High Wind in Montana, September 11, 2003

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
300 AM MDT THU SEP 11 2003

.DISCUSSION...TODAY...MID-HIGH LEVEL MOISTURE ASSOCIATED WITH A
STRONG PACIFIC JET IS ALREADY STREAMING INTO WESTERN MONTANA. ALSO...
THE SURFACE PRESSURE GRADIENT IS IN THE PROCESS OF TIGHTENING ACROSS
NORTH AND CENTRAL MONTANA. THESE FACTORS ARE SETTING THE STAGE FOR A
WINDY DAY ACROSS MOST OF THE CWA...WITH THE STRONGEST WINDS ALONG THE
ROCKY MOUNTAIN FRONT AND ADJACENT PLAINS. I SEE NO REASON TO DEVIATE
FROM THE CURRENT HIGH WIND WARNING IN THE NORTHWEST. OROGRAPHIC LIFT
OVER THE WESTERN MOUNTAINS WILL BRING SOME SHOWERS THERE...BUT
DOWNSLOPE WINDS WILL KEEP ALL OTHER AREAS DRY. THERE WILL BE AN
INCREASE IN MID-HI LEVEL CLOUDS THOUGH.

TONIGHT AND FRIDAY...A COLD FRONT WILL DROP SOUTHWARD FROM CANADA
TONIGHT...MAKING IT INTO SOUTHWEST MONTANA BY FRIDAY MORNING.
ALTHOUGH THERE WILL BE NOT A LOT OF MOISTURE TO WORK WITH...LOW-LEVEL
CONVERGENCE AND DYNAMICS ALOFT SHOULD PROVIDE ENOUGH LIFT TO GENERATE
SCATTERED SHOWERS AHEAD OF AND ALONG THE FRONT. WHILE PRECIP AMOUNTS
WILL BE LIGHT...BOTH ETA/GFS BRING A SWATH OF QPF THROUGH. SO I HAVE
BUMPED UP POPS TO 30-40% RANGE ACROSS NORTH AND CENTRAL ZONES. WINDS
WILL SHIFT TO THE NORTHWEST BEHIND THE FRONT. SCATTERED SHOWERS WILL
MOVE INTO SOUTHWEST MONTANA FRIDAY MORNING. MUCH COOLER AIR WILL
FILTER INTO THE AREA FRIDAY...WITH BREEZY CONDITIONS MAKING IT FEEL
RATHER COOL FOR MID-SEPTEMBER.

FRIDAY NIGHT AND SATURDAY...JUST A SLIGHT CHANCE OF LINGERING
SHOWERS FRIDAY NIGHT WITH CYCLONIC NORTHWEST FLOW ALOFT OVER
MONTANA. SURFACE HIGH PRESSURE AND WARMING TEMPS ALOFT WILL MOVE IN
FOR SATURDAY BRINGING DRY CONDITIONS. VILLANI

SATURDAY NIGHT THROUGH TUESDAY...LATEST RUN OF GFS HAS DONE AN ABOUT
FACE FROM ITS 12Z WED RUN IN THAT PREVIOUS RUN HAD AN UPPER RIDGE
OVER THE NRN ROCKIES TOWARDS MIDWEEK WHILE LATEST RUN HAS A DEEP
TROUGH. NORMALLY WOULD BE LEERY OF BELIEVING THIS RADICAL CHANGE BUT
LAST FEW RUNS OF THE UKMET AND ALSO 12Z WED RUN OF THE ECMWF ARE ALSO
FORECASTING A DEEP UPPER TROUGH TO DEVELOP OVER THE WRN U.S. DID
NOTICE GFS IS A LITTLE SLOWER WITH THE UPPER TROUGH THEN THE
UKMET/ECMWF. MODELS CONTINUE TO FORECAST NW FLOW ALOFT EARLY SATURDAY
NIGHT BACKING TO WSW OR SW ON SUN FOR UNSEASONABLY MILD TEMPERATURES.
MOISTURE ON SUN SHOULD STAY N OF THE BORDER. MON APPEARS TO BE
TRANSITION DAY BEFORE COLDER AND UNSETTLED WEATHER MOVES IN MON NIGHT
OR TUE. THERE IS A 10 TO 15 DEGREE DIFFERENCE BETWEEN LATEST MEX
(GFS) TEMPERATURE GUIDANCE AND INHERITED TEMPERATURES FOR TUE
AFTERNOON. WILL LOWER INHERITED TEMPERATURES CLOSER TO THOSE OF THE
MEX. BLANK

WEDNESDAY AND THURSDAY...THE LOW PRESSURE TROUGH MOVES TO THE EAST BY
WEDNESDAY MORNING WITH THE LOW PRESSURE CENTER MOVING NE INTO CANADA.
THE STATE PRETTY WELL DRIES OUT WITH HIGH PRESSURE BUILDING INTO THE
STATE FROM THE WEST. THURSDAY AFTERNOON HAS A LARGE SURFACE HIGH
CENTERED OVER WYOMING KEEPING US DRY WITH LIGHT WINDS AND WARMER
TEMPERATURES. PREWITT

.CCF NUMBERS
GTF BB 072/045 063/038 064 16042
    BUBEB 042/077 044/073 037/061 036/063 034 10000003200
CTB NN 068/041 059/037 062 16242
    BNBEB 039/070 042/066 035/055 034/056 027 10000003100
HLN EE 072/047 063/039 066 16042
    BUBEB 038/077 041/073 039/066 036/064 035 10000003200
BZN BE 069/044 063/035 062 16033
    BUBEB 034/074 036/075 036/066 032/067 036 10000003200
WEY BE 063/037 056/026 053 16012
    BUBEU 027/063 028/069 030/058 025/061 032 2000022430-
DLN EE 067/047 060/032 062 16033
    BUBEB 037/070 039/073 036/063 035/064 035 20000004210
HVR BB 076/044 064/039 065 16042
    BUBEB 038/075 041/073 037/063 036/063 032 10000003200
LWT BB 071/044 060/036 061 16042
    BUBEB 037/075 042/073 036/063 035/065 034 10000003200

.TFX...HIGH WIND WARNING FOR THE ROCKY MOUNTAIN FRONT AND ADJACENT
       PLAINS FOR TODAY /ZONES 9-10-46-48/.

MTZ008>015-044>055-120010-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
615 AM MDT THU SEP 11 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST
MONTANA

.DAY ONE...TODAY

...HIGH WIND WARNING FOR THE ROCKY MOUNTAIN FRONT AND ADJOINING
PLAINS...
FOR THE FOLLOWING ZONES: NORTHERN ROCKY MOUNTAIN FRONT-EASTERN
GLACIER -LIBERTY-SOUTHERN ROCKY MOUNTAIN FRONT

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.