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000
FXUS63 KLSX 171115
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
615 AM CDT MON JUN 17 2013

.SHORT TERM...(THROUGH LATE TONIGHT)
ISSUED AT 333 AM CDT MON JUN 17 2013

TSRA OVERNIGHT HAS BEEN STRONGLY BOUNDARY-LED WITH DECENTLY HI CAPE
VALUES IN A WEAK SHEAR AND LO CINH ENVIRONMENT...BUT IT APPEARS THAT
MULTIPLE ITERATIONS OF OUTFLOWS HAVE FINALLY BEGUN TO SHOW
DIMINISHING RETURNS ON WHAT THEY CAN KICK OFF WITH RESPECT TO PCPN
AND ANTICIPATE THIS TREND TO CONTINUE THRU SUNRISE PER THE 4KM ARW
WRF FROM NSSL WHICH SEEMS TO HAVE A REASONABLE HANDLE ON THIS THUS
FAR.  LARGE BOW ECHO CURRENTLY OVER SRN KS AND NRN OK WILL CONTINUE
TO DROP E-SEWD AND MISS US.

SYNOPTICALLY...WE HAVE A STATIONARY WEAK FRONT BISECTING OUR
REGION...FROM SERN KS THRU CNTRL MO JUST S OF KCOU/KJEF AND THRU THE
NRN STL METRO AREA AND HEADING INTO CNTRL IL.  THIS SHOULD COME INTO
PLAY ONCE THE HEATING OF THE DAY ENSUES AND WEAKENING WHAT CAP
MANAGES TO BUILD IN DURING THE MORNING HOURS.  WE ARE STILL LOOKING
AT LIKELY AND HIGHER POPS FROM ROUGHLY THE I-70 CORRIDOR AND S WHERE
SFC FRONT CURRENTLY EXISTS AND IS EXPECTED TO BE AT THAT TIME AS
WELL AND AN UPPER LEVEL DISTURBANCE MOVING THRU THIS AFTERNOON.
PROBABLY WILL SEE ANOTHER ROUND OF PULSE TSRA AS THE CONVECTIVE MODE
DU JOUR WITH WEAK SHEAR PERSISTING WITH DECENTLY HI CAPES OF
2000-3000 J/KG...AND SO ISOLD STRONG-SEVERE NOT OUT OF THE
QUESTION.  ANTICIPATED SLOW MOVING NATURE OF ANY CONVECTION WILL
ALSO MAKE LOCALLY HEAVY RAINFALL A THREAT AS WELL.

MOS TEMPS ONCE AGAIN LOOK TOO WARM FOR THIS DAY MOST PLACES...AND
HAVE UNDERCUT BY ABOUT A CATEGORY...WITH LO 80S IN CNTRL-SERN MO AND
MID 80S ELSEWHERE.

WEAK FRONTAL BOUNDARY SHOULD FINALLY BE MAKING A PUSH TO THE S BY
LATE THIS AFTERNOON AND INTO THIS EVENING...SHUNTING THE TSRA THREAT
FURTHER AND FURTHER INTO SERN MO AND SRN IL...BUT APPEARS WILL BE A
SLOW TRANSITION AT THAT...AND SO HAVE CONTINUED THE TREND OF BACKING
UP POPS A BIT MORE TO THE NW FOR TONIGHT.

TES

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 333 AM CDT MON JUN 17 2013

(TUESDAY - WEDNESDAY)

A RELATIVELY DRY PERIOD WILL FOLLOW WITH SFC HI PRES DOMINATING
TUESDAY AND WEDNESDAY AND NW FLOW ALOFT.  MAX TEMPS BOTH DAYS WILL
BE AT OR JUST BELOW NORMAL.

