000
FXUS65 KGGW 240307
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
907 PM MDT THU MAY 23 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...
UPDATE...MINOR TWEAKS TO THE SHORT TERM TONIGHT. ADJUSTED SKY
COVER AND POPS TO CURRENT TRENDS AS WEAK CONVECTION AND SHOWER
ACTIVITY MOVES NORTHWARD AND JUST BEGAN TO AFFECT THE SOUTHWEST
ZONES. MODEL GUIDANCE STILL HINTS AT PRECIP SPREADING EASTWARD
SLIGHTLY TO AFFECT THE MISSOURI RIVER VALLEY...SO DECIDED TO LEAVE
THAT IN. ALSO ADJUSTED WINDS IN THE SOUTHEAST AS SUSTAINED WINDS
AND GUSTS REMAIN QUITE HIGH...BUT STILL LOOK TO TAPER OFF THROUGH
THE NIGHT. OTHERWISE...FORECAST LOOKS GOOD. BARNWELL

PREVIOUS SHORT TERM DISCUSSION...WATER VAPOR IMAGERY AND 500 MB
HEIGHT FIELD SHOWS A HIGHLY AMPLIFIED AND DYNAMIC WEATHER PATTERN
ACROSS THE CONUS. FOR NORTHEAST MONTANA...THE OBVIOUS AND GREATEST
IMPACTS PERTAIN TO THE NEAR-STATIONARY OR SLIGHTLY RETRO-GRADING
LARGE LOW- PRESSURE SYSTEM OVER THE PACIFIC NORTHWEST AND NORTHERN
ROCKIES REGIONS THROUGHOUT THE SHORT TERM FORECAST PERIOD.

FORECAST CHALLENGES WILL FOCUS ON THE STRONG...YET DIMINISHING WINDS
TONIGHT AND POSSIBLE SEVERE THUNDERSTORMS SATURDAY AFTERNOON AND EVENING.

ALTHOUGH A FEW LOCATIONS BRIEFLY REACHED SUSTAINED WINDS OF 40
MPH TODAY...IT DID NOT LAST MORE THAN 15 TO 30 MINUTES AT A TIME.
WE CLOSELY WATCHED AREA WIND OBSERVATIONS AND IT LOOKS LIKE IT
WAS A GOOD CALL TO HOLD BACK AND NOT ISSUE A HIGH WIND
WARNING...BUT IT WAS VERY CLOSE.

THIS REGIONAL STORM SYSTEM SEEMS TO BE DIRECTING SUBSTANTIAL
AMOUNTS OF MOISTURE FROM BOTH THE PACIFIC AND GULF OF MEXICO
NORTHWARD THROUGH THE ROCKY MOUNTAINS AND HIGH PLAINS REGIONS.

CHOSE TO GIVE THE POPS GRIDS A BIT MORE FINE TUNING GIVEN
CONTINUED RUN TO RUN CONSISTENCY AND GOOD CONSENSUS BETWEEN THE
SHORT TERM MODEL SOLUTIONS. AFTER SPENDING MOST OF THE DAY TODAY
THROUGH CENTRAL MONTANA...THE SCATTERED SHOWERS AND A FEW
THUNDERSTORMS WILL LIKELY INCREASE AND SPREAD EASTWARD TO IMPACT
MORE OF OUR WESTERN CWA. THEN...THROUGH THE MIDNIGHT
HOURS...EXPECT SHOWERS TO ROTATE AROUND AND EASTWARD THROUGH OUR
NORTHERN TIER ZONES.

FRIDAY WILL BRING GENERALLY CLEARING SKIES AND NO PRECIP...FOR
SITES SOUTH OF THE NORTHERN TIER...AS THE NORTHWESTERN STATES LOW
PRESSURE SYSTEM IS PUSHED BACK BY HIGHER PRESSURES FROM THE
SOUTHEAST AMID SOME MODERATE SUBSIDENCE.

SATURDAY...WITH A SHORT WAVE IMPULSE RIDING ALONG THE
SOUTHWESTERLY FLOW ALOFT...CONVECTIVE PARAMETERS FAVOR THE
DEVELOPMENT OF STRONG TO SEVERE THUNDERSTORMS THROUGH SATURDAY
NIGHT. LATE MORNING SHOWERS ARE EXPECTED TO DEVELOP GENERALLY
ALONG A LINE FROM WIBAUX COUNTY NORTHWESTWARD THROUGH NORTHERN
VALLEY COUNTY. LIFTED INDEX VALUES FROM -4 TO -8 ARE FORECAST FOR
THE EASTERN TWO-THIRDS OF OUR CWA. 1000 TO 2000 J/KG OF CAPE WILL
SPREAD THROUGH THE SAME REGION AND EVEN PUSH A BIT MORE WESTWARD
SATURDAY EVENING. CHOSE TO INCLUDE WIND AND HAIL WORDING IN THE
FORECAST FOR SATURDAY AND SATURDAY NIGHT. BMICKELSON

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
THE GOING FORECAST IN OVERALL EXCELLENT SHAPE DEPICTING UNSETTLED
CONDITIONS AS NORTHEAST MONTANA REMAINS UNDER THE INFLUENCE OF AN
UPPER TROUGH THROUGH THE PERIOD. THE ONLY TWEAK MADE WAS TO TREND
UP POPS FOR SATURDAY EVENING AS EXCELLENT POTENTIAL FOR STRONG TO
SEVERE THUNDERSTORM ACTIVITY WILL CONTINUE ACROSS THE EAST THROUGH
THE EVENING HOURS. GILCHRIST

PREVIOUS DISCUSSION...UPPER TROF ALONG THE WEST COAST WILL
CONTINUE TO DOMINATE THE WEATHER PATTERN THROUGH THE EXTENDED
PERIOD...RESULTING IN UNSETTLED WEATHER AND NEAR NORMAL
TEMPERATURES.

CLOSED LOW CURRENTLY OVER THE PACIFIC NORTHWEST EXPECTED TO LIFT
INTO WESTERN CANADA DURING THE WEEKEND. WITH INVERTED TROF/DRY
LINE IN PLACE OVER EASTERN MONTANA...WITH SOUTHEAST LOW LEVEL FLOW
SPREADING GULF MOISTURE INTO THE NORTHERN PLAINS ALONG WITH
ANOTHER UPPER LEVEL SOUTHWEST JET CROSSING THE NORTHERN ROCKIES
EXPECT ORGANIZED CONVECTION MAINLY OVER THE EASTERN ZONES SATURDAY
EVENING.

PATTERN FOR THE REMAINDER OF THE PERIOD IS MORE DISORGANIZED WITH
GREATER MODEL SPREAD. OVERALL PATTERN IS FOR WEST COAST TROF TO
DIG INTO THE DESERT SOUTHWEST WITH SOME SPLITTING OCCURRING AS
ANOTHER UPPER LOW SLIDES FROM ALASKA TOWARD THE PACIFIC NORTHWEST.
SOME HINTS IN THE GEFS/GEM OF RIDGE TILTING BACK INTO THE NORTHERN
PLAINS AROUND MID WEEK TO SHUT OFF CONVECTION BUT WITH MODEL
SPREAD KEPT POPS NEAR CLIMO. EBERT

&&

.AVIATION...
VFR WITH MID TO HIGH CLOUDS THROUGH THIS EVENING. SHOWERS AND/OR
THUNDERSTORMS COULD IMPACT THE TERMINALS OVERNIGHT WITH BRIEF
MVFR CONDITIONS. A LOWER CEILING MVFR WILL BUILD INTO ALL THE THE
TERMINALS EARLY FRIDAY MORNING...LINGERING THROUGH MIDDAY BEFORE
SKIES CLEAR IN THE EARLY AFTERNOON.

STRONG AND GUSTY SOUTHEAST WINDS WILL CONTINUE INTO EARLY FRIDAY
MORNING...BEFORE GOING WESTERLY AND DECREASING TO 10 TO 20 KTS BY
MID MORNING.


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 4 AM MDT FRIDAY FOR FORT PECK LAKE FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 232127
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
327 PM MDT THU MAY 23 2013

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

WATER VAPOR IMAGERY AND 500 MB HEIGHT FIELD SHOWS A HIGHLY
AMPLIFIED AND DYNAMIC WEATHER PATTERN ACROSS THE CONUS. FOR
NORTHEAST MONTANA...THE OBVIOUS AND GREATEST IMPACTS PERTAIN TO
THE NEAR-STATIONARY OR SLIGHTLY RETRO-GRADING LARGE LOW-PRESSURE
SYSTEM OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES REGIONS
THROUGHOUT THE SHORT TERM FORECAST PERIOD.

FORECAST CHALLENGES WILL FOCUS ON THE STRONG...YET DIMINISHING WINDS
TONIGHT AND POSSIBLE SEVERE THUNDERSTORMS SATURDAY AFTERNOON AND EVENING.

ALTHOUGH A FEW LOCATIONS BRIEFLY REACHED SUSTAINED WINDS OF 40
MPH TODAY...IT DID NOT LAST MORE THAN 15 TO 30 MINUTES AT A TIME.
WE CLOSELY WATCHED AREA WIND OBSERVATIONS AND IT LOOKS LIKE IT
WAS A GOOD CALL TO HOLD BACK AND NOT ISSUE A HIGH WIND
WARNING...BUT IT WAS VERY CLOSE.

THIS REGIONAL STORM SYSTEM SEEMS TO BE DIRECTING SUBSTANTIAL
AMOUNTS OF MOISTURE FROM BOTH THE PACIFIC AND GULF OF MEXICO
NORTHWARD THROUGH THE ROCKY MOUNTAINS AND HIGH PLAINS REGIONS.

CHOSE TO GIVE THE POPS GRIDS A BIT MORE FINE TUNING GIVEN
CONTINUED RUN TO RUN CONSISTENCY AND GOOD CONSENSUS BETWEEN THE
SHORT TERM MODEL SOLUTIONS. AFTER SPENDING MOST OF THE DAY TODAY
THROUGH CENTRAL MONTANA...THE SCATTERED SHOWERS AND A FEW
THUNDERSTORMS WILL LIKELY INCREASE AND SPREAD EASTWARD TO IMPACT
MORE OF OUR WESTERN CWA. THEN...THROUGH THE MIDNIGHT
HOURS...EXPECT SHOWERS TO ROTATE AROUND AND EASTWARD THROUGH OUR
NORTHERN TIER ZONES.

FRIDAY WILL BRING GENERALLY CLEARING SKIES AND NO PRECIP...FOR
SITES SOUTH OF THE NORTHERN TIER...AS THE NORTHWESTERN STATES LOW
PRESSURE SYSTEM IS PUSHED BACK BY HIGHER PRESSURES FROM THE
SOUTHEAST AMID SOME MODERATE SUBSIDENCE.

SATURDAY...WITH A SHORT WAVE IMPULSE RIDING ALONG THE
SOUTHWESTERLY FLOW ALOFT...CONVECTIVE PARAMETERS FAVOR THE
DEVELOPMENT OF STRONG TO SEVERE THUNDERSTORMS THROUGH SATURDAY
NIGHT. LATE MORNING SHOWERS ARE EXPECTED TO DEVELOP GENERALLY
ALONG A LINE FROM WIBAUX COUNTY NORTHWESTWARD THROUGH NORTHERN
VALLEY COUNTY. LIFTED INDEX VALUES FROM -4 TO -8 ARE FORECAST FOR
THE EASTERN TWO-THIRDS OF OUR CWA. 1000 TO 2000 J/KG OF CAPE WILL
SPREAD THROUGH THE SAME REGION AND EVEN PUSH A BIT MORE WESTWARD
SATURDAY EVENING. CHOSE TO INCLUDE WIND AND HAIL WORDING IN THE
FORECAST FOR SATURDAY AND SATURDAY NIGHT. BMICKELSON

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
THE GOING FORECAST IN OVERALL EXCELLENT SHAPE DEPICTING UNSETTLED
CONDITIONS AS NORTHEAST MONTANA REMAINS UNDER THE INFLUENCE OF AN
UPPER TROUGH THROUGH THE PERIOD. THE ONLY TWEAK MADE WAS TO TREND
UP POPS FOR SATURDAY EVENING AS EXCELLENT POTENTIAL FOR STRONG TO
SEVERE THUNDERSTORM ACTIVITY WILL CONTINUE ACROSS THE EAST THROUGH
THE EVENING HOURS. GILCHRIST

PREVIOUS DISCUSSION...UPPER TROF ALONG THE WEST COAST WILL
CONTINUE TO DOMINATE THE WEATHER PATTERN THROUGH THE EXTENDED
PERIOD...RESULTING IN UNSETTLED WEATHER AND NEAR NORMAL
TEMPERATURES.

CLOSED LOW CURRENTLY OVER THE PACIFIC NORTHWEST EXPECTED TO LIFT
INTO WESTERN CANADA DURING THE WEEKEND. WITH INVERTED TROF/DRY
LINE IN PLACE OVER EASTERN MONTANA...WITH SOUTHEAST LOW LEVEL FLOW
SPREADING GULF MOISTURE INTO THE NORTHERN PLAINS ALONG WITH
ANOTHER UPPER LEVEL SOUTHWEST JET CROSSING THE NORTHERN ROCKIES
EXPECT ORGANIZED CONVECTION MAINLY OVER THE EASTERN ZONES SATURDAY
EVENING.

PATTERN FOR THE REMAINDER OF THE PERIOD IS MORE DISORGANIZED WITH
GREATER MODEL SPREAD. OVERALL PATTERN IS FOR WEST COAST TROF TO
DIG INTO THE DESERT SOUTHWEST WITH SOME SPLITTING OCCURRING AS
ANOTHER UPPER LOW SLIDES FROM ALASKA TOWARD THE PACIFIC NORTHWEST.
SOME HINTS IN THE GEFS/GEM OF RIDGE TILTING BACK INTO THE NORTHERN
PLAINS AROUND MID WEEK TO SHUT OFF CONVECTION BUT WITH MODEL
SPREAD KEPT POPS NEAR CLIMO. EBERT


&&

.AVIATION...
VFR WITH MID TO HIGH CLOUDS THROUGH THIS EVENING. SHOWERS AND/OR
THUNDERSTORMS COULD IMPACT THE TERMINALS THIS EVENING AND
OVERNIGHT WITH BRIEF MVFR CONDITIONS. A LOWER CEILING MVFR WILL
BUILD INTO ALL THE THE TERMINALS EARLY FRIDAY MORNING...LINGERING
THROUGH MIDDAY.

