000 FXUS65 KBYZ 071529 CCA AFDBIL SOUTH CENTRAL AND SOUTHEAST MONTANA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE BILLINGS MT 925 AM MDT SUN SEP 7 2003 .SHORT TERM...VALID FOR TDY AND MON... CORRECTED TO INCLUDE FIRE WEATHER WATCH IN WATCH/WARNING/ADVISORY BLOCK. UPDATE TO ZFP. NO UPDATE TO AFP. PREVIOUS FORECAST WAS IN GOOD SHAPE. ONLY CHANGES TO UPDATED ZFP WILL BE TO RAISE CLOUD COVER A LITTLE OVER THE SOUTH CENTRAL ZONES AND TO INCREASE WIND SPEEDS OVER THE W. REMNANTS OF SHORTWAVE OVER SW MT WILL MOVE E THIS AFTERNOON. ANOTHER SHORTWAVE WAS OVER CO THIS MORNING. WATER VAPOR IMAGERY AND 12Z UPPER AIR PLOTS DEPICTED COPIOUS AMOUNTS OF HIGH AND MID LEVEL MOISTURE ADVECTING N INTO FORECAST AREA IN ADVANCE OF CO WAVE. THIS MOISTURE WILL CREATE PARTLY CLOUDY SKIES OVER MOST OF THE REGION THIS AFTERNOON. THE 20 POPS OVER CENTRAL AND EASTERN PORTIONS LOOKED REASONABLE GIVEN LIFT FROM THE SHORTWAVE MOVING E AND MOISTURE MOVING INTO THE AREA. ANOTHER WARM AFTERNOON WILL BE IN STORE FOR THE AREA WITH 700 MB TEMPERATURES AROUND +10 DEGREES C AND GOOD MIXING OF AIRMASS. WILL HAVE SOME WIND GUSTS TO NEAR 20 KNOTS OVER THE W SO RAISED WIND SPEEDS. WILL UPDATE FWF TO INCREASE HAINES INDICES OVER CENTRAL AND E ZONES. OTHERWISE...FIRE WEATHER WATCH LOOKS GOOD FOR NOW AND WILL FURTHER EVALUATE SITUATION THIS AFTERNOON. ARTHUR .LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT... NOT MUCH CHANGE TO THE GOING FORECAST...JUST A FEW TWEAKS HERE AND THERE AS STRONG UPPER TROF MOVES CLOSER. STILL DISAGREEMENT BETWEEN MODELS AS TO HOW DEEP AND WHAT SORT OF TIMING THE SERIES OF UPPER LEVEL DISTURBANCES WILL BE. ECMWF THE DEEPEST...COOLEST...AND SLOWEST OF THE SYSTEMS. UKMET IS THE FASTER AND WARMER SOLUTION WITH THE GFS IN BETWEEN. AS A RESULT WILL NOT TRY AND MICRO-MANAGE PRECIPITATION POTENTIAL GIVEN UNCERTAINTY...WIDESPREAD POTENTIAL LOOKS GOOD TUESDAY THROUGH THURSDAY. LOWERED TEMPERATURES A FEW DEGREES THROUGH THE PERIOD AS GFS MIDDLE OF THE ROAD SOLUTION INDICATING LOW TO MID 60S ACROSS THE AREA BY THURSDAY AND FRIDAY. MODELS TRYING TO PUSH UP SOME WARM AIR UP FROM WYOMING AHEAD OF SUCCESSIVE SURFACE FRONTS TUE-FRI BUT ONCE COOLER AIR IS ENTRENCHED EAST OF THE DIVIDE WOULD TAKE SUSTAINED WARM AIR ADVECTION TO MOVE IT OUT...CURRENT SOLUTION SHOWS ONLY 6 TO 12 HOURS AND THEN A GOOD COLD PUSH SO WILL GO A BIT COOLER. SLIGHTLY WARMER TEMPERATURES FOR SATURDAY AS HEIGHTS BEGIN TO RISE ON BACK SIDE OF TROF. ECMWF HAS A DIFFERENT PLAN WITH A DEEPENING TROF AND CUT OFF LOW OVER SOUTHERN IDAHO KEEPING TEMPERATURES COOL. FOR NOW WILL STICK WITH SLIGHT WARMING TREND. THE FRONT ON WEDNESDAY NIGHT AND THURSDAY LOOKS LIKE IT MAY HAVE SOME VERY WINDY CONDITIONS WITH IT AS 140 KT JET STREAM PUSHES OVER THE AREA WITH 40 TO 50 KTS MIXING DOWN TO 850 MB THURSDAY AFTERNOON. CHAMBERS TDY MON TUE WED THU FRI SAT ------------------------------------------------------- BIL 089 070/085 049/069 044/065 042/064 042/064 041/065 2/T 02/T 32/W 33/W 33/W 30/B 00/B LVM 087 061/072 045/065 040/061 036/059 036/059 036/067 0/B 03/T 33/W 33/W 33/W 30/B 00/B HDN 092 068/087 049/073 044/067 044/064 044/064 042/068 2/T 00/E 32/W 33/W 33/W 30/B 00/B MLS 097 064/096 054/073 043/067 043/063 043/063 041/068 2/T 20/G 32/W 33/W 33/W 30/B 00/B 4BQ 096 063/096 051/075 044/067 044/063 044/063 041/069 2/T 20/G 33/W 33/W 33/W 30/B 00/B BHK 096 058/096 051/074 041/066 041/062 041/062 038/068 2/T 20/G 33/W 33/W 33/W 30/B 00/B SHR 092 059/085 048/075 043/066 043/063 043/063 041/067 2/T 00/E 32/W 33/W 33/W 30/B 00/B .BYZ... MT...FIRE WEATHER WATCH ZONES 123 THROUGH 133 TONIGHT THROUGH MONDAY EVENING. WY...FIRE WEATHER WATCH ZONE 284 TONIGHT THROUGH MONDAY EVENING. $$