High Wind in Wyoming, December 23, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
359 AM MST FRI DEC 23 2005

.SHORT TERM...VALID FOR TDY AND SAT...

FAST-MOVING AND SOMEWHAT VIGOROUS SHORTWAVE NOW DRIVING INTO
SOUTHWEST MONTANA (COURTESY OF 130KT H3 JET). MID LEVEL LAPSE
RATES WILL BE QUITE STEEP FOR A BRIEF TIME...AND SOME LIGHTNING
HAS BEEN NOTED WITH THIS WAVE AS IT HAS TRACKED ACROSS THE PACIFIC
NORTHWEST. AT THE SURFACE...A COLD FRONT IS MAKING ITS WAY INTO
THE WESTERN FORECAST AREA NOW. WIND SHIFT NOTED AT LVM AROUND 09Z.
MAIN FORECAST CONCERNS ARE WINDS AND PCPN TODAY...THEN ONLY TEMPS
AS WE GET INTO THE WEEKEND.

GOING FORECAST IS IN PRETTY GOOD SHAPE. WILL KEEP WIND ADVY GOING
FOR THE LVM/NYE AREAS...THOUGH THIS WILL PROBABLY BE BRIEF AS WE
TRANSITION AWAY FROM GAP WINDS WITH ONSET OF COLD ADVECTION. WILL
KEEP STRONG WIND WORDING FOR THE REMAINING CWA. WAS A BIT
CONCERNED ABOUT THE FAR EAST WHERE COLD ADVECTION AND POTENTIAL
FOR LOW LEVEL MIXING WILL BE GREATEST (CONCURRENT WITH PRES RISE
MAX WORKING IN)...BUT WITHOUT STRONG SUBSIDENCE OR TEMP ADVECTION
(EVEN SOME LIFT THIS AFTN IN THE EAST AS UPPER TROF SWINGS
THROUGH)...BELIEVE WINDS WILL STAY BELOW WARNING CRITERIA.

REGARDING PCPN...GREATEST CHANCE OF PCPN OVER THE PLAINS TODAY
SHOULD BE EAST OF BILLINGS...THOUGH WILL PROBABLY SEE A BRIEF
BAND OF SHOWERS COME THROUGH EARLY THIS MORNING WITH FRONT FROM
LVM TO BIL AND SHR. GENERAL ISOLD-SCT POPS SHOULD WORK FINE. SNOW
LEVELS ARE FALLING AS WE WRITE (THEY HAVE BEEN NEAR 8KFT UNTIL
NOW)...BUT BRIEF PERIOD OF DYNAMICS AND STEEP LAPSE RATES WARRANT
ONLY 1-2 INCHES OVER THE CRAZIES/BEARTOOTHS/BIGHORNS.

TEMPS A BIT TRICKY TODAY AS COLD ADVECTION ALREADY KICKING IN
AFTER A WARM NIGHT TO THIS POINT. WE WILL SEE A DROP WITH THE
FRONT (ALREADY DOWN TO 35 A LVM AT 10Z AFTER BEING NEAR 50)...THEN
SOME MODERATION AS THE DAY WEARS ON AND WE GET SOME SUN. HAVE
LOWERED EXPECTED HIGHS A FEW DEGREES DUE TO THE FAST TIMING OF THE
FRONT THIS MORNING.

THING QUIET DOWN THIS EVENING...THEN RAPIDLY TRANSITION TO A LEE-
TROFFING REGIME LATE TONIGHT INTO SATURDAY. THERE APPEARS TO BE
ENOUGH MID LEVEL MOISTURE WITH WARM ADVECTION TO WARRANT LOW POPS
FOR LIGHT SHOWERS/SPRINKLES/FLURRIES ACROSS THE WEST/NORTHWEST
SATURDAY MORNING...BUT BETTER LIFT SHOULD MAKE ITS WAY QUICKLY
NORTH OF US BY AFTERNOON. SHOULD THEN WARM UP NICELY IN THE WEST
ON SATURDAY (HIGHS NEARING 50 AGAIN)...BUT THE EAST SHOULD BE A
BIT COOLER (40S). IF EASTERLY COMPONENT OF WIND SETS UP IN THE
MLS/BHK AREAS ON SATURDAY (ALONG WITH CLOUD COVER ASSOCIATED WITH
WARM FRONT) THEN GUIDANCE WILL BE MUCH TOO WARM. AS IT IS HAVE
STAYED NEAR THE COOL SIDE OF MOS. WILL BE WINDY AND MILD SATURDAY
NIGHT ALONG THE EASTERN SLOPES...AND WOULD BE SURPRISED IF LOW
TEMPS FELL BELOW 40 AT SUCH PLACES AS LVM AND NYE.