STRONG AND GUSTY SOUTHEAST WINDS WILL CONTINUE INTO EARLY FRIDAY
MORNING...BEFORE GOING WESTERLY AND DECREASING TO 10 TO 20 KTS BY
MID MORNING. GILCHRIST

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 4 AM MDT FRIDAY FOR FORT PECK LAKE FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 231607 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
1007 AM MDT THU MAY 23 2013

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

SENT AN UPDATE THIS MORNING FOR SOME MINOR ADJUSTMENTS MAINLY
REGARDING POPS. SHORT TERM MODEL CONSENSUS SHRINKS BACK THE
CHANCES FOR PRECIPITATION TOWARD THE WEST ACROSS OUR CWA WHILE
AFTERNOON STORM BUILD OVER CENTRAL MONTANA WHICH MAY JUST CLIP OUR
WESTERN PETROLEUM COUNTY. WINDS ARE ALSO CONCERNING TODAY...BUT
WILL CONTINUE TO CLOSELY MONITOR OBSERVATIONS THROUGHOUT THE DAY.
BMICKELSON

PREVIOUS SHORT TERM DISCUSSION...TODAY AND TONIGHT...MAIN CONCERN
WILL BE THE GUSTY WINDS ACROSS NORTHEAST MONTANA. MODELS ARE IN
EXCELLENT AGREEMENT WITH A LOW LEVEL SOUTHEASTERLY JET TRANSLATING
THROUGH THE FORECAST AREA TODAY INTO TONIGHT. THE 00Z NAM/GFS BOTH
HAVE AROUND 50-55 KT WINDS AT 850MB FOR A TIME THIS EVENING...WITH
THE 00Z ECMWF SLIGHTLY LOWER. BUFKIT SOUNDINGS SHOW THESE LOW
LEVEL WINDS QUITE WELL. GIVEN THAT THE STRONGEST WINDS DO NOT EXIT
TO THE EAST UNTIL NEAR MORNING ON FRIDAY...HAVE GONE AHEAD AND
EXTENDED THE LAKE WIND ADVISORY UNTIL 10Z...OR 4AM FRIDAY MORNING.
LAPSE RATES IN THE LOW LEVELS ALSO APPEAR TO BE BETWEEN 8-10 DEG
CELSIUS PER KM. WILL EXPECT THE ENTIRE CWA TO SEE SUSTAINED WINDS
FOR A TIME THIS AFTERNOON AND EVENING BETWEEN 25 AND 35 MPH. GUSTS
IN THE 45-55 MPH RANGE ARE CERTAINLY A POSSIBILITY. THESE
CONDITIONS ARE A BIT SHY OF HIGH WIND CRITERIA...BUT THE DAY SHIFT
WILL HAVE TO TAKE A VERY CLOSE LOOK AT THE 12Z MODELS AND WILL
NEED TO MONITOR OBSERVATIONS VERY CAREFULLY. NOTING SOME SHOWERS
ENTERING PETROLEUM COUNTY EARLY THIS MORNING AND SO INCREASED POPS
A LITTLE FOR THE WESTERN ZONES FOR TODAY AS WELL.

FRIDAY INTO SATURDAY...UPPER TROUGH WITH CLOSED LOW ACROSS THE
WESTERN U.S. WILL CONTINUE TO PLACE NORTHEAST MONTANA SITUATED
WITHIN A REGIME OF SOUTHWEST FLOW ALOFT. SHORTWAVE FEATURES WILL
PROPAGATE THROUGH THIS FLOW BRINGING CHANCES OF SHOWERS AND
THUNDERSTORMS. THE FIRST POTENTIAL LOOKS TO BE DURING THE MORNING
HOURS ON FRIDAY...LIFTING NORTH OF THE BORDER INTO SASKATCHEWAN BY
FRIDAY AFTERNOON AND EVENING. THEREFORE...FOR THE CWA THUNDERSTORM
POTENTIAL SHOULD BE QUITE LIMITED AND SO LOWERED POPS QUITE A BIT
FOR FRIDAY EVENING AND FRIDAY NIGHT. SATURDAY COULD BE VERY BUSY
ACROSS NORTHEAST MONTANA. LOW LEVEL SE FLOW WILL PUMP GULF OF
MEXICO MOISTURE INTO THE REGION. THE 850MB TEMPERATURES WILL BE
RISING AND SO WITH A WARM MOIST LOW LEVEL BOUNDARY LAYER IN
PLACE...NOTING A NICE THETA-E RIDGE SETTING UP ACROSS THE CWA.
BUFKIT SOUNDINGS CLEARLY INDICATE MID LEVEL DRY AIR ACROSS THE CWA
AS WELL. THERE IS ALSO GOOD 0-6 KM DIRECTIONAL WIND SHEAR WITH
ABOUT 35 KTS OF SPEED SHEAR...ESPECIALLY IN THE EASTERN ZONES.
CAPE MAY RANGE BETWEEN 1500-2000 J/KG FOR A TIME IN THE EASTERN
ZONES AS WELL SATURDAY EVENING...WITH LI APPROACHING -4 TO -8 AND
TOTAL TOTALS RISING ABOVE 60. SHORTWAVE ENERGY ALSO APPROACHES
THIS THERMODYNAMIC ENVIRONMENT AT JUST THE RIGHT TIME SATURDAY
AFTERNOON AND EVENING THAT THE COMBINATION SHOULD BE HIGHLY
CONDUCIVE FOR CONVECTION INITIATION. THERE IS ALSO EXCELLENT
AGREEMENT AND SUPPORT FOR THESE CONDITIONS IN THE 00Z
NAM...GFS...AND THE ECMWF. WITH MODELS CONVERGING ON SATURDAY BEING
THE BEST OPPORTUNITY IN THE SHORT TERM FOR CONVECTION...THERE IS
MUCH HIGHER CONFIDENCE IN THIS FORECAST. DO EXPECT SOME OF THESE
STORMS TO BECOME PARTICULARLY STRONG...AND POSSIBLY SEVERE. GUSTY
WINDS AND HAIL SEEM TO BE CONCERNS GIVEN THESE CONDITIONS. WITH
THE UPPER LEVEL WAVE TAPPING INTO THE INSTABILITY...AND DECENT
DIFFLUENT FLOW ALOFT IN PLACE...VERTICAL ASCENT AND LOWERING
PRESSURES WILL BE VERY FAVORED. FUTURE SHIFTS WILL BE ABLE TO
ASSESS THE CAPE/SHEAR PROFILE AS WELL AS OTHER INSTABILITY PARAMETERS
AND BETTER DETERMINE THE MOST LIKELY MODE OF CONVECTION...AS WELL
AS PRECISE TIMING AND PLACEMENT. THIS IS BECAUSE MUCH OF THE
PRECISE DETAILS OF THIS PORTION OF THE FORECAST WILL BE DEPENDENT
UPON MESOSCALE PROCESSES WHICH ARE DIFFICULT TO DETERMINE MORE
THAN A COUPLE OF DAYS OUT IN THE FORECAST PERIOD. MALIAWCO


.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
UPPER TROF ALONG THE WEST COAST WILL CONTINUE TO DOMINATE THE
WEATHER PATTERN THROUGH THE EXTENDED PERIOD...RESULTING IN
UNSETTLED WEATHER AND NEAR NORMAL TEMPERATURES.

CLOSED LOW CURRENTLY OVER THE PACIFIC NORTHWEST EXPECTED TO LIFT
INTO WESTERN CANADA DURING THE WEEKEND. WITH INVERTED TROF/DRY
LINE IN PLACE OVER EASTERN MONTANA...WITH SOUTHEAST LOW LEVEL FLOW
SPREADING GULF MOISTURE INTO THE NORTHERN PLAINS ALONG WITH
ANOTHER UPPER LEVEL SOUTHWEST JET CROSSING THE NORTHERN ROCKIES
EXPECT ORGANIZED CONVECTION MAINLY OVER THE EASTERN ZONES SATURDAY
EVENING.

PATTERN FOR THE REMAINDER OF THE PERIOD IS MORE DISORGANIZED WITH
GREATER MODEL SPREAD. OVERALL PATTERN IS FOR WEST COAST TROF TO
DIG INTO THE DESERT SOUTHWEST WITH SOME SPLITTING OCCURRING AS
ANOTHER UPPER LOW SLIDES FROM ALASKA TOWARD THE PACIFIC NORTHWEST.
SOME HINTS IN THE GEFS/GEM OF RIDGE TILTING BACK INTO THE NORTHERN
PLAINS AROUND MID WEEK TO SHUT OFF CONVECTION BUT WITH MODEL
SPREAD KEPT POPS NEAR CLIMO. EBERT


&&

.AVIATION...
VFR WITH MID TO HIGH CLOUDS. SHOWERS OR THUNDERSTORMS COULD IMPACT
KGGW BY THE END OF THE TAF CYCLE. STRONG AND GUSTY SOUTHEAST WINDS
EXPECTED ACROSS THE REGION AGAIN TODAY.


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 4 AM MDT FRIDAY FOR FORT PECK LAKE FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 231002
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
402 AM MDT THU MAY 23 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
TODAY AND TONIGHT...MAIN CONCERN WILL BE THE GUSTY WINDS ACROSS
NORTHEAST MONTANA. MODELS ARE IN EXCELLENT AGREEMENT WITH A LOW
LEVEL SOUTHEASTERLY JET TRANSLATING THROUGH THE FORECAST AREA
TODAY INTO TONIGHT. THE 00Z NAM/GFS BOTH HAVE AROUND 50-55 KT
WINDS AT 850MB FOR A TIME THIS EVENING...WITH THE 00Z ECMWF
SLIGHTLY LOWER. BUFKIT SOUNDINGS SHOW THESE LOW LEVEL WINDS QUITE
WELL. GIVEN THAT THE STRONGEST WINDS DO NOT EXIT TO THE EAST UNTIL
NEAR MORNING ON FRIDAY...HAVE GONE AHEAD AND EXTENDED THE LAKE
WIND ADVISORY UNTIL 10Z...OR 4AM FRIDAY MORNING. LAPSE RATES IN
THE LOW LEVELS ALSO APPEAR TO BE BETWEEN 8-10 DEG CELSIUS PER KM.
WILL EXPECT THE ENTIRE CWA TO SEE SUSTAINED WINDS FOR A TIME THIS
AFTERNOON AND EVENING BETWEEN 25 AND 35 MPH. GUSTS IN THE 45-55
MPH RANGE ARE CERTAINLY A POSSIBILITY. THESE CONDITIONS ARE A BIT
SHY OF HIGH WIND CRITERIA...BUT THE DAY SHIFT WILL HAVE TO TAKE A
VERY CLOSE LOOK AT THE 12Z MODELS AND WILL NEED TO MONITOR
OBSERVATIONS VERY CAREFULLY. NOTING SOME SHOWERS ENTERING
PETROLEUM COUNTY EARLY THIS MORNING AND SO INCREASED POPS A LITTLE
FOR THE WESTERN ZONES FOR TODAY AS WELL.

FRIDAY INTO SATURDAY...UPPER TROUGH WITH CLOSED LOW ACROSS THE
WESTERN U.S. WILL CONTINUE TO PLACE NORTHEAST MONTANA SITUATED
WITHIN A REGIME OF SOUTHWEST FLOW ALOFT. SHORTWAVE FEATURES WILL
PROPAGATE THROUGH THIS FLOW BRINGING CHANCES OF SHOWERS AND
THUNDERSTORMS. THE FIRST POTENTIAL LOOKS TO BE DURING THE MORNING
HOURS ON FRIDAY...LIFTING NORTH OF THE BORDER INTO SASKATCHEWAN BY
FRIDAY AFTERNOON AND EVENING. THEREFORE...FOR THE CWA THUNDERSTORM
POTENTIAL SHOULD BE QUITE LIMITED AND SO LOWERED POPS QUITE A BIT
FOR FRIDAY EVENING AND FRIDAY NIGHT. SATURDAY COULD BE VERY BUSY
ACROSS NORTHEAST MONTANA. LOW LEVEL SE FLOW WILL PUMP GULF OF
MEXICO MOISTURE INTO THE REGION. THE 850MB TEMPERATURES WILL BE
RISING AND SO WITH A WARM MOIST LOW LEVEL BOUNDARY LAYER IN
PLACE...NOTING A NICE THETA-E RIDGE SETTING UP ACROSS THE CWA.
BUFKIT SOUNDINGS CLEARLY INDICATE MID LEVEL DRY AIR ACROSS THE CWA
AS WELL. THERE IS ALSO GOOD 0-6 KM DIRECTIONAL WIND SHEAR WITH
ABOUT 35 KTS OF SPEED SHEAR...ESPECIALLY IN THE EASTERN ZONES.
CAPE MAY RANGE BETWEEN 1500-2000 J/KG FOR A TIME IN THE EASTERN
ZONES AS WELL SATURDAY EVENING...WITH LI APPROACHING -4 TO -8 AND
TOTAL TOTALS RISING ABOVE 60. SHORTWAVE ENERGY ALSO APPROACHES
THIS THERMODYNAMIC ENVIRONMENT AT JUST THE RIGHT TIME SATURDAY
AFTERNOON AND EVENING THAT THE COMBINATION SHOULD BE HIGHLY
CONDUCIVE FOR CONVECTION INITIATION. THERE IS ALSO EXCELLENT
AGREEMENT AND SUPPORT FOR THESE CONDITIONS IN THE 00Z
NAM...GFS...AND THE ECMWF. WITH MODELS CONVERGING ON SATURDAY BEING
THE BEST OPPORTUNITY IN THE SHORT TERM FOR CONVECTION...THERE IS
MUCH HIGHER CONFIDENCE IN THIS FORECAST. DO EXPECT SOME OF THESE
STORMS TO BECOME PARTICULARLY STRONG...AND POSSIBLY SEVERE. GUSTY
WINDS AND HAIL SEEM TO BE CONCERNS GIVEN THESE CONDITIONS. WITH
THE UPPER LEVEL WAVE TAPPING INTO THE INSTABILITY...AND DECENT
DIFFLUENT FLOW ALOFT IN PLACE...VERTICAL ASCENT AND LOWERING
PRESSURES WILL BE VERY FAVORED. FUTURE SHIFTS WILL BE ABLE TO
ASSESS THE CAPE/SHEAR PROFILE AS WELL AS OTHER INSTABILITY PARAMETERS
AND BETTER DETERMINE THE MOST LIKELY MODE OF CONVECTION...AS WELL
AS PRECISE TIMING AND PLACEMENT. THIS IS BECAUSE MUCH OF THE
PRECISE DETAILS OF THIS PORTION OF THE FORECAST WILL BE DEPENDENT
UPON MESOSCALE PROCESSES WHICH ARE DIFFICULT TO DETERMINE MORE
THAN A COUPLE OF DAYS OUT IN THE FORECAST PERIOD. MALIAWCO


.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
UPPER TROF ALONG THE WEST COAST WILL CONTINUE TO DOMINATE THE
WEATHER PATTERN THROUGH THE EXTENDED PERIOD...RESULTING IN
UNSETTLED WEATHER AND NEAR NORMAL TEMPERATURES.

