000
FXUS63 KLSX 121934
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
234 PM CDT WED JUN 12 2013

.SHORT TERM...(THROUGH TONIGHT)
ISSUED AT 155 PM CDT WED JUN 12 2013

FOCUS THRU THE PERIOD WILL BE POPS AND SVR THREAT.

SFC LOW...CURRENTLY NEAR KALO IN IA...IS PROGD TO MOVE EWD INTO
NRN IL...THEN NRN IN LATE TONIGHT. STRONG CAP REMAINS IN PLACE
OVER THE CWA THIS AFTERNOON. MDL GUIDANCE IS IN GENERAL AGREEMENT
THAT AS THIS LOW MOVE EWD AND THE CDFNT DROPS INTO THE CWA...TSRA
ARE EXPECTED TO FORM SE OF THE MAIN MCS ALONG THE CDFNT. THE MAIN
QUESTION FOR TONIGHT IS HOW FAR SW THESE TSRA WILL
DEVELOP/PROPAGATE. BASED ON 12Z GUIDANCE...BELIEVE TSRA WILL
REMAIN ALONG AND MAINLY E OF THE MIS RIVER TONIGHT. HAVE ADJUSTED
POPS A LITTLE FARTHER W TONIGHT BASED ON THE 12Z DATA.

THAT SAID...HAVE SLIGHT CHANCE POPS THAT MAY BE TOO FAR W...BUT
HAVE DONE SO DUE TO AMOUNT OF UNCERTAINTY REGARDING WHERE STRONGER
CAP WILL REMAIN IN PLACE AS THE CDFNT MOVES S. BASED ON 18Z
SOUNDINGS FROM DVN/ILX...ANY STORM THAT DEVELOPS ALONG THE FNT AS
IT MOVES S HAS A HIGH PROBABILITY OF BECOMING SVR WITH MAIN
THREATS OF DAMAGING WIND GUSTS AND LARGE HAIL.

AS FOR TEMPS TONIGHT...HAVE TRENDED TWD WARMEST GUIDANCE DUE TO A
RATHER WARM DAY TODAY AND NOT MUCH COOLING ANTICIPATED
TONIGHT...EVEN BEHIND THE FNT.

TILLY

.LONG TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 337 AM CDT WED JUN 12 2013

AFTERNOON/EVENING CONVECTION SHOULD BE EXITING THE AREA BY 06Z.
CANNOT RULE OUT A STRAY SHOWER OR STORM OUT AHEAD OF OR RIGHT ON THE
COLD FRONT AS IT PUSHES THROUGH EAST CENTRAL AND SOUTHEAST MISSOURI
AND SOUTHERN ILLINOIS.  NORTHWEST FLOW WILL BRING COOLER AND DRIER
AIR WITH SURFACE DEWPOINTS DROPPING BACK INTO THE UPPER 50S AND
LOWER 60S.  850MB TEMPS ALSO DROP INTO THE LOW TO MID TEENS BEHIND
THE FRONT.  MODELS HAVE BEEN CONSISTENTLY AMPLIFYING THE FLOW
THURSDAY INTO FRIDAY WITH A FULL LONGWAVE TROF OVER THE EAST COAST
AND THE UPPER LEVEL RIDGE BUILDING ACROSS THE GREAT PLAINS INTO THE
UPPER MIDWEST.  THIS SHOULD KEEP THE LOW LEVEL RIDGE LOCKED IN
ACROSS THE MISSISSIPPI VALLEY AT LEAST THROUGH FRIDAY.  SEASONABLY
COOL GUIDANCE TEMPS LOOK PRETTY REASONABLE WITH AFOREMENTIONED COOL
AND DRY RIDGE IN PLACE.  THERE IS A SMALL CHANCE THAT INCREASING
WARM ADVECTION ON THE WESTERN PERIPHERY OF THE LOW LEVEL RIDGE MAY
PRODUCE ISOLATED SHOWERS OR STORMS FRIDAY OVER PARTS OF CENTRAL AND
NORTHEAST MISSOURI SO HAVE SOME SLIGHT CHANCE POPS IN THOSE AREAS.

THE WEEKEND IS LOOKING MORE AND MORE STORMY AS THE UPPER LEVEL RIDGE
BREAKS DOWN IN RESPONSE TO A SHORTWAVE WHICH IS PULLED NORTHEAST OUT
OF THE GULF OF MEXICO.  THIS WAVE IS LIKELY TO HAVE QUITE A BIT OF
MOISTURE ASSOCIATED WITH IT.  AM UNSURE WHAT THE POTENTIAL FOR
SEVERE WEATHER WILL BE AT THIS TIME...BUT IT DOES LOOK LIKE THERE
WILL BE THUNDERSTORMS ON AND OFF FROM SATURDAY AFTERNOON AT LEAST
THROUGH SUNDAY NIGHT OR MONDAY AND SOME LOCALLY HEAVY RAIN MAY BE
POSSIBLE.  TUESDAY LOOKS DRIER AS THE WAVE MOVES EAST AND WEAK
RIDGING BUILDS BACK ACROSS THE MID MISSISSIPPI VALLEY.  TEMPERATURES
THROUGH THE PERIOD LOOK TO BE NEAR NORMAL.