.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...

GOOD AGREEMENT CONTINUES BETWEEN THE MODELS FOR THE EXTENDED
PERIOD. GFS HAS ALSO SHOWN GOOD RUN-TO-RUN CONSISTENCY. WARM
AND DRY WEATHER WILL PREVAIL OVER MUCH OF THE AREA THROUGH WED AS
WEAK UPPER RIDGING AND ZONAL FLOW DOMINATE THE AREA. WEAK
SHORTWAVES WILL MOVE THROUGH THIS FLOW BRINGING THE CHANCE OF
MAINLY MOUNTAIN PRECIP. POPS WERE IN GOOD SHAPE. RAISED MAX
TEMPERATURES SUN THROUGH TUE BASED ON DOWNSLOPE FLOW AND PROGGED
850 TEMPS. SUN WILL BE THE WARMEST OF THE FOUR DAYS AS 850 MB
TEMPS FORECAST TO BE BETWEEN +5 AND +10 DEGREES C.

MODELS CONTINUED TO BRING A FAIRLY DEEP UPPER TROUGH ACROSS THE
AREA ON THU AND HAD A DEEP MOIST NW FLOW OVER THE REGION FOR FRI.
POPS LOOKED REASONABLE FOR THU. ON FRI...WENT WITH CLIMO POPS
ACROSS THE AREA. TEMPS WILL BE ABOVE NORMAL FOR THE END OF THE
WEEK. ARTHUR

&&

.AVIATION...

A COLD FRONT NEAR A KBIL-KMLS LINE AT 11Z WILL MOVE SE THROUGH THE
REMAINDER OF THE AREA THROUGH 14Z. ALONG THE FRONT...EXPECT
SURFACE WIND GUSTS IN EXCESS OF 35 KT AND WIDELY SCATTERED SHOWERS
AND THUNDERSTORMS WITH ACCOMPANYING BRIEF MVFR CONDITIONS. BRIEF
PERIODS OF SLEET WILL ALSO BE POSSIBLE AS THE FRONT CROSSES THE
AREA.

CONDITIONS WILL IMPROVE TO VFR REGIONWIDE AFTER 14Z. ARTHUR

&&

.PRELIMINARY POINT TEMP/POPS...

    TDY SAT     SUN     MON     TUE     WED     THU
-------------------------------------------------------
BIL 048 032/050 039/056 039/049 032/045 032/045 032/042
    2/W 00/N    00/B    00/B    02/W    00/B    03/R
LVM 048 034/050 040/056 040/048 036/046 035/045 035/042
    4/W 01/M    00/N    00/B    12/W    22/W    24/R
HDN 048 030/048 030/054 030/049 026/044 026/045 028/042
    3/W 00/B    00/B    00/B    02/W    00/B    03/R
MLS 047 029/045 028/053 030/047 024/043 024/042 022/040
    4/W 00/B    00/B    00/B    01/E    00/B    02/S
4BQ 049 027/044 027/055 030/048 022/043 022/043 024/040
    4/W 00/B    00/B    00/B    02/J    00/B    03/R
BHK 046 025/042 027/052 028/045 024/041 023/040 021/040
    4/W 20/B    00/B    00/B    01/E    00/B    02/R
SHR 050 026/049 029/057 032/049 025/045 023/044 026/041
    4/T 00/B    00/B    00/B    02/W    00/B    02/R

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 5 PM MST THIS AFTERNOON FOR
      ZONES 65-66.
WY...NONE.

&&

WEATHER.GOV/BILLINGS

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BILLINGS MT
424 AM MST FRI DEC 23 2005

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 AM     NON-TSTM WND GST REED POINT              45.70N 109.55W
12/23/2005  65 MPH           STILLWATER         MT   MESONET

&&

JKL