AREA FORECAST DISCUSSION

 
 FXUS65 KTFX 251735
 AFDTFX
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE GREAT FALLS MT
 1035 AM MST WED NOV 25 2009
 
 ...UPDATE TO AVIATION...
 
 .AVIATION (18Z TAFS)...
 
 MINOR AVIATION CONCERNS AT BEST WITH SOME GUSTY WINDS AT AIRPORTS
 ALONG THE ROCKY MOUNTAIN FRONT...MAINLY CTB AND GTF. VFR
 CONDITIONS SHOULD CONTINUE THROUGH THE ENTIRE PERIOD...WITH LITTLE
 BUT SOME HIGH CLOUD COVER MAKING IT ACROSS THE ROCKIES. GUSTS AT
 CTB AND GTF MAY REACH 30 TO 35 KTS ON THE HIGH END THIS AFTERNOON
 AND EVENING BEFORE RELAXING SOME DURING THE OVERNIGHT PERIOD.
 OUTSIDE OF CTB AND GTF...WINDS MAY BECOME LIGHT AND VARIABLE OR
 LIGHT SOUTHERLIES OVERNIGHT.  SCHOTT
 
 &&
 
 .UPDATE...
 ONLY CHANGE MADE THIS MORNING WAS TO LOWER CLOUD COVER OVER NORTH-
 CENTRAL MONTANA. KEPT PARTLY CLOUDY CONDITIONS OVER THE DIVIDE AS
 SOME MOISTURE MOVES OVER THE UPPER-LEVEL RIDGE...HOWEVER RIDGE
 AXIS WILL CONTINUE TO SHIFT EASTWARD TODAY. REMAINDER OF THE
 FORECAST IS RIGHT ON TRACK WITH QUIET CONDITIONS AND ABOVE AVERAGE
 TEMPERATURES. MLS
 
 &&
 
 .PREVIOUS DISCUSSION /ISSUED 518 AM MST WED NOV 25 2009/
 
 TODAY THROUGH FRIDAY...A MOIST NORTHWESTERLY FLOW ALOFT AHEAD OF
 AN UPPER LEVEL HIGH PRESSURE RIDGE WILL KEEP AREAS OF MID AND
 HIGH CLOUDS OVER THE TFX CWA THIS MORNING. SKIES WILL BEGIN TO
 CLEAR THIS AFTERNOON AS THE RIDGE AXIS MOVES INTO THE AREA.
 BREEZY WESTERLY WINDS WILL ALSO PERSIST ALONG THE ROCKY MOUNTAIN
 FRONT AS A SURFACE TROUGH DEEPENS OVER THE EAST SLOPES OF THE
 ROCKIES. WINDS WILL INCREASE FURTHER OVERNIGHT INTO THANKSGIVING
 DAY AS DISTURBANCES EJECTING FROM AN UPPER LEVEL LOW PRESSURE OFF
 THE PACIFIC COAST FLATTEN THE UPPER RIDGE AND INCREASE THE FLOW
 ALOFT. AM EXPECTING THE WINDS TO BECOME STRONG ALONG THE ROCKY
 MOUNTAIN FRONT DURING THIS TIME...BUT THEY SHOULD REMAIN BELOW
 HIGH WIND CRITERIA. THE BULK OF THE MOISTURE IN THIS INCREASING
 WESTERLY FLOW ALOFT WILL REMAIN ALONG THE CANADIAN
 BORDER...KEEPING MAINLY HIGH CLOUDINESS OVER THE AREA WITH A
 CHANCE FOR A CHINOOK ARCH JUST TO THE LEE OF THE ROCKIES. WINDS
 AND CLOUDS WILL DECREASE SOMEWHAT THURSDAY NIGHT AS THE UPPER
 TROUGH MOVES ONSHORE AND AMPLIFIES THE UPPER RIDGE OVER THE AREA.
 HOWEVER...THE RESULTING SOUTHWESTERLY FLOW ALOFT WILL BECOME MORE
 MOIST ON FRIDAY AS THE UPPER TROUGH FURTHER APPROACHES THE
 AREA...WHICH WILL LIKELY BRING SHOWERS TO THE WESTERN MONTANA
 MOUNTAINS AND A CHANCE OF SHOWERS IN SOUTHWEST MONTANA. INCREASING
 SOUTHWEST DOWNSLOPE WINDS ON FRIDAY WILL GENERALLY KEEP THE PLAINS
 OF NORTH CENTRAL AND CENTRAL MONTANA DRY BUT WITH INCREASING
 CLOUDS. TEMPERATURES WILL WARM FROM ABOUT 10 TO 15 DEGREES ABOVE
 SEASONAL AVERAGES TODAY TO 15 TO 25 DEGREES ABOVE NORMAL ON
 THANKSGIVING DAY. THE INCREASING CLOUDS AND APPROACHING TROUGH
 WILL COOL TEMPERATURES ABOUT 5 TO 10 DEGREES ON FRIDAY.  COULSTON
 
