FXUS65 KGGW 301636 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
936 AM MST MON NOV 30 2009

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
THE UPPER LEVEL RIDGE WILL FLATTEN A BIT DUE TODAY TO A SHORT-WAVE
TROUGH MOVING OVER THE CANADIAN ROCKIES. AS A RESULT THE UPPER
FLOW WILL BECOME MORE ZONAL TODAY. SCATTERED HIGH CLOUDS IN THE
UPPER FLOW WILL KEEP SKIES PARTLY CLOUDY TODAY. OTHERWISE WITH
SUNSHINE MOSTLY MAKING THROUGH AND THICKNESS HEIGHTS WELL ABOVE
AVERAGE WILL MAKE FOR A MILD DAY. THE CURRENT FORECAST GENERALLY
REFLECTS CURRENT CONDITIONS. HOWEVER DID ADJUST SKY COVER TO
BETTER REPRESENT ACTUAL CONDITIONS. SCT

PREVIOUS DISCUSSION...
A RETURN TO REALITY IS EXPECTED FOR THE BEGINNING OF DECEMBER AS A
STRONG COLD FRONT PLOWS THROUGH NORTHEAST MONTANA BRINGING AN END
TO THE MILD CONDITIONS OF THE PAST MONTH AND TRIGGERING A PATTERN
CHANGE THAT COULD SEND TEMPERATURES PLUMMETING WELL BELOW SEASONAL
AVERAGES AS ARCTIC AIR RETURNS TO NORTH AMERICA.

AN UPPER RIDGE WILL REMAIN OVER THE AREA TODAY BRINGING RATHER
PLEASANT CONDITIONS. 1000-500MB THICKNESS VALUES RANGE FROM
ROUGHLY 545-550DAM. HOWEVER...LIMITED SOLAR INSOLATION DUE TO THE
TIME OF YEAR AND AMOUNT OF CHINOOK ARCH RELATED CLOUD COVER WILL
INHIBIT TEMPERATURES FROM REACHING THEIR FULL POTENTIAL.
NEVERTHELESS...MAXIMUM TEMPERATURES IN THE 50S ARE EXPECTED IN THE
SOUTHWEST ZONES WITH A DOWNSLOPING SOUTHWEST WIND.

THE AFOREMENTIONED COLD FRONT WILL ARRIVE LATE TONIGHT WITH
CURRENT MODEL GUIDANCE SUGGESTING A FRONTAL PASSAGE FROM NORTHWEST
TO SOUTHEAST COMMENCING AROUND 06Z. 850MB WIND SPEEDS OF AROUND
45KT ACCOMPANY THE INITIAL FRONTAL PASSAGE...WHICH SHOULD RESULT
IN SOME GUSTS AROUND 50MPH AT THE SURFACE WITH TURBULENT MIXING
ALONG THE FRONTAL BOUNDARY. STRONG COLD AIR ADVECTION SHOULD CARRY
A STRONG SURFACE WIND OUT OF THE NORTHWEST THEREAFTER LASTING
THROUGH THE DAY THURSDAY. 850MB WIND SPEEDS SLOWLY RELAX FROM
NEAR 40KT TO 30KT THROUGHOUT THE DAY. SURFACE WIND SPEEDS OF 25 TO
35MPH WITH GUSTS OF 40 TO 45MPH ARE LIKELY TUESDAY...BUT OVERALL
THERE IS NOT QUITE ENOUGH STRENGTH WITH THIS FRONTAL SYSTEM TO
WARRANT HIGH WIND HEADLINES AT THIS TIME. THE STRONGEST SHORTWAVE
DYNAMICS WILL RACE FROM SOUTHERN SASKATCHEWAN INTO NORTH DAKOTA.
LATEST MODEL SOLUTIONS SUGGEST THE FAR NORTHEAST ZONES GET CLIPPED
WITH A PERIOD OF SNOW. LITTLE TO NO ACCUMULATION IS EXPECTED.
HOWEVER...A PERIOD OF SNOW COMBINED WITH THE STRONG WIND COULD
PRODUCE A BRIEF EPISODE OF REDUCED VISIBILITY. TEMPERATURES WILL
GENERALLY BE NEARLY STEADY FROM MONDAY NIGHT THROUGH TUESDAY.

BY TUESDAY NIGHT AN UPPER LOW SETTLES OVER THE UPPER MIDWEST AND IT
SLOWLY AMBLES EAST TOWARD THE GREAT LAKES BY WEDNESDAY. THIS
PLACES NORTHEAST MONTANA UNDER CYCLONIC NORTHERLY FLOW WITH WEAK
UPPER SHORTWAVE DYNAMICS PROGRESSING OVERHEAD. THIS WILL MAINTAIN
CLOUD COVER AND A SLIGHT CHANCE OF FLURRIES OVER ESPECIALLY THE
EASTERN ZONES. 1000-500MB THICKNESS VALUES FALL INTO THE 510S WITH
850MB TEMPERATURES RANGING FROM -10 TO -15C SOUTHWEST TO NORTHEAST
ACROSS THE CWA WEDNESDAY. AT FULL MIXING POTENTIAL MAXIMUM
TEMPERATURES WOULD REACH THE LOW 20S TO LOW 30S.
HOWEVER...TEMPERATURES COULD EVEN BE A FEW DEGREES COOLER IN THE
NORTHEAST DEPENDING ON THE AMOUNT OF CLOUD COVER. AJZ

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
COLD AIR LINGERS OVER THE AREA WEDNESDAY NIGHT WITH UPPER TROUGH
OVER NORTH DAKOTA. MODEL HAVE DIFFERENT TIMING WITH A SHORTWAVE
RIDGE LATE IN THE WEEK WITH THE GFS BRINGING IT IN ON THURSDAY...
THE CANADIAN ON FRIDAY AND ECMWF ON SATURDAY. THEY ALL FOLLOW THE
RIDGE WITH A STRONG COLD FRONT A DAY LATER. GFS IS LIKELY TOO FAST
WITH THE PROGRESSION OF THE SYSTEM. WILL TREND FORECAST TOWARDS
SLOWER ECMWF FOR NOW AND TIME THE COLD FRONT SATURDAY NIGHT. MUCH
COLDER AIR MASS DROPS SOUTH FOR EARLY NEXT WEEK. WITH LIMITED
MOISTURE AT THE MOMENT... WILL KEEP FORECAST DRY. FORRESTER

&&

.AVIATION...
HIGH CLOUDS WILL MOVE THROUGH THE TAF SITES TODAY WITH WEST WINDS
AROUND 10 KNOTS. STRONG COLD FRONT TONIGHT WILL BRING NORTHWEST
WINDS 20 TO 30 KNOTS WITH LOW CLOUDS THAT MAY PRODUCE MVFR CEILING
ALONG WITH A CHANCE OF SNOW.

&&

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

&&

$$

WEATHER.GOV/GLASGOW