FXUS65 KBYZ 291003
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
303 AM MST SUN NOV 29 2009
.SHORT TERM...VALID FOR TDY AND MON...
DRY NORTHWEST FLOW ACROSS THE FORECAST AREA TODAY AS A RIDGE OF
HIGH PRESSURE ALOFT BUILDS OVER THE REGION. THIS WILL BRING
WARMER TEMPERATURES TO THE AREA TODAY AND MONDAY WITH 40S AND 50S
EXPECTED. SEVERAL STRONG SHORT WAVES MOVING ACROSS SOUTHERN
BRITISH COLUMBIA TONIGHT AND MONDAY. THESE WAVES WILL BRING
PRESSURE FALLS ACROSS NORTHERN MONTANA AND ALLOW LEE SIDE TROUGH
TO DEVELOP. SURFACE PRESSURE GRADIENT NOT IDEAL FOR STRONG GAP
FLOW WINDS AS SURFACE HIGH IS SET UP OVER EASTERN
IDAHO...CREATING MORE OF A WESTERLY WIND. THIS PRESSURE PATTERN
WILL ALSO BRING GUSTY WINDS TO THE PLAINS LATE TONIGHT AND
MONDAY. HAVE KEPT WINDS IN THE LIVINGSTON AND NYE AREA FOR
TONIGHT THROUGH MONDAY JUST BELOW ADVISORY CRITERIA AS SURFACE
GRADIENT NOT IDEAL FOR STRONG WINDS AT THIS TIME. FLOW ALOFT
BECOMING NORTHWEST ACROSS SOUTHERN MONTANA ON MONDAY AS A RIDGE
OF HIGH PRESSURE BUILDS ALONG THE WEST COAST. THIS WILL SET UP AN
UNSTABLE NORTHWEST FLOW LATE MONDAY NIGHT AND ALSO DRIVE A COLD
FRONT THROUGH THE AREA FROM CANADA. MODELS BRINGING WEAK QG
FORCING WITH ENERGY PUSHING ACROSS THE AREA MIDNIGHT MONDAY. THIS
WILL BRING A SLIGHT CHANCE OF SNOW SHOWERS TO THE FAR WESTERN AND
NORTHWEST ZONES. HAVE PUT IN ISOLATED POPS FOR NOW. RICHMOND
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
EXTENDED MODELS CONTINUE TO BE IN GOOD AGREEMENT TUESDAY AND
WEDNESDAY BUT THEN DIVERGE CONSIDERABLY THURSDAY AND BEYOND. AS A
RESULT...CONFIDENCE REMAINS LOW FOR MOST OF THE EXTENDED FORECAST
AND THEREFORE HAVE NOT MADE ANY MAJOR CHANGES WITH THIS PACKAGE.
A STRONG DISTURBANCE DIVES SOUTHEAST OUT OF CANADA TUESDAY
BRINGING MUCH COOLER TEMPERATURES ALONG WITH A CHANCE FOR LIGHT
SNOW. THE BULK OF THE ENERGY CONTINUES TO BE TO OUR NORTHEAST
ACROSS THE DAKOTAS. AT THE SAME TIME...A STRONG SURFACE LOW MOVES
ACROSS SOUTHERN CANADA SWEEPING A STRONG COLD FRONT ACROSS THE
FORECAST AREA EARLY IN THE MORNING. STRONG NORTHWEST WINDS WILL
USHER IN BEHIND THE FRONT ESPECIALLY ACROSS THE EASTERN PLAINS.
RIDGING BEGINS TO BUILD BACK ACROSS THE FORECAST AREA WEDNESDAY
BRINGING DRY WEATHER AND MILDER TEMPERATURES. MODELS DIVERGE
THURSDAY ONWARD AS THE GFS KEEPS A RIDGE OVER THE AREA THURSDAY
WHEREAS THE ECMWF KEEPS A NORTHERLY FLOW ALOFT OVER THE EASTERN
HALF OF THE STATE. FRIDAY INTO NEXT WEEKEND...THE GFS PLACES A
LARGE TROUGH AND MUCH COLDER TEMPERATURES ACROSS THE NORTHERN
ROCKIES. HOWEVER...THE ECMWF TRIES TO KEEP RIDGING OVER THIS SAME
AREA. AS A RESULT...WILL KEEP GOING FORECAST ABOUT THE SAME DURING
THIS TIME AND USED A BLEND OF MODELS AS NO MODEL OF CHOICE IS
PREFERRED AT THIS TIME. HOOLEY
&&
.AVIATION...
A FEW MID AND HIGH LEVEL CLOUDS WILL MOVE ACROSS THE FORECAST
AREA TODAY. IN ADDITION...SOUTHWEST WINDS OF 15-25 KTS CAN BE
EXPECTED ALONG THE EASTERN SLOPES OF THE BEARTOOTH/ABSAROKA
MOUNTAINS. OTHERWISE...SKIES WILL BE MOSTLY SUNNY WITH VFR
CONDITIONS PREVAILING. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 047 030/052 031/040 020/031 018/039 020/039 020/032
0/U 00/N 03/O 21/B 11/B 11/B 11/B
LVM 042 027/049 027/037 018/029 013/037 013/037 020/030
0/N 00/N 24/S 21/B 11/N 11/B 11/B
HDN 049 027/055 029/043 018/033 017/041 018/041 017/035
0/B 00/U 02/S 21/B 11/B 11/B 11/B
MLS 046 028/052 027/040 018/033 017/038 017/038 016/032
0/B 00/U 02/S 11/B 11/B 11/B 11/B
4BQ 045 026/054 028/042 019/032 015/036 016/038 015/032
0/B 00/U 02/S 22/J 21/B 11/B 11/B
BHK 043 026/051 026/039 015/031 010/034 011/034 010/030
0/B 00/U 02/S 11/B 21/B 11/B 11/B
SHR 046 027/054 027/040 018/031 015/039 018/039 017/032
0/B 00/U 03/S 22/J 11/B 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
