High Wind in Montana, September 1, 2001

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
300 PM MDT SAT SEP 1 2001

WSW FLOW ALOFT TO CONTINUE THROUGH THE PERIOD WITH FLOW ALSO WEAKLY
ANTICYCLONIC. ALTHOUGH SEVERAL WEAK SHORTWAVES ARE FORECAST TO MOVE
THROUGH THE FLOW RHS AT OR ABOVE 70 PCT ARE FORECAST TO BE NEAR OR
ABOVE 500 MBS. ALSO MODELS KEEP LIFTED INDICES NEAR OR ABOVE ZERO.
SO WITH STABLE AND DRY AIRMASS WILL GO WITH ZERO PCT POPS ACROSS THE
BOARD FOR ALL STATIONS. AS FOR THE HIGH WIND WARNING...SURFACE WINDS
IN THE WARNING AREA ARE NOT ALL THAT STRONG AS OF 20Z BUT EXPECT
THEM TO PICK UP LATER THIS AFTERNOON AS A SHORTWAVE APPROACHES THE
WARNING AREA. 18Z MESOETA  HAS BACKED OFF JUST A FEW KNOTS ON THE 700
MB WINDS FORECAST FOR 00Z SUN. ALTHOUGH SITUATION LOOKS RATHER
MARGINAL FOR HIGH WINDS LATE THIS AFTERNOON AND EVENING DO PLAN TO
CONTINUE THE WARNING. SURFACE WINDS ARE EXPECTED TO BE LIGHTER SUN
OVER THE PLAINS AS SURFACE GRADIENTS ARE MUCH WEAKER AND 700 MB WINDS
ARE ABOUT HALF THOSE FORECAST FOR SAT AFTERNOON. A SHORTWAVE MOVING
THROUGH SRN CAN ON LABOR DAY IS FORECAST TO RESULT IN STRONGER 700 MB
WINDS THOUGH NOT AS STRONG AS THOSE OF SATURDAY. IN ADDITION AVN
FORECASTS WEAK SURFACE DOWNSLOPE GRADIENTS TO DEVELOP. PATTERN LOOKS
STRONG ENOUGH TO POSSIBLY WARRANT ANOTHER FIRE WEATHER WATCH BUT WILL
HOLD OFF UNTIL SUNDAY BEFORE MAKING FINAL DECISION ON WHETHER TO
ISSUE A FIRE WEATHER HIGHLIGHT AND IF SO WHICH KIND TO ISSUE. BLANK

EXTENDED...MEDIUM RANGE MODELS IN FAIRLY DECENT AGREEMENT. MRF HAS
COME AROUND TO A CLOSER POSITION TO THE ECMWF. UPPER TROF
APPROACHES THE WEST COAST DAY 3 PLACING CWA UNDER SOUTHWEST FLOW
ALOFT. BY DAY 4 A CLOSED UPPER LOW DEVELOPS OFFSHORE OF NORTHERN
CALIFORNIA AND REMAINS THERE THROUGH DAY 6. THIS DIFFERS FROM
YESTERDAYS SOLUTION THAT HAD THE UPPER LOW OVER NEVADA DURING THE
SAME PERIOD. THE LOW MOVES INLAND DAY 7 AND THROWS A UPPER RIDGE
OVER THE AREA. WILL CONTINUE A FORECAST OF PRECIPITATION ACROSS THE
AREA DAYS 3 THROUGH 5 WITH DRY CONDITIONS RETURNING DAYS 6 AND 7.

CCF NUMBERS
GTF BB 050 080 052 087 050 040000
CTB EN 046 075 048 082 046 040000
HLN BB 052 084 052 088 052 040000
BZN BB 047 084 047 087 048 040000
WEY BB 038 080 038 082 040 040000
DLN BB 045 084 047 086 048 040000
HVR BB 050 085 050 092 050 040000
LWT BB 048 079 048 086 047 040000