274 
FXUS65 KGGW 010305
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
905 PM MDT THU OCT 31 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
UPDATE....SCATTERED RAIN SHOWERS FROM THIS AFTERNOON AND EARLY
EVENING HAVE DIMINISHED FOR THE MOST PART. MEANWHILE... ISOLATED
SHOWERS REMAIN UPSTREAM IN SW SASKATCHEWAN AND SE ALBERTA. WILL
MAINTAIN SLIGHT CHANCE OF SHOWERS FOR THE REST OF THE EVENING.
WHILE NORTHWEST WINDS HAVE DIMINISHED... SHORTWAVE CURRENTLY
MOVING THROUGH SW SASKATCHEWAN WILL MOVE THROUGH NORTHEAST MONTANA
OVERNIGHT AND INCREASE THE WINDS AGAIN. FORECAST CURRENTLY HANDLES
THIS WELL. NO UPDATED PLANNED. FORRESTER
PREVIOUS SHORT TERM...
SHORTWAVE ENERGY IN AN NORTHWEST FLOW ALOFT WILL BRING ISOLATED
SHOWER ACTIVITY TO NORTHEAST MONTANA THIS EVENING...AND JUST THE
EASTERN ZONES LATE TONIGHT. PRECIPITATION TYPE LOOKS TO BE
RAIN...HOWEVER RIGHT NEAR SUNRISE IT COULD BRIEFLY CHANGE OVER TO
FREEZING RAIN AS SURFACE TEMPS FALL BELOW FREEZING. GUSTY POST
FRONTAL NORTHWEST WINDS WILL DECREASE TO 10 TO 20 MPH THIS
EVENING...BEFORE PICKING UP AGAIN FOR FRIDAY. THE CURRENT LAKE
WIND ADVISORY IN EFFECT THROUGH FRIDAY AFTERNOON LOOKS ON TRACK
FOR NOW. CONDITIONS WILL DRY OUT AND SKY COVER WILL DECREASE FOR FRIDAY AS
UPPER RIDGING PUSHES IN FROM THE WEST. TEMPS WILL BE RIGHT NEAR
CLIMATOLOGICAL NORMALS.

FRIDAY NIGHT WINDS WILL QUICKLY DIE OFF AS HIGH PRESSURE AT THE
SURFACE BUILDS IN. DRY CONDITIONS WILL HOLD AS UPPER RIDGING
CONTINUES OVERHEAD. SKIES WILL BE MOSTLY CLEAR...ALLOWING TEMPS TO
AGAIN FALL TO RIGHT NEAR CLIMO LOWS. 

SATURDAY THE UPPER RIDGE WILL AGAIN HOLD AS A LEE SIDE TROUGH
DEVELOPS OVER CENTRAL MONTANA. AS A RESULT SOUTHEAST WINDS WILL BE
ON THE INCREASE AT 10-15 MPH. TEMPERATURES SHOULD ALSO WARM NICELY
GIVEN THIS FLOW...SO TRENDED UP TEMPS. SOME SHOWER ACTIVITY AND
CLOUD COVER COULD PUSH INTO PHILLIPS COUNTY ON SATURDAY AS THE
UPPER FLOW GOES SOUTHWESTERLY AHEAD OF AN UPPER TROUGH PUSHING
INTO THE PACIFIC NORTHWEST. PRECIP SHOULD BE LIGHT IN NATURE BUT
DID EXPAND COVERAGE SLIGHTLY. GILCHRIST

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
THE EXTENDED PERIOD BEGINS SATURDAY EVENING WITH AN UPPER RIDGE
AXIS PASSING EAST OF NORTHEAST MONTANA AND A STRONG UPPER TROUGH
DIGGING INTO THE WESTERN CANADA AND THE NORTHWESTERN STATES. THE
ASSOCIATED COLD FRONT WILL SWING ACROSS NEMONT ON SUNDAY...
DROPPING 850MB TEMPERATURES TO BELOW 0C. MOST STORM ENERGY MOVES
ACROSS CANADA...AND UNDERCUTS NEMONT. BUT LIGHT PRECIPITATION CAN
BE EXPECTED...BEGINNING AS RAIN THEN TRANSITIONING TO SNOW. WHILE
MODELS DO NOT LINE UP YET...SOME ACCUMULATION IS POSSIBLE IN THE 1
TO 2 INCH RANGE. SUNDAY NIGHT BOTH THE UPPER AND SURFACE LOWS
COULD CLOSE OFF AND BEGIN TO STACK UP. THIS WILL INTRODUCE STRONG
GUSTY WEST TO NORTHWEST WIND TO THE REGION THAT WILL CONTINUE
THROUGH MONDAY NIGHT. TEMPERATURES WILL TREND SIGNIFICANTLY LOWER
MONDAY AND BEYOND...WITH HIGHS AROUND 10F TO 15F BELOW NORMAL. ALL
CHANGES WERE OF THE MINOR VARIETY BASED ON THE LATEST GUIDANCE.
SCT 

