798 FXUS63 KLSX 070530 AFDLSX AREA FORECAST DISCUSSION...UPDATED AVIATION NATIONAL WEATHER SERVICE ST LOUIS MO 1130 PM CST WED MAR 6 2013 .UPDATE... ISSUED AT 901 PM CST WED MAR 6 2013 LOOKS LIKE THE FORECAST IS IN GOOD SHAPE THIS EVENING. ONLY ANTICIPATING MINOR CHANGES...PRIMARILY TO LOWER TEMPS A BIT OUTSIDE OF THE SNOW FIELD. ELSEWHERE AND OTHERWISE...STEADY AS SHE GOES. CARNEY && .SHORT TERM...(THROUGH LATE TONIGHT) ISSUED AT 310 PM CST WED MAR 6 2013 HEIGHTS ALOFT...ALONG WITH SURFACE PRESSURE...WERE ON THE RISE LATE THIS AFTERNOON AS THE CYCLONIC FLOW CAUSED BY THE DEPARTING MID ATLANTIC/EAST COAST CYCLONE LOOSENED ITS GRIP ON THE MIDWEST. AN APPROACHING RIDGE OF HIGH PRESSURE WILL LEAD TO IDEAL RADIATIONAL COOLING CONDITIONS OVERNIGHT. COLDEST TEMPERATURES...SOME 15 DEGREES BELOW NORMAL...WILL OCCUR ACROSS THE SNOW PACK FROM CENTRAL MISSOURI TO WEST CENTRAL ILLINOIS. CVKING && .LONG TERM...(THURSDAY THROUGH NEXT WEDNESDAY) ISSUED AT 310 PM CST WED MAR 6 2013 SURFACE RIDGE WILL BEGIN TO MOVE OFF TO THE EAST ON THURSDAY... BUT WINDS TO REMAIN FROM THE EAST TO SOUTHEAST. SO DESPITE PLENTY OF SUNSHINE TOMORROW...TEMPERATURES WILL STRUGGLE TO WARMUP... ESPECIALLY OVER SNOWPACK...WHICH IS STILL BETWEEN 3 AND 8 INCHES OVER A LARGE PORTION OF CENTRAL/NORTHEAST MO AS WELL AS WEST CENTRAL IL. SO ADJUSTED TEMPS DOWN IN THIS AREA TO ACCOUNT FOR SNOWPACK. HIGHS WILL RANGE FROM THE MID 30S FAR NORTH TO NEAR 50 FAR SOUTH. LIGHT EAST TO SOUTHEAST WINDS TO REMAIN OVER REGION THURSDAY NIGHT UNDER MOSTLY CLEAR SKIES. TEMPS TO DROP DOWN INTO THE MID TO UPPER 20S. BY FRIDAY...WILL BEGIN TO SEE MID AND HIGH CLOUDS MOVE IN AS WARM FRONT ASSOCIATED WITH NEXT WEATHER SYSTEM LIFTS NORTH THROUGH FORECAST AREA. SO DESPITE WINDS BEGINNING TO VEER TO THE SOUTH A BIT MORE...WILL SEE A LARGE TEMPERATURE GRADIENT ACROSS CWA DUE TO THE LINGERING SNOWPACK. WILL HAVE HIGHS IN THE MID 40S FAR NORTH TO THE MID 50S SOUTH. WEATHER SYSTEM WILL FINALLY BE ON SHORE OVER SOUTHERN CALIFORNIA FRIDAY AFTERNOON...AND BEGIN TO LIFT OUT TOWARDS GREAT PLAINS FRIDAY NIGHT. WITH LOW LEVEL MOISTURE ON THE INCREASE...WILL BEGIN TO SEE SOME PCPN DEVELOP AHEAD OF SYSTEM OVER WESTERN MO. BUT SHOULD REMAIN DRY THROUGH AT LEAST MIDDAY ON SATURDAY WITH BEST CHANCES OF PCPN SATURDAY NIGHT THROUGH SUNDAY NIGHT. SOME INSTABILITY WITH THIS SYSTEM...BUT CONFIDENCE IS LOW ON WIDESPREAD COVERAGE OF THUNDERSTORMS AT THIS TIME...SO JUST PUT IN SLIGHT CHANCE MENTION OF THUNDERSTORMS SATURDAY NIGHT AND SUNDAY. THEN AS SYSTEM SLIDES EAST THROUGH SOUTHERN MO SUNDAY NIGHT...THEN EVENTUALLY LIFT OUT NORTHEAST TOWARDS OHIO VALLEY ON MONDAY...WILL SEE ADDITIONAL ROUNDS OF PCPN...MAINLY IN THE FORM OF RAIN...BUT COULD BE MIXED WITH SNOW AT TIMES AS COLDER AIR FILTERS IN ON BACKSIDE OF SYSTEM. PCPN TO COME TO AN END BY LATE MONDAY AFTERNOON. AS FOR TEMPERATURES THROUGH THE PERIOD...WILL SEE HIGHS IN THE LOW 50S TO LOW 60S SATURDAY AND SUNDAY...BEFORE COOLING OFF INTO THE 40S ON MONDAY. AS FOR LOW TEMPS...MID TO UPPER 30S FRIDAY NIGHT...40S SATURDAY NIGHT...WITH MID 30S TO MID 40S SUNDAY NIGHT. BEYOND THAT...DRY WEATHER THROUGH MID WEEK WITH HIGHS IN THE LOW 40S TO LOW 50S TUESDAY AND WEDNESDAY. LOWS WILL BE IN THE UPPER 20S TO LOW 30S. BYRD && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT) ISSUED AT 1130 PM CST WED MAR 6 2013 WORST FEARS ARE COMING TRUE...AS LO CLOUD FIELD STARTING TO BUILD BACK INTO AREAS IT HAD CLEARED OUT OF EARLIER IN THE DAY AS LO LEVEL RIDGE IS STARING TO OVERTAKE THE CLOUD FIELD AND ITS E FLOW ON THE BACKSIDE IS PUSHING IT BACK IN. FORTUNATELY...THE E FLOW IS VERY LIGHT AND SHOULD ONLY MAKE MODEST GAINS OVERNIGHT. THIS SHOULD MEAN THAT ONLY KUIN IS UNDER ANY REAL THREAT FOR HAVING A LO CIG BUILD BACK IN AND HAVE CHANGED THE TAF TO REFLECT THIS... AND AS A RESULT...REMOVED THE FOG POTENTIAL. LO CLOUDS WILL NEED TO BE WATCHED CLOSELY FOR IMPACT ON STL METRO TERMINALS BUT BELIEVE FOR NOW THEY WILL STAY E THRU SUNRISE AND BY THAT TIME CLOUD LEVEL WINDS WILL HAVE VEERED MUCH MORE TO THE S. LGT/VRBL SFC WNDS WILL BECOME E-SE ON THURSDAY AND CONTINUE BELOW 10KTS THRU THE REMAINDER OF THE TAF PERIOD. SPECIFICS FOR KSTL...VFR THRU THE VALID PERIOD...LO CLOUDS SHOULD STAY TO THE E BUT WILL NEED WATCHING...LGT/VRBL SFC WNDS TO BECOME E-SE ARND 7KTS THURSDAY MORNING. TES && .LSX WATCHES/WARNINGS/ADVISORIES... MO...NONE. IL...NONE. && $$ WFO LSX