FXUS65 KBYZ 251024
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
324 AM MST WED NOV 25 2009
.SHORT TERM...VALID FOR TDY AND THU...
WITH A RIDGE BUILDING INTO THE REGION FOR THE NEXT COUPLE OF
DAYS THE ONLY CONCERN FOR THE SHORT TERM WILL BE STRONG WIND
POTENTIAL OVER WESTERN AREAS TONIGHT AND THURSDAY NIGHT.
THE ALBERTA CLIPPER THAT MOVED INTO THE REGION YESTERDAY
AFTERNOON IS NOW CENTERED OVER WESTERN SOUTH DAKOTA AND IS
QUICKLY MOVING AWAY FROM THE AREA. A CONVERGENCE LINE IS LOCATED
FROM SHERIDAN COUNTY TO AROUND HARLOWTON WITH SOME CLOUD COVER
AND ISOLATED LIGHT SNOW SHOWERS. WEB CAMS IN THE HILLS NORTH OF
SHERIDAN SHOW ENOUGH SNOW TO COVER THE GROUND FELL THERE
OVERNIGHT WITH THE TIE CREEK SNOTEL INDICATING UP TO 2 INCHES OF
SNOW IN THE HIGHER FOOTHILLS. COULD SEE A FEW SNOW SHOWERS LINGER
THROUGH MID MORNING IN THE WEST AND SOUTH CENTRAL ZONES...BUT
THIS EVENT IS JUST ABOUT OVER THIS MORNING.
THE UPPER LEVEL RIDGE AXIS IS NOT TOO FAR AWAY...JUST MOVING INTO
IDAHO AT THIS TIME. MODELS SHOW THE AREA REMAINING CAPPED IN THE
LOW LEVELS TODAY THUS THE FASTER NORTHERLY FLOW ALOFT IS NOT
EXPECTED TO MIX TO THE SURFACE. THIS WILL KEEP WINDY CONDITIONS
CONFINED TO WESTERN AREAS WHERE THE SURFACE PRESSURE GRADIENT IS
TIGHTEST...AND KEEP WINDS RELATIVELY LIGHT UNDER SURFACE HIGH
PRESSURE EAST. WITH DECREASING CLOUDS ACROSS THE AREA EXPECT
TEMPERATURES TO PUSH TOWARD 50 DEGREES OVER WESTERN AND CENTRAL
AREAS TODAY...WITH LOWER 40S UNDER CANADIAN SURFACE HIGH PRESSURE
IN THE EAST.
AS WARMER AIR ALOFT MOVES OVER THE AREA TONIGHT AND THE SURFACE
PRESSURE GRADIENT TIGHTENS WINDS WILL INCREASE ALONG THE
BEARTOOTH FRONT. THERE IS A CHANCE GIVEN THE CURRENT MODEL
SOLUTIONS THAT A WIND ADVISORY WILL BE NEEDED AFTER MIDNIGHT
TONIGHT FOR THE LIVINGSTON AND BEARTOOTH FOOTHILLS ZONES. THIS
EVENT LOOKS A BIT BETTER THAN YESTERDAYS MARGINAL EVENT AS THE
700MB WIND DIRECTION IS MORE WESTERLY. HOWEVER DON'T SEE A STRONG
PRESSURE FALL BULLSEYE DEVELOPING OVERNIGHT...AND IN FACT THE
MODELS ADVERTISE A SLIGHT PRESSURE RISE AFTER MIDNIGHT. IN
ADDITION THE PRESSURE GRADIENT ORIENTATION IS STILL NOT OPTIMAL
(SOUTH-NORTH) WHICH LEAVES THE POSSIBILITY THAT GAP FLOW WILL
STAY JUST BELOW ADVISORY LEVELS FOR THE MOST PART. HAVE HAD NEAR
ADVISORY TYPE WINDS ADVERTISED FOR THE PAST DAY OR TWO IN THESE
AREAS AND WILL CONTINUE THAT THIS MORNING. DAY SHIFT CAN TAKE A
FINAL LOOK TO SEE IF THE GUIDANCE BECOMES MORE FAVORABLE BEFORE
LAUNCHING THE HIGHLITE.
THANKSGIVING LOOKS VERY WARM...DRY AND WINDY. THE RIDGE OVER THE
REGION IS ABOUT TWO STANDARD DEVIATIONS ABOVE CLIMO AND SHOULD BE
STRONG ENOUGH TO PRODUCE TEMPERATURES IN THE LOWER 60S ACROSS THE
AREA...NORMAL HIGHS THIS TIME OF YEAR ARE IN THE UPPER 30S. STILL
IT DOESN'T LOOK LIKE WE WILL BREAK DAILY TEMPERATURE RECORDS
UNLESS TEMPERATURES GO 5 TO 10 DEGREES ABOVE CURRENT FORECAST.
WINDS WILL BE GUSTING TO 45 TO 55 MPH OVER WESTERN ZONES IN THE
MORNING...DECREASING TO 25 TO 40 MPH GUSTS IN THE AFTERNOON.
SUSTAINED WINDS OF 15 TO 30 MPH WILL EXTEND INTO CENTRAL ZONES
THURSDAY AFTERNOON. WIND SPEEDS WILL LIKELY INTENSIFY OVER GAP
FAVORED AREAS OF THE WEST ONCE AGAIN ON LATE THURSDAY NIGHT.
