Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 260344 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
944 PM MDT FRI JUL 25 2014

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

THE CLOSED STACKED LOW CAN BE SEEN ON GOES VISUAL THIS EVENING
SPINNING OVER SASKATOON. THE LOW CENTER IS EXPECTED TO MOVE
SOUTHEAST TO THE MANITOBA BORDER BY MORNING. THE ASSOCIATED CLOUD
DECK EXTENDS SOUTH CLOSE TO THE INTERNATIONAL BORDER...BUT SKIES
REMAIN CLEAR OVER NORTHEAST MONTANA. THE MAIN EFFECT OF THE LOW IS
TO SUSTAIN STRONG EVENING WEST-NORTHWEST WIND ACROSS THE FORECAST
AREA. THE UPPER WIND FEEDING THE WIND GUSTS SHOULD DECOUPLE AROUND
SUNSET AND WIND SHOULD DIMINISH SUFFICIENTLY TO ALLOW THE WIND
ADVISORY OVER FORT PECK LAKE TO BE CANCELLED. BASED ON THE
SOUTHEAST DIRECTION OF THE LOW THERE IS ALSO THE POSSIBILITY THAT
A FEW SHOWERS MAY BE PUSHED ACROSS THE BORDER AFTER MIDNIGHT. WITH
WEAK CONVECTIVE PARAMETERS THUNDERSTORMS ARE NOT EXPECTED.
OTHERWISE FEW CHANGES NEEDED. SCT

PREVIOUS DISCUSSION...
SYNOPTIC SET UP...A LARGE HIGH PRESSURE HEAT DOME SETS OVER THE
FOUR CORNERS. OPPOSITE OF THIS FEATURE...A TROUGH RUNS DOWN THE
BRITISH COLUMBIAN COAST THEN TURN INLAND OVER WASHINGTON AND THEN
RIDES UP INTO SOUTHERN ALBERTA AND SASKATCHEWAN WHERE IT
TERMINATES ABOVE CLOSED SURFACE LOW. BETWEEN THESE TWO LARGE
FEATURES ZONAL FLOW RUNS FROM THE PACIFIC NORTHWEST THROUGH THE
NORTHERN US ROCKIES AND HIGH PLAINS.

TONIGHT THROUGH SUNDAY...MOSTLY DRY CONDITIONS ARE EXPECTED AS
WESTERN TO NORTHWESTERN WINDS STABILIZE AND DRY THE ATMOSPHERE
OUT. THE ONLY EXCEPTION TO THIS IS SATURDAY MORNING WHEN THE
CLOSED LOW DROPS TO THE SOUTHEAST AND ENDS UP CLIPPING THE FAR
NORTHEAST SECTIONS OF THE CWA. THIS WILL BRING SOME CLOUD COVER
DOWN ALONG THAT AREA BRIEFLY AND WITH IT A SLIGHT CHANCE FOR RAIN.
BY SUNDAY THREAT DOME WILL REBOUND INTO THE INTER-MOUNTAIN WEST
AND AND BEGIN FORCING A RIDGE UP INTO IDAHO FORCING FLOW INTO A
NORTHWEST PATTERN. CONDITIONS SHOULD REMAIN DRY HERE AS WELL. GAH


.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
TWEAKED WINDS A BIT TOWARD MODEL CONSENSUS. OTHERWISE...MODELS
(MAINLY ECMWF) SHOWING SIGNS THAT A DISTURBANCE CAUGHT IN THE FRONT
SIDE OF THE UPPER RIDGE MOVES SE THROUGH THE AREA LATE FRIDAY. GFS
DOESN/T SEEM TO HAVE A GOOD HANDLE ON IT YET. THIS COULD BE OUR
NEXT CHANCE OF RAIN. TFJ

PREVIOUS DISCUSSION...
THE EXTENDED FORECAST PERIOD BEGINS WITH AN AMPLIFIED PATTERN
ACROSS CONUS. AN UPPER LEVEL RIDGE WILL BE ANCHORED BY THE
PERSISTENT GREAT BASIN HIGH AND THE RIDGE AXIS WILL BE CENTERED
ALONG THE NORTHERN ROCKIES. IN THE EAST ANOTHER LONG LASTING UPPER
LOW NEAR HUDSON BAY WILL MAINTAIN A LONG WAVE TROUGH ACROSS THE
EASTERN HALF OF CONUS.

THIS PATTERN WILL CHANGE VERY LITTLE. FLOW ALOFT OVER NORTHEAST
MONTANA WILL REMAIN NORTHWESTERLY THROUGH THE PERIOD. AN
OCCASIONAL EMBEDDED DISTURBANCE IN THE UPPER FLOW WILL CREATE
CHANCES FOR ISOLATED THUNDERSTORMS. BUT FOR THE MOST PART THE
FORECAST AREA WILL STAY SUNNY...DRY AND HOT LEADING TO FIRE
WEATHER CONCERNS. HOWEVER THERE DOES NOT APPEAR TO BE ANY BIG
WINDS NEXT WEEK. SCT

&&

.AVIATION...
FLIGHT CATEGORY: VFR

SYNOPSIS: A CLOSED UPPER LOW AND A CLOSED SURFACE LOW HAVE
STACKED UP OVER SOUTHERN SASKATCHEWAN KEEPING BREEZY WEATHER OVER
NORTHEAST MONTANA.

AREA WINDS: STRONG WEST WINDS OF 15 TO 30 KTS WILL SUBSIDE TO AROUND 10
KTS AFTER SUNSET. AFTER SUNRISE WINDS WILL SLOWLY VEER TO THE
NORTHWEST AND INCREASE TO 15 TO 30 KTS AGAIN BY SATURDAY
AFTERNOON.

&&

.FIRE WEATHER...
A STRONG LOW PRESSURE SYSTEM MOVING EAST JUST NORTH OF THE
INTERNATIONAL BORDER WILL AGAIN PRODUCE STRONG WINDS ACROSS
NORTHEAST MONTANA ON SATURDAY. CONTINUED LOW HUMIDITY AFTER POOR
OVERNIGHT RECOVERY WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS
ACROSS AND SOUTH OF THE CMR AGAIN. A FIRE WEATHER WATCH IS IN
EFFECT FOR THAT AREA.


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM 9 AM MDT SATURDAY THROUGH SATURDAY
EVENING FOR MTZ135>137.

&&

$$

WEATHER.GOV/GLASGOW





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