Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 062209
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
309 PM MST FRI MAR 6 2015

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

GIVEN THE EASE WITH WHICH TEMPERATURES HAVE WARMED TODAY...FELT IT
WAS BEST TO FOLLOW SUIT IN ADJUSTING FORECAST TEMPERATURES A BIT
HIGHER THAN PREVIOUSLY EXPECTED FOR MOST OF THE FORECAST PERIOD.

A COOL FRONT AND SHORT-WAVE DISTURBANCE WILL SWEEP THROUGH
NORTHEAST MONTANA BEGINNING TONIGHT AND RESULTING IN SOME LIGHT
RAIN SHOWERS SATURDAY AFTERNOON...MOST LIKELY FOCUSED NEAR AND
ALONG A LINE FROM THE LITTLE ROCKY MOUNTAINS SE THROUGH TERRY. THE
EC AND CMC MODELS INDICATE A MUCH WIDER SPREAD OF RAIN ON EITHER
SIDE OF THIS LINE WITH THE REMAINDER OF THE MODELS KEEP THE RAIN
IN A RELATIVELY NARROW BAND. EXPANDED THE POPS GRIDS DURING THIS
TIME TO ACCOUNT FOR THE WIDER SPREAD POSSIBILITY.

FOR SUNDAY...THE WESTERN STATES UPPER LEVEL RIDGE WILL RE-ASSERT
ITSELF TO ALLOW TEMPERATURES TO WARM AGAIN TO VERY COMFORTABLE
LEVELS AS ALL MODELS KEEP A VERY DRY FLOW ALOFT OVER THE REGION.
BMICKELSON

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...

MAJORITY OF ADJUSTMENTS MADE TO THE EXTENDED FORECAST WAS TO RAISE
TEMPERATURES HIGHER THAN GUIDANCE. HIGH TEMPERATURES EASILY CLIMBED
MORE THAN EXPECTED. SO...GIVEN THE CHANCE WITH A WESTERN RIDGE IN
PLACE THROUGH A GOOD PORTION OF THE FORECAST PERIOD...WOULD
EXPECT STRONGER WARMING TO ALSO BE EASY TO COME BY AGAIN AND
AGAIN. ALSO CHOSE TO DROP POPS COMPLETELY WHERE MODEL QPF OUTPUT
WAS IN EXCELLENT AGREEMENT SHOWING WIDE AREAS OF NO PRECIP
WHATSOEVER. MODELS BEGIN TO DIVERGE A BIT AND ENSEMBLE STANDARD
DEVIATIONS INCREASE FROM EACH OTHER BEGINNING ON TUESDAY. WOULD
HAVE A BIT LESS FORECAST CONFIDENCE LEADING INTO THE MIDDLE OF
NEXT WEEK. BMICKELSON

PREVIOUS LONG TERM DISCUSSION...THE ARCTIC AIR MASS IS EXPECTED
TO REMAIN LOCKED UP IN NORTHERN CANADA AND ALASKA THROUGHOUT THE
EXTENDED PERIOD. THE PERSISTENT PATTERN OF A LONG-WAVE TROUGH IN
EASTERN NORTH AMERICA AND UPPER LEVELING RIDGING IN THE WEST
SHOULD KEEP THE STATIONARY FRONTAL BOUNDARY TO THE NORTH OF
NORTHEAST MONTANA RESULTING IN TEMPERATURES WELL ABOVE NORMAL.

NORTHWEST FLOW ALOFT WILL BE A DRY PATTERN. THEN MONDAY NIGHT A
LARGE STORM SYSTEM IN CENTRAL CANADA WILL SEND A BACKDOOR COLD
FRONT SOUTH INTO NEMONT...WITH LITTLE AFFECT OTHER THAN TRIMMING A
FEW DEGREES OFF THE OVERNIGHT LOWS. THEN BY TUESDAY THE COLD
QUICKLY RETREATS EAST AS A WARM FRONT MOVES IN TO BRING MID TO
HIGH LEVEL OVERCAST. SO THE FLUCTUATING FRONTAL BOUNDARY WILL
MODIFY ALREADY WARMER THAN NORMAL TEMPERATURES.

WEDNESDAY AND BEYOND THE EC AND GFS BOTH SEE A TROUGH ALONG THE
COAST. BOTH 12Z MODELS HAD COMPLETELY DIFFERENT IDEAS AS TO WHAT
THE TROUGH WILL DO. THE 00Z GFS DRAGS A WEAKENED TROUGH ACROSS THE
DIVIDE ON THURSDAY. THE 12Z EC SENT THE TROUGH AS A CUTOFF LOW
DOWN THE COAST. HOWEVER THE 00Z EC CAME MORE IN LINE WITH THE
GFS...RAISING CONFIDENCE A BIT. CONSISTENCY NEEDS TO CONTINUE
BEFORE CONFIDENCE RISES MUCH MORE. HOWEVER DID RAISE TEMPERATURES
QUITE A BIT FROM WEDNESDAY ON...SINCE IN BOTH SCENARIOS
TEMPERATURES REMAIN WELL ABOVE NORMAL. SCT


&&

.AVIATION...

EXPECTING OVERALL MILD WEATHER CONDITIONS TODAY AND TONIGHT. A
SHORT-WAVE DISTURBANCE WILL SLIDE DOWN THE FRONT RANGE AND
NORTHERN PLAINS SATURDAY AFTERNOON A BRING A CHANCE FOR SOME RAIN
SHOWERS.

NW WINDS UP TO 20 KTS THIS AFTERNOON WILL DROP BACK DOWN BELOW 10
KTS LATER TONIGHT FROM THE WEST.

EXPECT SCT TO BKN MID-TO-HIGH CLOUDS EARLY WITH BKN LOW-TO-MID
CLOUDS BY SATURDAY AFTERNOON.

SCT/BLM

&&

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

&&

$$

WEATHER.GOV/GLASGOW




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