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000
FXUS63 KLSX 120503
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1203 AM CDT WED JUN 12 2013

.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 333 PM CDT TUE JUN 11 2013

MOST OF THE ISOLATED SHOWERS SHOULD SHIFT N-NE OF OUR FORECAST AREA
BY THIS EVNG AS THE WARM FRONT SHIFTS N-NE OF OUR AREA AND THE
ATMOSPHERE BECOMES MORE CAPPED DUE TO THE MID LEVEL RIDGE CENTERED
OVER THE SRN PLAINS.  THE OPERATIONAL MODELS KEEP ALL THE CONVECTION
N-NE OF OUR FORECAST AREA TGT...ALTHOUGH THE 4 KM NCEP WRF DOES HAVE
SCATTERED SHOWERS AND STORMS DROPPING SEWD THROUGH A SMALL PORTION
OF NERN MO AND W CNTRL AND SWRN IL ON THE EDGE OF THE CAP THIS
EVNG.  WILL INCLUDE SLIGHT CHANCE POPS ON THE EXTREME NRN AND ERN
PORTIONS OF OUR FORECAST AREA EARLY THIS EVNG AS CONVECTION MAY HUG
THE NRN AND ERN FRINGES OF OUR AREA THIS EVNG.  OTHERWISE JUST SOME
MID-HIGH LEVEL CLOUDS TGT.  WARMER...ABOVE NORMAL LOW TEMPERATURES
CAN BE EXPECTED TGT DUE TO WARM 850 MB TEMPERATURES...S-SWLY SFC
WINDS AND RELATIVELY HIGH SFC DEW POINTS.

GKS

.LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY)
ISSUED AT 333 PM CDT TUE JUN 11 2013

(WEDNESDAY)

UPPER LEVEL RIDGE WILL DOMINATE OUR REGION FOR MOST OF THIS
PERIOD...ENOUGH TO GIVE US ONE MORE HOT SUMMERLIKE DAY...BEFORE
GETTING REPRESSED BY A STRONG SHORTWAVE LATE IN THE DAY.

MAX TEMPS AT OR JUST ABOVE PERSISTENCE EXPECTED TO BE THE RULE WITH
A WARMER START TO THE DAY...MORE SUNSHINE...AND COMPARABLE H850-900
TEMPS.  SIDED WITH THE WARMER MOS OR JUST A DEG OR SO ABOVE.

APPROACH OF SHORTWAVE LATE IN THE DAY...AND DEPENDING ON HOW FAR S
AN OUTFLOW FROM WHAT SHOULD BE A CONVECTIVE WIND EVENT IN NRN IL
EARLY IN THE DAY...WILL SETUP THE BOUNDARIES NEEDED TO BEGIN
BREAKING WHAT SHOULD BE A WEAKER CAP IN PLACE OVER IN IL...
INITIALLY...AND THEN MAY SPREAD WWD ALONG THE FRONT DURING WEDNESDAY
EVENING BUT STRONGER CAP ON THE MO SIDE OF THE MS RIVER SHOULD HAVE
A BETTER TIME SUPPRESSING OR AT LEAST LIMITING CONVECTION.  WHAT
DOES DEVELOP DURING THE LATE AFTERNOON AND EVENING...HOWEVER...WILL
LIKELY HAVE THE POTENTIAL FOR SOME SEVERE WITH OVER 3000 J/KG OF
CAPE AND DECENT 40KTS OF 0-6KM BULK SHEAR WITH LARGE HAIL AND
DAMAGING WINDS THE PRIMARY THREATS.  SYNOPTIC CDFNT WILL THEN KEEP
THE THREAT FOR PCPN GOING THRU WEDNESDAY NIGHT ALTHOUGH ONCE THE
MAIN SVR EVENT IS DONE LATER WEDNESDAY EVENING...POPS WILL BE
MINIMAL.

