000 
FXUS63 KLSX 042330
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
530 PM CST SUN NOV 4 2007

.DISCUSSION...
THE PRIMARY FORECAST CHALLENGE CONTINUES TO BE TIMING AND STRENGTH 
OF THE COLD FRONT WHICH WILL SWEEP THROUGH THE AREA TOMORROW. SHORT 
RANGE MODELS HAVE COME INTO PRETTY GOOD AGREEMENT WITH TIMING THE 
FROPA ACROSS THE CWFA TOMORROW...BUT THERE CONTINUE TO BE MAJOR 
DIFFERENCES BETWEEN HIGH TEMPERATURE FORECASTS BETWEEN THE GFS AND 
THE NAM.  FOR INSTANCE...MAV HIGH FOR KSTL TOMORROW IS 70 WHILE MET 
HIGH IS 59.  SINCE BOTH MODELS ARE SHOWING THE WINDSHIFT THROUGH THE 
MAJORITY OF THE AREA BY 18Z...HAVE LEANED TOWARD THE COOLER GUIDANCE 
EXCEPT IN SOUTHERN SECTIONS OF THE CWFA WHICH LOOK LIKE THEYLL STAY 
SOUTH OF THE FRONT UNTIL 2-3 PM TOMORROW.  FROPA STILL LOOKS DRY 
SINCE ALL OF THE MOISTURE STAYS LOCKED UP SOUTH OF THE OZARKS IN THE 
LOWER MISSISSIPPI VALLEY.  WOULDNT BE TOO SURPRISED TO SEE SOME 
SPRINKLES WITH THE FROPA...OR JUST BEHIND THE FRONT...BUT CHANCES 
MEASURABLE PRECIPITATION LOOK NEGLIGIBLE.

THIS STILL LOOKS LIKE THE COLDEST AIR OF THE SEASON FUNNELING OUT OF 
CANADA BEHIND THE FRONT.  TEMPS FOR TUESDAY THROUGH THURSDAY STILL 
LOOK ON TRACK AND HAVE MADE LITTLE OR NO CHANGE TO THE GOING 
FORECAST IN THOSE PERIODS.  MEDIUM RANGE MODELS ARE ADVERTISING 
ANOTHER STORM SYSTEM MOVING THROUGH THE MIDWEST NEXT WEEKEND...AND 
THIS ONE MIGHT ACTUALLY PRODUCE SOME PRECIPITATION OVER THE BI-STATE 
AREA.  HOWEVER...ANTECEDENT DRY (VERY DRY) CONDITIONS MAKE ME 
CAUTIOUS ABOUT MENTIONING RAIN IN THE FORECAST 6 AND 7 DAYS OUT.  
WOULD LIKE TO SEE A FEW MORE MODEL RUNS TO BUILD UP SOME CONTINUITY 
BEFORE I START ADDING IN SIGNIFICANT POPS TO AVOID FLIP-FLOPPING IN 
THE EXTENDED.


CARNEY

&&

.AVIATION...
FOR THE 00Z TAFS...VFR CONDITIONS ARE EXPECTED TO PREVAIL AREAWIDE 
THROUGH THE ENTIRE VALID TAF PERIOD. LOW PRESSURE WAS LOCATED OVER 
NORTHEAST SD LATE THIS AFTERNOON WITH A COLD FRONT TRAILING 
SOUTHWESTWARD ACROSS THE CENTRAL PLAINS. THE COLD FRONT WILL SWEEP 
ACROSS THE AREA DURING THE DAY ON MONDAY. BY NOON THE FRONT IS 
EXPECTED TO EXTEND FROM NORTHEAST IN ACROSS SOUTHEAST MO INTO 
NORTHEAST TX. TIGHT GRADIENT AND SIGNIFICANT PRESSURE RISES IN THE 
COLD AIR SHOULD LEAD TO NORTHWEST WINDS GUSTING TO AROUND 25 KTS. 
VARIOUS TIME CROSS SECTIONS SUGGEST THAT SCATTERED STRATUS CLOUDS 
AROUND 1 THOUSAND FEET MAY DEVELOP ACROSS THE AREA LATE TONIGHT AND 
EARLY MONDAY MORNING. 

TPS

&&

.FIRE WEATHER...
ADJUSTED DEW POINT FORECAST DOWNWARD THIS AFTERNOON WITH VERY DRY
AIR ALOFT BEING ALLOWED TO MIX DOWN ONCE AGAIN THIS AFTERNOON.
THIS WILL RESULT IN RH VALUES BOTTOMING OUT AROUND 20PCT. IN
COMBINATION WITH LOW FUEL MOISTURE OF 7-8PCT...TEMPS OVER
60F...AND GUSTY WINDS FOR A TIME...THIS WILL CREATE ELEVATED FIRE
DANGER CONDITIONS FOR THIS AFTERNOON. WINDS ARE EXPECTED TO
DIMINISH FROM W TO E ON APPROACH OF A SFC RIDGE THIS AFTERNOON.

TES

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX