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000
FXUS65 KGGW 140342 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
942 PM MDT MON MAY 13 2013

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

AFTER SOME SURPRISE SEVERE THUNDERSTORM WIND GUSTS TONIGHT...THE
REMAINDER OF THE NIGHT LOOKS TO BE DOMINATED BY BY WIDESPREAD
SHOWERS AND SCATTERED THUNDERSTORMS. INCREASED POPS BASED ON RADAR
TRENDS AND EXCELLENT SHORT TERM MODEL AGREEMENT. BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...THE UPPER TROUGH REMAIN WELL OFF
TO THE WEST...BUT THE EXIT REGION HAS BEEN HIGHLIGHTED FOR SLIGHT
CHANCE FOR SEVERE THUNDERSTORMS BY SPC. THIS AREA EXTENDS WELL
INTO THE WESTERN HALF OF THE CWA. TODAY WAS WARM LIKE SUNDAY BUT
THE DEW POINTS WERE A LITTLE HIGHER...INCREASING THE LEVEL OF
INSTABILITY. YET THE COLD FRONT WILL BE POSITIONED ALONG THE FRONT
RANGE AT 00Z THIS EVENING AND SHOULD NOT REACH NORTHEAST MONTANA
UNTIL MID EVENING...WHEN INSTABILITY IS BEGINNING TO LOSE ITS
STRENGTH AROUND SUNSET. THE MAIN THREAT TO ANY THUNDERSTORM
APPEARS TO THE POSSIBILITY OF STRONG WINDS AS INDICATED BY THE
INVERTED-V SOUNDING PROFILE AT 00Z. CONVECTIVE PARAMETERS SHOW
MODERATE TO GOOD SUPPORT FOR A GENERAL THUNDERSTORM THREAT ACROSS
NORTHEAST MONTANA THIS EVENING AND TONIGHT. OVERALL SEVERE
THUNDERSTORM PARAMETERS DIMINISH THROUGH NORTHEAST MONTANA THROUGH
THE EVENING HOURS. A GOOD WETTING RAIN CAN BE EXPECTED FOR MUCH OF
OUR CWA. MODELS FAVOR AREAS NORTH OF THE HI-LINE FOR THE BEST
QPF...UP TO A QUARTER INCH. LESSER AMOUNTS ARE EXPECTED SOUTH OF
THE MISSOURI RIVER.

STRONG WIND TODAY WITH LOW RH HAS CREATED CRITICAL FIRE WX
CONDITIONS. THEREFORE ISSUED A RED FLAG WARNING THROUGH TUESDAY
EVENING. SEE FIRE WX DISCUSSION. IN ADDITION...WIND OVER FORT PECK
LAKE BECAME HAZARDOUS TO BOATERS WITH CONDITIONS CONTINUING THROUGH
TUESDAY WENT AHEAD AND ISSUED A LAKE WIND ADVISORY THROUGH TUESDAY
EVENING.

TUESDAY...THE VIGOROUS COLD FRONT PASSING THROUGH THE CWA LATE
TONIGHT AND EARLY TUESDAY MORNING WILL BRING STRONG SUBSIDENCE
AND COLD AIR ADVECTION BEHIND THE FRONT. THIS WILL ALLOW STRONG
AND ENHANCED WINDS BEHIND THE FRONT TO PERSIST THROUGHOUT MOST OF
THE DAY ON AS ISOLATED SHOWERS LINGER ALONG THE CANADIAN BORDER.
THE COOLER AIR WILL CAP MAXIMUM TEMPERATURES MUCH LOWER THAN
THOSE ON MONDAY...BUT WITH GOOD MIXING...HIGHS WILL CONTINUE ABOVE
AVERAGE. CRITICAL FIRE WEATHER CONDITIONS LOOK MORE LIKELY ON
TUESDAY WITH WIDESPREAD SUSTAINED WINDS IN EXCESS OF 25 TO 20
KNOTS. SEE FIRE WEATHER DISCUSSION.

TUESDAY NIGHT AND WEDNESDAY...WIND DIMINISHES RAPIDLY IN THE
EVENING AS THE SHORT WAVE MOVES INTO THE GREAT LAKES REGION.
ZONAL FLOW WILL SETTLE THINGS DOWN FOR A MILD DAY. THIS WILL ALLOW
TEMPERATURES TO CREEP UP SLIGHTLY OVER HIGHS ON TUESDAY AS A VERY
WEAK RIDGE COVERS THE REGION. SCT

.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
UPDATE...GOING FORECAST WAS IN OVERALL EXCELLENT SHAPE DEPICTING A
DRY ZONAL FLOW THROUGH MIDWEEK...FOLLOWED BY A COOLER MORE
UNSETTLED UPPER TROUGH FOR THURSDAY AND BEYOND. ONLY TWEAKS WERE
MAINLY MADE FOR CONSISTENCYS SAKE...NO SIGNIFICANT CHANGES WERE
MADE. GILCHRIST

PREVIOUS DISCUSSION...EXTENDED PERIOD OPENS WITH DRY ZONAL FLOW
OVER MONTANA. BY THURSDAY MORNING FLOW BEGINS TO TURN INCREASINGLY
SOUTHWEST WITH UPPER TROF PUSHING ACROSS THE WEST COAST AND INTO
THE GREAT BASIN. MODELS IN GOOD AGREEMENT WITH SLOWLY LIFTING THIS
TROF INTO THE NORTHERN PLAINS OVER THE WEEKEND THEN FORMING A
CLOSED LOW IN THE UPPER MIDWEST EARLY NEXT WEEK. SOME INDICATION
OF THE FIRST GOOD LOW LEVEL JET FROM THE GULF INTO THE NORTHERN
PLAINS DEVELOPING ON THURSDAY. THIS WILL INCREASE THE MOISTURE
AVAILABLE FOR THE INCOMING SYSTEM...WHICH ALREADY WILL CONTAIN MID
TO HIGH LEVEL PACIFIC MOISTURE...LEADING TO THE POTENTIAL FOR
SIGNIFICANT RAINFALL FOR MUCH OF THE REGION SOMETIME OVER THE
WEEKEND. EBERT

&&

.AVIATION...
MAINLY VFR CEILINGS ARE EXPECTED THOUGH THE TAF CYCLE.
HOWEVER...SOME REDUCED VISIBILITIES ARE TEMPORARILY POSSIBLE IN
SHOWER AND THUNDERSTORM ACTIVITY AS IT PUSHES THROUGH ALONG WITH
AN ASSOCIATED COLD FRONT. MVFR AND IFR CONDITIONS ARE POSSIBLE AT
TIMES. LIGHT WESTERLY WINDS TONIGHT WILL INCREASE ON TUESDAY TO A
RANGE OF 15 TO 25 KTS WITH GUSTS AS HIGH AS 35 KTS. GROUND
OPERATIONS AT THE TERMINALS MAY WANT TO BE AWARE OF VERTICAL WIND
SHEAR DURING THE DAY TOMORROW AS WELL. MALIAWCO

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 6 AM TO 9 PM MDT TUESDAY FOR MTZ137.

RED FLAG WARNING UNTIL 9 PM MDT TUESDAY FOR MTZ120-122-134>136.

LAKE WIND ADVISORY UNTIL 9 PM MDT TUESDAY FOR FOR FORT PECK
LAKEFORT PECK LAKE.

&&

$$

WEATHER.GOV/GLASGOW