE.

WEDNESDAY LOOKS DRY AND MILD AT THIS POINT WITH UPPER RIDGE AXIS
OVER MONTANA. UPPER TROUGH MOVES INLAND FROM THE PACIFIC WEDNESDAY
NIGHT AND THURSDAY WHICH WILL TURN THE FLOW ALOFT TO THE SW OVER
MONTANA. INCREASING MOISTURE AND DEVELOPING LOW PRESSURE SYSTEM
WILL BRING A CHANCE OF RAIN AND SNOW BY THURSDAY NIGHT. FORRESTER



&&

.AVIATION...
SYNOPSIS: AN UPPER LEVEL RIDGE WILL CONTINUE TO BUILD OVER THE
SPINE OF NORTHERN ROCKIES WITH NORTHWEST FLOW OVER NORTHEAST
MONTANA. A SURFACE FRONT WILL REMAIN IN THE VICINITY KEEPING
CLOUDS AND SOME AREAS OF LIGHT SNOW.

FLIGHT CATEGORY: MVFR WITH SCT AREAS OF IFR.

WX: SHOULD REMAIN MOSTLY SNOW AND A VERY LOW RISK OF FREEZING
PRECIPITATION.

WIND: CONTINUED EAST WIND STARTING OUT UNDER 10 KNOTS AND THEN
INCREASING TO 10 TO 20 KNOTS BY THE END OF THE TAF CYCLE.

PROTON

&&

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

&&

$$

WEATHER.GOV/GLASGOW


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