FXUS65 KBYZ 300410 AAA
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
910 PM MST SUN NOV 29 2009
.SHORT TERM...VALID FOR MON AND TUE...
NOT A LOT TO CHANGE ON THE GOING FORECAST. SURFACE PRESSURE
GRADIENTS WERE TIGHTENING UP SOME WITH LEE TROUGHING...BUT NOT
OVERLY SNUG AT THIS TIME. PRESSURE DIFFERENCES FROM IDAHO FALLS
TO LEWISTOWN WERE ON THE ORDER OF 10MB. WINDS HAVE INCREASED AT
LIVINGSTON TO WITHIN FORECAST PARAMETERS. LOWERING PRESSURE OVER
SOUTHERN CANADA AND NORTHERN MONTANA SHOULD LEAD TO FURTHER
STRENGTHENING OF WINDS AT LIVINGSTON TONIGHT. AM NOT ANTICIPATING
WIND ADVISORY TYPE OF WINDS OVERNIGHT AS GRADIENTS DO NOT LOOK
ORIENTATED QUITE RIGHT. WILL BE CLOSE THOSE SO WILL HAVE TO KEEP
AN EYE ON THIS ONE OVERNIGHT. INVERSION BECOME LESS OF A FACTOR
ON MONDAY AND WIND WILL BECOME MORE OF A MIXING TYPE OF EVENT.
GRADIENTS LOOK BETTER MONDAY AFTERNOON AND THIS IS WHEN ADVISORY
TYPE OF WINDS COULD BE MET. TOUGH CALL THOUGH AS THE AFTERNOON IS
NOT A VERY FAVORABLE TIME FOR HIGH WINDS THERE. WILL PASS WORD ON
TO MIDNIGHT SHIFT. TEMPERATURES HAVE FALLEN QUICKLY THIS EVENING
AND SOME READINGS WERE RAPIDLY APPROACHING FORECAST LOWS. BAND OF
THICK CIRRUS ARCING SOUTHEAST INTO THE FORECAST AREA WILL SLOW
THE DECENT SOME...BUT STILL MADE A DOWNWARD ADJUSTMENT BY A
COUPLE OF DEGREES FOR SOME CENTRAL AND EASTERN LOCATIONS.
HUMPHREY
.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...
VFR CONDITIONS EXPECTED AT ALL TERMINALS THROUGHOUT THE PERIOD
UNDER PARTLY CLOUDY SKIES. RIDGING DOMINATES THE CURRENT WEATHER
PATTERN WITH PACIFIC MOISTURE MAKING IT OVER THE RIDGE WILL CAUSE HIGH
CLOUDS. DOWN SLOPE WINDS IN THE LEE OF THE BEARTOOTH AND ABSAROKA
MOUNTAINS WILL CONTINUE TO CAUSE GUSTY WINDS AT KLVM. SOME GUSTS
TO 40KTS CAN BE EXPECTED OVERNIGHT AT KLVM WITH POSSIBLE HIGHER
GUSTS MONDAY AFTERNOON. LEACH/HUMPHREY
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 032/055 037/038 018/033 018/039 020/039 020/032 020/027
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 028/055 030/041 018/035 016/038 016/038 018/032 017/027
00/U 02/W 11/B 11/B 11/B 11/B 10/B
4BQ 026/057 031/040 017/034 015/035 015/038 017/032 016/027
00/U 02/W 12/J 21/B 11/B 11/B 10/B
BHK 024/052 029/037 018/033 013/034 012/034 012/030 012/025
00/U 02/J 11/B 21/B 11/B 11/B 10/B
SHR 022/054 029/037 012/033 016/039 018/039 019/032 018/027
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
