FXUS65 KBYZ 292200
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
300 PM MST SUN NOV 29 2009
.SHORT TERM...VALID FOR MON AND TUE...
AN UPPER LEVEL RIDGE WILL BUILD OVER THE AREA THROUGH MONDAY
NIGHT. AFTER THAT A STRONG BUT FAST MOVING SYSTEM WILL MOVE
THROUGH THE AREA TUESDAY WITH A COLD FRONT AND A SHOT AT SNOW
SHOWERS...PARTICULARLY ALONG THE NORTHERN FOOTHILLS OF AREA
MOUNTAINS. WINDS WILL BE GUSTY OVER WESTERN AREAS TONIGHT...WITH A
SLIGHT CHANCE OF EXCEEDING ADVISORY WIND SPEEDS IN GAP AREAS FROM
LIVINGSTON TO NYE BY MONDAY MORNING. PRESSURE GRADIENT ORIENTATION
AND 700MB WIND DIRECTION ARE JUST NOT QUITE OPTIMAL TO CHANNEL
WINDS THROUGH THESE AREAS SO KEPT SPEEDS JUST UNDER ADVISORY
LEVELS BUT WILL HAVE TO KEEP AN EYE ON THIS. WESTERLY WINDS WILL
SPREAD OUT ACROSS THE PLAINS MONDAY AFTERNOON...BOOSTING
TEMPERATURES INTO THE 50S FOR HIGHS. WINDS FROM BIG TIMBER TO
HARLOWTON WILL APPROACH WARNING CRITERIA AROUND 40 MPH SUSTAINED
WITH GUSTS OVER 55 MPH MONDAY AFTERNOON. MONDAY NIGHT WILL SEE
CLOUD COVER INCREASING FROM THE NORTHWEST AS THE UPPER DISTURBANCE
AND COLD FRONT APPROACH THE AREA. PRECIPITATION LOOKS TO BEGIN
OVER NORTHWEST SECTIONS AFTER MIDNIGHT...SPREADING SOUTHEAST
THROUGH THE MORNING HOURS TUESDAY. GAP WINDS LATE MONDAY NIGHT
LOOK FAVORABLE FOR AT LEAST ADVISORY SPEEDS FROM LIVINGSTON TO
NYE. THE PRESSURE GRADIENT AND 700 MB WINDS BECOME MORE FAVORABLE
AHEAD OF THE FRONT AT THAT TIME. RECENT STRONG WIND EVENTS HAVE
BEEN OCCURING IN THE 6 HOURS AHEAD OF A FRONTAL PASSAGE AS WELL.
HAVE STRONG WINDS IN THE FORECAST AND WILL EVALUATE FOR A POSSIBLE
HIGHLITE ONCE THE POTENTIAL FOR WIND HIGHLITES TONIGHT IN THESE
AREAS PASSES. THE SYSTEM QUICKLY EXITS TO THE SOUTH TUESDAY
AFTERNOON LEAVING COOLER TEMPERATURES AND GUSTY NORTHWEST WINDS
ACROSS THE AREA INTO TUESDAY EVENING. TEMPERATURES TUESDAY NIGHT
LOOK TO BE IN THE TEENS AS COLD AIR BUILDS IN WITH CLEARING SKIES.
CHAMBERS
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
THE MAIN CONCERN FOR THE LONG TERM FORECAST IS THE POTENTIAL FOR
SOME COOLER AIR FOR THE UPCOMING WEEKEND.
DECIDED TO NOT MAKE TOO MANY CHANGES TO THE
EXTENDED FORECAST...AS PREVIOUS MID SHIFT HANDLED FORECAST PRETTY
WELL. KEPT TEMPERATURES FAIRLY CONSISTENT THROUGHOUT THE
PERIOD. AS FAR AS PRECIPITATION IS CONCERNED...BEST CHANCE FOR
ANYTHING WOULD BE OVER EASTERN MONTANA WEDNESDAY MORNING. HIGHER
ELEVATIONS IN THE WEST MAY SEE SOME OCCASIONAL SNOWFALL THROUGHOUT
THE PERIOD.
EXTENDED PERIOD BEGINS WEDNESDAY MORNING WITH MOST OF THE CWA
UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE WHICH WILL BE
AMPLIFIED BY A STRONG BUNDLE OF ENERGY PLUNGING SOUTHWARD OUT OF
CANADA OVER THE EASTER DAKOTAS AND MINNESOTA. BY THURSDAY
NIGHT...BOTH MODELS ARE SHOWING ANOTHER UPPER LEVEL LOW PRESSURE
SYSTEM OVER BRITISH COLUMBIA WHICH WILL HELP TO USHER IN SOME
COLDER SURFACE TEMPERATURES FOR MUCH OF SOUTH CENTRAL MONTANA. IT
IS AFTER THIS POINT WHERE THE GFS AND ECMWF START TO REALLY
DIVERGE. THE GFS SOLUTION DIGS A FAIRLY DEEP POSITIVELY TILTED
TROUGH OVER MUCH OF THE WESTERN UNITED STATES...WHILE THE ECMWF
DECIDES TO CLOSE OFF THE UPPER LEVEL LOW OVER VANCOUVER AS WELL AS
GENERATE ANOTHER LOW OFF THE CALIFORNIA COAST BY MONDAY MORNING.
ONE OTHER THING THAT MAY BE WORTH MENTIONING...
TAKING A QUICK LOOK AT HPC GEFS ANOMALIES OUT THROUGH DAY
EIGHT...IT HIGHLIGHTS A STRONG UPPER LEVEL LOW OVER ALASKA...THREE
STANDARD DEVIATIONS OFF THE NORM. THIS MAY BE ATTRIBUTED TO THE
REMNANTS OF WHAT IS NOW TYPHOON NIDA...WHICH IS CURRENTLY STAGNATING
OUT IN THE WESTERN PACIFIC. THE PROGRESSION OF NIDA OVER THE NEXT
WEEK MAY HAVE AN COLDER IMPACT ON TEMPERATURES OVER THE
NORTHWESTERN UNITED STATES BY EARLY NEXT WEEK. SINGER
&&
.AVIATION...
EXPECTING MOSTLY SUNNY SKIES AND VFR FLYING CONDITIONS THROUGH
THE PERIOD FOR ALL TERMINALS WITH SOME POTENTIALLY CONSISTENT
SOUTHWESTERLY WINDS OF 15-30 KTS ON THE LEEWARD SIDE OF THE
BEARTOOTH AND ABSAROKA MOUNTAINS. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 034/055 037/038 018/033 018/039 020/039 020/032 020/027
00/N 04/W 11/B 11/B 11/B 11/B 10/B
LVM 034/050 034/037 014/031 008/037 011/037 017/030 013/025
00/N 25/J 21/B 11/N 11/B 11/B 10/B
HDN 031/057 034/041 017/035 017/041 018/041 019/035 018/030
00/U 03/W 11/B 11/B 11/B 11/B 10/B
MLS 029/055 030/041 018/035 016/038 016/038 018/032 017/027
00/U 02/W 11/B 11/B 11/B 11/B 10/B
4BQ 028/057 031/040 017/034 015/035 015/038 017/032 016/027
00/U 02/W 12/J 21/B 11/B 11/B 10/B
BHK 026/052 029/037 018/033 013/034 012/034 012/030 012/025
00/U 02/J 11/B 21/B 11/B 11/B 10/B
SHR 026/054 029/037 012/033 016/039 018/039 019/032 018/027
00/U 05/W 22/J 11/B 11/B 11/B 10/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