CLOSED LOW CURRENTLY OVER THE PACIFIC NORTHWEST EXPECTED TO LIFT
INTO WESTERN CANADA DURING THE WEEKEND. WITH INVERTED TROF/DRY
LINE IN PLACE OVER EASTERN MONTANA...WITH SOUTHEAST LOW LEVEL FLOW
SPREADING GULF MOISTURE INTO THE NORTHERN PLAINS ALONG WITH
ANOTHER UPPER LEVEL SOUTHWEST JET CROSSING THE NORTHERN ROCKIES
EXPECT ORGANIZED CONVECTION MAINLY OVER THE EASTERN ZONES SATURDAY
EVENING.

PATTERN FOR THE REMAINDER OF THE PERIOD IS MORE DISORGANIZED WITH
GREATER MODEL SPREAD. OVERALL PATTERN IS FOR WEST COAST TROF TO
DIG INTO THE DESERT SOUTHWEST WITH SOME SPLITTING OCCURRING AS
ANOTHER UPPER LOW SLIDES FROM ALASKA TOWARD THE PACIFIC NORTHWEST.
SOME HINTS IN THE GEFS/GEM OF RIDGE TILTING BACK INTO THE NORTHERN
PLAINS AROUND MID WEEK TO SHUT OFF CONVECTION BUT WITH MODEL
SPREAD KEPT POPS NEAR CLIMO. EBERT


&&

.AVIATION...
VFR WITH MID TO HIGH CLOUDS. SHOWERS OR THUNDERSTORMS COULD IMPACT
KGGW BY THE END OF THE TAF CYCLE. STRONG AND GUSTY SOUTHEAST WINDS
EXPECTED ACROSS THE REGION AGAIN TODAY.


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 4 AM MDT FRIDAY FOR FORT PECK LAKE FOR
CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...
GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 230228
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
828 PM MDT WED MAY 22 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
UPDATE...
MINOR ADJUSTMENTS TO SKY COVER AND TEMPERATURES WERE MADE FOR THE
EVENING UPDATE. PUT IN LOW END CHANCE POPS AFTER MIDNIGHT FOR MAINLY
SOUTHWEST PHILLIPS AND PETROLEUM COUNTIES. THERE IS SOME SHOWER
ACTIVITY TO THE SOUTH AND WEST OF THE CWA AND SOME OF THAT MAY TRY
TO SNEAK IN OVERNIGHT AND TOWARDS MORNING AS INDICATED BY THE
HRRR. THERE IS ADDITIONAL SUPPORT FROM THE THE 12Z ECMWF ALTHOUGH
THE 12Z GFS AND THE 00Z NAM ARE BOTH DRY. OTHERWISE THE ATTENTION
WILL TURN TO THE WIND POTENTIAL FOR TOMORROW INTO TOMORROW NIGHT.
LAKE WIND ADVISORY CURRENTLY REMAINS IN EFFECT AND WILL GO UNTIL
MIDNIGHT THURSDAY NIGHT. THIS HEADLINE LOOKS GOOD...BUT MAY NEED
TO CONSIDER EXTENDING UNTIL FRIDAY MORNING AS SOME OF THE GUIDANCE
KEEPS THE WINDS GUSTY UNTIL THEN. WILL MAKE A CAREFUL INSPECTION
OF THE 00Z GUIDANCE AND DISCUSS THOUGHTS WITH THE MORNING PACKAGE.
WILL ALSO ASSESS CONVECTIVE POTENTIAL GOING INTO THE START OF THE
WEEKEND. MALIAWCO

PREVIOUS SHORT TERM DISCUSSION...
A TIGHT SURFACE PRESSURE GRADIENT IS APPARENT OVER CENTRAL AND
EASTERN MONTANA WHERE SOUTHEAST WIND HAS PICKED UP STRONGLY.
MODELS SUGGEST THIS GRADIENT WILL TIGHTEN TONIGHT AND THURSDAY.
THERE IS A WIND ADVISORY FOR FORT PECK LAKE IN EFFECT THAT
CONTINUE THROUGH THURSDAY EVENING. THE SURFACE HIGH OVER SOUTHERN
SASKATCHEWAN WHICH HELPED TO PRODUCE THE PRESSURE GRADIENT IS ALSO
CLEARING CLOUDS OUT OF THE AREA.

NORTHEAST MONTANA REMAINS BETWEEN SYSTEMS IN A NARROW UPPER LEVEL
RIDGE. BUT THE STRONG LOW CHURNING OVER WASHINGTON/OREGON WILL
NUDGE A COLD FRONT OVER THE DIVIDE TONIGHT. WITH PACIFIC MOISTURE
PICKED UP AND EJECTED NORTH INTO THE REGION...CENTRAL MONTANA CAN
EXPECT SHOWERS AND THUNDERSTORMS TONIGHT AND THURSDAY. SOME OF
THIS ACTIVITY MIGHT AFFECT OUR FAR WESTERN COUNTIES BY THURSDAY.

THURSDAY NIGHT AND FRIDAY...AN EMBEDDED SHORTWAVE SPINNING AROUND
THE LOW WILL SEND ANOTHER COLD FRONT ACROSS NORTHEAST MONTANA
FIRST BRINGING A BETTER CHANCE FOR STORMS IN THE EVENING AND
POSSIBLY ON FRIDAY. BOTH GFS AND THE NAM SUGGEST THE WAVE WILL BE
PUSHED NORTH ACROSS THE INTERNATIONAL BOUNDARY FRIDAY SENDING MOST
STORMS INTO CANADA. SO A FEW THUNDERSTORMS ARE POSSIBLE.

EXPECT NEAR NORMAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES DURING
THE SHORT TERM PERIOD. WIND WILL LIGHTEN UP ON FRIDAY BEHIND THE
FRONT. SCT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE GOING FORECAST LARGELY STANDS AND WELL REPRESENTS THE UPCOMING
EXCELLENT POTENTIAL FOR SHOWERS AND THUNDERSTORMS AS NORTHEAST
MONTANA REMAINS UNDER THE INFLUENCE OF AN UPPER TROUGH THROUGH THE
EXTENDED PERIOD. TIMING INDIVIDUAL DISTURBANCES UNDER THE UPPER
TROUGH WILL BE DIFFICULT...THUS THE MORE BROADBRUSHED FORECAST
LOOKS GOOD. SATURDAY AND POSSIBLE SUNDAY CONTINUE TO LOOK GOOD
FOR STRONGER STORM DEVELOPMENT...ESPECIALLY ACROSS THE EAST WHERE
A STRONG MOISTURE PUSH FROM THE GULF OF MEXICO WILL ALLOW FOR
STEEP LAPSE RATES AND FAVORABLE SHEAR PROFILES. THE ONLY
SIGNIFICANT TWEAK MADE WAS TO TREND DOWN POPS SLIGHTLY FOR FRIDAY
EVENING AS MODELS HAVE TRENDED A BIT DRIER. REMAINDER OF FORECAST
STANDS. GILCHRIST

PREVIOUS DISCUSSION...FRIDAY NIGHT THROUGH SATURDAY NIGHT...A CLOSED
UPPER LEVEL LOW SITUATED OFF OF THE PACIFIC NORTHWEST WILL SEND
LOBES OF SHORTWAVE ENERGY THROUGH SOUTHWEST FLOW ALOFT INTO
NORTHEAST MONTANA THROUGH THE EXTENDED. THE PRECISE TIMING OF
THESE SHORTWAVE FEATURES WILL BE CRITICAL IN DETERMINING THE
POTENTIAL FOR CONVECTION INITIATION ON ANY GIVEN DAY. IF A TIME
OCCURS WHERE THE SHORTWAVE ENERGY TRACKS THROUGH NE MT DURING PEAK
HEATING AND COINCIDENT WITH THE BEST INSTABILITY...THERE COULD BE
RESULTANT STRONG THUNDERSTORM DEVELOPMENT.

BOTH THE 00Z ECMWF AND GFS HAVE BOTH SHIFTED THE VIGOROUS UPPER
LEVEL SHORTWAVE TRACK FURTHER TO THE NORTHWEST INTO ALBERTA AND
SASKATCHEWAN. THE TRACK IS AS SUCH THAT IT WOULD FAVOR THE BEST
CHANCES OF CONVECTION INTO THOSE LOCATIONS AND PERHAPS EXTENDING
INTO THE NORTHERN ZONES OF THE CWA. ANOTHER RIPPLE OF SHORTWAVE
ENERGY PASSES THROUGH THE CWA ON SATURDAY AFTERNOON. THE GFS IS A
BIT STRONGER THAN THE ECMWF AND GIVEN THE DIFFERENCES IN MODEL
SOLUTION HAVE ONLY MADE MINOR TWEAKS TO POPS IN THAT PERIOD.

SUNDAY INTO SUNDAY NIGHT...THE 00Z MODEL SUITE HAS SHOWN BOTH
CONSISTENT AGREEMENT AND EXCELLENT CONTINUITY THAT THIS PERIOD
COULD OFFER THE BEST POTENTIAL FOR THUNDERSTORM DEVELOPMENT
ACROSS THE FORECAST REGION...WITH THE POTENTIAL FOR SOME STRONG
THUNDERSTORMS CAPABLE OF HAIL AND GUSTY WINDS. ACROSS THE CWA IS
THE PRESENCE OF A NICE THETA-E RIDGE INDICATING ABUNDANCE OF WARM
LOW LEVEL MOISTURE. FORECAST SOUNDINGS IN THE MODELS DO SHOW
DRYING AT THE MID LEVELS. CONVECTIVE INDICIES ACROSS THE CWA ARE
ALSO FAVORABLE WITH LIFTED INDICIES SUNDAY AFTERNOON AND EVENING
RANGING BETWEEN -3 AND -7. ALSO NOTED THAT CAPE REACHES AROUND
1000 TO 1500 J/KG. SOUNDINGS FURTHERMORE ARE INDICATING A NICE
VEERING WIND PROFILE WITH A LOW LEVEL EASTERLY 850MB JET OF AROUND
40 KTS. WHILE NOT IMPRESSIVE...THIS DOES PROVIDE DECENT
DIRECTIONAL AND SPEED SHEAR ACROSS THE CWA. PWATS ALSO LOOK TO BE
OVER 1 INCH INDICATING ABUNDANT MOISTURE IN THE VERTICAL COLUMN.
UPPER LEVEL DYNAMICS COULD LINE UP VERY WELL WITH THESE
THERMODYNAMIC PARAMETERS AS MODELS ARE IN EXCELLENT AGREEMENT ON
GOOD DIFFLUENT FLOW ALOFT SUPPORTIVE OF FORCED VERTICAL ASCENT AND
LOWERING PRESSURES. WITH SHORTWAVE ENERGY APPROACHING THE AREA
DURING THE AFTERNOON AND EVENING HOURS...TIMING SHOULD BE
IDEAL...BEING COINCIDENT WITH MAXIMUM HEATING AND BEST
INSTABILITY. WILL NEED TO WATCH THIS CLOSELY OVER THE NEXT SEVERAL
DAYS...HOWEVER...CURRENT THINKING IS THAT GIVEN EXCELLENT MODEL
AGREEMENT...RUN TO RUN CONTINUITY...AND FAVORABLE UPPER LEVEL
DYNAMICS LINING UP IN BOTH IDEAL TIMING AND PLACEMENT WITH
THERMODYNAMIC VARIABLES...SUNDAY AFTERNOON AND EVENING COULD PROVE
TO BE A BUSY WEATHER DAY ACROSS NORTHEAST MONTANA. THIS IS STILL
OUT IN DAY 5 AND SO THERE IS UNCERTAINTY THIS FAR OUT...BUT AS IT
GETS CLOSER...MESOSCALE DETAILS WILL BECOME CLEARER AND SO WILL BE
ABLE TO HAVE A BETTER HANDLE ON THE MODE OF CONVECTION THAT WOULD
OCCUR AS WELL AS BETTER CONFIDENCE ON PRECISE TIMING AND LOCATION.

MONDAY AND BEYOND...LONG RANGE GUIDANCE CONTINUES TO KEEP NE MT IN
A SOUTHWEST FLOW ALOFT REGIME...WITH ADDITIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS DEPENDENT ON EMBEDDED SHORTWAVE FEATURES
THAT ARE DIFFICULT TO PINPOINT THAT FAR IN ADVANCE...AND SO
PAINTED THE CWA WITH LOW END CHANCE POPS THROUGH MUCH OF THE EARLY
TO MIDDLE PORTION OF NEXT WEEK. WITH NOT MUCH CHANGE IN THE
OVERALL FLOW PATTERN...WOULD NOT EXPECT MANY FLUCTUATIONS IN
TEMPERATURES...AND SO DID NOT INTRODUCE MUCH IN THE WAY OF WARM
UPS OR COOL DOWNS IN THE EXTENDED PERIOD. MALIAWCO

&&

.AVIATION...
VFR. SCT-BKN MID AND HIGH CLOUDS WILL DECREASE THIS EVENING TO
SCT-SKC. THE BIG STORY OVER THE NEXT 24 HOURS WILL BE STRONG GUSTY
SOUTHEAST WINDS...ESPECIALLY AT KGGW WHICH WILL SEE AN ENHANCED
SURFACE FLOW THANKS TO LOCAL EFFECTS. GILCHRIST

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL MIDNIGHT MDT THURSDAY NIGHT FOR FORT
PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND
SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 222029
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
229 PM MDT WED MAY 22 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH FRIDAY...
A TIGHT SURFACE PRESSURE GRADIENT IS APPARENT OVER CENTRAL AND
EASTERN MONTANA WHERE SOUTHEAST WIND HAS PICKED UP STRONGLY.
MODELS SUGGEST THIS GRADIENT WILL TIGHTEN TONIGHT AND THURSDAY.
THERE IS A WIND ADVISORY FOR FORT PECK LAKE IN EFFECT THAT
CONTINUE THROUGH THURSDAY EVENING. THE SURFACE HIGH OVER SOUTHERN
SASKATCHEWAN WHICH HELPED TO PRODUCE THE PRESSURE GRADIENT IS ALSO
CLEARING CLOUDS OUT OF THE AREA.

