260
FXUS65 KBYZ 210349
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
849 PM MST FRI NOV 20 2009
EVENING UPDATE
FORECAST ON TRACK AND HAVE ONLY MADE A FEW MINOR ADJUSTMENTS.
SATELLITE SHOWING A LARGE TROUGH CURRENTLY MOVING ACROSS THE
PACIFIC NORTHWEST COAST AND INTO THE NORTHERN ROCKIES AREA. DEEP
SOUTHWEST FLOW ALOFT AHEAD OF THIS TROUGH IS BRINGING ABUNDANT
MID AND HIGH LEVEL CLOUDS ACROSS THE FORECAST AREA THIS EVENING.
AS A RESULT...HAVE INCREASED SKY COVER ACROSS THE AREA ESPECIALLY
THE EASTERN ZONES. MODELS HAVE SLOWED THE PROGRESSION OF THIS
TROUGH JUST A BIT WITH PRECIP NOT MAKING IT MUCH INTO OUR WESTERN
ZONES UNTIL VERY LATE TOWARD 12Z SATURDAY. AREA RADARS NOT
SHOWING ANY ACTIVITY APPROACHING AS WELL. HAVE THEREFORE TRIMMED
BACK POPS IN THE NORTHWEST AND WESTERN LOWER ELEVATION ZONES. DID
ALSO LOWER POP CHANCES JUST A BIT AS WELL FOR THE SOUTHWEST
MOUNTAINS. WINDS HAVE ALSO DECREASED QUITE A BIT IN THE
LIVINGSTON AREA SO HAVE LOWERED THESE FOR THE REMAINDER OF THE
NIGHT. TEMPERATURES ACROSS PORTIONS OF THE CENTRAL AND WEST
REMAIN IN THE 40S THIS EVENING. STILL EXPECT MIXING TO CONTINUE
THROUGHOUT THE NIGHT AND LATEST GUIDANCE COMING IN A BIT WARMER AS
WELL. SO HAVE BUMPED UP READINGS IN A FEW LOCATIONS. UPDATE OUT
SHORTLY. HOOLEY
LONG TERM...VALID FOR MON...TUE...WED...THU...FRI
WHILE THE FAIRLY BENIGN WEATHER PATTERN CONTINUES INTO THE
EXTENDED THE MODELS ARE NOT IN REAL STRONG AGREEMENT. ON MONDAY
ECMWF AND GFS ARE VERY DIFFERENT IN THE TRACK OF AN UPPER LOW
THROUGH THE AREA WITH THE ECMWF THE PREFERRED SOLUTION. GFS TRACKS
AN UPPER TROUGH ACROSS THE AREA WHILE THE ECMWF DIVES A SYSTEM
SOUTH THROUGH WYOMING. GFS HINTS AT SOME WRAP AROUND PRECIPITATION
AS THE SYSTEM AND GFS HAS BEEN TRENDING UPWARD WITH POPS SO HAVE
KEPT SOME POPS IN SOUTHEAST MONTANA AS A HEDGE...BUT GENERALLY
PREFER ECMWF SOLUTION. WILL CONTINUE COOL UNDER NORTHERLY FLOW
ALOFT THE REMAINDER OF THE DAY. TUESDAY MODELS CONTINUE TO
DISAGREE WITH A ANOTHER WAVE COMING THROUGH THE NORTHWEST FLOW
AND AMPLIFYING IT ON THE GFS WHILE THE ECMWF HAS A LIGHTER ZONAL
FLOW. SINCE THE ECMWF IS DOING A BETTER JOB OF CUTTING OFF THE
SYSTEM OVER THE PLAINS WHICH HAS BEEN THE TREND AS OF LATE. LOOKS
DRY EITHER WAY AND DO NOT STRENGTHEN WINDS AS MUCH AS GFS WOULD
INDICATE. BOTH MODELS BRING AN UPPER LEVEL RIDGE INTO THE AREA FOR
WEDNESDAY AND THURSDAY FOR TEMPERATURES 10 TO 15 DEGREES ABOVE
NORMAL AND A DOWNSLOPING WIND PATTERN. RIDGE BREAKS DOWN ON BOTH
MODELS FOR FRIDAY AND THE WEEKEND BUT AGAIN MODELS DISAGREE ON
TRACKS OF SYSTEM THROUGH THE REGION. DEFINITELY COOLER AS THE
TRANSITION OCCURS BUT NOT REALLY SURE ABOUT PRECIPITATION AT THIS
POINT. BORSUM
AVIATION
RAIN AND SNOW SHOWERS ARE EXPECTED IN AND AROUND KLVM AND IN THE
HIGH TERRAIN BY AROUND MIDNIGHT...AS A COLD FRONT PUSHES FROM WEST
TO EAST ACROSS THE REGION OVERNIGHT. MAINLY VFR FLIGHT CONDITIONS
CAN BE EXPECTED TO PREVAIL OVER THE PLAINS. EXPECT INCREASING
CLOUDINESS OVER THE MOUNTAINS AND FOOTHILL REGION...WITH CEILINGS
DROPPING TO MVFR LEVELS AFTER MIDNIGHT. MOUNTAIN OBSCURATIONS AND
LOWER CEILINGS WILL CONTINUE THROUGH TOMORROW AFTERNOON. GILSTAD
PRELIMINARY POINT TEMP/POPS
SAT SUN MON TUE WED THU FRI
-----------------------------------------------------------
BIL 034/046 024/041 026/041 025/044 026/050 031/052 031/053
03/W 02/O 22/S 11/N 10/B 00/B 01/N
LVM 031/041 022/037 018/037 024/041 025/048 030/051 029/047
24/J 04/S 31/B 12/S 10/B 00/N 02/R
HDN 028/051 024/043 024/045 023/048 023/051 023/052 024/053
02/W 02/O 22/S 12/S 20/B 00/B 01/B
MLS 026/050 024/046 024/044 021/045 022/048 025/052 027/052
02/W 02/O 21/B 12/S 20/B 00/B 01/B
4BQ 027/051 023/042 021/041 021/046 021/044 025/049 025/050
02/W 22/O 22/S 12/S 21/B 00/B 01/B
BHK 026/054 024/044 021/040 018/041 020/042 023/051 024/051
02/W 20/B 22/S 12/S 21/B 00/B 01/B
SHR 029/047 019/043 020/040 018/047 019/047 022/050 021/049
03/W 22/O 22/S 12/S 20/B 00/B 01/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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