Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 270239 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
839 PM MDT SUN APR 26 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY...

SENT AN UPDATE TONIGHT MAINLY TO GET A BETTER HOLD OF EXACTLY HOW
THE PRECIPITATION IS FALLING ACROSS NE MONTANA TONIGHT.
INDICATIONS ON RADAR IMAGERY SHOW THAT SOME...IF NOT MOST OF THE
RAIN IS PROBABLY NOT REACHING THE GROUND. CUT BACK SOME AREAS OF
POPS ACCORDINGLY. ALSO...CHOSE TO SPLIT THE POPS AND WEATHER GRIDS
UP INTO 3-HOURLIES TO SHOW THE PROGRESSION THROUGH THE CWA TONIGHT
AND INTO MONDAY MORNING. ALREADY BEGINNING TO SEE THE WESTERN EDGE
OF THE END OF PRECIP OVER OUR WESTERN ZONES. ACCUMULATION IS MORE
LIKELY OVER OUR EASTERN AND SOUTHEASTERN ZONES AS THIS SYSTEM
FINALLY EXITS THE AREA. MUCH WARMER DAYS JUST AROUND THE CORNER.
BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...OVERCAST CONDITIONS ARE EXPECTED
TO CONTINUE INTO TONIGHT ACROSS NORTHEAST MONTANA WITH THE UPPER
TROUGH CONTINUING TO HAVE INFLUENCE AS SHOWN NICELY ON WATER VAPOR
AND VISIBLE SATELLITE IMAGERY PRODUCTS. MOISTURE WILL STREAM OUT
AHEAD OF THE TROUGH BRINGING SOME RAIN TO ESPECIALLY SOUTHEAST
PORTIONS OF THE CWA INTO TONIGHT...THOUGH SOME QUESTION EXISTS AS
TO THE WESTERN EXTENT.

THE TROUGH WILL TRANSLATE EAST LATE TONIGHT ALLOWING FOR CLEARING
SKY CONDITIONS FROM WEST TO EAST. AN UPPER LEVEL RIDGE WILL BUILD
INTO THE REGION MONDAY INTO TUESDAY ALLOWING FOR RISING HEIGHTS
LEADING TO WARMER TEMPERATURES AND DRY CONDITIONS. THE LATEST
850MB TEMPERATURES BY 00Z WEDNESDAY ADVERTISED BY THE NEW ECMWF
RANGE FROM +10C TO +15C ACROSS THE FORECAST AREA...WHICH WOULD
EASILY SUPPORT HIGH TEMPERATURES IN THE 60S AND 70S. MALIAWCO


.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...

NOT MUCH CHANGE TO THE EXTENDED AND THE TRENDS MENTIONED BY THE
MID SHIFT ARE STILL THE SAME ISSUES THIS AFTERNOON. THE GFS IS
STILL FASTER WITH THE NEXT SYSTEM TO KEEP AN EYE ON WITH IT
BRINGING IN SOME SHOWERS ALONG THE TROF/WEAK FRONTAL PASSAGE ON
WEDNESDAY NIGHT NOW INSTEAD OF THURSDAY. THE EC AND DGEX ARE IS
MUCH WETTER THAN THE GFS IS WITH THIS SYSTEM. AND THEY HAVE
TIGHTER GRADIENTS LEADING TO MORE WIND ON THURSDAY INTO FRIDAY
THAN THE GFS IS SHOWING. FRANSEN

THE EXTENDED FORECAST PERIOD BEGINS WITH NE MONTANA ENJOYING THE
BENEFITS OF A STRONG AND WARM RIDGE WITH STRONG MODEL CONSENSUS
FOR A DRY AND WARM MID-WEEK PERIOD. MODEL DIFFERENCES BEGIN TO
SHOW UP WITH THE ADVANCE OF THE NEXT APPROACHING TROUGH AND STORM
SYSTEM FROM THE PACIFIC NORTHWEST BEGINNING LATE WEDNESDAY NIGHT
OR THURSDAY MORNING. THE GFS BRINGS THROUGH A STRONGER AND FASTER TROUGH
WHILE THE EC ADVERTISES A MUCH WEAKER AND SLIGHTLY SLOWER TROUGH.
BOTH MODEL PRECIP OUTPUT IS GENERALLY SCATTERED IN NATURE WITH
SOME AREAS OF BETTER RAINFALL ACCUMULATION.

INTO THE WEEKEND...IN THE WAKE OF THIS TROUGH...THE EC AND GFS
CAMPS GRADUALLY DIVERGE FROM EACH OTHER INTO SIGNIFICANTLY
DIFFERENT FLOW REGIMES THE GFS KEEPS A DRIER NORTHWEST FLOW ALOFT
WHILE THE EC FLOW IS MORE ZONAL AND SOUTHWEST WITH SOME DECENT
PRECIP FOR OUR SOUTHERN ZONES. TRIED TO SHOW A GENERAL BLEND OF
THESE TWO CAMPS FOR NOW GIVEN THE REGULAR LEVELS OF UNCERTAINTY IN
THE EXTENDED FORECAST PERIOD.

A VERY WARM WEDNESDAY WILL BE FOLLOWED BY COMFORTABLY WARM
TEMPERATURES THROUGH THE REMAINDER OF THE FORECAST. BMICKELSON

&&

.AVIATION...

CONDITIONS: MVFR/VFR.

SYNOPSIS: LOW PRESSURE IN EAST CENTRAL SASKATCHEWAN IS BRINGING
SOME MOISTURE INTO THE REGION WITH THE BEST CHANCE OF ACCUMULATING
RAIN AT KGDV...AT KSDY...LESSER SO AT KOLF AND LITTLE TO NOTHING
AT KGGW.

CEILINGS: MVFR CEILINGS ARE EXPECTED TO AFFECT KGDV AND KSDY BY
LATE TONIGHT. CEILINGS ARE EXPECTED TO IMPROVE AT KGGW TONIGHT TO VFR.

WINDS: WILL BE LIGHT NW. FRANSEN/TFJ

&&

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

&&

$$

WEATHER.GOV/GLASGOW





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