Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 170201
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
801 PM MDT TUE SEP 16 2014

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
UPDATE...NO UPDATE. UPPER RIDGING IS KEEPING FAIR SKIES OVER
NORTHEAST MONTANA THIS EVENING.  PROTON

UPPER RIDGING WILL MAKE FOR WARM TEMPERATURES...DRY CONDITIONS
AND LIGHT WINDS TONIGHT INTO WEDNESDAY NIGHT.

THURSDAY AFTERNOON THE UPPER RIDGE WILL BEGIN TO BE BROKEN DOWN BY
AN APPROACHING SPLITTING UPPER TROUGH OVER THE WESTERN CONUS. THIS
WILL MAKE FOR ISOLATED SHOWERS AND THUNDERSTORMS ACROSS THE
WESTERN ZONES DURING THE AFTERNOON. ALSO PUT IN MENTION OF ISOLATED
THUNDERSTORMS ACROSS THE EAST AS MOISTURE ADVECTION IN A SOUTHEAST
SURFACE FLOW WILL ALLOW FOR SIGNIFICANT POTENTIAL INSTABILITY TO
DEVELOP. WITH THAT SAID...THERE WILL BE A CAP PRESENT WHICH SHOULD
KEEP STORMS IN CHECK BUT WITH THAT POTENTIAL PRESENT PUT MENTION
OF ISOLATED THUNDERSTORMS IN THE FORECAST. GILCHRIST


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...

GENERAL LONG WAVE RIDGE PATTERN IS BROKEN LATE THURSDAY OR FRIDAY
WHEN AN UPPER SHORT WAVE MANAGES TO CUT THROUGH THE RIDGE. THIS
EVENT IS PRECEDED BY A SURFACE TROUGH THAT PROGRESS EASTWARD
ACROSS MONTANA INTO THE DAKOTAS LATE ON THURSDAY...WITH SOME
CHANCE FOR SHOWERS OR THUNDERSTORMS AHEAD OF AND BEHIND THE
TROUGH/FRONTAL BOUNDARY. BEST MOISTURE IS PUSHED EASTWARD INTO
NORTH DAKOTA...AND STRONG THUNDERSTORMS ARE NOT EXPECTED...EXCEPT
POSSIBLY NEAR THE MONTANA-NORTH DAKOTA BORDER LATE ON THURSDAY.
MOISTURE IS LIMITED BEHIND THE FRONT WITH CLOUD BASES UP AROUND
8000 FT. AGL AND PRECIPITABLE WATER DOWN AROUND 3/4 INCHES...AND
SIGNIFICANT PRECIPITATION IS NOT ANTICIPATED.

TROUGH PASSAGE COMPLETES BY SATURDAY AFTERNOON AND RIDGE REASSERTS
ITSELF AND CUTS-OFF ALL CHANCES FOR PRECIPITATION THROUGH NEXT
TUESDAY. PASSAGE OF FRONT BY FRIDAY MORNING WILL CAUSE SOME
COOLING BUT PREVAILING ABOVE NORMAL TEMPERATURES WILL PERSIST WITH
HIGHS SATURDAY IN THE 70S...AND HIGHS AROUND 80 SUNDAY THROUGH
TUESDAY AS THE RIDGE REBUILDS.

PRESSURE GRADIENT ASSOCIATED WITH THE SURFACE TROUGH WILL CREATE
SOME STRONGER SOUTHERLY WINDS THAT WILL PERSIST LATE THURSDAY AND
VEER TO THE WEST AND NORTHWEST WITH TROUGH PASSAGE FRIDAY MORNING
THROUGH SATURDAY AFTERNOON. MARTIN.

PREVIOUS LONG-TERM DISCUSSION...
NEARLY ZONAL FLOW ALOFT ON FRIDAY WILL
BRING A SHORTWAVE TROUGH WITH A COLD FRONT THROUGH THE FORECAST
AREA. THE SYSTEM SHOULD HAVE ENOUGH MOISTURE FOR A CHANCE OF
SHOWERS AND THUNDERSTORMS. FLOW ALOFT TURNS TO THE NORTHWEST ON
SATURDAY WITH SOMEWHAT COOLER TEMPERATURES. THE UPPER RIDGE BUILDS
OVER THE WESTERN U.S. OVER THE WEEKEND AND MOVES INLAND MONDAY AND
TUESDAY GIVING MONTANA WARM AND DRY WEATHER. FORRESTER

&&

.AVIATION...

A BROAD UPPER LEVEL RIDGE WILL CREATE CALM AND MOSTLY CLEAR
CONDITIONS FOR THE NEXT 24 HOURS. CEILING AND VISIBILITY WILL BE
UNLIMITED EARLY ON...WITH LIGHT EASTERLY TO VARIABLE WINDS BELOW
10 KTS THROUGH WEDNESDAY MORNING AND SOUTHEASTERLY WINDS UP TO 15
KTS WEDNESDAY AFTERNOON. A LITTLE BIT OF MID-LEVEL MOISTURE WILL
CREATE A FEW TO SCATTERED CLOUDS AROUND FL100 ON WEDNESDAY.
MARTIN/BMICKELSON


&&

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

&&

$$

WEATHER.GOV/GLASGOW




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