High Wind in Montana, November 27 to 29, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
947 PM MST TUE NOV 27 2012

.UPDATE...

THE REGION WILL REMAIN UNDERNEATH THE INFLUENCE OF A HIGH PRESSURE
RIDGE TONIGHT ALTHOUGH THE NORTHEASTERN ZONES WILL STAY ON THE
COLD SIDE OF A COLD FRONT. WARM ADVECTION DURING THE PAST 24 HOURS
SHOULD ALLOW FOR SOME WARMER OVER NIGHT LOW TEMPS. CURRENT TEMPS
ARE ALSO RUNNING WARMER THAN LAST NIGHT SO WILL RAISE TEMPS ACROSS
CENTRAL AND SOUTHWEST MONTANA. FAIRLY HIGH DEW POINTS REMAIN OVER
THE NORTHEAST ZONES AND HAVE INCREASED AREA COVERED BY FOG AFTER
MIDNIGHT. ZELZER

&&

.AVIATION...
UPDATED 0000Z.
HIGH PRESSURE ALOFT BUILDING OVER THE NORTHERN ROCKIES WILL MAINTAIN
A DRY NW FLOW ALOFT OVER THE REGION THROUGH THE NEXT 24 HRS WITH
SCATTERED TO BROKEN HIGH CLOUD-COVER. POTENTIAL FOR FOG EXISTS IN
VALLEYS ALONG THE MILK AND MISSOURI RIVERS AS FAR SOUTH AS FT BENTON
TONIGHT...INCLUDING THE KHVR TERMINAL. OTHERWISE VFR CONDITIONS WILL
PREVAIL. A WEAK CANADIAN FRONTAL BOUNDARY WILL PUSH SOUTH ACROSS THE
BORDER WEDNESDAY MORNING...POTENTIALLY PUSHING AS FAR SOUTH AS KGTF
TO KLWT BY WEDNESDAY AFTERNOON. MAIN IMPACT FROM THIS FEATURE WILL
BE A WIND SHIFT TO NORTH OR NORTHEAST WINDS...HOWEVER SOME LOW
CLOUDS ARE ALSO POSSIBLE FURTHER NORTH NEAR THE KCTB AND KHVR
TERMINALS. HOENISCH

&&

.PREV DISCUSSION...
/ISSUED 410 PM MST TUE NOV 27 2012/

TONIGHT THROUGH THURSDAY...THE AXIS OF THE UPPER LEVEL RIDGE OF
HIGH PRESSURE WILL SHIFT FROM THE PACIFIC NORTHWEST TO THE
NORTHERN ROCKIES BY WEDNESDAY AFTERNOON...KEEPING THE TFX CWA DRY
BUT WITH PERSISTENT HIGH CLOUDINESS THROUGH THAT PERIOD. THE
SURFACE FRONTAL BOUNDARY NORTHEAST OF A CUT BANK-TO-LEWISTOWN
LINE SEPARATES THE COOLER AIRMASS (NORTHEAST OF THE BOUNDARY) FROM
THE MILDER AIRMASS. AM EXPECTING RIVER VALLEY FOG DEVELOPMENT IN
THIS COOLER AIRMASS...SIMILAR TO LAST NIGHT. WILL NEED TO MONITOR
THE SITUATION FOR A POSSIBLE DENSE FOG ADVISORY. THE BOUNDARY WILL
SAG SOUTH A BIT ALONG THE EAST SLOPES OF THE ROCKIES LATE
TONIGHT (INCLUDING THE CUT BANK AREA)...WHICH SHOULD ALLOW COOLER
AIR TO MOVE INTO THAT AREA FOR THURSDAY...ALONG WITH PATCHY FOG IN
THE MARIAS RIVER VALLEY WEDNESDAY MORNING. SOUTHWEST OF THIS
BOUNDARY...TEMPERATURES ON WEDNESDAY WILL BE ABOUT 10 DEGREES
WARMER THAN NORMAL. FOR WEDNESDAY NIGHT...A SHORTWAVE TROUGH WILL
MOVE THROUGH THE RIDGE AND BRING PRECIPITATION MAINLY TO THE
MOUNTAINS OF WESTERN AND SOUTHWEST MONTANA. SNOW LEVELS WILL
REMAIN FAIRLY HIGH...LIMITING ACCUMULATING SNOWFALL TO THE
MOUNTAIN PEAKS. RAIN FALLING ON SNOWPACK MAY CAUSE RIVERS/STREAMS
ALONG THE EAST SLOPES TO RISE SOMEWHAT...SO THIS SITUATION WILL
NEED TO BE MONITORED. PRECIPITATION IS GENERALLY NOT EXPECTED OVER
THE PLAINS. HOWEVER...WARMER AIR AT MID LEVELS MOVING OVER THE
COOLER AIRMASS MAY CAUSE LIGHT DRIZZLE/FREEZING DRIZZLE IN THE
NORTHEASTERN PORTION OF THE CWA...SO HAVE ADDED A SLIGHT CHANCE OF
THIS FOR THERE. THE SHORTWAVE WILL EXIT THE AREA QUICKLY ON
THURSDAY FOR A DECREASING CHANCE OF PRECIPITATION. THE PASSAGE OF
THIS SHORTWAVE WILL ALSO HELP NUDGE THE FRONTAL BOUNDARY NORTHEAST
AND CONSEQUENTLY SPREAD BREEZY SOUTHWEST WINDS AND MORE OF THE
MILDER AIRMASS NORTHEAST AS WELL. COULSTON