NORTHEAST MONTANA REMAINS BETWEEN SYSTEMS IN A NARROW UPPER LEVEL
RIDGE. BUT THE STRONG LOW CHURNING OVER WASHINGTON/OREGON WILL
NUDGE A COLD FRONT OVER THE DIVIDE TONIGHT. WITH PACIFIC MOISTURE
PICKED UP AND EJECTED NORTH INTO THE REGION...CENTRAL MONTANA CAN
EXPECT SHOWERS AND THUNDERSTORMS TONIGHT AND THURSDAY. SOME OF
THIS ACTIVITY MIGHT AFFECT OUR FAR WESTERN COUNTIES BY THURSDAY.

THURSDAY NIGHT AND FRIDAY...AN EMBEDDED SHORTWAVE SPINNING AROUND
THE LOW WILL SEND ANOTHER COLD FRONT ACROSS NORTHEAST MONTANA
FIRST BRINGING A BETTER CHANCE FOR STORMS IN THE EVENING AND
POSSIBLY ON FRIDAY. BOTH GFS AND THE NAM SUGGEST THE WAVE WILL BE
PUSHED NORTH ACROSS THE INTERNATIONAL BOUNDARY FRIDAY SENDING MOST
STORMS INTO CANADA. SO A FEW THUNDERSTORMS ARE POSSIBLE.

EXPECT NEAR NORMAL TO SLIGHTLY ABOVE NORMAL TEMPERATURES DURING
THE SHORT TERM PERIOD. WIND WILL LIGHTEN UP ON FRIDAY BEHIND THE
FRONT. SCT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE GOING FORECAST LARGELY STANDS AND WELL REPRESENTS THE UPCOMING
EXCELLENT POTENTIAL FOR SHOWERS AND THUNDERSTORMS AS NORTHEAST
MONTANA REMAINS UNDER THE INFLUENCE OF AN UPPER TROUGH THROUGH THE
EXTENDED PERIOD. TIMING INDIVIDUAL DISTURBANCES UNDER THE UPPER
TROUGH WILL BE DIFFICULT...THUS THE MORE BROAD-BRUSHED FORECAST
LOOKS GOOD. SATURDAY AND POSSIBLE SUNDAY CONTINUE TO LOOK GOOD
FOR STRONGER STORM DEVELOPMENT...ESPECIALLY ACROSS THE EAST WHERE
A STRONG MOISTURE PUSH FROM THE GULF OF MEXICO WILL ALLOW FOR
STEEP LAPSE RATES AND FAVORABLE SHEAR PROFILES. THE ONLY
SIGNIFICANT TWEAK MADE WAS TO TREND DOWN POPS SLIGHTLY FOR FRIDAY
EVENING AS MODELS HAVE TRENDED A BIT DRIER. REMAINDER OF FORECAST
STANDS. GILCHRIST

PREVIOUS DISCUSSION...FRIDAY NIGHT THROUGH SATURDAY NIGHT...A CLOSED
UPPER LEVEL LOW SITUATED OFF OF THE PACIFIC NORTHWEST WILL SEND
LOBES OF SHORTWAVE ENERGY THROUGH SOUTHWEST FLOW ALOFT INTO
NORTHEAST MONTANA THROUGH THE EXTENDED. THE PRECISE TIMING OF
THESE SHORTWAVE FEATURES WILL BE CRITICAL IN DETERMINING THE
POTENTIAL FOR CONVECTION INITIATION ON ANY GIVEN DAY. IF A TIME
OCCURS WHERE THE SHORTWAVE ENERGY TRACKS THROUGH NE MT DURING PEAK
HEATING AND COINCIDENT WITH THE BEST INSTABILITY...THERE COULD BE
RESULTANT STRONG THUNDERSTORM DEVELOPMENT.

BOTH THE 00Z ECMWF AND GFS HAVE BOTH SHIFTED THE VIGOROUS UPPER
LEVEL SHORTWAVE TRACK FURTHER TO THE NORTHWEST INTO ALBERTA AND
SASKATCHEWAN. THE TRACK IS AS SUCH THAT IT WOULD FAVOR THE BEST
CHANCES OF CONVECTION INTO THOSE LOCATIONS AND PERHAPS EXTENDING
INTO THE NORTHERN ZONES OF THE CWA. ANOTHER RIPPLE OF SHORTWAVE
ENERGY PASSES THROUGH THE CWA ON SATURDAY AFTERNOON. THE GFS IS A
BIT STRONGER THAN THE ECMWF AND GIVEN THE DIFFERENCES IN MODEL
SOLUTION HAVE ONLY MADE MINOR TWEAKS TO POPS IN THAT PERIOD.

SUNDAY INTO SUNDAY NIGHT...THE 00Z MODEL SUITE HAS SHOWN BOTH
CONSISTENT AGREEMENT AND EXCELLENT CONTINUITY THAT THIS PERIOD
COULD OFFER THE BEST POTENTIAL FOR THUNDERSTORM DEVELOPMENT
ACROSS THE FORECAST REGION...WITH THE POTENTIAL FOR SOME STRONG
THUNDERSTORMS CAPABLE OF HAIL AND GUSTY WINDS. ACROSS THE CWA IS
THE PRESENCE OF A NICE THETA-E RIDGE INDICATING ABUNDANCE OF WARM
LOW LEVEL MOISTURE. FORECAST SOUNDINGS IN THE MODELS DO SHOW
DRYING AT THE MID LEVELS. CONVECTIVE INDICIES ACROSS THE CWA ARE
ALSO FAVORABLE WITH LIFTED INDICIES SUNDAY AFTERNOON AND EVENING
RANGING BETWEEN -3 AND -7. ALSO NOTED THAT CAPE REACHES AROUND
1000 TO 1500 J/KG. SOUNDINGS FURTHERMORE ARE INDICATING A NICE
VEERING WIND PROFILE WITH A LOW LEVEL EASTERLY 850MB JET OF AROUND
40 KTS. WHILE NOT IMPRESSIVE...THIS DOES PROVIDE DECENT
DIRECTIONAL AND SPEED SHEAR ACROSS THE CWA. PWATS ALSO LOOK TO BE
OVER 1 INCH INDICATING ABUNDANT MOISTURE IN THE VERTICAL COLUMN.
UPPER LEVEL DYNAMICS COULD LINE UP VERY WELL WITH THESE
THERMODYNAMIC PARAMETERS AS MODELS ARE IN EXCELLENT AGREEMENT ON
GOOD DIFFLUENT FLOW ALOFT SUPPORTIVE OF FORCED VERTICAL ASCENT AND
LOWERING PRESSURES. WITH SHORTWAVE ENERGY APPROACHING THE AREA
DURING THE AFTERNOON AND EVENING HOURS...TIMING SHOULD BE
IDEAL...BEING COINCIDENT WITH MAXIMUM HEATING AND BEST
INSTABILITY. WILL NEED TO WATCH THIS CLOSELY OVER THE NEXT SEVERAL
DAYS...HOWEVER...CURRENT THINKING IS THAT GIVEN EXCELLENT MODEL
AGREEMENT...RUN TO RUN CONTINUITY...AND FAVORABLE UPPER LEVEL
DYNAMICS LINING UP IN BOTH IDEAL TIMING AND PLACEMENT WITH
THERMODYNAMIC VARIABLES...SUNDAY AFTERNOON AND EVENING COULD PROVE
TO BE A BUSY WEATHER DAY ACROSS NORTHEAST MONTANA. THIS IS STILL
OUT IN DAY 5 AND SO THERE IS UNCERTAINTY THIS FAR OUT...BUT AS IT
GETS CLOSER...MESOSCALE DETAILS WILL BECOME CLEARER AND SO WILL BE
ABLE TO HAVE A BETTER HANDLE ON THE MODE OF CONVECTION THAT WOULD
OCCUR AS WELL AS BETTER CONFIDENCE ON PRECISE TIMING AND LOCATION.

MONDAY AND BEYOND...LONG RANGE GUIDANCE CONTINUES TO KEEP NE MT IN
A SOUTHWEST FLOW ALOFT REGIME...WITH ADDITIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS DEPENDENT ON EMBEDDED SHORTWAVE FEATURES
THAT ARE DIFFICULT TO PINPOINT THAT FAR IN ADVANCE...AND SO
PAINTED THE CWA WITH LOW END CHANCE POPS THROUGH MUCH OF THE EARLY
TO MIDDLE PORTION OF NEXT WEEK. WITH NOT MUCH CHANGE IN THE
OVERALL FLOW PATTERN...WOULD NOT EXPECT MANY FLUCTUATIONS IN
TEMPERATURES...AND SO DID NOT INTRODUCE MUCH IN THE WAY OF WARM
UPS OR COOL DOWNS IN THE EXTENDED PERIOD. MALIAWCO

&&

.AVIATION...
VFR. SCT-BKN MID AND HIGH CLOUDS WILL DECREASE THIS EVENING TO
SCT-SKC. THE BIG STORY OVER THE NEXT 24 HOURS WILL BE STRONG GUSTY
SOUTHEAST WINDS...ESPECIALLY AT KGGW WHICH WILL SEE AN ENHANCED
SURFACE FLOW THANKS TO LOCAL EFFECTS. GILCHRIST

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL MIDNIGHT MDT THURSDAY NIGHT FOR FORT
PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND
SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 221519 AAA
AFDGGW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
919 AM MDT WED MAY 22 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
A TIGHT SURFACE PRESSURE GRADIENT IS APPARENT OVER CENTRAL MONTANA
WHERE WIND IS PICKING UP STRONGLY. MODELS SUGGEST THIS GRADIENT
WILL TRANSITION EAST OVER NORTHEAST MONTANA WITHIN A FEW HOURS
PICKING UP SOUTHEAST WIND HERE. THERE IS A WIND ADVISORY FOR FORT
PECK LAKE THAT WILL GO IN EFFECT A 10 AM THIS MORNING. THIS
ADVISORY WILL GO THROUGH THURSDAY. THE SURFACE HIGH OVER SOUTHERN
SASKATCHEWAN WHICH IS HELPING TO PRODUCE THE PRESSURE GRADIENT IS
ALSO DRYING THINGS FROM THE EAST. THE MID-LEVEL OVERCAST WILL
DISSIPATE TODAY BRINGING IN CLEARER SKIES BY AFTERNOON AND
EVENING. FEW CHANGES TO THE FORECAST...OTHER THAN WIND AND SKY
GRID ADJUSTMENTS. SCT

PREVIOUS DISCUSSION...
HIGH PRESSURE DROPPING INTO NORTH DAKOTA ALONG WITH NARROW UPPER
RIDGE OVER EASTERN MONTANA FOR DRY CONDITIONS TODAY. STRONG CLOSED
UPPER LOW PUSHING INTO THE PACIFIC NORTHWEST BEGINNING TO DEVELOP
TROF ALONG THE ROCKIES FOR TIGHTENING GRADIENT ACROSS MONTANA
TODAY. STRONG SOUTHEAST WINDS EXPECTED BY LATE THIS MORNING SO
TIMING OF THE START OF THE LAKE WIND ADVISORY LOOKS ON TRACK.

UPPER SYSTEM TO THE WEST MOVES VERY LITTLE OVER THE NEXT FEW DAYS
ALTHOUGH UPPER RIDGE AXIS EXPECTED TO SHIFT INTO THE DAKOTAS.
VORTICITY AROUND THE UPPER LOW GRADUALLY PUSHES THE LOW LEVEL TROF
INTO THE PLAINS...PROVIDING SOME FOCUS FOR CONVECTIVE ACTIVITY
ACROSS MAINLY CENTRAL MONTANA TONIGHT INTO THURSDAY...THEN MOVING
INTO EASTERN MONTANA THURSDAY NIGHT INTO FRIDAY. STRONG SOUTHEAST
LOW LEVEL FLOW WILL CONTINUE AHEAD OF THE FRONT FOR LAKE WIND
CONDITIONS THROUGH THURSDAY EVENING...PERHAPS INTO FRIDAY MORNING.
AS FRONT LIFTS ACROSS NORTHEAST MONTANA ON FRIDAY...COULD GET
DRIER DOWNSLOPE FLOW INTO THE SOUTHWEST ZONES IN THE AFTERNOON.
EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
FRIDAY NIGHT THROUGH SATURDAY NIGHT...A CLOSED UPPER LEVEL LOW
SITUATED OFF OF THE PACIFIC NORTHWEST WILL SEND LOBES OF
SHORTWAVE ENERGY THROUGH SOUTHWEST FLOW ALOFT INTO NORTHEAST
MONTANA THROUGH THE EXTENDED. THE PRECISE TIMING OF THESE
SHORTWAVE FEATURES WILL BE CRITICAL IN DETERMINING THE POTENTIAL
FOR CONVECTION INITIATION ON ANY GIVEN DAY. IF A TIME OCCURS WHERE
THE SHORTWAVE ENERGY TRACKS THROUGH NE MT DURING PEAK HEATING AND
COINCIDENT WITH THE BEST INSTABILITY...THERE COULD BE RESULTANT
STRONG THUNDERSTORM DEVELOPMENT.

BOTH THE 00Z ECMWF AND GFS HAVE BOTH SHIFTED THE VIGOROUS UPPER
LEVEL SHORTWAVE TRACK FURTHER TO THE NORTHWEST INTO ALBERTA AND
SASKATCHEWAN. THE TRACK IS AS SUCH THAT IT WOULD FAVOR THE BEST
CHANCES OF CONVECTION INTO THOSE LOCATIONS AND PERHAPS EXTENDING
INTO THE NORTHERN ZONES OF THE CWA. ANOTHER RIPPLE OF SHORTWAVE
ENERGY PASSES THROUGH THE CWA ON SATURDAY AFTERNOON. THE GFS IS A
BIT STRONGER THAN THE ECMWF AND GIVEN THE DIFFERENCES IN MODEL
SOLUTION HAVE ONLY MADE MINOR TWEAKS TO POPS IN THAT PERIOD.

