FXUS65 KBYZ 261007
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
307 AM MST THU NOV 26 2009
.SHORT TERM...VALID FOR TDY AND FRI...
MAIN FORECAST CHALLENGE WILL BE THE POTENTIAL FOR STRONG WINDS
ALONG THE FOOTHILLS OF THE BEARTOOTH/ABSAROKA MOUNTAINS. SURFACE
ANALYSIS SHOWING FAVORABLE SURFACE PRESSURE PATTERN FOR GAP FLOW
WINDS IN THE LIVINGSTON AND NYE AREAS WHILE MODELS AGAIN
UNDERESTIMATING SURFACE FEATURES. SHORT WAVE ENERGY IS TRACKING
ACROSS SOUTHERN BRITISH COLUMBIA WHICH IS ALLOWING LEE SIDE
TROUGH TO DEEPEN. LEE SIDE TROUGH ALONG WITH SURFACE HIGH OVER
EASTERN IDAHO WILL COMBINE TO BRING STRONG WINDS TO THESE AREAS
THROUGH THE MORNING. WINDS HAVE BEEN SLOWLY INCREASING OVERNIGHT
IN THE LIVINGSTON AND NYE AREA AND EXPECT THEM TO REACH ADVISORY
CRITERIA BY SUNRISE. THE PRESSURE GRADIENT WILL WEAKEN BY MIDDAY
AS LEE SIDE TROUGH SHIFTS EAST. WILL KEEP CURRENT WINDS ADVISORY
GOING THROUGH 1 PM TODAY. BREEZY DAY IN STORE FOR MOST OF THE
PLAINS THIS AFTERNOON. STRONG MIXING TODAY WILL ALLOW
TEMPERATURES TO RUN 15 TO 20 DEGREES ABOVE NORMAL.
GAP FLOW WINDS INCREASING AGAIN OVERNIGHT AS SURFACE PATTERN
LOOKS FAVORABLE. BUFKIT SHOWING STABLE LAYER AT MOUNTAIN TOP
LEVEL BUT 700MB WINDS NOT AS STRONG AS TODAY. WILL HOLD OFF ON
ANY ADDITIONAL ADVISORIES AND LET DAY SHIFT TAKE A LOOK AT 12Z
MODEL RUN. UPPER RIDGE OVER THE AREA WILL BEGIN FLATTENING AS A
PACIFIC SHORT WAVE MOVES INTO THE AREA FRIDAY. DRY WEATHER
EXPECTED AHEAD OF THIS SYSTEM WITH GOOD MIXING TO ALLOW FOR
ANOTHER MILD DAY. TEMPERATURES WILL BE SLIGHTLY COOLER WITH
READINGS IN THE 50S. SHORT WAVE MOVING THROUGH THE AREA ON FRIDAY
WILL BEGIN SHEARING APART AS IT MOVES OVER THE FORECAST AREA WITH
THE STRONGEST LIFT STAYING NORTH AND SOUTH OF THE FORECAST AREA.
MODELS DO BRING WEAK QG FORCING ALONG WITH INCREASING LOW LEVEL
MOISTURE FRIDAY NIGHT. WHAT UPPER LEVEL LIFT IS OVER THE AREA
WILL HAVE TO CONTEND WITH DOWN SLOPING WINDS AND WILL CONTINUE
SCATTERED POPS FOR FRIDAY NIGHT IN THE WEST AND ONLY ISOLATED IN
THE EAST. RICHMOND
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
MODELS ARE IN GOOD AGREEMENT FOR THIS WEEKEND INTO EARLY NEXT
WEEK BUT DIVERGE SOMEWHAT BY THE MIDDLE OF NEXT WEEK. ANOTHER
WAVE MOVES SOUTHEAST OUT OF CANADA SATURDAY ALONG WITH A PACIFIC
COLD FRONT. NOT A LOT OF MOISTURE OR DYNAMICS WITH THIS WAVE BUT
ENOUGH TO JUSTIFY A CONTINUED SLIGHT CHANCE FOR A SHOWER ACROSS
THE PLAINS WITH HIGHER CHANCES OVER THE MOUNTAINS. UPPER LEVEL
RIDGING BUILDS IN FOR SUNDAY AND ESPECIALLY FOR SUNDAY NIGHT AND
MONDAY. THIS WILL BRING WARMING TEMPERATURES AND DRY CONDITIONS
EXCEPT FOR A CHANCE FOR SOME MOUNTAIN SNOW SHOWERS MONDAY. A
STRONGER UPPER LEVEL WAVE MOVES DOWN OUT OF CANADA MONDAY AND
TUESDAY ALONG WITH A MUCH STRONGER COLD FRONT. THIS WILL BRING
ANOTHER CHANCE FOR SHOWERS BUT THE MAIN CONCERN WILL BE STRONG
WINDS ACROSS THE PLAINS. AS A RESULT...INCREASED WIND GRIDS
ACROSS THE PLAINS FOR THIS TIME AND WILL MOST LIKELY NEED TO
INCREASE THEM MORE WITHIN THE NEXT FEW DAYS. MODELS BEGIN TO
DIFFER WEDNESDAY INTO THURSDAY. ALTHOUGH BOTH THE GFS AND ECMWF
BRING A MUCH COLDER NORTHERLY FLOW ALOFT ACROSS THE FORECAST
AREA...THE EC BRINGS MUCH COLDER AIR INTO THE STATE AND NORTHERN
HIGH PLAINS. WENT AHEAD AND LOWERED TEMPS JUST A TAD BUT BEING
THIS FAR OUT WILL CONTINUE TO MONITOR AND TREND AS NECESSARY.
HOOLEY
&&
.AVIATION...
EXPECT SOME MID AND HIGH LEVEL CLOUDS TO MOVE ACROSS THE FORECAST
AREA TODAY. DRY CONDITIONS WILL CONTINUE WITH VFR CONDITIONS
PREVAILING THROUGHOUT THE DAY. THE MAIN CONCERN WILL BE STRONG
WINDS ACROSS THE UPPER YELLOWSTONE AND STILLWATER VALLEYS THROUGH
EARLY THIS AFTERNOON. WINDS OF 25 TO 40KTS WITH A FEW GUSTS
AROUND 50KTS ARE LIKELY. EXPECT THE STRONG WINDS TO BEGIN TO
TAPER OFF THIS AFTERNOON. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 060 031/054 031/041 025/040 023/050 026/040 023/031
0/N 00/B 22/W 20/B 00/B 22/J 11/B
LVM 058 028/051 022/036 017/038 025/046 026/037 020/029
0/N 02/W 32/J 21/B 00/N 33/J 11/B
HDN 062 030/058 031/044 020/043 022/051 023/044 020/034
0/U 00/B 22/W 21/B 00/B 12/W 11/B
MLS 059 028/056 032/044 019/042 020/048 022/040 021/036
0/U 00/B 22/W 21/B 00/B 12/J 11/B
4BQ 063 028/059 031/043 020/041 020/048 022/042 021/033
0/U 00/U 22/W 21/B 00/U 02/J 11/B
BHK 058 030/055 032/041 020/038 017/044 021/039 020/036
0/U 00/U 22/W 21/B 00/B 12/J 11/B
SHR 061 035/057 028/042 020/041 017/054 021/039 019/031
0/U 00/B 23/J 21/B 00/U 12/J 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 1 PM MST THIS AFTERNOON FOR
ZONES 65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
