Area Forecast Discussion
Issued by NWS Glasgow, MT

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000
FXUS65 KGGW 271546
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
946 AM MDT FRI MAR 27 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SUNDAY...
GOING FORECAST IN GOOD SHAPE WITH A TWEAK ON THE SKY AS SUNNY
CONDITIONS EXIST IN THE CENTRAL ZONES. HOURLY TEMPS/DEWPOINTS AND RH
WHERE ALSO TWEAKED TOWARD CURRENT CONDITIONS. REST OF FORECAST
LOOKED GOOD. TFJ

PREVIOUS DISCUSSION...
THE AMPLIFIED WAVE PATTERN CONTINUES OVER CONUS WITH A LONG-WAVE
RIDGE IN THE WEST AND A LONG-WAVE TROUGH IN THE EAST. THE BOUNDARY
BETWEEN THE TWO AIR MASSES WILL DRIFT OUT OF NORTHEAST MONTANA
TODAY AS THE RIDGE AXIS SHIFT EAST OVER THE NORTHERN ROCKIES. A
LEE-SIDE SURFACE TROUGH CENTERED OVER THE AREA TODAY SHIFTS EAST
CAUSING A WIND SHIFT TO THE NORTHWEST. AS SHOWN BY THE 00Z KGGW
SOUNDING TEMPERATURES ALOFT ARE WARMING. THE INCREASED HEIGHTS
WILL BRING ABOUT A RATHER WARM DAY...ABOUT 20 DEGREES ABOVE
NORMAL. FRIDAY NIGHT THE WARMING ALOFT CONTINUES AS THE RIDGE AXIS
MOVES INTO EASTERN MONTANA. THIS WILL PRODUCE ANOTHER RELATIVELY
WARM NIGHT.

SATURDAY...CONDITIONS CHANGE RAPIDLY. A WARM START TO THE DAY WILL
AND WESTERLY WINDS IN THE MORNING WILL HELP DRIVE TEMPERATURES
CLOSE TO THOSE EXPECTED TODAY. A STRONG NARROW WAVE AND STORM
SYSTEM MOVES INTO THE PACIFIC NORTHWEST THIS MORNING. THE WAVE
QUICKLY CROSSES THE DIVIDE AROUND NOON SATURDAY. THIS CLIPPER-LIKE
AND QUICK-MOVING STORM BRINGS MOISTURE WITH IT. THEN THE WAVE AND
COLD FRONT MOVES FULLY INTO NEMONT BY LATE AFTERNOON. INSTABILITY
IS ENOUGH FOR SPC TO PUT OUR EASTERN ZONES IT THE CONVECTIVE
OUTLOOK FOR GENERAL TS. HOWEVER THE BEST AREA FOR GENERAL TS SEEMS
TO BE EAST OF OUR BORDER FOR NOW. MODELS HAVE HAD DIFFICULTY IN
WITH THE WAVE AND ARE SHOWING AN INCREASING AMOUNT OF QPF NOW.
AFTERNOON WINDS HAVE BACKED OFF A FEW KNOTS AS THE SYSTEM MOISTENS
UP MORE. THE WET AND WINDY CONDITIONS MOVE INTO SATURDAY NIGHT
ALSO. WINDS CONTINUE MARGINAL FOR HEADLINES...EXCEPT FOR SW
PHILLIPS COUNTY. WILL INSTALL A HIGH WIND WATCH FOR THAT AREA FROM
NOON UNTIL 9PM. DEPENDING ON HOW MUCH ICE IS LEFT ON FORT PECK
LAKE...THE FIRST WIND ADVISORY MAY BE NEEDED. ANOTHER CONCERN IS
FIRE WX. SEE FIRE WX DISCUSSION.

LATE SATURDAY NIGHT AND SUNDAY...MODELS SHOW PRECIPITATION FALLING
OFF AFTER MIDNIGHT AND WINDS CALMING DOWN AS THE TROUGH RAPIDLY
DEPARTS EAST. THICKNESS HEIGHTS DROP DOWN CLOSER TO NORMAL AND
TEMPERATURES COOL DOWN. SCT

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
UPPER RIDGE REBOUNDS FOLLOWING WEEKEND COLD FRONT FOR WARM AND
DRY CONDITIONS RETURNING FOR EARLY NEXT WEEK. NEXT SHORTWAVE
PUSHES THROUGH THE RIDGE INTO THE NORTHERN ROCKIES BY TUESDAY WITH
A STRONG LEE CYCLONE DEVELOPING OVER ALBERTA. COLD FRONT
ASSOCIATED WITH THE SYSTEM FORECAST BY MEDIUM RANGE MODELS TO PUSH
THROUGH EASTERN MONTANA TUESDAY AFTERNOON. MOISTURE HOLDS BACK
UNTIL THE LOW BEGINS TO MOVE ACROSS THE CANADIAN PRAIRIES WRAPPING
INTO NORTHERN MONTANA WITH THE COLD AIR ADVECTION BEHIND THE
SYSTEM. WINDS ALSO EXPECTED TO INCREASE WITH THE TIGHT
GRADIENT...COLD AIR ADVECTION AND CYCLONIC JET TUESDAY NIGHT INTO
WEDNESDAY.

UPPER FLOW REMAINS ZONAL TO SLIGHTLY CYCLONIC INTO THE END OF THE
WEEK WITH ANOTHER SHORTWAVE DROPPING INTO THE GREAT BASIN ON
THURSDAY. THIS WILL MAINTAIN COOLER AND MORE UNSETTLED WEATHER
INTO FRIDAY. EBERT


&&

.AVIATION...
FLIGHT CATEGORY: VFR

SYNOPSIS: A NW TO SE STATIONARY FRONT OVER THE AREA WILL KEEP MID-
LEVEL CLOUDS IN THE AREA TODAY. OTHERWISE EXCELLENT FLYING
CONDITIONS.

AREA WINDS: OUT OF THE WEST TO NORTHWEST AROUND 10 TO 15 THROUGH
TODAY... THEN SWITCHING TO THE SOUTHEAST AFTER SUNDOWN.

EQUIPMENT: KGDV CEILOMETER IS OUT. UNTIL IT RETURNS...
AMD LTD TO VIS AND WIND.

GAH


&&

.FIRE WEATHER...
A COLD FRONT MOVING THROUGH THE REGION ON SATURDAY AFTERNOON AND
EVENING WILL GENERATE STRONG TO VERY STRONG WINDS OF 25 TO 35 MPH
WITH GUSTS OF 45 TO 55 MPH. HOWEVER RAIN SHOWERS ARE ALSO
EXPECTED. MODELS ARE STILL EVOLVING ON THE AMOUNTS AND LOCATION OF
THE RAIN. SO FAR THE CHANCE FOR WETTING RAINS ARE BEST NORTH OF
THE MISSOURI RIVER AND EAST OF FORT PECK LAKE.

THERE SEEMS LESS UNCERTAINTY CONCERNING WINDS AND RH VALUES. THE
RED FLAG DECISION CHART PLACES FIRE WX ZONES 135...136 AND 137 AT
POSSIBLE FOR A FIRE WX HEADLINE WITH RH VALUES IN THE UPPER 20S
AND LOWER 30S. SO WILL GO AHEAD WITH A FIRE WX WATCH FOR THOSE
AREAS FROM NOON TO 9PM SATURDAY.

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY
EVENING FOR MTZ135>137.

HIGH WIND WATCH FROM SATURDAY AFTERNOON THROUGH SATURDAY EVENING
FOR SOUTHWEST PHILLIPS.

&&

$$

WEATHER.GOV/GLASGOW





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