CARNEY

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1230 PM CDT WED JUN 12 2013

A COLD FRONT CURRENTLY EXTENDING FROM WESTERN IOWA SOUTHWESTWARD
THROUGH EAST CENTRAL KANSAS WILL MOVE THROUGH THE AREA THIS
FORECAST PERIOD. CURRENT THINKING IS THAT DRY VFR CONDITIONS WILL
PREVAIL AT AREA TAF SITES THROUGH THE PERIOD...WITH A POTENTIAL TO
DECREASE TO LOW-END MVFR DURING THE LATE OVERNIGHT AND EARLY
MORNING HOURS ON THURSDAY AFTER FROPA. THE MAIN UNCERTAINTY THIS
FORECAST PERIOD REVOLVES AROUND TSRA CHANCES...WITH KUIN
MAINTAINING HIGHEST PROBABILITY OF SEEING SHRA/TSRA DURING THE
LATE AFTERNOON AND EARLY EVENING. ANY STORMS THAT DEVELOP COULD
BECOME SEVERE...ACCOMPANIED BY DAMAGING WINDS AND LARGE HAIL.
HOWEVER...FEEL THAT MAIN FOCUS FOR STORMS REMAINS FURTHER NORTH
ACROSS IOWA...THUS HAVE MAINTAINED VCTS IN THE KUIN TAF GIVEN
UNCERTAINTIES DUE TO COVERAGE THAT FAR SOUTH. WHILE THERE IS A
CHANCE FOR SOME SHRA/TSRA ACTIVITY AHEAD OF THE FRONT...EXPECT
MAJORITY OF THE COVERAGE TO REMAIN NORTH AND EAST OF METRO AREA
TAF SITES AT THIS TIME. EXPECT FROPA TO OCCUR AROUND THE 06-07Z
TIME FRAME AT KCOU AND KUIN...AND 08-09Z FOR METRO TAF SITES.

OTHERWISE...GUSTY SOUTHWEST WINDS WILL CONTINUE THROUGH THE
REMAINDER OF THE AFTERNOON BEFORE THE GUSTS DIMINISH AFTER SUNSET.
WINDS WILL GRADUALLY VEER TO THE NORTHWEST BEHIND THE
FRONT...AND DESPITE THE WINDS REMAINING BETWEEN 10-12KT...DO NOT
EXPECT IT TO BE AS GUSTY ON THURSDAY.

SPECIFICS FOR KSTL...

DRY AND VFR CONDITIONS SHOULD PREVAIL FOR A MAJORITY OF THIS
FORECAST PERIOD. THERE EXISTS THE POTENTIAL FOR SOME SHRA/TSRA
ACTIVITY AHEAD OF AN ADVANCING COLD FRONT...THOUGH CONFIDENCE
REMAINS TOO LOW TO INCLUDE MENTION IN THE TAF. LOW-END MVFR
CONDITIONS ARE POSSIBLE IN THE WAKE OF THE FRONT DURING THE LATE
OVERNIGHT AND EARLY MORNING HOURS ON THURSDAY...HOWEVER...EXPECT
DRIER AIR TO FILTER IN BEHIND THE FRONT AND THUS NOT TOO SURE
WHETHER THE LOWER CIGS WILL REMAIN SCT OR GO BKN-OVC...THEREFORE
HAVE MAINTAINED TRENDS FOR KSTL AT THIS TIME. OTHERWISE...GUSTY
WINDS TODAY WILL DIMINISH AFTER SUNSET...AND THOUGH WINDS WILL
REMAIN AOA 12KT OVERNIGHT...DO NOT EXPECT IT TO BE AS GUSTY ON
THURSDAY IN THE WAKE OF THE FRONT.

JP

&&

.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS     96  69  84  62 /  30  40   5   0
QUINCY          93  63  81  57 /  50  50   0   5
COLUMBIA        95  67  83  61 /  10  10   0  10
JEFFERSON CITY  96  68  83  62 /  10  10   0  10
SALEM           95  69  81  58 /  30  50   5   0
FARMINGTON      95  67  83  57 /  10  20  10   0

&&

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

$$

WFO LSX