SUNDAY INTO SUNDAY NIGHT...THE 00Z MODEL SUITE HAS SHOWN BOTH
CONSISTENT AGREEMENT AND EXCELLENT CONTINUITY THAT THIS PERIOD
COULD OFFER THE BEST POTENTIAL FOR THUNDERSTORM DEVELOPMENT
ACROSS THE FORECAST REGION...WITH THE POTENTIAL FOR SOME STRONG
THUNDERSTORMS CAPABLE OF HAIL AND GUSTY WINDS. ACROSS THE CWA IS
THE PRESENCE OF A NICE THETA-E RIDGE INDICATING ABUNDANCE OF WARM
LOW LEVEL MOISTURE. FORECAST SOUNDINGS IN THE MODELS DO SHOW
DRYING AT THE MID LEVELS. CONVECTIVE INDICIES ACROSS THE CWA ARE
ALSO FAVORABLE WITH LIFTED INDICIES SUNDAY AFTERNOON AND EVENING
RANGING BETWEEN -3 AND -7. ALSO NOTED THAT CAPE REACHES AROUND
1000 TO 1500 J/KG. SOUNDINGS FURTHERMORE ARE INDICATING A NICE
VEERING WIND PROFILE WITH A LOW LEVEL EASTERLY 850MB JET OF AROUND
40 KTS. WHILE NOT IMPRESSIVE...THIS DOES PROVIDE DECENT
DIRECTIONAL AND SPEED SHEAR ACROSS THE CWA. PWATS ALSO LOOK TO BE
OVER 1 INCH INDICATING ABUNDANT MOISTURE IN THE VERTICAL COLUMN.
UPPER LEVEL DYNAMICS COULD LINE UP VERY WELL WITH THESE
THERMODYNAMIC PARAMETERS AS MODELS ARE IN EXCELLENT AGREEMENT ON
GOOD DIFFLUENT FLOW ALOFT SUPPORTIVE OF FORCED VERTICAL ASCENT AND
LOWERING PRESSURES. WITH SHORTWAVE ENERGY APPROACHING THE AREA
DURING THE AFTERNOON AND EVENING HOURS...TIMING SHOULD BE
IDEAL...BEING COINCIDENT WITH MAXIMUM HEATING AND BEST
INSTABILITY. WILL NEED TO WATCH THIS CLOSELY OVER THE NEXT SEVERAL
DAYS...HOWEVER...CURRENT THINKING IS THAT GIVEN EXCELLENT MODEL
AGREEMENT...RUN TO RUN CONTINUITY...AND FAVORABLE UPPER LEVEL
DYNAMICS LINING UP IN BOTH IDEAL TIMING AND PLACEMENT WITH
THERMODYNAMIC VARIABLES...SUNDAY AFTERNOON AND EVENING COULD PROVE
TO BE A BUSY WEATHER DAY ACROSS NORTHEAST MONTANA. THIS IS STILL
OUT IN DAY 5 AND SO THERE IS UNCERTAINTY THIS FAR OUT...BUT AS IT
GETS CLOSER...MESOSCALE DETAILS WILL BECOME CLEARER AND SO WILL BE
ABLE TO HAVE A BETTER HANDLE ON THE MODE OF CONVECTION THAT WOULD
OCCUR AS WELL AS BETTER CONFIDENCE ON PRECISE TIMING AND LOCATION.

MONDAY AND BEYOND...LONG RANGE GUIDANCE CONTINUES TO KEEP NE MT IN
A SOUTHWEST FLOW ALOFT REGIME...WITH ADDITIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS DEPENDENT ON EMBEDDED SHORTWAVE FEATURES
THAT ARE DIFFICULT TO PINPOINT THAT FAR IN ADVANCE...AND SO
PAINTED THE CWA WITH LOW END CHANCE POPS THROUGH MUCH OF THE EARLY
TO MIDDLE PORTION OF NEXT WEEK. WITH NOT MUCH CHANGE IN THE
OVERALL FLOW PATTERN...WOULD NOT EXPECT MANY FLUCTUATIONS IN
TEMPERATURES...AND SO DID NOT INTRODUCE MUCH IN THE WAY OF WARM
UPS OR COOL DOWNS IN THE EXTENDED PERIOD. MALIAWCO

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. PERSISTENT
SOUTH EAST WINDS LIKELY TO OCCUR TODAY AND TONIGHT FROM 15 TO 25
KTS WITH SOME GUSTS POTENTIALLY OVER 30 KTS AT THE TERMINAL SITES.
MALIAWCO


&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL MIDNIGHT MDT THURSDAY NIGHT FOR FORT
PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND
SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 221000
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
400 AM MDT WED MAY 22 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
HIGH PRESSURE DROPPING INTO NORTH DAKOTA ALONG WITH NARROW UPPER
RIDGE OVER EASTERN MONTANA FOR DRY CONDITIONS TODAY. STRONG CLOSED
UPPER LOW PUSHING INTO THE PACIFIC NORTHWEST BEGINNING TO DEVELOP
TROF ALONG THE ROCKIES FOR TIGHTENING GRADIENT ACROSS MONTANA
TODAY. STRONG SOUTHEAST WINDS EXPECTED BY LATE THIS MORNING SO
TIMING OF THE START OF THE LAKE WIND ADVISORY LOOKS ON TRACK.

UPPER SYSTEM TO THE WEST MOVES VERY LITTLE OVER THE NEXT FEW DAYS
ALTHOUGH UPPER RIDGE AXIS EXPECTED TO SHIFT INTO THE DAKOTAS.
VORTICITY AROUND THE UPPER LOW GRADUALLY PUSHES THE LOW LEVEL TROF
INTO THE PLAINS...PROVIDING SOME FOCUS FOR CONVECTIVE ACTIVITY
ACROSS MAINLY CENTRAL MONTANA TONIGHT INTO THURSDAY...THEN MOVING
INTO EASTERN MONTANA THURSDAY NIGHT INTO FRIDAY. STRONG SOUTHEAST
LOW LEVEL FLOW WILL CONTINUE AHEAD OF THE FRONT FOR LAKE WIND
CONDITIONS THROUGH THURSDAY EVENING...PERHAPS INTO FRIDAY MORNING.
AS FRONT LIFTS ACROSS NORTHEAST MONTANA ON FRIDAY...COULD GET
DRIER DOWNSLOPE FLOW INTO THE SOUTHWEST ZONES IN THE AFTERNOON.
EBERT


.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
FRIDAY NIGHT THROUGH SATURDAY NIGHT...A CLOSED UPPER LEVEL LOW
SITUATED OFF OF THE PACIFIC NORTHWEST WILL SEND LOBES OF
SHORTWAVE ENERGY THROUGH SOUTHWEST FLOW ALOFT INTO NORTHEAST
MONTANA THROUGH THE EXTENDED. THE PRECISE TIMING OF THESE
SHORTWAVE FEATURES WILL BE CRITICAL IN DETERMINING THE POTENTIAL
FOR CONVECTION INITIATION ON ANY GIVEN DAY. IF A TIME OCCURS WHERE
THE SHORTWAVE ENERGY TRACKS THROUGH NE MT DURING PEAK HEATING AND
COINCIDENT WITH THE BEST INSTABILITY...THERE COULD BE RESULTANT
STRONG THUNDERSTORM DEVELOPMENT.

BOTH THE 00Z ECMWF AND GFS HAVE BOTH SHIFTED THE VIGOROUS UPPER
LEVEL SHORTWAVE TRACK FURTHER TO THE NORTHWEST INTO ALBERTA AND
SASKATCHEWAN. THE TRACK IS AS SUCH THAT IT WOULD FAVOR THE BEST
CHANCES OF CONVECTION INTO THOSE LOCATIONS AND PERHAPS EXTENDING
INTO THE NORTHERN ZONES OF THE CWA. ANOTHER RIPPLE OF SHORTWAVE
ENERGY PASSES THROUGH THE CWA ON SATURDAY AFTERNOON. THE GFS IS A
BIT STRONGER THAN THE ECMWF AND GIVEN THE DIFFERENCES IN MODEL
SOLUTION HAVE ONLY MADE MINOR TWEAKS TO POPS IN THAT PERIOD.

SUNDAY INTO SUNDAY NIGHT...THE 00Z MODEL SUITE HAS SHOWN BOTH
CONSISTENT AGREEMENT AND EXCELLENT CONTINUITY THAT THIS PERIOD
COULD OFFER THE BEST POTENTIAL FOR THUNDERSTORM DEVELOPMENT
ACROSS THE FORECAST REGION...WITH THE POTENTIAL FOR SOME STRONG
THUNDERSTORMS CAPABLE OF HAIL AND GUSTY WINDS. ACROSS THE CWA IS
THE PRESENCE OF A NICE THETA-E RIDGE INDICATING ABUNDANCE OF WARM
LOW LEVEL MOISTURE. FORECAST SOUNDINGS IN THE MODELS DO SHOW
DRYING AT THE MID LEVELS. CONVECTIVE INDICIES ACROSS THE CWA ARE
ALSO FAVORABLE WITH LIFTED INDICIES SUNDAY AFTERNOON AND EVENING
RANGING BETWEEN -3 AND -7. ALSO NOTED THAT CAPE REACHES AROUND
1000 TO 1500 J/KG. SOUNDINGS FURTHERMORE ARE INDICATING A NICE
VEERING WIND PROFILE WITH A LOW LEVEL EASTERLY 850MB JET OF AROUND
40 KTS. WHILE NOT IMPRESSIVE...THIS DOES PROVIDE DECENT
DIRECTIONAL AND SPEED SHEAR ACROSS THE CWA. PWATS ALSO LOOK TO BE
OVER 1 INCH INDICATING ABUNDANT MOISTURE IN THE VERTICAL COLUMN.
UPPER LEVEL DYNAMICS COULD LINE UP VERY WELL WITH THESE
THERMODYNAMIC PARAMETERS AS MODELS ARE IN EXCELLENT AGREEMENT ON
GOOD DIFFLUENT FLOW ALOFT SUPPORTIVE OF FORCED VERTICAL ASCENT AND
LOWERING PRESSURES. WITH SHORTWAVE ENERGY APPROACHING THE AREA
DURING THE AFTERNOON AND EVENING HOURS...TIMING SHOULD BE
IDEAL...BEING COINCIDENT WITH MAXIMUM HEATING AND BEST
INSTABILITY. WILL NEED TO WATCH THIS CLOSELY OVER THE NEXT SEVERAL
DAYS...HOWEVER...CURRENT THINKING IS THAT GIVEN EXCELLENT MODEL
AGREEMENT...RUN TO RUN CONTINUITY...AND FAVORABLE UPPER LEVEL
DYNAMICS LINING UP IN BOTH IDEAL TIMING AND PLACEMENT WITH
THERMODYNAMIC VARIABLES...SUNDAY AFTERNOON AND EVENING COULD PROVE
TO BE A BUSY WEATHER DAY ACROSS NORTHEAST MONTANA. THIS IS STILL
OUT IN DAY 5 AND SO THERE IS UNCERTAINTY THIS FAR OUT...BUT AS IT
GETS CLOSER...MESOSCALE DETAILS WILL BECOME CLEARER AND SO WILL BE
ABLE TO HAVE A BETTER HANDLE ON THE MODE OF CONVECTION THAT WOULD
OCCUR AS WELL AS BETTER CONFIDENCE ON PRECISE TIMING AND LOCATION.

MONDAY AND BEYOND...LONG RANGE GUIDANCE CONTINUES TO KEEP NE MT IN
A SOUTHWEST FLOW ALOFT REGIME...WITH ADDITIONAL CHANCES FOR
SHOWERS/THUNDERSTORMS DEPENDENT ON EMBEDDED SHORTWAVE FEATURES
THAT ARE DIFFICULT TO PINPOINT THAT FAR IN ADVANCE...AND SO
PAINTED THE CWA WITH LOW END CHANCE POPS THROUGH MUCH OF THE EARLY
TO MIDDLE PORTION OF NEXT WEEK. WITH NOT MUCH CHANGE IN THE
OVERALL FLOW PATTERN...WOULD NOT EXPECT MANY FLUCTUATIONS IN
TEMPERATURES...AND SO DID NOT INTRODUCE MUCH IN THE WAY OF WARM
UPS OR COOL DOWNS IN THE EXTENDED PERIOD. MALIAWCO

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. PERSISTENT
EASTERLY WINDS LIKELY TO OCCUR TODAY AND TONIGHT FROM 15 TO 25 KTS
WITH SOME GUSTS POTENTIALLY OVER 30 KTS AT THE TERMINAL SITES. MALIAWCO

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO MIDNIGHT MDT
THURSDAY NIGHT FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST
PHILLIPS...CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...
PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 220218
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
818 PM MDT TUE MAY 21 2013

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

MODEST UPDATE THIS EVENING. REDUCED OVERNIGHT TEMPERATURES SOME AS
THERE IS SOME CLEARING IN WESTERN PARTS OF THE CWA AND DEWPOINTS
ARE WELL BELOW GUIDANCE VALUES. HRRR AND NAM HINT AT SOME POSSIBLE
LIGHT SHOWERS OVER SOUTHERN PARTS OF THE CWA TONIGHT IN RESPONSE
TO A SUBTLE IMPROVEMENT IN THE UPPER FLOW...SO SPREAD THE SLIGHT
CHANCE FOR A SHOWERS IN THE FORECAST WESTWARD TO PHILLIPS COUNTY.

NEXT SEVERAL DAYS LOOK TO BE SOMEWHAT WINDY AS A STRONG SURFACE
LOW DEVELOPS OVER WESTERN WYOMING AND MONTANA AHEAD OF THE NEXT
LONG WAVE SYSTEM...AND THE LAKE WIND ADVISORY MIGHT BE NEEDED
THROUGH FRIDAY. MARTIN

PREVIOUS DISCUSSION...
AN UPPER LEVEL LOW OVER EASTERN SOUTH DAKOTA WILL
CONTINUE TO DRIVE WRAPAROUND LIGHT SHOWER ACTIVITY OVER THE
SOUTHEAST THIS EVENING. SHOWER ACTIVITY WILL QUICKLY TAPER OFF
AFTER MIDNIGHT AS THE UPPER LOW PUSHES TO THE EAST.

DRY AND WARM CONDITIONS WILL RULE ON WEDNESDAY AS UPPER RIDGING
DOMINATES AHEAD OF AN APPROACHING UPPER TROUGH OVER THE PACIFIC
NORTHWEST. GUSTY SOUTHEAST WINDS WILL ALSO PICK UP DURING THE LATE
MORNING IN RESPONSE TO THE APPROACHING LOW...NECESSITATING A LAKE
WIND ADVISORY THAT WILL LAST INTO LATE THURSDAY EVENING.

SOUTHERLY FLOW ALOFT ASSOCIATED WITH THE APPROACHING UPPER LOW
LOOKS TO BUILD INTO THE WESTERN ZONES BY WEDNESDAY EVENING.
DISTURBANCES IN THIS FLOW WILL CREATE DECENT CHANCES FOR SHOWERS
AND THUNDERSTORMS ACROSS THE WEST INTO THURSDAY. GILCHRIST


.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE UPPER LEVEL RIDGE GETS PUSHED ASIDE THURSDAY NIGHT AND FRIDAY
BY A LOBE OFF THE STRONG PAC-NW CLOSED LOW SWINGING NORTH THROUGH
MONTANA. WEAK INSTABILITY DEVELOPS TO THE SOUTHWEST LATE THURSDAY
SO THE DISTURBANCE COULD GENERATE SCATTERED RAIN SHOWERS AND
ISOLATED THUNDER MAINLY IN THE WESTERN ZONES. A MORE DISTINCT COLD
FRONT WILL PUSH THROUGH THE AREA ON FRIDAY...BUT AGAIN...THE BEST
INSTABILITY AND MOISTURE REMAIN OUTSIDE NORTHEAST MONTANA...
ACCORDING TO THE GFS. THE TIMING IS DIFFERENT IN THE EC...WHICH COULD
BRING THE FRONT INTO THE AREA FRIDAY AFTERNOON WITH INSTABILITY.
WITH MODEL DIFFERENCES ON FRIDAY...WILL LEAVE POPS AS IS. MODEL
DIFFERENCES CONTINUE INTO SATURDAY. THERE COULD BE SHOWERS AND
THUNDER OR NOT...DEPENDING ON THE MODEL. SO AGAIN WILL LEAVE
ALONG. THERE IS AT LEAST THE POTENTIAL WITH THE GFS MODEL TO MATCH
UP A TEMPERATURE BOUNDARY WITH SOME VERY UNSTABLE CONDITIONS...
WHICH COULD LEAD TO SOME ENERGETIC THUNDERSTORMS. SUNDAY LOOKS
LIKE THE BEST DAY FOR TIMING AND LOCATION TO BRING ABOUT POSSIBLY
VERY ENERGETIC STORMS. THE GRIDS HANDLE THIS UNCERTAINTY WELL...SO
FEW CHANGE PAST DAY FOUR. SCT

PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS THURSDAY NIGHT
WITH A CLOSED UPPER TROUGH ACROSS THE WEST AND AN UPPER LEVEL
RIDGE ACROSS THE SOUTHERN U.S. THAT EXTENDS THROUGH THE PLAINS.
THIS PLACES NORTHEAST MONTANA IN DIFFLUENT SOUTHWEST FLOW ALOFT.
THE 00Z MODEL SUITE IS POINTING TO A ROBUST SHORTWAVE PUSHING
THROUGH THE FLOW WHICH COULD LEAD TO ENHANCED DYNAMIC LIFT ACROSS
PARTS OF THE CWA. THE 850MB LEVEL EASTERLY/SOUTHEASTERLY WINDS
WILL HELP TO PUMP IN LOW LEVEL MOISTURE...AND ALSO SUGGEST THE
PRESENCE OF A LOW LEVEL JET WHICH COULD HELP TO FORCE CONVECTION
IF THE OTHER DYNAMIC INGREDIENTS DISCUSSED COME TOGETHER
COINCIDENT LY. DECENT EQUIVALENT POTENTIAL TEMPERATURE RIDGE LOOKS
TO BE IN PLACE ACROSS THE CWA BY FRIDAY AFTERNOON WITH WARMING
TEMPERATURES OUT AHEAD OF THE TROUGH. THE MID LEVELS ALSO LOOK
PRETTY DRY. THIS LEADS TO THE CONCERN THAT SOME STORMS THAT
DEVELOP MAY PRODUCE HAIL. THE 00Z ECMWF FORECAST SOUNDINGS SHOW LI
BETWEEN -1 AND 1 ACROSS THE CWA AND TOTAL TOTALS IN THE UPPER 40S
AND NOT MUCH CAPE. NOTICE A NICE VEERING PROFILE IN THE ECMWF
FORECAST SOUNDINGS WITH ABOUT 40 KTS OF 0-6 KM SPEED SHEAR. THE
GFS SHOWS ACTUALLY HIGHER LIFTED INDEX VALUES AND IS LESS
SUGGESTIVE OF STRONG CONVECTION IN SHORT...THE INGREDIENTS ARE
THERE FOR GOOD THUNDERSTORM DEVELOPMENT BUT SOME PARAMETERS APPEAR
ONLY MARGINAL AND SO CONFIDENCE ON STRONG STORMS IS NOT YET THERE.
WILL NEED TO LOOK AT FUTURE MODEL RUNS FOR CONSISTENCY. TIMING OF
THE SHORTWAVE AS IT INTERSECTS THE THETA-E RIDGE WILL ALSO BE
KEY...RIGHT NOW IT APPEARS THE NORTHERN ZONES AND SOUTHERN
SASKATCHEWAN MAY BE IN THE BEST LOCATION FOR FRIDAY AFTERNOON FOR
CONVECTION INITIATION IF FOLLOWING THE EC GUIDANCE. ANY CONVECTION
SHOULD SLOWLY DWINDLE FRIDAY NIGHT WITH THE LOSS OF DAYTIME
HEATING.

ON SATURDAY...UPPER FLOW PATTERN MAINTAINS SOUTHWEST FLOW ALOFT
OVER THE CWA WITH RIDGE AXIS RUNNING FROM TEXAS...NORTHWESTWARD
THROUGH THE PLAINS AND INTO NE MT. THIS SHOULD ACTUALLY LEAD TO
WARMER TEMPERATURES WHICH COULD LEND TO ENHANCING THE POTENTIAL
FOR CONVECTION INITIATION. NICE UPPER LEVEL DIFFLUENCE IS NOTED
AND SOME OF THE FORECAST SOUNDINGS ARE CERTAINLY INDICATIVE OF
CONVECTIVE POTENTIAL. THERE IS ALSO SOME SUBTLE EMBEDDED SHORTWAVE
ENERGY THAT PUSHES THROUGH SHORTWAVE FLOW ALOFT...BUT NOTHING AS
IMPRESSIVE AS THE WAVE ON FRIDAY.

SUNDAY INTO SUNDAY NIGHT PRESENTLY LOOKS TO BE THE BEST POTENTIAL
FOR THUNDERSTORMS TO DEVELOP WHICH COULD BECOME STRONG IN NATURE.
THERE IS MUCH BETTER AGREEMENT IN BOTH THE ECMWF AND GFS WITH BOTH
FORECAST SOUNDINGS SHOWING LIFTED INDEX VALUES BETWEEN -5 AND -8
ACROSS THE CWA. THE GFS BUFKIT SOUNDING SHOWS AROUND 1500 J/KG OF
CAPE AND TOTAL TOTALS APPROACHING 60. THOUGH A NICE VEERING WIND
PROFILE EXISTS IN BOTH ECMWF/GFS SOUNDINGS... THOUGH WOULD LIKE
TO SEE MORE SPEED SHEAR IN THE SOUNDINGS. SHOULD ALSO POINT OUT
THAT FORECAST SOUNDINGS FROM BOTH MODELS ARE SHOWING PWATS OF OVER
AN INCH. WITH AGAIN DRY AIR PRESENT IN THE MID LEVELS...WOULD BE
CONCERNED ABOUT HAIL FORMATION WITH ANY STORMS. THERE IS AGAIN A
LOW LEVEL 850MB EASTERLY JET THAT FORMS...WHICH SHOULD HELP TO
PUMP IN LOW LEVEL MOISTURE. NICE THETA-E RIDGE AXIS OVER THE CWA
ALONG WITH A COUPLE OF SHORTWAVES THAT PASS OFF TO THE WEST COULD
ALSO HELP PROVIDE DECENT LIFT IF THE TIMING IS RIGHT...AND THAT
WILL BE THE KEY FOR DETERMINING THE OVERALL EXTENT OF THE
THUNDERSTORM POTENTIAL. OF ALL OF THE DAYS IN THE EXTENDED
PERIOD...THIS LOOKS TO BE THE ONE WITH THE BEST MODEL AGREEMENT
AND THE BEST IN TERMS OF VARIOUS INGREDIENTS COMING TOGETHER BOTH
DYNAMICALLY AND THERMODYNAMICALLY THAT ARE COINCIDENT WITH EACH
OTHER. WILL OF COURSE NEED TO WATCH FOR CONTINUITY IN THE MODEL
SOLUTIONS TO DETERMINE IF THIS CONTINUES. WILL ALSO NEED TO HONE
IN ON MESOSCALE DETAILS WHICH ARE DIFFICULT TO DETERMINE THIS FAR
IN ADVANCE. WHERE THESE INGREDIENTS COME TOGETHER...THE PRECISE
TIMING OF THE SHORTWAVE FEATURES...AND HOW EVERYTHING INTERACTS
WITH MESOSCALE PROCESSES WILL DETERMINE THE PRECISE EXTENT OF
CONVECTIVE POTENTIAL.

MONDAY AND BEYOND...NE MT IS EXPECTED TO REMAIN IN SOUTHWEST FLOW
ALOFT WITH THE ECMWF GUIDANCE SUGGESTING PERHAPS THE UPPER
PATTERN COULD BECOME MORE ZONAL LATE NEXT WEEK. THE GFS ON THE
OTHER HAND KEEPS THE OVERALL PATTERN ALOFT FROM THE SOUTHWEST. THIS
OVERALL PATTERN WOULD BE CONSIDERED FAVORABLE FOR A CONTINUED
POTENTIAL FOR CONVECTIVE SHOWERS AND THUNDERSTORMS TO DEVELOP
DEPENDING ON TIMING/TRACK OF SHORTWAVE FEATURES IN THE FLOW. MALIAWCO.

&&

.AVIATION...
PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
CANNOT RULE OUT SOME LOW END VFR/MARGINAL MVFR CEILINGS FOR A TIME
AT KSDY AND KGDV THROUGH TONIGHT. LOOK FOR PERSISTENT 10 TO 20 KT
EASTERLY WINDS THROUGH THE OVERNIGHT...INCREASING TO 15 TO 25 KT
ON WEDNESDAY. MALIAWCO

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 10 AM WEDNESDAY TO MIDNIGHT MDT THURSDAY
NIGHT FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...
CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 212016
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
216 PM MDT TUE MAY 21 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY...
AN UPPER LEVEL LOW OVER EASTERN SOUTH DAKOTA WILL CONTINUE TO
DRIVE WRAPAROUND LIGHT SHOWER ACTIVITY OVER THE SOUTHEAST THIS
EVENING. SHOWER ACTIVITY WILL QUICKLY TAPER OFF AFTER MIDNIGHT AS
THE UPPER LOW PUSHES TO THE EAST.

DRY AND WARM CONDITIONS WILL RULE ON WEDNESDAY AS UPPER RIDGING
DOMINATES AHEAD OF AN APPROACHING UPPER TROUGH OVER THE PACIFIC
NORTHWEST. GUSTY SOUTHEAST WINDS WILL ALSO PICK UP DURING THE LATE
MORNING IN RESPONSE TO THE APPROACHING LOW...NECESSITATING A LAKE
WIND ADVISORY THAT WILL LAST INTO LATE THURSDAY EVENING.

SOUTHERLY FLOW ALOFT ASSOCIATED WITH THE APPROACHING UPPER LOW
LOOKS TO BUILD INTO THE WESTERN ZONES BY WEDNESDAY EVENING.
DISTURBANCES IN THIS FLOW WILL CREATE DECENT CHANCES FOR SHOWERS
AND THUNDERSTORMS ACROSS THE WEST INTO THURSDAY. GILCHRIST

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE UPPER LEVEL RIDGE GETS PUSHED ASIDE THURSDAY NIGHT AND FRIDAY
BY A LOBE OFF THE STRONG PAC-NW CLOSED LOW SWINGING NORTH THROUGH
MONTANA. WEAK INSTABILITY DEVELOPS TO THE SOUTHWEST LATE THURSDAY
SO THE DISTURBANCE COULD GENERATE SCATTERED RAIN SHOWERS AND
ISOLATED THUNDER MAINLY IN THE WESTERN ZONES. A MORE DISTINCT COLD
FRONT WILL PUSH THROUGH THE AREA ON FRIDAY...BUT AGAIN...THE BEST
INSTABILITY AND MOISTURE REMAIN OUTSIDE NORTHEAST MONTANA...
ACCORDING TO THE GFS. THE TIMING IS DIFFERENT IN THE EC...WHICH COULD
BRING THE FRONT INTO THE AREA FRIDAY AFTERNOON WITH INSTABILITY.
WITH MODEL DIFFERENCES ON FRIDAY...WILL LEAVE POPS AS IS. MODEL
DIFFERENCES CONTINUE INTO SATURDAY. THERE COULD BE SHOWERS AND
THUNDER OR NOT...DEPENDING ON THE MODEL. SO AGAIN WILL LEAVE
ALONG. THERE IS AT LEAST THE POTENTIAL WITH THE GFS MODEL TO MATCH
UP A TEMPERATURE BOUNDARY WITH SOME VERY UNSTABLE CONDITIONS...
WHICH COULD LEAD TO SOME ENERGETIC THUNDERSTORMS. SUNDAY LOOKS
LIKE THE BEST DAY FOR TIMING AND LOCATION TO BRING ABOUT POSSIBLY
VERY ENERGETIC STORMS. THE GRIDS HANDLE THIS UNCERTAINTY WELL...SO
FEW CHANGE PAST DAY FOUR. SCT

PREVIOUS DISCUSSION... THE EXTENDED PERIOD BEGINS THURSDAY NIGHT
WITH A CLOSED UPPER TROUGH ACROSS THE WEST AND AN UPPER LEVEL
RIDGE ACROSS THE SOUTHERN U.S. THAT EXTENDS THROUGH THE PLAINS.
THIS PLACES NORTHEAST MONTANA IN DIFFLUENT SOUTHWEST FLOW ALOFT.
THE 00Z MODEL SUITE IS POINTING TO A ROBUST SHORTWAVE PUSHING
THROUGH THE FLOW WHICH COULD LEAD TO ENHANCED DYNAMIC LIFT ACROSS
PARTS OF THE CWA. THE 850MB LEVEL EASTERLY/SOUTHEASTERLY WINDS
WILL HELP TO PUMP IN LOW LEVEL MOISTURE...AND ALSO SUGGEST THE
PRESENCE OF A LOW LEVEL JET WHICH COULD HELP TO FORCE CONVECTION
IF THE OTHER DYNAMIC INGREDIENTS DISCUSSED COME TOGETHER
COINCIDENT LY. DECENT EQUIVALENT POTENTIAL TEMPERATURE RIDGE LOOKS
TO BE IN PLACE ACROSS THE CWA BY FRIDAY AFTERNOON WITH WARMING
TEMPERATURES OUT AHEAD OF THE TROUGH. THE MID LEVELS ALSO LOOK
PRETTY DRY. THIS LEADS TO THE CONCERN THAT SOME STORMS THAT
DEVELOP MAY PRODUCE HAIL. THE 00Z ECMWF FORECAST SOUNDINGS SHOW LI
BETWEEN -1 AND 1 ACROSS THE CWA AND TOTAL TOTALS IN THE UPPER 40S
AND NOT MUCH CAPE. NOTICE A NICE VEERING PROFILE IN THE ECMWF
FORECAST SOUNDINGS WITH ABOUT 40 KTS OF 0-6 KM SPEED SHEAR. THE
GFS SHOWS ACTUALLY HIGHER LIFTED INDEX VALUES AND IS LESS
SUGGESTIVE OF STRONG CONVECTION IN SHORT...THE INGREDIENTS ARE
THERE FOR GOOD THUNDERSTORM DEVELOPMENT BUT SOME PARAMETERS APPEAR
ONLY MARGINAL AND SO CONFIDENCE ON STRONG STORMS IS NOT YET THERE.
WILL NEED TO LOOK AT FUTURE MODEL RUNS FOR CONSISTENCY. TIMING OF
THE SHORTWAVE AS IT INTERSECTS THE THETA-E RIDGE WILL ALSO BE
KEY...RIGHT NOW IT APPEARS THE NORTHERN ZONES AND SOUTHERN
SASKATCHEWAN MAY BE IN THE BEST LOCATION FOR FRIDAY AFTERNOON FOR
CONVECTION INITIATION IF FOLLOWING THE EC GUIDANCE. ANY CONVECTION
SHOULD SLOWLY DWINDLE FRIDAY NIGHT WITH THE LOSS OF DAYTIME
HEATING.

ON SATURDAY...UPPER FLOW PATTERN MAINTAINS SOUTHWEST FLOW ALOFT
OVER THE CWA WITH RIDGE AXIS RUNNING FROM TEXAS...NORTHWESTWARD
THROUGH THE PLAINS AND INTO NE MT. THIS SHOULD ACTUALLY LEAD TO
WARMER TEMPERATURES WHICH COULD LEND TO ENHANCING THE POTENTIAL
FOR CONVECTION INITIATION. NICE UPPER LEVEL DIFFLUENCE IS NOTED
AND SOME OF THE FORECAST SOUNDINGS ARE CERTAINLY INDICATIVE OF
CONVECTIVE POTENTIAL. THERE IS ALSO SOME SUBTLE EMBEDDED SHORTWAVE
ENERGY THAT PUSHES THROUGH SHORTWAVE FLOW ALOFT...BUT NOTHING AS
IMPRESSIVE AS THE WAVE ON FRIDAY.

SUNDAY INTO SUNDAY NIGHT PRESENTLY LOOKS TO BE THE BEST POTENTIAL
FOR THUNDERSTORMS TO DEVELOP WHICH COULD BECOME STRONG IN NATURE.
THERE IS MUCH BETTER AGREEMENT IN BOTH THE ECMWF AND GFS WITH BOTH
FORECAST SOUNDINGS SHOWING LIFTED INDEX VALUES BETWEEN -5 AND -8
ACROSS THE CWA. THE GFS BUFKIT SOUNDING SHOWS AROUND 1500 J/KG OF
CAPE AND TOTAL TOTALS APPROACHING 60. THOUGH A NICE VEERING WIND
PROFILE EXISTS IN BOTH ECMWF/GFS SOUNDINGS... THOUGH WOULD LIKE
TO SEE MORE SPEED SHEAR IN THE SOUNDINGS. SHOULD ALSO POINT OUT
THAT FORECAST SOUNDINGS FROM BOTH MODELS ARE SHOWING PWATS OF OVER
AN INCH. WITH AGAIN DRY AIR PRESENT IN THE MID LEVELS...WOULD BE
CONCERNED ABOUT HAIL FORMATION WITH ANY STORMS. THERE IS AGAIN A
LOW LEVEL 850MB EASTERLY JET THAT FORMS...WHICH SHOULD HELP TO
PUMP IN LOW LEVEL MOISTURE. NICE THETA-E RIDGE AXIS OVER THE CWA
ALONG WITH A COUPLE OF SHORTWAVES THAT PASS OFF TO THE WEST COULD
ALSO HELP PROVIDE DECENT LIFT IF THE TIMING IS RIGHT...AND THAT
WILL BE THE KEY FOR DETERMINING THE OVERALL EXTENT OF THE
THUNDERSTORM POTENTIAL. OF ALL OF THE DAYS IN THE EXTENDED
PERIOD...THIS LOOKS TO BE THE ONE WITH THE BEST MODEL AGREEMENT
AND THE BEST IN TERMS OF VARIOUS INGREDIENTS COMING TOGETHER BOTH
DYNAMICALLY AND THERMODYNAMICALLY THAT ARE COINCIDENT WITH EACH
OTHER. WILL OF COURSE NEED TO WATCH FOR CONTINUITY IN THE MODEL
SOLUTIONS TO DETERMINE IF THIS CONTINUES. WILL ALSO NEED TO HONE
IN ON MESOSCALE DETAILS WHICH ARE DIFFICULT TO DETERMINE THIS FAR
IN ADVANCE. WHERE THESE INGREDIENTS COME TOGETHER...THE PRECISE
TIMING OF THE SHORTWAVE FEATURES...AND HOW EVERYTHING INTERACTS
WITH MESOSCALE PROCESSES WILL DETERMINE THE PRECISE EXTENT OF
CONVECTIVE POTENTIAL.

MONDAY AND BEYOND...NE MT IS EXPECTED TO REMAIN IN SOUTHWEST FLOW
ALOFT WITH THE ECMWF GUIDANCE SUGGESTING PERHAPS THE UPPER
PATTERN COULD BECOME MORE ZONAL LATE NEXT WEEK. THE GFS ON THE
OTHER HAND KEEPS THE OVERALL PATTERN ALOFT FROM THE SOUTHWEST. THIS
OVERALL PATTERN WOULD BE CONSIDERED FAVORABLE FOR A CONTINUED
POTENTIAL FOR CONVECTIVE SHOWERS AND THUNDERSTORMS TO DEVELOP
DEPENDING ON TIMING/TRACK OF SHORTWAVE FEATURES IN THE FLOW. MALIAWCO.

&&

.AVIATION...
MOSTLY VFR THROUGH WEDNESDAY...ALTHOUGH BRIEF MVFR CEILINGS ARE
POSSIBLE TODAY AT KSDY AND KGDV.

THE CLOSED LOW PRESSURE SYSTEM IS NOW CENTERED OVER EASTERN SOUTH
DAKOTA...WITH THE BACK EDGE OF THE LOW LEVEL STRATUS CLOUD DECK
COVERING EASTERN COUNTIES IN NORTHEAST MONTANA THIS MORNING. SO
FAR...SEEING CEILINGS OF AROUND 3.5KFT-4KFT OVER KSDY AND KGDV.
OTHERWISE SATELLITE IMAGERY REVEALS AN OVERCAST OF THIN HIGH
STRATUS OVER KGGW AND KOLF. BY THIS TIME ON WEDNESDAY THE LOW
STRATUS SHOULD HAVE MOVED WELL TO THE EAST

EXPECT WIND TO BECOME EASTERLY TODAY AT 12KT TO 20KT. ON WEDNESDAY
A DEVELOPING SURFACE TROUGH IN THE LEE OF THE NORTHERN ROCKIES
WILL SET UP STRONGER EASTERLY WIND ACROSS THE AREA. EXPECT WIND TO
REACH 15KT TO 25 KT BY AFTERNOON. SCT

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 10 AM WEDNESDAY TO MIDNIGHT MDT THURSDAY
NIGHT FOR FORT PECK LAKE FOR CENTRAL AND SOUTHEAST PHILLIPS...
CENTRAL AND SOUTHERN VALLEY...GARFIELD...MCCONE...PETROLEUM.

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 211522
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
922 AM MDT TUE MAY 21 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
THE GOING FORECAST IS IN OVERALL EXCELLENT SHAPE. ONLY TWEAK WAS
TO TREND UP POPS THIS MORNING GIVEN ONGOING LIGHT SHOWER ACTIVITY
ACROSS THE SOUTHEAST. REMAINDER OF FORECAST WAS UNCHANGED. GILCHRIST

PREVIOUS DISCUSSION...THE SHORT TERM BEGINS WITH THE UPPER LOW OVER THE
EASTERN DAKOTAS SLOWLY MOVING EAST ALLOWING A SHORT LIVED RIDGE TO
SLIDE OVER NORTHEASTERN MONTANA. BY THE END OF THE SHORT TERM ON
THURSDAY ANOTHER UPPER LOW BEGINS TO SLIDE CLOSER TO THE REGION.

THE SHORT TERM WILL FEATURE SLIGHTLY WARMER TEMPERATURES...BUT NOT
MAJOR INCREASE. A FEW SHOWERS TODAY IN THE SOUTHEAST AND DRY
CONDITIONS ELSEWHERE.

WEDNESDAY AND THURSDAY THE APPROACHING UPPER LOW TO THE WEST WILL
START A STEADY RAMPING UP OF EASTERLY WINDS ACROSS THE REGION
WHICH WILL LIKELY REQUIRE A LAKE WIND ADVISORY.

THURSDAY AFTERNOON HAS A POSSIBILITY OF SOME THUNDER IN THE
WESTERN ZONES...HOWEVER CONDITIONS ARE NOT THAT FAVORABLE FOR ANY
FORMING CONVECTION TO MOVE TOO FAR INTO THE REGION.       PROTON

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED PERIOD BEGINS THURSDAY NIGHT WITH A CLOSED UPPER
TROUGH ACROSS THE WEST AND AN UPPER LEVEL RIDGE ACROSS THE
SOUTHERN U.S. THAT EXTENDS THROUGH THE PLAINS. THIS PLACES
NORTHEAST MONTANA IN DIFFLUENT SOUTHWEST FLOW ALOFT. THE 00Z MODEL
SUITE IS POINTING TO A ROBUST SHORTWAVE PUSHING THROUGH THE FLOW
WHICH COULD LEAD TO ENHANCED DYNAMIC LIFT ACROSS PARTS OF THE CWA.
THE 850MB LEVEL EASTERLY/SOUTHEASTERLY WINDS WILL HELP TO PUMP IN
LOW LEVEL MOISTURE...AND ALSO SUGGEST THE PRESENCE OF A LOW LEVEL
JET WHICH COULD HELP TO FORCE CONVECTION IF THE OTHER DYNAMIC
INGREDIENTS DISCUSSED COME TOGETHER COINCIDENT LY. DECENT
EQUIVALENT POTENTIAL TEMPERATURE RIDGE LOOKS TO BE IN PLACE ACROSS
THE CWA BY FRIDAY AFTERNOON WITH WARMING TEMPERATURES OUT AHEAD OF
THE TROUGH. THE MID LEVELS ALSO LOOK PRETTY DRY. THIS LEADS TO THE
CONCERN THAT SOME STORMS THAT DEVELOP MAY PRODUCE HAIL. THE 00Z
ECMWF FORECAST SOUNDINGS SHOW LI BETWEEN -1 AND 1 ACROSS THE CWA
AND TOTAL TOTALS IN THE UPPER 40S AND NOT MUCH CAPE. NOTICE A NICE
VEERING PROFILE IN THE ECMWF FORECAST SOUNDINGS WITH ABOUT 40 KTS
OF 0-6 KM SPEED SHEAR. THE GFS SHOWS ACTUALLY HIGHER LIFTED INDEX
VALUES AND IS LESS SUGGESTIVE OF STRONG CONVECTION IN SHORT...THE
INGREDIENTS ARE THERE FOR GOOD THUNDERSTORM DEVELOPMENT BUT SOME
PARAMETERS APPEAR ONLY MARGINAL AND SO CONFIDENCE ON STRONG STORMS
IS NOT YET THERE. WILL NEED TO LOOK AT FUTURE MODEL RUNS FOR
CONSISTENCY. TIMING OF THE SHORTWAVE AS IT INTERSECTS THE THETA-E
RIDGE WILL ALSO BE KEY...RIGHT NOW IT APPEARS THE NORTHERN ZONES
AND SOUTHERN SASKATCHEWAN MAY BE IN THE BEST LOCATION FOR FRIDAY
AFTERNOON FOR CONVECTION INITIATION IF FOLLOWING THE EC GUIDANCE.
ANY CONVECTION SHOULD SLOWLY DWINDLE FRIDAY NIGHT WITH THE LOSS OF
DAYTIME HEATING.

ON SATURDAY...UPPER FLOW PATTERN MAINTAINS SOUTHWEST FLOW ALOFT
OVER THE CWA WITH RIDGE AXIS RUNNING FROM TEXAS...NORTHWESTWARD
THROUGH THE PLAINS AND INTO NE MT. THIS SHOULD ACTUALLY LEAD TO
WARMER TEMPERATURES WHICH COULD LEND TO ENHANCING THE POTENTIAL
FOR CONVECTION INITIATION. NICE UPPER LEVEL DIFFLUENCE IS NOTED
AND SOME OF THE FORECAST SOUNDINGS ARE CERTAINLY INDICATIVE OF
CONVECTIVE POTENTIAL. THERE IS ALSO SOME SUBTLE EMBEDDED SHORTWAVE
ENERGY THAT PUSHES THROUGH SHORTWAVE FLOW ALOFT...BUT NOTHING AS
IMPRESSIVE AS THE WAVE ON FRIDAY.