PREVIOUS DISCUSSION... 
THE EXTENDED LOOKS TO BEGIN WITH A LARGE TROUGH ACROSS THE
WESTERN U.S. CARVED OUT IN THE H5 FIELD ON SATURDAY NIGHT AND
SUNDAY. LOW PRESSURE WILL TRACK ACROSS SOUTHERN SASKATCHEWAN WITH
AN APPENDING COLD FRONT DRAGGING THROUGH THE CWA ON SUNDAY
AFTERNOON. THIS FRONTAL PASSAGE WILL TRANSLATE TO COLDER
TEMPERATURES ACROSS THE REGION. WILL INCLUDE SLIGHT CHANCE POPS
THROUGH THE PERIOD WITH THERMAL PROFILES SUPPORTING RAIN SHOWERS
THROUGH SUNDAY...BUT THERE COULD BE A MIX AND/OR CHANGE TO SNOW
SHOWERS ON SUNDAY NIGHT WITH COLD AIR ADVECTION IN CONJUNCTION
WITH DYNAMICAL PROCESSES COOLING THE VERTICAL. GREATEST PVA AHEAD
OF SHORTWAVE WILL BE ACROSS SOUTHERN CANADA CLOSER TO THE SURFACE
LOW...SO PLACED HIGHEST POPS ALONG THE INTERNATIONAL BORDER FOR
SUNDAY. AT THIS TIME MAINTAINED POPS BELOW THE CHANCE RANGE GIVEN
SOME MODEL DIFFERENCES IN QPF PLACEMENT.

MONDAY THROUGH WEDNESDAY NIGHT...THE 31/00Z GFS AND ECMWF BOTH
SHOW AN AMPLIFYING UPPER LEVEL TROUGH ACROSS THE WESTERN CONUS.
THIS WILL KEEP NEAR/BELOW NORMAL TEMPERATURES ACROSS NORTHEAST
MONTANA. PRECIPITATION CHANCES MAY LINGER INTO MONDAY BUT WILL
WANE MONDAY NIGHT AS INITIAL SYSTEM IN THE EXTENDED PUSHES
EASTWARD. ADDITIONAL SHORTWAVE PULSES PROPAGATING THROUGH
NORTHWEST FLOW ALOFT ON THE BACKSIDE OF THE TROUGH ACROSS THE
WESTERN PORTIONS OF THE STATE MAY BRING ENOUGH FORCING FOR A FEW
SHOWERS IN THE FAR SOUTHWESTERN ZONES BY ABOUT WEDNESDAY BUT
CONFIDENCE IS LOW.

AFTER A COLD EARLY/MIDDLE PORTION OF THE WEEK...THE 850MB
TEMPERATURE FIELD BY THURSDAY LOOKS TO RECOVER TO -1C TO +3C
ACROSS THE CWA WHICH SHOULD SUPPORT HIGHS APPROACHING THE LOWER
AND MIDDLE 40S. MALIAWCO


&&

.AVIATION...
FLIGHT CATEGORY: VFR

PRECIPITATION: A WEAK MID LEVEL DISTURBANCE ON NORTHWEST FLOW
ALOFT TONIGHT WILL BRING INTERMITTENT LIGHT RAIN SHOWERS
OVERNIGHT. CHANCES ARE TOO LOW TO PLACE IN THE TAFS DIRECTLY.
REDUCTIONS TO VISIBILITIES SHOULD ALSO BE NEGLIGIBLE.

AREA WINDS: OUT OF THE NORTHWEST BETWEEN 10 TO 20 KTS SUSTAINED
THROUGHOUT THE TAF CYCLE. 

GAH


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 6 PM MDT FRIDAY FOR FORT PECK LAKE FOR 
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW