Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 020200
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
800 PM MDT TUE SEP 1 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
GOING FORECAST LOOKED TO BE IN GOOD SHAPE. THERE ISN/T A WHOLE LOT
GOING ON WITH SW FLOW BRINING IN DRY AIR AND PATCHY HIGH CLOUDS.
WINDS WILL BEGIN TO PICK UP FROM THE SE TONIGHT THEN TURN TO THE
SW AHEAD OF AN APPROACHING COLD FRONT WEDNESDAY. COULD BE THE
LAST 90 DAY OF THE YEAR FOR FOR SOME PLACES. TFJ

PREVIOUS DISCUSSION...
THE UPPER FLOW PATTERN TONIGHT BEGINS WITH A STORM SYSTEM/TROUGH
MOVING SOUTH DOWN THROUGH SOUTHEAST ALASKA AND WESTERN BRITISH
COLUMBIA. A BROAD BUT SHALLOW UPPER RIDGE SPREADS ACROSS CENTRAL
AND EASTERN CONUS. HOT DESERT AIR STILL OCCUPIES THE GREAT BASIN
AND THE SOUTHWEST. THROUGH THE SHORT TERM PERIOD THE TROUGH DROPS
FULLY INTO THE PACIFIC NORTHWEST...FIRMING UP A DISTINCT COLD
FRONT THAT WILL STRETCH NE TO SW ACROSS MONTANA. THIS FRONT WILL
SLOWLY MOVE EAST

WEDNESDAY...THE HOT DESERT AIR MOVES INTO THE LOCAL REGION AND
THICKNESS  RAMP UP TO AROUND 580DM. TEMPERATURES WILL RISE TO
AROUND 15F ABOVE NORMAL. THE COOLER AIR ALOFT BEHIND THE COLD
FRONT REMAINS TO THE WEST. THEREFORE CONDITIONS WILL REMAIN
STABLE. BUT STRONG LAPSE RATES COULD OCCASIONALLY MIX SOME OF THE
STRONGER WINDS ALOFT TOWARDS THE SURFACE.

WEDNESDAY NIGHT/THURSDAY...THE INITIAL SURFACE COLD FRONT PUSHES
THROUGH NORTHEAST MONTANA. BUT THE COOLER 700MB AIR ONLY REACHES
INTO THE CWA`S WESTERN EDGE BY LATE AFTERNOON...ESSENTIALLY
CAPPING MOST OF THE AREA. SO A FEW THUNDERSTORMS MAY BE POSSIBLE
FOR MAINLY PHILLIPS COUNTY AND AREAS NEAR THE INTERNATIONAL
BORDER. THE FRONTAL PASSAGE WILL SHIFT SURFACE WIND AROUND TO
THE NORTH AND INCREASE TO AROUND 15KT. THIS WILL HAVE TO BE
MONITORED FOR LAKE WIND.

SCT


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
CHANGES TO THE EXTENDED WERE NOT SIGNIFICANT. INCREASED WINDS A
BIT FOR SATURDAY FROM THE EAST. TOOK A LOOK AT THE MODEL GUIDANCE
AND VARIOUS SOLUTIONS FOR POPS. WENT WITH A WETTER SOLUTION FOR
THURSDAY THROUGH MONDAY. WHILE THERE IS STILL A LOT OF DIFFERENCE
IN TIMING AND PLACEMENT OF THE HIGHEST QPF...ALL MODELS ARE
SHOWING A SIGNFICANT PRECIPITATION EVENT FOR NE MONTANA WITH THEIR
HIGHEST AMOUNTS VARYING BY 50-100 MILES. ALL IN ALL...EVERYONE
SHOULD SEE SOME GOOD MEASURABLE PRECIPITATION WHILE SOME WILL SEE
OVER AN INCH AND A FEW MAY SEE OVER 2 INCHES. HAVE BRIEFED OUR
PARTNERS ON THIS EVENT AND POSTED INFORMATION ON THE WEBSITE AND
SOCIAL MEDIA. FRANSEN

BETWEEN THURSDAY NIGHT AND SATURDAY NIGHT...EASTERN MONTANA WILL
BE IN SOUTHWEST FLOW ALOFT BETWEEN AN UPPER TROUGH/LOW TO THE
WEST. THERE WILL BE A QUASI-STATIONARY FRONT OVER THE DAKOTAS AT
THE SAME TIME WITH AN 850 MB TEMPERATURE GRADIENT (WARM
EAST...COOL WEST) ACROSS THE FORECAST AREA.

THURSDAY NIGHT AND FRIDAY...IT LOOKS LIKE THE SHORTWAVES IN THE SW
FLOW ALOFT WILL BE PRIMARILY OVER CENTRAL MONTANA WITH NORTHEAST
MONTANA IN A DRY SLOT. COULD STILL SEE SOME SHOWERS AND
THUNDERSTORMS DEVELOP IN SOMEWHAT UNSTABLE AIRMASS. WILL MENTION
CHANCE WEST AND SLIGHT CHANCE EAST.

FRIDAY NIGHT AND SATURDAY...THE UPPER TROUGH DIGS DEEPER INTO THE
PACIFIC NW AND AS FAR SOUTH AS NEVADA WHILE SHORTWAVES MOVE
THROUGH EASTERN MONTANA WITH MORE MOISTURE. WILL BROADBRUSH A GOOD
CHANCE OF SHOWERS WITH THUNDERSTORMS AT TIMES.

SATURDAY NIGHT AND SUNDAY... THE UPPER TROUGH/LOW MOVES EAST
ACROSS MONTANA. ECMWF HAS CLOSED LOW AND GFS HAS OPEN TROUGH.
EITHER WAY... IT LOOKS WET AND COOL FOR NORTHEAST MONTANA. WILL
MAINTAIN GOOD CHANCE OF SHOWERS WITH THUNDERSTORMS AT TIMES.

MODELS DIFFER ON HOW QUICKLY TO LIFT THE TROUGH TO THE NORTHEAST
SUNDAY NIGHT AND MONDAY. WILL HAVE A SLIGHT CHANCE OF SHOWERS FOR
NOW.

SHORTWAVE RIDGE BUILDS INTO THE AREA MONDAY NIGHT AND TUESDAY WITH
DRY AND WARMER WEATHER. FORRESTER



&&

.AVIATION...

FLIGHT CATEGORY: VFR

SYNOPSIS: HIGH PRESSURE WILL REMAIN OVER THE REGION DURING
FORECAST PERIOD. LOOK FOR EITHER CLEAR SKIES OR SCT MID AND HIGH
CLOUDS THROUGH WEDNESDAY.

WINDS: LIGHT AND VARIABLE AFTER SUNSET... BECOMING EAST AND
INCREASING TO 10 KTS AROUND MIDNIGHT... INCREASING TO 10 TO 15 KTS
AND VEERING SLOWLY TO THE SOUTH ON WEDNESDAY.

GAH/SCT


&&

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

&&

$$

WEATHER.GOV/GLASGOW



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