 FRIDAY NIGHT THROUGH MONDAY NIGHT...PROGRESSIVE PATTERN WILL
 CONTINUE THROUGH THE PERIOD. UPPER LEVEL RIDGE WILL PUSH EASTWARD
 AS A BROAD UPPER TROUGH MOVES OVER THE AREA. MODELS ARE BETTER
 ALIGNED THAN IN PREVIOUS RUNS AND WILL BRING THE TROUGH OVER THE
 FORECAST AREA FRIDAY NIGHT. THIS FEATURE MOVES THROUGH FAIRLY
 QUICKLY AND IS NOT ALL THAT STRONG. BEST THREAT FOR PRECIPITATION
 WITH THIS SYSTEM WILL BE OVER THE MOUNTAINS OF THE ROCKY MOUNTAIN
 FRONT AND SW MT. THERE IS ONLY A SLIGHT CHANCE OF PRECIPITATION
 OVER THE LOWER ELEVATIONS. A RIDGE WILL MOVE OVER THE AREA
 STARTING SUNDAY MORNING AND REMAIN IN PLACE THROUGH LATE MONDAY
 NIGHT BRINGING DRIER CONDITIONS AND ABOVE AVERAGE TEMPERATURES. ON
 SATURDAY TEMPERATURES WILL BE NEAR...TO SLIGHTLY ABOVE...NORMAL.
 ON SUNDAY AND MONDAY TEMPERATURES WILL INCREASE DUE TO A SW FLOW
 AND BE 10 TO 15 DEGREES ABOVE NORMAL. MERCER
 
 TUESDAY THROUGH WEDNESDAY...MODELS PRESENT A SIMILAR SOLUTION
 DURING THIS PERIOD. AN UPPER LEVEL TROUGH AND ASSOCIATED CANADIAN
 COLD FRONT MOVE ACROSS THE FORECAST AREA TUESDAY. BEHIND THE FRONT
 WINDS WILL SHIFT NORTHERLY WITH STEADY OR FALLING TEMPERATURES.
 MODELS HAD HAD SOME RUN TO RUN INCONSISTENCIES IN THE STRENGTH AND
 TIMING OF THESE SYSTEMS. FOR NOW THIS FORECAST WILL INTRODUCE A
 TEN TO 15 DEGREE DROP IN TEMPERATURES WITH A CHANCE OR SLIGHT
 CHANCE OF SNOW FOR MOST AREAS. BY THE NEXT RUN...THE FORECAST MAY
 REFLECT COLDER TEMPERATURES WITH A GREATER LIKELIHOOD OF SNOW. EK
 
 &&
 
 .PRELIMINARY POINT TEMPS/POPS...
 GTF  55  39  61  35 /   0   0   0   0 
 CTB  53  37  59  33 /   0   0   0   0 
 HLN  50  30  54  26 /   0   0   0   0 
 BZN  44  21  47  18 /   0   0   0   0 
 WEY  35  13  40  13 /   0   0   0   0 
 DLN  45  23  48  21 /   0   0   0   0 
 HVR  55  31  61  29 /   0   0   0   0 
 LWT  53  32  60  30 /   0   0   0   0 
 
 &&
 
 .TFX WATCHES/WARNINGS/ADVISORIES...
 NONE.
 &&
 
 $$
 
 SHORT TERM...COULSTON
 LONG TERM...MERCER
 AVIATION...SCHOTT
 
 WEATHER.GOV/GREATFALLS