Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 030847
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
247 AM MDT THU SEP 3 2015

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
A COLD FRONT WAS LOCATED NEAR MILES CITY... GLENDIVE AND SIDNEY
AT 08Z. THIS FRONT WILL DRIFT INTO NORTH DAKOTA THIS MORNING AND
REMAIN QUASI-STATIONARY INTO THE WEEKEND. THE FRONT WILL BE
PARALLEL TO THE SOUTHWEST FLOW ALOFT OVER THE REGION.

UPPER TROUGH/LOW WILL CONTINUE TO DIG SOUTH ACROSS THE PACIFIC
NORTHWEST TODAY AND THE BASE OF THE TROUGH WILL DIP AS FAR SOUTH
AS CALIFORNIA AND NEVADA TONIGHT. THE SW FLOW ALOFT OVER EASTERN
MONTANA WILL CONTINUE TO BE DRY FOR THE MOST PART TODAY. AN 850 MB
TEMPERATURE GRADIENT ACROSS THE REGION WILL BRING HIGHS THAT WILL
BE MAINLY IN THE 70S IN THE WEST AND 80S IN THE EAST.

A SHORTWAVE TROUGH MOVING NE THROUGH THE DAKOTAS TONIGHT WILL
BRING A BAND OF MOISTURE ACROSS THE FORECAST AREA TONIGHT WITH A
CHANCE OF SHOWERS POSSIBLY A THUNDERSTORM IF ELEVATED CONVECTION
OCCURS WITHIN AN UNSTABLE MID LEVEL.

MODELS DIFFER ON FRIDAY ON WHETHER OR NOT THERE WILL BE ANY
MOISTURE OVERRUNNING THE FRONT WHICH WILL BE ACROSS WYOMING AND
THE DAKOTAS. WILL MAINTAIN A CHANCE OF SHOWERS WITH A SLIGHT
CHANCE OF THUNDERSTORMS AS ELEVATED CONVECTION REMAINS POSSIBLE.

FRIDAY NIGHT AND SATURDAY... CHANCES OF OVERRUNNING MOISTURE
INCREASE AS LOW LEVEL FLOW TAPS INTO MOISTURE FROM THE GULF OF
MEXICO. A SURFACE LOW DEVELOPS OVER WYOMING AND MOVES INTO SOUTH
DAKOTA. UPPER TROUGH STAYS TO THE WEST KEEPING SOUTH TO SOUTHWEST
FLOW ALOFT OVER THE AREA. WILL INCREASE CHANCE OF SHOWERS TO
LIKELY LATE FRIDAY NIGHT AND SATURDAY WITH A CHANCE OF
THUNDERSTORMS AS ELEVATED CONVECTION REMAINS POSSIBLE.



.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...

SYNOPTIC SET UP... LONG RANGE BEGINS WITH A RIDGE OF HOT HIGH
PRESSURE OVER-STRETCHING FROM THE TEXAS PANHANDLE UP TO SOUTH
DAKOTA. A LARGE COOL CORE TROUGH HAS INVADED THE INTERMOUNTAIN
WEST INCLUDING WESTERN MONTANA. NORTHEAST MONTANA BEGINS UNDER
THE CLASH OF THESE TWO AIRMASSES AS A LOW PRESSURE SYSTEM HAS
WINDED UP AND TAPPED INTO COLD AIR OVER CENTRAL SASKATCHEWAN.

SATURDAY NIGHT THROUGH SUNDAY NIGHT... DEPENDING ON THE MODEL A
LOW PRESSURE SYSTEM WILL BEGIN CENTERED SOMEWHERE OVER SOUTHEAST
MONTANA TO SOUTHERN SASKATCHEWAN. PLACEMENT OF THE LOW WILL
DETERMINE WHERE STRONG WINDS AND THE TROWAL WITH EXCESSIVE
RAINFALL ON THE BACKSIDE WILL BE IN RELATION TO THE LOW`S
POSITION. CONFIDENCE IN THESE FEATURES IS LOW. HOWEVER... RAIN IS
PRESENT ON EVERY SIDE OF THE LOW. SO... CONFIDENCE IN RAIN AND
POPS DURING THESE PERIODS IS HIGH.

MONDAY TO TUESDAY NIGHT... COLD STABLE HIGH PRESSURE WILL SETTLE
INTO THE AREA AND CONDITIONS SHOULD DRY OUT WITH ONLY ISOLATED
SHOWERS POSSIBLE. FLOW ALOFT WILL BECOME ZONAL AND A MORE AUTUMN
LIKE ATMOSPHERE SHOULD SETTLE IN.

WEDNESDAY ONWARD... SYNOPTIC MODEL BREAKDOWN OCCURS AT THIS
POINT. TEMPERATURES SHOULD REMAIN SEASONAL FOR THE MOST PART... BUT
DEPENDING ON THE MODEL... SHORT TO SYNOPTIC WAVES BRING INCREASED
CHANCES FOR LIGHT RAINFALL AGAIN. GAH



&&

.AVIATION...
FLIGHT CATEGORY: VFR NEXT 24 HOURS.

SYNOPSIS: A COLD FRONT WILL EXIT THE AREA THIS MORNING. THE MAIN
EFFECT OF THE COLD FRONT WILL BE TO INCREASE SKY COVER THROUGH
TODAY AND INTO TONIGHT. THE PATTERN WILL REMAIN MOSTLY DRY. WITH
ISOLATED SHOWERS BEGINNING TO APPEAR AFTER MIDNIGHT. CONFIDENCE IN
A DIRECT TERMINAL HIT IS NOT YET HIGH ENOUGH TO INCLUDE IN THE
TAFS.

WINDS: NORTHERLY BETWEEN 5 TO 15 KTS.

WEEKEND STORM SYSTEM: A WIND UP LOW IS EXPECTED TO FORM THIS
WEEKEND. OBSCURATION FROM EXCESSIVE RAINFALL... IFR CEILINGS...
AND STRONG CROSSWINDS WILL BE A STRONG POSSIBILITY DURING THAT
TIME. MAIN TERMINAL IMPACTS WILL LIKELY KICK IN FRIDAY EVENING AND
LAST THROUGH MONDAY MORNING.

GAH


&&

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

&&

$$

WEATHER.GOV/GLASGOW


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