SUNDAY INTO SUNDAY NIGHT PRESENTLY LOOKS TO BE THE BEST POTENTIAL
FOR THUNDERSTORMS TO DEVELOP WHICH COULD BECOME STRONG IN NATURE.
THERE IS MUCH BETTER AGREEMENT IN BOTH THE ECMWF AND GFS WITH BOTH
FORECAST SOUNDINGS SHOWING LIFTED INDEX VALUES BETWEEN -5 AND -8
ACROSS THE CWA. THE GFS BUFKIT SOUNDING SHOWS AROUND 1500 J/KG OF
CAPE AND TOTAL TOTALS APPROACHING 60. THOUGH A NICE VEERING WIND
PROFILE EXISTS IN BOTH ECMWF/GFS SOUNDINGS... THOUGH WOULD LIKE
TO SEE MORE SPEED SHEAR IN THE SOUNDINGS. SHOULD ALSO POINT OUT
THAT FORECAST SOUNDINGS FROM BOTH MODELS ARE SHOWING PWATS OF OVER
AN INCH. WITH AGAIN DRY AIR PRESENT IN THE MID LEVELS...WOULD BE
CONCERNED ABOUT HAIL FORMATION WITH ANY STORMS. THERE IS AGAIN A
LOW LEVEL 850MB EASTERLY JET THAT FORMS...WHICH SHOULD HELP TO
PUMP IN LOW LEVEL MOISTURE. NICE THETA-E RIDGE AXIS OVER THE CWA
ALONG WITH A COUPLE OF SHORTWAVES THAT PASS OFF TO THE WEST COULD
ALSO HELP PROVIDE DECENT LIFT IF THE TIMING IS RIGHT...AND THAT
WILL BE THE KEY FOR DETERMINING THE OVERALL EXTENT OF THE
THUNDERSTORM POTENTIAL. OF ALL OF THE DAYS IN THE EXTENDED
PERIOD...THIS LOOKS TO BE THE ONE WITH THE BEST MODEL AGREEMENT
AND THE BEST IN TERMS OF VARIOUS INGREDIENTS COMING TOGETHER BOTH
DYNAMICALLY AND THERMODYNAMICALLY THAT ARE COINCIDENT WITH EACH
OTHER. WILL OF COURSE NEED TO WATCH FOR CONTINUITY IN THE MODEL
SOLUTIONS TO DETERMINE IF THIS CONTINUES. WILL ALSO NEED TO HONE
IN ON MESOSCALE DETAILS WHICH ARE DIFFICULT TO DETERMINE THIS FAR
IN ADVANCE. WHERE THESE INGREDIENTS COME TOGETHER...THE PRECISE
TIMING OF THE SHORTWAVE FEATURES...AND HOW EVERYTHING INTERACTS
WITH MESOSCALE PROCESSES WILL DETERMINE THE PRECISE EXTENT OF
CONVECTIVE POTENTIAL.

MONDAY AND BEYOND...NE MT IS EXPECTED TO REMAIN IN SOUTHWEST FLOW
ALOFT WITH THE ECMWF GUIDANCE SUGGESTING PERHAPS THE UPPER
PATTERN COULD BECOME MORE ZONAL LATE NEXT WEEK. THE GFS ON THE
OTHER HAND KEEPS THE OVERALL PATTERN ALOFT FROM THE SOUTHWEST. THIS
OVERALL PATTERN WOULD BE CONSIDERED FAVORABLE FOR A CONTINUED
POTENTIAL FOR CONVECTIVE SHOWERS AND THUNDERSTORMS TO DEVELOP
DEPENDING ON TIMING/TRACK OF SHORTWAVE FEATURES IN THE FLOW. MALIAWCO.


&&

.AVIATION...
VFR THROUGH WEDNESDAY...ALTHOUGH BRIEF MVFR CEILINGS ARE POSSIBLE
TODAY AT KSDY AND KGDV.

THE CLOSED LOW PRESSURE SYSTEM IS NOW CENTERED OVER EASTERN SOUTH
DAKOTA...WITH THE BACK EDGE OF THE LOW LEVEL STRATUS CLOUD DECK
COVERING EASTERN COUNTIES IN NORTHEAST MONTANA THIS MORNING. SO
FAR...SEEING CEILINGS OF AROUND 3.5KFT-4KFT OVER KSDY AND KGDV.
OTHERWISE SATELLITE IMAGERY REVEALS AN OVERCAST OF THIN HIGH
STRATUS OVER KGGW AND KOLF. BY THIS ON WEDNESDAY THE LOW STRATUS
SHOULD HAVE MOVED WELL TO THE EAST

EXPECT WIND TO BECOME EASTERLY TODAY AT 12KT TO 20KT. ON WEDNESDAY
A DEVELOPING SURFACE TROUGH IN THE LEE OF THE NORTHERN ROCKIES
WILL SET UP STRONGER EASTERLY WIND ACROSS THE AREA. EXPECT WIND TO
REACH 15KT TO 25 KT BY AFTERNOON. SCT

&&

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

&&

$$

WEATHER.GOV/GLASGOW

000
FXUS65 KGGW 210948
AFDGGW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
348 AM MDT TUE MAY 21 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY...
THE SHORT TERM BEGINS WITH THE UPPER LOW OVER THE EASTERN DAKOTAS
SLOWLY MOVING EAST ALLOWING A SHORT LIVED RIDGE TO SLIDE OVER
NORTHEASTERN MONTANA. BY THE END OF THE SHORT TERM ON THURSDAY
ANOTHER UPPER LOW BEGINS TO SLIDE CLOSER TO THE REGION.

THE SHORT TERM WILL FEATURE SLIGHTLY WARMER TEMPERATURES...BUT NOT
MAJOR INCREASE. A FEW SHOWERS TODAY IN THE SOUTHEAST AND DRY
CONDITIONS ELSEWHERE.

WEDNESDAY AND THURSDAY THE APPROACHING UPPER LOW TO THE WEST WILL
START A STEADY RAMPING UP OF EASTERLY WINDS ACROSS THE REGION
WHICH WILL LIKELY REQUIRE A LAKE WIND ADVISORY.

THURSDAY AFTERNOON HAS A POSSIBILITY OF SOME THUNDER IN THE
WESTERN ZONES...HOWEVER CONDITIONS ARE NOT THAT FAVORABLE FOR ANY
FORMING CONVECTION TO MOVE TOO FAR INTO THE REGION.       PROTON

.LONG TERM...THURSDAY NIGHT THROUGH TUESDAY...
THE EXTENDED PERIOD BEGINS THURSDAY NIGHT WITH A CLOSED UPPER
TROUGH ACROSS THE WEST AND AN UPPER LEVEL RIDGE ACROSS THE
SOUTHERN U.S. THAT EXTENDS THROUGH THE PLAINS. THIS PLACES
NORTHEAST MONTANA IN DIFFLUENT SOUTHWEST FLOW ALOFT. THE 00Z MODEL
SUITE IS POINTING TO A ROBUST SHORTWAVE PUSHING THROUGH THE FLOW
WHICH COULD LEAD TO ENHANCED DYNAMIC LIFT ACROSS PARTS OF THE CWA.
THE 850MB LEVEL EASTERLY/SOUTHEASTERLY WINDS WILL HELP TO PUMP IN
LOW LEVEL MOISTURE...AND ALSO SUGGEST THE PRESENCE OF A LOW LEVEL
JET WHICH COULD HELP TO FORCE CONVECTION IF THE OTHER DYNAMIC
INGREDIENTS DISCUSSED COME TOGETHER COINCIDENT LY. DECENT
EQUIVALENT POTENTIAL TEMPERATURE RIDGE LOOKS TO BE IN PLACE ACROSS
THE CWA BY FRIDAY AFTERNOON WITH WARMING TEMPERATURES OUT AHEAD OF
THE TROUGH. THE MID LEVELS ALSO LOOK PRETTY DRY. THIS LEADS TO THE
CONCERN THAT SOME STORMS THAT DEVELOP MAY PRODUCE HAIL. THE 00Z
ECMWF FORECAST SOUNDINGS SHOW LI BETWEEN -1 AND 1 ACROSS THE CWA
AND TOTAL TOTALS IN THE UPPER 40S AND NOT MUCH CAPE. NOTICE A NICE
VEERING PROFILE IN THE ECMWF FORECAST SOUNDINGS WITH ABOUT 40 KTS
OF 0-6 KM SPEED SHEAR. THE GFS SHOWS ACTUALLY HIGHER LIFTED INDEX
VALUES AND IS LESS SUGGESTIVE OF STRONG CONVECTION IN SHORT...THE
INGREDIENTS ARE THERE FOR GOOD THUNDERSTORM DEVELOPMENT BUT SOME
PARAMETERS APPEAR ONLY MARGINAL AND SO CONFIDENCE ON STRONG STORMS
IS NOT YET THERE. WILL NEED TO LOOK AT FUTURE MODEL RUNS FOR
CONSISTENCY. TIMING OF THE SHORTWAVE AS IT INTERSECTS THE THETA-E
RIDGE WILL ALSO BE KEY...RIGHT NOW IT APPEARS THE NORTHERN ZONES
AND SOUTHERN SASKATCHEWAN MAY BE IN THE BEST LOCATION FOR FRIDAY
AFTERNOON FOR CONVECTION INITIATION IF FOLLOWING THE EC GUIDANCE.
ANY CONVECTION SHOULD SLOWLY DWINDLE FRIDAY NIGHT WITH THE LOSS OF
DAYTIME HEATING.

ON SATURDAY...UPPER FLOW PATTERN MAINTAINS SOUTHWEST FLOW ALOFT
OVER THE CWA WITH RIDGE AXIS RUNNING FROM TEXAS...NORTHWESTWARD
THROUGH THE PLAINS AND INTO NE MT. THIS SHOULD ACTUALLY LEAD TO
WARMER TEMPERATURES WHICH COULD LEND TO ENHANCING THE POTENTIAL
FOR CONVECTION INITIATION. NICE UPPER LEVEL DIFFLUENCE IS NOTED
AND SOME OF THE FORECAST SOUNDINGS ARE CERTAINLY INDICATIVE OF
CONVECTIVE POTENTIAL. THERE IS ALSO SOME SUBTLE EMBEDDED SHORTWAVE
ENERGY THAT PUSHES THROUGH SHORTWAVE FLOW ALOFT...BUT NOTHING AS
IMPRESSIVE AS THE WAVE ON FRIDAY.

SUNDAY INTO SUNDAY NIGHT PRESENTLY LOOKS TO BE THE BEST POTENTIAL
FOR THUNDERSTORMS TO DEVELOP WHICH COULD BECOME STRONG IN NATURE.
THERE IS MUCH BETTER AGREEMENT IN BOTH THE ECMWF AND GFS WITH BOTH
FORECAST SOUNDINGS SHOWING LIFTED INDEX VALUES BETWEEN -5 AND -8
ACROSS THE CWA. THE GFS BUFKIT SOUNDING SHOWS AROUND 1500 J/KG OF
CAPE AND TOTAL TOTALS APPROACHING 60. THOUGH A NICE VEERING WIND
PROFILE EXISTS IN BOTH ECMWF/GFS SOUNDINGS... THOUGH WOULD LIKE
TO SEE MORE SPEED SHEAR IN THE SOUNDINGS. SHOULD ALSO POINT OUT
THAT FORECAST SOUNDINGS FROM BOTH MODELS ARE SHOWING PWATS OF OVER
AN INCH. WITH AGAIN DRY AIR PRESENT IN THE MID LEVELS...WOULD BE
CONCERNED ABOUT HAIL FORMATION WITH ANY STORMS. THERE IS AGAIN A
LOW LEVEL 850MB EASTERLY JET THAT FORMS...WHICH SHOULD HELP TO
PUMP IN LOW LEVEL MOISTURE. NICE THETA-E RIDGE AXIS OVER THE CWA
ALONG WITH A COUPLE OF SHORTWAVES THAT PASS OFF TO THE WEST COULD
ALSO HELP PROVIDE DECENT LIFT IF THE TIMING IS RIGHT...AND THAT
WILL BE THE KEY FOR DETERMINING THE OVERALL EXTENT OF THE
THUNDERSTORM POTENTIAL. OF ALL OF THE DAYS IN THE EXTENDED
PERIOD...THIS LOOKS TO BE THE ONE WITH THE BEST MODEL AGREEMENT
AND THE BEST IN TERMS OF VARIOUS INGREDIENTS COMING TOGETHER BOTH
DYNAMICALLY AND THERMODYNAMICALLY THAT ARE COINCIDENT WITH EACH
OTHER. WILL OF COURSE NEED TO WATCH FOR CONTINUITY IN THE MODEL
SOLUTIONS TO DETERMINE IF THIS CONTINUES. WILL ALSO NEED TO HONE
IN ON MESOSCALE DETAILS WHICH ARE DIFFICULT TO DETERMINE THIS FAR
IN ADVANCE. WHERE THESE INGREDIENTS COME TOGETHER...THE PRECISE
TIMING OF THE SHORTWAVE FEATURES...AND HOW EVERYTHING INTERACTS
WITH MESOSCALE PROCESSES WILL DETERMINE THE PRECISE EXTENT OF
CONVECTIVE POTENTIAL.

MONDAY AND BEYOND...NE MT IS EXPECTED TO REMAIN IN SOUTHWEST FLOW
ALOFT WITH THE ECMWF GUIDANCE SUGGESTING PERHAPS THE UPPER
PATTERN COULD BECOME MORE ZONAL LATE NEXT WEEK. THE GFS ON THE
OTHER HAND KEEPS THE OVERALL PATTERN ALOFT FROM THE SOUTHWEST. THIS
OVERALL PATTERN WOULD BE CONSIDERED FAVORABLE FOR A CONTINUED
POTENTIAL FOR CONVECTIVE SHOWERS AND THUNDERSTORMS TO DEVELOP
DEPENDING ON TIMING/TRACK OF SHORTWAVE FEATURES IN THE FLOW. MALIAWCO.


&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT ALL OF THE TAF SITES.
SOME RAIN SHOWERS ARE POSSIBLE AT KSDY AND KGDY THROUGH THIS
EVENING...BUT SHOULD NOT LEAD TO A REDUCTION IN EITHER CEILINGS OR
VISIBILITIES ENOUGH TO AFFECT GROUND OPERATIONS. SURFACE WINDS
TODAY WILL BE OUT OF THE NORTHEAST FROM 10 TO 20 KTS...BECOMING
EASTERLY AT AROUND 10 KTS OVERNIGHT. MALIAWCO


&&

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

&&

$$

WEATHER.GOV/GLASGOW