High Wind in Montana, January 2, 2003

SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
843 PM MST THU JAN 02 2003

.SHORT TERM...VALID FOR FRI AND SAT...

UPDATE FOR ZFP ONLY OUT SHORTLY...WILL KEEP HIGH WIND WARNING OUT FOR
PARK COUNTY UNTIL 5 AM. WINDS WEAKENED BRIEFLY THIS EVENING AS UPPER
LEVEL DISTURBANCE PASSED OVER THE AREA ALLOWING SURFACE PRESSURE TO RISE
A BIT IN THE LEE OF THE MOUNTAINS...IN ADDITION A BIT OF COLD AIR
ADVECTION ALOFT ALLOWED FOR INVERSION TO WEAKEN A BIT. LATEST MODELS
SUGGEST PRESSURES WILL BEGIN TO DROP LEE OF THE ROCKIES OVER THE NEXT
COUPLE OF HOURS AS STRONGER 850-700MB FLOW OUT OF THE WEST DEVELOPS
BEHIND SHORTWAVE. CURRENT PRESSURE PATTERN STILL FAVORABLE FOR SUSTAINED
WINDS IN THE 50 TO 55 MPH RANGE AS SUBSIDENCE INVERSION DEVELOPS AROUND
MIDNIGHT AND PRESSURES ONCE AGAIN DROP LEE OF THE ROCKIES STRENGTHENING
GAP FLOW CONDITIONS. LOOKS LIKE GAP FLOW WILL END BY EARLY AFTERNOON
AS STRONG COLD AIR ADVECTION FOLLOWS NEXT SHORTWAVE INTO THE AREA. WILL
ADJUST CLOUD COVER DOWN A BIT PER LATEST SATELLITE AS SUBSIDENT SLOT IS
DISSIPATING MID LEVEL CLOUD DECK A BIT OVER CENTRAL AND EASTERN ZONES.
TEMPERATURES ARE RUNNING A GOOD 10 DEGREES ABOVE LAST NIGHTS READINGS
AT THIS TIME. WITH SOME WARM ADVECTION AND STRONG 850 MB WINDS ACROSS
THE EAST...AND STRONG SURFACE FLOW KEEPING LOWEST 100-150 MB MIXED OUT
IN THE WEST...WILL BUMP TEMPERATURES UP ABOUT 5 DEGREES EVERYWHERE.
TEMPTED TO GO MORE OUT EAST WHERE TEMPERATURES HAVE ACTUALLY RISEN LAST
COUPLE OF HOURS INTO THE LOWER 40S...BUT WINDS SHOULD DECOUPLE BEHIND
SHORTWAVE ALLOWING TEMPERATURES TO FALL PRETTY QUICKLY THEREAFTER...SO
THE 5 DEGREE BUMP SHOULD SUFFICE. CHAMBERS