CHAMBERS
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
WAVE PROGGED TO MOVE THROUGH NORTHERN MONTANA ON FRIDAY BRINGING A
ROUND OF DOWNSLOPE WINDS TO THE REGION AND TIMING OF SYSTEM LOOKS
A BIT SLOWER THAN PREVIOUS THINKING. THIS SHOULD ALLOW FOR WINDY
CONDITIONS AND MILDER TEMPERATURES A COLD FRONT MOVING INTO THE
WESTERN ZONES DURING THE AFTERNOON. HAVE BOOSTED TEMPERATURES AND
WINDS TO COVER THIS SLOWER TIMING. PRECIPITATION LOOKS TO BE
SLOWER AS WELL AND HAVE DELAYED SHOWER ACTIVITY UNTIL THE
AFTERNOON HOURS FOR THE WESTERN ZONES SPREADING ACROSS SOUTHERN
MONTANA AND NORTHERN WYOMING BEHIND THE FRONT FRIDAY NIGHT.
NORTHWESTERLY FLOW ALOFT PROGGED BEHIND THIS WAVE FOR SATURDAY
WITH MODELS TRYING TO SWING A SHORTWAVE THROUGH IDAHO BEHIND THE
INITIAL TROUGH. THIS WAVE LOOKS TO TRACK SOUTH AND WEST OF THE
AREA WITH ONLY THE MOUNTAINS LOOKING IMPACTED WITH DYNAMICS BUT
STILL NOT RULING OUT ISOLATED SHOWERS UNDER THE COLD AIR ALOFT. WINDS
SHOULD BE DECREASED FOR SATURDAY AND TEMPERATURES COOLER AS MIXING
SHOULD BE LESS PRONOUNCED BUT GRADIENTS WILL STILL BE DOWNSLOPISH.
SUNDAY UPPER LEVEL RIDGE BEGINS TO POSITIVELY TILT INTO THE AREA
BRINGING STABILIZATION AND DRYING OF THE AIRMASS WITH CONTINUED
COOL TEMPERATURES BUT STILL NEED SEASONAL NORMALS. DO EXPECT SOME
NORTHWESTERLY WINDS OVER THE EASTERN TWO THIRDS OF THE AREA AS
MOMENTUM ALOFT MAY MIX DOWN. UPPER FLOW INCREASES OVER THE
CANADIAN ROCKIES MONDAY AS THE UPPER RIDGE WEAKENS BUT STILL KEEPS
PRONOUNCED ANTICYCLONIC FLOW OVER THE AREA. THIS SHOULD BRING
INCREASING GAP FLOW AND DOWNSLOPE WINDS WITH A VERY STRONG WAVE
PROJECTED BY BOTH EXTENDED MODELS TO MOVE THROUGH THE PACIFIC
NORTHWEST MONDAY NIGHT AND INTO WESTERN MONTANA EARLY TUESDAY.
THIS SETS THE STAGE FOR A STRONG WIND PATTERN AND HAVE BEGUN
INCREASING WINDS IN RESPONSE TO THIS WAVE. COLD FRONT TO MOVE
ACROSS MONTANA AND WYOMING DURING THE DAY ON TUESDAY BUT BEST
CHANCE FOR LIFT LOOKS TO STAY NORTH OF THE AREA BUT HAVE INCLUDED
A CHANCE OF SHOWERS ALONG AND BEHIND THE FRONT. MONDAY SHOULD WARM
AHEAD OF THE FRONT WITH THE DOWNSLOPE WITH COOLER TEMPERATURES
ARRIVING FOR TUESDAY. BORSUM
&&
.AVIATION...
UNTIL 18Z ISOLATED SNOW SHOWERS OVER THE MOUNTAINS MAY CAUSE
REDUCTIONS IN CEILINGS AND VISIBILITIES. OTHERWISE UPPER LEVEL
RIDGE MOVING INTO THE AREA WITH DRYING CONDITIONS TODAY WITH ONLY
MID AND HIGH LEVEL CLOUDS EXPECTED BY MID DAY. EXPECT WINDS TO
INCREASE OVER THE FAVORED AREAS IN THE FOOTHILLS LATE TONIGHT.
BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 053 034/060 032/054 028/040 023/038 026/046 029/042
0/U 00/N 00/B 22/W 20/B 00/B 12/W
LVM 053 033/057 034/048 022/035 020/040 023/044 024/038
2/J 00/N 02/W 32/J 21/B 11/N 12/J
HDN 054 029/061 030/056 025/045 019/042 021/046 024/046
0/U 00/U 00/U 22/W 21/B 10/B 12/W
MLS 047 027/060 029/055 027/045 018/039 021/045 024/045
0/U 00/U 00/U 22/W 21/B 11/B 12/W
4BQ 048 027/062 029/055 026/043 018/040 020/044 024/044
0/U 00/U 00/U 22/W 21/B 10/B 12/W
BHK 042 024/057 028/052 024/042 018/038 020/039 022/042
0/B 00/U 00/U 22/W 21/B 00/B 12/J
SHR 052 028/061 030/056 024/041 016/040 018/045 019/043
2/J 00/U 00/B 23/J 21/B 10/B 12/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