THURSDAY NIGHT THROUGH TUESDAY...AN UPPER LEVEL DISTURBANCE WILL
CONTINUE TO MOVE THROUGH THE REGION FROM THURSDAY NIGHT INTO
SATURDAY MORNING. THE BEST CHANCES FOR PRECIPITATION WILL BE IN
THE MOUNTAINS...BUT ISOLATED CHANCES FOR SHOWERS WILL BE POSSIBLE
AT LOWER ELEVATIONS AS THIS SYSTEM MOVES THROUGH. ON
SUNDAY...THINGS BECOME A BIT TRICKY...AS THE ECMWF MODEL IS
FAIRLY WET...WHILE THE OZ GFS IS FAIRLY DRY. HOWEVER...THE LATEST
6Z GFS IS LEANING MORE TOWARDS THE WETTER OZ ECMWF.
THEREFORE...MOST AREAS HAVE AT LEAST A SMALL CHANCE FOR A
SHOWER...WITH AGAIN SLIGHTLY HIGHER POPS IN THE MOUNTAINS. FOR
NEXT MONDAY INTO TUESDAY...EXPECT A FAIRLY STRONG UPPER LEVEL
RIDGE OF HIGH PRESSURE TO BUILD OVER THE REGION. THUS THE CHANCES
FOR PRECIPITATION ARE QUITE LOW OVER THE PLAINS...WITH A PASSING
SHOWER NOT COMPLETELY RULED OUT FOR MOUNTAIN LOCATIONS...
ESPECIALLY OVER THE WESTERN MOUNTAINS. IN TERMS OF
TEMPERATURES... ALL MODELS CONTINUE TO PROG HIGH TEMPERATURES IN
THE UPPER 40S TO MID 50S FOR MUCH OF THE EXTENDED. I HAVE LEANED
THAT WAY...BUT WOULD NOT BE SURPRISED IF I AM A TOUCH TO
WARM...AS THE DAYS KEEP GETTING SHORTER/LOWER SUN ANGLE...SO IT
IS HARDER TO WARM UP...EVEN WITH BARE GROUND AT SOME LOWER
ELEVATION LOCATIONS. EVEN SO...WITH AFTERNOON TEMPERATURES AT
LEAST EXPECTED TO BE IN THE MID 40S AT LOWER ELEVATIONS FOR THE
FIRST WEEK OF DECEMBER...IT WOULD STILL BE QUITE A BIT ABOVE
NORMAL FOR MANY LOCATIONS. BRUSDA

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  34  47  31  50 /   0   0  10  10
CTB  25  38  19  46 /   0   0  10  10
HLN  22  45  27  47 /   0   0  20  10
BZN  20  47  25  48 /   0   0  20  10
WEY  14  40  22  38 /   0   0  30  20
DLN  27  47  30  48 /   0   0  20  10
HVR  10  32  13  36 /   0   0  20  20
LWT  22  47  24  48 /   0   0  10  10

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

WEATHER.GOV/GREATFALLS

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GREAT FALLS MT
255 PM MST TUE NOV 27 2012

MTZ010-011-013-044>047-051-281300-
EASTERN GLACIER-HILL-CHOUTEAU-TOOLE-LIBERTY-EASTERN PONDERA-
BLAINE-FERGUS-
255 PM MST TUE NOV 27 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA
AND NORTH CENTRAL MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

PATCHY FREEZING FOG WILL LIKELY REDEVELOP IN THE MILK AND MISSOURI
RIVER VALLEYS TONIGHT...AND THEN SPREAD INTO THE MARIAS RIVER
VALLEY BY WEDNESDAY MORNING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE FOG WILL LIKELY DIMINISH BY LATE WEDNESDAY MORNING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

MTZ008-009-012-014-015-048>050-052>055-281300-
BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-CASCADE-
CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-
SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-JUDITH BASIN-
JEFFERSON-BROADWATER-MEAGHER-GALLATIN-
255 PM MST TUE NOV 27 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.