.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
UPPER WAVE PUSHES INTO NORTHERN ROCKIES/PLAINS SATURDAY NIGHT INTO
SUNDAY. BOTH GFS AND ETA HAVE BEEN PUSHING SURFACE FEATURES WITH THIS
SYSTEM FURTHER EAST IN LAST FEW RUNS...SO BEST CHANCE OF PRECIP LOOKS
TO BE ASSOCIATED WITH COLD FRONT SATURDAY NIGHT. LOWER LEVELS REMAIN
FAIRLY DRY WITH BEST MOISTURE AROUND 700MB...SO CHANCES FOR PRECIP
SLIGHT AT BEST. ANY PRECIP SHOULD END BY SUNDAY AFTERNOON WITH DRY AIR
WORKING IN BEHIND SYSTEM...AND THIS COMBINED WITH PRESSURE RISES AND
COLD ADVECTION SHOULD GIVE EAST WINDY CONDITIONS SUNDAY AFTERNOON.
WILL NOT COOL TEMPS MUCH IN WEST COMPARED TO SATURDAY WITH EASTERLY
TREND OF SYSTEM...BUT WILL DROP TEMPS IN EAST WITH POSSIBLE PRECIP...
CLOUDS...AND COLD ADVECTION LIMITING WARMING.
.
UNSEASONAL TEMPERATURES CONTINUE MONDAY AND TUESDAY WITH UPPER RIDGE
NOSING BACK INTO THE AREA. FORECASTED FIFTIES LOOK VERY REASONABLE
DESPITE FACT THAT THIS IS 20-25 DEGREES ABOVE CLIMATOLOGY. MAJOR
CHANGES COMING ON WEDNESDAY WITH A RETURN TO WINTER LOOKING VERY
LIKELY. GFS HAS BEEN CONSISTENT AND OTHER MODELS ALSO SHOWING STRONG
COLD FRONT DROPPING THROUGH MONTANA TUESDAY NIGHT INTO WEDNESDAY.
TEMPERATURE FORECAST VERY TRICKY AS TIMING OF FRONT WILL PLAY MAJOR
ROLE...WITH 20-25 DEGREE TEMP GRADIENT POSSIBLE ACROSS SOUTHERN
MONTANA BY MIDDAY WEDNESDAY. STRONG BAROCLINIC ZONE ASSOCIATED WITH
THIS FRONT SHOULD BE ENOUGH TO SQUEEZE OUT SOME SNOW...ESPECIALLY WITH
ATMOSPHERE SATURATING RAPIDLY BEHIND FRONT. WINDS WILL ALSO BE
STRONG WITH VERY DEEP COLD ADVECTION AND STRONG WINDS JUST ABOVE THE
SURFACE...AND WILL CONTINUE WITH WINDY WORDING. WILL LINGER PRECIP IN
THE SOUTH AND EAST INTO THURSDAY...AS UPSLOPE FLOW SHOULD DEVELOP AS
HIGH SINKS SOUTH INTO MONTANA. WILL DRASTICALLY COOL TEMPS FOR
THURSDAY...WITH HIGHS STRUGGLING TO REACH TWENTY IN MANY AREAS. JZ

    FRI     SAT     SUN     MON     TUE     WED     THU
-----------------------------------------------------------
BIL 035/054 034/051 034/048 034/053 034/054 033/039 014/024
    00/E    00/E    00/E    00/B    00/B    03/J    33/J
LVM 036/052 036/049 035/046 033/051 035/052 031/036 013/023
    00/N    00/N    00/E    00/B    00/B    03/J    33/J
HDN 033/051 028/051 033/047 032/055 033/055 031/038 013/023
    00/E    03/O    00/E    00/B    00/B    03/J    33/J
MLS 030/049 025/048 029/044 023/049 026/054 027/034 009/020
    00/E    23/O    22/J    00/B    00/B    03/J    30/E
4BQ 032/053 028/048 029/046 026/050 026/054 028/041 012/022
    00/E    20/E    22/J    00/B    00/B    03/J    33/J
BHK 029/048 025/045 026/042 021/046 023/050 024/036 006/018
    00/C    22/O    22/J    00/B    00/E    03/J    30/E
SHR 027/052 025/048 030/048 028/053 028/054 028/044 014/022
    00/E    00/E    00/E    00/B    00/B    03/J    33/J

.BYZ...
MT...HIGH WIND WARNING TONIGHT FOR THE UPPER YELLOWSTONE VALLEY.
WY...NONE.

MTZ028>042-056>058-WYZ098-099-031200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BILLINGS MT
300 PM MST THU JAN 2 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL...SOUTHEAST
MONTANA AND NORTH CENTRAL WYOMING.

.DAY ONE...
STRONG SOUTHWEST WINDS OF 40 TO 55 MPH WITH GUSTS TO 65 MPH WILL
CONTINUE OVER THE UPPER YELLOWSTONE VALLEY THIS AFTERNOON AND
TONIGHT BEFORE DIMINISHING FRIDAY MORNING. REFER TO GTFNPWBYZ FOR
FURTHER DETAILS.

.DAYS TWO THROUGH SEVEN...
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.
HOWEVER...STRONG GUSTY WINDS ARE POSSIBLE ACROSS THE EASTERN PLAINS
ON SUNDAY.

WCJIN-WYNW-WYNE

JZ