THE ONE FLY-IN-THE-OINTMENT WILL BE POTENTIAL FOR ISOLD TSRA TO
DEVELOP ALONG WEAK CONVERGENCE GENERATED BY A BACKDOOR CDFNT
DROPPING SWWD FROM THE GREAT LAKES REGION...REACHING CNTRL AND SRN
IL DURING TUESDAY AFTERNOON-EVENING.  DECENT DEEP LAYER SHEAR OF
35-40KTS TO ACCOMPANY THIS.  MOISTURE HOWEVER WILL BE MORE MARGINAL
AND SHOULD LIMIT DEVELOPMENT.  HAVE THROWN IN SLIGHT CHCS FOR MOST
AREAS IN IL FOR THIS TIMEFRAME.

(THURSDAY - EARLY FRIDAY)

THE UPPER LEVEL RIDGE WILL BEGIN TO REBUILD OVER THE HI PLAINS BUT
BEFORE IT GETS TOO STRONG...MODELS HAVE A RIDGE-RUNNER SHORTWAVE
SLIPPING THRU AND AFFECTING OUR AREA DURING THIS TIME ALONG WITH A
SFC WRMFNT GRADUALLY MOVING THRU.  THE END RESULT WILL BE A SCENARIO
STILL WORTHY OF CHC POPS WHICH HAVE BEEN IN THE FCST FOR A FEW DAYS
NOW.  HAVE CONTINUED.  DAYTIME MAX TEMPS WILL EDGE ABOVE NORMAL AS
INFLUENCE OF COOL AIRMASS FADES...WITH READINGS EXPECTED TO BE IN
THE MID-UPR 80S THURSDAY.

(FRIDAY - SUNDAY)

THE UPPER LEVEL RIDGE IS STILL EXPECTED TO MAKE A COMEBACK AND
DOMINATE OUR REGION DURING THE WEEKEND.  BEING THE SECOND HALF OF
JUNE...THAT IS NOT ALL THAT UNUSUAL...WITH WHAT SHOULD BE A VERY
WARM LOWER ATMOSPHERE AND CAPPED...AND SHOULD KEEP PCPN CHCS TO A
MINIMUM OUTSIDE OF ANY UNFORESEEN CONVECTIVE COMPLEXES WHICH WE ARE
UNABLE TO RESOLVE AT THIS TIME.  DAYTIME MAX TEMPS WILL BE SEVERAL
DEGS ABOVE NORMAL...WITH READINGS IN THE LO-MID 90S.  AFTERNOON HEAT
INDICES WILL LIKEWISE BE AROUND 100F...ESPECIALLY FOR CNTRL MO AND
THE STL METRO AREA.

TES

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 533 AM CDT MON JUN 17 2013

FOG IN UIN AND CPS SHOULD DISSIPATE QUICKLY BY 13Z MON. DIURNAL
CUMULUS CLOUDS WILL DEVELOP LATE THIS MRNG AND AFTN DUE TO DAYTIME
HEATING WITH SCATTERED SHOWERS AND STORMS THIS AFTN INTO THIS EVNG
FROM COU TO THE ST LOUIS METRO AREA NEAR A WEAK STATIONARY FRONT.
THIS CONVECTION SHOULD SHIFT SE OF THE ST LOUIS METRO AREA BY LATE
EVNG. MOST OF THE CLOUDS SHOULD ALSO CLEAR OUT TGT. SFC WINDS
WILL BE LGT AND VARIABLE TODAY...THEN MAINLY N-NWLY TGT AND
CONTINUED LGT.

SPECIFICS FOR KSTL...MID-HIGH LEVEL CLOUD COVER TODAY ALONG WITH
SCT-BKN DIURNAL CUMULUS CLOUDS LATE THIS MRNG AND AFTN. SCATTERED
SHOWERS AND STORMS SHOULD DEVELOP THIS AFTN AND CONTINUE INTO THE
EARLY EVNG. MAY JUST INCLUDE VCTS IN THE STL TAF DURING THIS TIME
PERIOD. MOST OF THE CLOUDS SHOULD CLEAR OUT TGT...MAY BE JUST
LINGERING HIGH LEVEL CLOUDS. SFC WIND WILL BE LGT AND VARIABLE
TODAY...THEN MAINLY N-NWLY TGT...AND INCREASING TO 7-8 KTS BY LATE
TUE MRNG.

GKS

&&

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

$$

WFO LSX