(THURSDAY - FRIDAY)

UPPER LEVEL RIDGE WILL RETREAT FARTHER TO THE SRN PLAINS AND GIVE US
A COUPLE OF DAYS OF NW FLOW...ALLOWING A SFC CDFNT TO PUSH INTO THE
DEEP SOUTH BY LATE THURSDAY AFTERNOON AND MAINTAIN THE INFLUENCE OF
COOLER HI PRES THRU FRIDAY.

THIS SHOULD GIVE US A REPRIEVE FROM THE RAIN CHCS AND HOT WX...WITH
MAX TEMPS ANTICIPATED TO ONLY BE IN THE LO-MID 80S THURSDAY AND UPR
70-LO 80S FRIDAY.

A MODEL DEPICTED CONVECTIVELY INDUCED VORT IS DEPICTED AS MOVING
THRU FRIDAY AND MAY TRY TO PUSH SOME TSRA INTO THE AREA...BUT MODELS
ARE VERY BULLISH ON THE DRY...AND CONSEQUENTLY STABLE...AIR AND PROG
WHATEVER DOES TRY TO MOVE IN TO FATALLY WEAKEN.  HAVE MAINTAINED THE
SLGT CHC POPS FROM PREV FCST AS FEEL IT IS WORTH AT LEAST A
MAINTENANCE OF THAT.

(SATURDAY - NEXT TUESDAY)

AFTER UPPER LEVEL RIDGE BRIEFLY TRIES TO RE-ASSERT ITSELF ON
SATURDAY...THE PATTERN AGAIN BREAKS DOWN WHERE THE RIDGE RETROGRADES
TO THE WRN CONUS...BUT NOT AS AMPLIFIED AS THE MODELS SHOWN
YESTERDAY...GIVING US ANOTHER ROUND OF WHAT SHOULD BE ACTIVE NW FLOW
AS A SERIES OF UPPER LEVEL DISTURBANCES AND A SFC FRONT MOVE INTO OR
THRU THE REGION.

HAVE GONE WITH PERSISTENT CHCS FOR TSRA THIS PERIOD...WHICH IS A
CONTINUATION OF THE FCST FROM THE LAST DAY OR TWO...AND CONSEQUENTLY
THE PCPN SHOULD LIMIT TEMPS INTO THE 80S AND KEEP THE HEAT AT BAY.

TES

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1153 PM CDT TUE JUN 11 2013

VFR CONDITIONS ARE EXPECTED TO DOMINATE MUCH OF THE PERIOD. BOUTS
OF HIGH CLOUDS WILL CONTINUE TO IMPACT EASTERN MO AND WESTERN
ILLINOIS INTO WED MORNING. SOUTH SOUTHWESTERLY SURFACE WINDS WILL
THEN INCREASE AROUND MID-MORNING ON WEDNESDAY WITH GUSTS AOA 25
KTS. THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS
PORTIONS OF NE MO AND WEST CENTRAL IL DURING THE LATER PART OF
WEDNESDAY AFTERNOON AND INTO THE EARLY EVENING AS A COLD FRONT
DROPS SOUTH INTO THE AREA. CONFIDENCE AT THIS TIME IS TOO LOW FOR
AN ACTUAL AIRPORT IMPACT TO INCLUDE IN THE KUIN TAF.

SPECIFICS FOR KSTL...

VFR CONDITIONS ARE EXPECTED TO DOMINATE MUCH OF THE PERIOD WITH
BOUTS OF HIGH CLOUDS CONTINUING OVERNIGHT THROUGH WEDNESDAY
MORNING. SOUTH SOUTHWESTERLY SURFACE WINDS WILL THEN INCREASE
AROUND MID-MORNING ON WEDNESDAY WITH GUSTS AOA 25 KTS. A COLD
FRONT WILL BE DROPPING INTO EASTERN MO ON WEDNESDAY EVENING AND IT
COULD BE ACCOMPANIED BY SCATTERED THUNDERSTORMS. IF THERE IS ANY
IMPACT AT KSTL...CURRENT INDICATIONS ARE THAT 04-07Z WOULD BE THE
OPTIMAL TIME FRAME...HOWEVER CONFIDENCE IS TOO LOW TO MENTION AT
THIS TIME.

GLASS

&&

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

$$

WFO LSX