Area Forecast Discussion
Issued by NWS Glasgow, MT

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FXUS65 KGGW 290207
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
807 PM MDT THU MAY 28 2015

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

UPDATE...
THE COLD FRONT CONTINUES TO MOVE SOUTH THROUGH THE FORECAST AREA
THIS EVENING AND SHOULD EXIT THE REGION BY 10 PM. THE FRONT WILL
TAKE THE CHANCE OF SHOWERS AND VERY ISOLATED THUNDERSTORMS WITH
IT. HIGH PRESSURE WILL BUILD INTO THE NORTHERN TIER OF COUNTIES
OVERNIGHT FOR TEMPERATURES IN THE 30S TO LOW 40S BY DAY BREAK ON
FRIDAY.  PROTON

PREVIOUS DISCUSSION...
COLD FRONT DROPPING THROUGH THE AREA THIS AFTERNOON
WITH LINE OF THUNDERSTORMS NEAR THE FRONT AND SCATTERED STORMS OUT
AHEAD OF THE LINE. EXPECTING GUSTY WINDS WITH THE FRONT TO 40 MPH
LATE THIS AFTERNOON.

THINGS QUIET DOWN THIS EVENING WITH WINDS DIMINISHING THIS EVENING
FINALLY OVER THE SOUTHERN ZONES. SIGNIFICANT COOL DOWN OCCURS AS
TEMPS TONIGHT DROP INTO THE UPPER 30S AND 40S.

SURFACE HIGH PRESSURE OVER NORTHERN CANADA WILL BUILD IN FRIDAY TO
BRING A SUNNY BUT COOL DAY WITH LIGHT NORTHEAST WINDS. TEMPERATURES
WILL ONLY RISE INTO THE 60S MOST PLACES.

AN UPPER LOW OVER BRITISH COLUMBIA THEN SENDS A DISTURBANCE ACROSS
MONTANA SATURDAY THAT BRINGS A CHANCE OF THUNDERSTORMS. TFJ

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
AFTERNOON UPDATE...NO SIGNIFICANT CHANGES MADE TO THE EXTENDED.
WILL BE HIGHLIGHTING THE INCREASED POTENTIAL FOR PRECIPITATION AND
EVEN SEVERE WEATHER IN A WEATHER STORY THAT WILL BE SENT ONCE
TODAYS CONVECTION DIES DOWN. FRANSEN

THE LONG RANGE PERIOD GETS UNDERWAY SATURDAY NIGHT WITH AN UPPER
LEVEL SHORTWAVE TROUGH RIDING THROUGH ZONAL FLOW ALOFT AS IT TREKS
ACROSS THE STATE OF MONTANA AND INTO THE DAKOTAS. THIS FEATURE
WILL PROVIDE ENOUGH DYNAMIC FORCING FOR ASCENT AND COMBINE WITH
ENOUGH MOISTURE TO NECESSITATE CARRYING A CHANCE FOR SHOWERS AND
THUNDERSTORMS.

THE LATEST 00Z GUIDANCE SHOWS A BUILDING UPPER RIDGE ACROSS THE
NORTHERN HIGH PLAINS ON SUNDAY WITH THE RIDGE AXIS TRANSLATING
EAST OF THE CWA BY MONDAY AS AN ENERGETIC TROUGH DIGS INTO THE
PACIFIC SHORE. THIS WILL USHER IN SOUTHWEST FLOW ALOFT AS AN UPPER
SHORTWAVE APPROACHES. OUT AHEAD OF THIS TROUGH WILL BE VERY WARM
850MB TEMPERATURES...IN THE NEIGHBORHOOD OF +20C. AS SUCH EXPECT
HIGHS MONDAY COULD REACH THE LOWER AND MIDDLE 80S. SURFACE EAST
WINDS WILL HELP PUMP IN LOW LEVEL MOISTURE AND SO HAVE DEW POINTS
IN THE LOWER AND MID 50S. MODEL ANALYSIS SHOWS THE CWA IN SORT OF
A THETA-E RIDGE AS THE SHORTWAVE APPROACHES MONDAY AFTERNOON.
EXTENDED FORECAST GFS BUFKIT SOUNDINGS ARE BEGINNING TO SHOW
FAVORABLE CONVECTIVE PARAMETERS FOR THUNDERSTORMS EARLY NEXT WEEK
AS WELL WITH 500-1500 J/KG CAPE ACROSS NORTHEAST MONTANA...HIGHEST
SOUTH OF THE MISSOURI RIVER. FUTURE SHIFTS WILL NEED TO MONITOR
THIS TIME PERIOD FOR THE POTENTIAL OF A COUPLE OF STRONGER STORMS.
AS THIS SYSTEM ENTERS THE SHORT TERM OVER THE NEXT FEW
DAYS...HIGHER RESOLUTION MODELS WILL BE ABLE TO PICK IT UP AND
CONFIDENCE SHOULD START TO INCREASE REGARDING DETAILS. FOR NOW
WILL MAINTAIN LIKELY POPS FOR EARLY NEXT WEEK WITH AT LEAST A
CHANCE FOR THUNDERSTORMS.
WEDNESDAY AND BEYOND...WITH A TROUGH IN THE VICINITY MAINTAINING
LOWER 500MB HEIGHTS...WILL HAVE A COOLING TREND IN PLACE. MODEL
GUIDANCE STARTS SHOWING INCREASING SPREAD THIS FAR OUT SO AS
CONFIDENCE DECLINES...DECIDED TO TREND POPS TOWARD CLIMATOLOGY TO
FINISH OUT THE FORECAST PERIOD. MALIAWCO

&&

.AVIATION...
FLIGHT CATEGORY: VFR

SYNOPSIS: SCATTERED SHOWERS ARE BRINGING SOME BRIEF RAIN TO THE
KSDY AND KGDV AREAS. REDUCED CIG AND VSBY MAY ACCOMPANY ANY
STEADY SHOWER ACTIVITY. BUT THESE CHANCES WILL RAPIDLY WANE AS THE
EVENING CONTINUES

AREA WINDS: DECREASING TO 5 TO 15 KTS OUT OF THE NORTHEAST
THROUGH MIDNIGHT... FURTHER VEERING TO THE EAST FRIDAY AND
DECREASING TO LESS THAN 10 KTS THROUGH THE END OF THE CYCLE.

&&

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

&&

$$

WEATHER.GOV/GLASGOW




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