Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 231502
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
902 AM MDT WED APR 23 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...

MORNING UPDATE...
CHANGES TO THE FORECAST FOR THIS MORNING WERE FEW. POPS SEEM FINE
AS SHOWERS ACROSS THE NORTHERN PORTIONS OF THE CWA ON RADAR SEEM
TO BE FOLLOWING THE NORTHERN TRACK SET UP BY THE PREVIOUS
FORECASTER. HOURLY TEMPERATURES ALSO APPEAR TO BE FOLLOWING THE
PREVIOUSLY FORECASTED TRACK WHEN COMPARED TO CURRENT OBS. THE ONLY
THING THAT NEEDED SLIGHT TWEAKING WAS WINDS FIELDS ALONG THE
FRONTAL SHIFT LINE AND OUTSIDE OF THAT ZONE AS SUSTAINED WIND
SPEEDS ARE A BIT LIGHTER THAN ANTICIPATED. WIND GUSTS HOWEVER DO
LOOK TO STAY ON TRACK AS 30 TO 40 KTS NEAR THE TOP OF MIXING LAYER
SHOWS UP IN FORECAST SOUNDINGS AND A FEW 35 TO 40 KTS GUSTS HAVE
ALREADY REARED THEIR UGLY HEADS ON OBSERVATIONS ACROSS THE AREA.
GAH


PREVIOUS SHORT TERM DISCUSSION...
UPPER TROUGH OVER IDAHO AND BRITISH COLUMBIA AT 09Z WILL MOVE
ACROSS MONTANA TODAY. A COLD FRONT AHEAD OF THE TROUGH WILL MOVE
THROUGH EASTERN MONTANA THIS MORNING WHICH WILL TURN THE STRONG
EAST WINDS INTO STRONGER WEST WINDS. AN UPPER LOW WILL FORM ALONG THE
UPPER TROUGH IN SOUTHERN ALBERTA AS IT SPLITS AWAY FROM BC PORTION
OF THE TROUGH TO THE WEST. AT THE SAME TIME...THE SURFACE LOW IN
EASTERN MONTANA WILL BECOME STACKED WITH THE ALBERTA UPPER LOW.

AT THIS POINT...MOST OF THE RAIN IS EITHER ALONG THE FRONT OR WITHIN
A 100 MILES BEHIND IT. AS A RESULT...THE BEST CHANCE OF RAIN
TODAY WILL BE AS THE FRONT MOVES THROUGH THE FORECAST AREA THIS
MORNING AND THE NORTHEAST THIS AFTERNOON.

AFTER THE FRONT MOVES THROUGH NORTHEAST MONTANA...SOMEWHAT DRIER
AIR MOVES IN. UNSTABLE AIRMASS WILL ALLOW FOR SOME SHOWERS THIS
AFTERNOON POSSIBLY A THUNDERSTORM.

THE UPPER LOW MOVES ACROSS SOUTHERN SASKATCHEWAN TONIGHT AND
THURSDAY. NORTHEAST MONTANA WILL BE ON THE DRIER SOUTH SIDE OF THE
SYSTEM AND MODELS HAVE DIMINISHED THE AMOUNT OF WRAP AROUND
MOISTURE ASSOCIATED WITH THE SYSTEM. HAVE LOWER CHANCE OF SHOWERS
TO CHANCE NORTH AND SLIGHT CHANCE SOUTH. GUSTY WEST TO NORTHWEST
WINDS WILL PREVAIL UNTIL THE LOW MOVES TO THE EAST THURSDAY NIGHT
AND A SHORTWAVE RIDGE BUILDS INTO EASTERN MONTANA.

THAT RIDGE WILL BRING DRY WEATHER ON FRIDAY WITH TEMPERATURES NEAR
NORMAL. EAST WINDS WILL DEVELOP DURING THE DAY AHEAD OF THE NEXT
SYSTEM THAT WILL IMPACT THE FORECAST AREA THIS WEEKEND. FORRESTER


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...

THE EXTENDED FORECAST PERIOD BEGINS FRIDAY EVENING WITH A TROUGH
OVER THE WEST COAST WITH ITS BASE PICKING UP PACIFIC MOISTURE OFF
SOUTHERN CALIFORNIA. THIS MOISTURE WILL BE EJECTED NORTHEAST INTO
MONTANA BEGINNING FRIDAY NIGHT. THIS TROUGH...AND THE COLD TROUGH
CENTERED OVER HUDSON BAY...WILL HAVE SQUEEZED UP A RIDGE OVER
MONTANA THAT WILL SWIFTLY MOVE SOUTHEAST. THIS WILL PLACE THE
BOUNDARY...SEPARATING THE NORTHERN COLD AIR MASS FROM THE SOUTHERN
AIR MASS...OVER NORTHEAST MONTANA. THE OVERRUNNING MOISTURE WILL
FIND THIS BOUNDARY AS A FOCAL POINT FOR PRECIPITATION INTO
SATURDAY AND SATURDAY NIGHT. BY SUNDAY MORNING THE TROUGH MOVES
INTO COLORADO WHERE IT STACKS UP THE THE SURFACE LOW TO FORM AN
INVERTED TROUGH OVER EASTERN MONTANA. THIS WILL CHANNEL MORE
MOISTURE IN FROM THE SOUTHEAST FOR WRAP-AROUND PRECIPITATION
THROUGH SUNDAY...TAPERING OFF THROUGH MONDAY. A SIGNIFICANT
UNCERTAINTY IS THE PRECIPITATION TYPE...WITH THE GFS FAVORING RAIN
AND THE EC FAVORING SNOW. WENT MIDDLE OF THE ROAD AND KEPT BOTH
RAIN AND SNOW IN THE GRIDS.

THE SITUATION BECOMES EVEN MORE CLOUDED AFTER MONDAY WHEN A RIDGE
BEGINS TO BUILD UP OVER THE WEST. THE GFS PUSHES A WARM FRONT OVER
EASTERN MONTANA ON TUESDAY. THE EC HOWEVER KEEPS THE WARM AIR MASS
WELL TO THE SOUTHWEST...OVER CALIFORNIA. SO...THE EC MAINTAINS WET
AND COOL. THUS...THERE IS GREAT UNCERTAINTY WITH TEMPERATURES BETWEEN
THE MODELS TOWARDS THE END OF THE EXTENDED PERIOD CONCERNING
NORTHEAST MONTANA.


&&

.AVIATION...
VFR. CONDITIONS ARE EXPECTED TO IMPROVE THIS MORNING FOR KGGW BUT
MAY FLIRT BRIEFLY WITH MVFR AT KOLF AND KSDY THIS MORNING AS A
BAND OF RAINSHOWERS MOVE NORTHEAST THROUGH THE AREA. THE GREATEST
IMPACT TODAY MAY BE THE SHIFTING WINDS AT KSDY...WHERE WINDS ARE
EXPECTED TO SWITCH TO THE WEST AT ABOUT 20 KTS BETWEEN 9 AND 11 AM.
TFJ


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THURSDAY FOR FORT PECK LAKE
FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN
VALLEY...GARFIELD...MCCONE...PETROLEUM.


&&

$$

WEATHER.GOV/GLASGOW




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