Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 131509 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
909 AM MDT SUN JUL 13 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH TUESDAY...
DESERT HIGH PRESSURE OVER THE GREAT BASIN ANCHORS A PERSISTENT
UPPER LEVEL RIDGE CENTERED OVER THE SPINE OF THE NORTHERN ROCKY
MOUNTAINS AND CLOSED LOW SYSTEM HOVERING AROUND HUDSON BAY WILL
MAINTAIN NORTHWEST FLOW ALOFT ACROSS NORTHEAST MONTANA TODAY.
VISUAL SATELLITE IMAGERY REVEALS SMOKE FROM CANADIAN WILD FIRES
IS ENTRAINED IN THE UPPER FLOW RESULTING IN LOCAL SMOKEY HAZE THAT
AFFECTS VISIBILITY.

THE CANADIAN LOW IS LOOSELY STACKED UP WHICH WILL LEAD TO
INCREASING NORTHWEST SURFACE WIND TODAY THAT WILL VEER MORE TO THE
NORTH AS THE LOW MOVES FARTHER EAST. AS SUCH...THERE IS A WIND
ADVISORY IN EFFECT FOR FORT PECK LAKE. GUIDANCE SUGGESTS THAT WIND
WILL WAIT UNTIL LATE AFTERNOON TO GET GOING STRONG OVER THE LAKE.
THERE WILL ALSO BE A SLIGHT COOLING EFFECT FROM THE NORTHERLY
WIND WITH HIGHS NEAR OR SLIGHTLY BELOW NORMAL. THE SURFACE
ANALYSIS ALSO PLACES NEMONT ON THE NORTHERN SIDE OF THE STATIONARY
BOUNDARY WHICH ACTS AS A BARRIER TO THE MUCH HOTTER AIR TO THE
SOUTHWEST.

FORECAST IS IN GOOD SHAPE WITH ONLY MINOR TWEAKS HERE AND THERE. SCT

PREVIOUS DISCUSSION...
DOME OF HIGH PRESSURE WILL CONTINUE TO SIT ACROSS THE SOUTHWESTERN
U.S. FOR THIS AFTERNOON WITH AN APPENDING RIDGE EXTENDING NORTH
THROUGH WESTERN MONTANA AND INTO SOUTHERN ALBERTA. A TROUGH ACROSS
ONTARIO THAT EXTENDS ACROSS THE UPPER MIDWEST AND GREAT LAKES
REGION WILL ALSO PERSIST THROUGH THIS AFTERNOON. THIS PLACES
NORTHEAST MONTANA IN NORTHWEST FLOW ALOFT. AS GUIDANCE IS A BIT
HIGHER WITH WIND SPEEDS TODAY...DECIDED TO ISSUE A LOW-END LAKE
WIND ADVISORY FOR FORT PECK LAKE. NORTH/NORTHWEST SURFACE WINDS ON
THE BACKSIDE OF A RATHER STRONG SURFACE LOW ACROSS FAR EASTERN
ONTARIO AND OUT AHEAD OF A SURFACE HIGH TO THE WEST OF THE CWA
WILL CREATE A RATHER TIGHT PRESSURE GRADIENT. BETTER CHANCES FOR
GUSTY WINDS MAY EXIST ALONG THE MT/ND BORDER...BUT EVEN AROUND
FORT PECK LAKE...NORTH TO NORTHWEST WINDS MAY REACH 15 TO 25 MPH
AT SOME POINT THIS AFTERNOON OR EVENING.

PROXIMITY OF UPPER TROUGH WILL MAINTAIN SEASONABLY COOL
TEMPERATURES ACROSS THE REGION FOR MONDAY AND TUESDAY. WEAK
SHORTWAVE PUSHING THROUGH NORTHWEST FLOW AROUND THE RIDGE OVER THE
WESTERN CONUS MAY BRING CHANCES FOR A FEW SHOWERS/THUNDERSTORMS
ACROSS WESTERN/CENTRAL MONTANA...BUT AT THIS POINT BEST FORCING
FOR ASCENT LOOKS TO PASS JUST TO THE SOUTH/WEST OF THE CWA. AS
SUCH WILL MAINTAIN A DRY FORECAST THROUGH THE REMAINDER OF THE
SHORT TERM FOR NOW. IT WOULD NOT TAKE MUCH OF AN EASTWARD SHIFT
HOWEVER TO AFFECT THE FAR WESTERN PORTIONS OF THE
AREA...SUCH AS PETROLEUM COUNTY. MALIAWCO


.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
LOOK FOR A DRY NORTHWEST FLOW ALOFT ON WEDNESDAY. TEMPERATURES
WILL WARM AS THE UPPER TROUGH TO THE EAST MOVES FURTHER EAST AND
RIDGE TO THE WEST EXERTS MORE INFLUENCE ON THE REGION`S WEATHER.

WEAK SHORTWAVE TROUGH AND FRONTAL SYSTEM ON THURSDAY MAY BRING
ENOUGH MOISTURE AND INSTABILITY FOR A SLIGHT CHANCE OF
THUNDERSTORMS. THEN... A SOMEWHAT DEEPER UPPER TROUGH DIGS INTO
THE AREA FRIDAY AND SATURDAY WITH A LOW PRESSURE SYSTEM. LOOM FOR
A CHANCE OF SHOWERS AND THUNDERSTORMS.

BY NEXT SUNDAY...MODELS ARE ADVERTISING A RIDGE OF WHICH THE ECMWF
IS STRONGER THAN THE GFS. AT THIS POINT...IT LOOKS DRY. FORRESTER


&&

.AVIATION...
FLIGHT CATEGORY: VFR

MOSTLY CLEAR SKIES WITH A FEW MID LEVEL CLOUDS WILL PREVAIL TODAY
AND TONIGHT. DRY COLD FRONT BETWEEN 18Z AND 21Z TODAY WILL
INCREASE NORTHERLY WINDS TO 15 TO 20 KNOTS THIS AFTERNOON. WINDS
WILL DIMINISH AFTER SUNSET THIS EVENING AND TURN NORTHEAST AND
THEN EAST AS HIGH PRESSURE BUILDS INTO SASKATCHEWAN.

&&

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

&&

$$

WEATHER.GOV/GLASGOW




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