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000
FXUS63 KLSX 200818
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
318 AM CDT THU JUN 20 2013

.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 317 AM CDT THU JUN 20 2013

EARLY THIS MORNING...A RIDGE-RUNNER SHORTWAVE IS LOCATED JUST W OF
THE MS RIVER AND HAS BEEN KICKING UP CLOUDS AS A RESULT.  WEAKER
UPPER LEVEL DISTURBANCES EXIST FURTHER UPSTREAM IN NRN KS AND
NEBRASKA CLOSER TO THE CURRENT LOCATION OF THE UPPER LEVEL RIDGE
AXIS.  AT THE SFC...HI PRES CENTERED OVER THE ERN GREAT LAKES REGION
CONTINUES TO HAVE A WIDE INFLUENCE AND RESULTING IN A LIGHT SE FLOW.
MOSTLY CLEAR SKIES GRACE MUCH OF THE FA WITH TEMPS IN THE 60S.

UPPER LEVEL RIDGE OVER THE PLAINS WILL STRENGTHEN AND AMPLIFY TODAY
AND THEREFORE MAKE IT MUCH MORE DIFFICULT FOR ANY ADDITIONAL UPPER
LEVEL DISTURBANCES TO SUCCESSFULLY CROSS THRU.  ONE SUCH IS LOCATED
OVER IN ERN CO ATTM AND IS LOOKING INCREASINGLY LIKELY IT WILL BE
STUCK ON THE PLAINS AS A RESULT...WHICH WOULD DISCOUNT THE 00Z NAM
FCST WHICH HAS THIS FEATURE MAKING A RUN ON ERN MO LATE THIS AFTN.
CLOSER TO HOME...THE SHORTWAVE OVER ERN MO IS EXPECTED TO VERY
SLOWLY OOZE EWD TODAY...AND SHOULD STILL BE OVER SWRN IL THIS
AFTERNOON.  THE ENVIRONMENT WILL BE AGAIN GEARED TOWARDS ORDINARY
CELLS WITH WEAK SHEAR...NO CINH...AND MODEST CAPE GENERALLY LESS
THAN 1000 J/KG.  THE ONLY FOCUS TO REALLY KEY IN ON IS THE
RIDGE-RUNNER SHORTWAVE WHICH WILL PROVIDE SOME SOURCE OF LIFT AND
MIGHT BE ENOUGH SANS A DECENT SFC BOUNDARY TO KICK OFF ISOLD
SHRA/TSRA.  WILL NEED TO MONITOR FOR POTENTIAL OF /SUNRISE SURPRISE/
THRU MID MORNING BUT LOOKING DOUBTFUL.  AT THIS TIME...AND UNTIL A
BETTER SOURCE OF LIFT PRESENTS ITSELF...CAN ONLY JUSTIFY NO MORE
THAN SLIGHT CHCS IN THIS SETUP AND CENTERED ON THE AFTERNOON HOURS.

H850 TEMPS EXPECTED TO BE ABOUT 1-2C HIGHER THAN PERSISTENCE WITH
SIMILAR SUNSHINE AND MORE SLY ORIENTED WINDS...AND SHOULD TRANSLATE
TO ABOUT A 2-4F INCREASE FROM MAX TEMPS ON WEDNESDAY...OR MAX TEMPS
IN THE 85-90F RANGE.

TES

.LONG TERM...(THURSDAY THROUGH NEXT WEDNESDAY)
ISSUED AT 340 PM CDT WED JUN 19 2013

(THURSDAY THROUGH SATURDAY)

FORECAST AREA TO REMAIN IN WARM SECTOR ON THURSDAY. AS FOR PCPN
CHANCES WILL DEPEND ON HOW FAR EAST THE REMNANTS OF AN MCS OVER KS
MAKES IT AS IT DRIFTS EAST TOWARDS CENTRAL MO BY MIDDAY THURSDAY.
FOR NOW HAVE CHANCE POPS OVER CENTRAL/NORTHEAST MO...WITH SLIGHT
CHANCES FURTHER EAST. OTHERWISE...WARMING TREND TO CONTINUE WITH
HIGHS IN THE MID 80S TO AROUND 90.

THURSDAY NIGHT...LOW LEVEL JET AND FRONTAL BOUNDARY FOCUS ACTIVITY
JUST TO OUR NORTH OVER IOWA...NOT SURE HOW FAR SOUTH SOUTHERN EDGE
MAY BE...SO KEPT SLIGHT CHANCE/CHANCE POPS IN OUR FAR NORTHERN
COUNTIES AFTER 06Z FRIDAY. MILD CONDITIONS TO PERSIST WITH LOWS ONLY
DIPPING INTO THE UPPER 60S.

MODELS CONTINUE TO SHOW CORFIDI VECTORS POINTING TO A
SOUTHEASTERLY/SOUTHERLY TRAJECTORY FOR ANY COMPLEX THAT DEVELOPS TO
OUR NORTH...SO COULD SEE DYING MCS MOVE INTO FORECAST AREA ON
FRIDAY. FOR NOW HAVE BEST CHANCES OVER FAR NORTHERN PORTIONS OF
CWA...WITH SILENT SLIGHT CHANCE POPS FURTHER SOUTH. HIGHS WILL BE IN
THE UPPER 80S TO LOW 90S.

COULD SEE A REPEAT OF THIS FRIDAY NIGHT AND SATURDAY...BUT WITH
REMNANTS A BIT FURTHER EAST ON SATURDAY...SO HAVE SILENT SLIGHT
CHANCE POPS DURING THE DAY ON SATURDAY. LOWS FRIDAY NIGHT WILL BE IN
THE LOW 70S AND HIGHS ON SATURDAY IN THE LOW 90S.

(SATURDAY NIGHT THROUGH WEDNESDAY)

UPPER LEVEL RIDGE BUILDS IN A BIT MORE FOR THE LAST HALF OF THE
WEEKEND WITH ACTIVITY SHIFTING A BIT FURTHER NORTH. BUT HOT AND
HUMID CONDITIONS TO PERSIST WITH HIGHS ON SUNDAY IN THE LOW 90S.

THEN UPPER LEVEL RIDGE TO FLATTEN A BIT FOR THE BEGINNING OF THE
WORK WEEK...THEN NEXT WEATHER SYSTEM APPROACHES AREA BY WEDNESDAY.
BUT CONFIDENCE IS LOW ON HOW FAR SOUTH AND EAST ACTIVITY WILL MAKE
IT SO KEPT SILENT SLIGHT CHANCE POPS FOR REST OF FORECAST PERIOD FOR
PORTIONS OF THE FORECAST PERIOD. OTHERWISE...HIGHS WILL REMAIN IN
THE UPPER 80S TO LOW 90S AND LOWS IN THE LOW 70S.

BYRD

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1136 PM CDT WED JUN 19 2013

NO MAJOR CHANGES IN EARLIER THINKING...WITH WESTERN PERIPHERY OF
SURFACE RIDGE CONTINUING VFR CONDITIONS ACROSS OUR AREA FOR THE REST
OF TONIGHT AND INTO AT LEAST THURSDAY MORNING.  00Z NAM IS FOCUSING
ON CONVECTIVE CLUSTER FIRING ACROSS KANSAS OVERNIGHT WHICH GENERATES
AN MCV THAT IN TURN WORKS INTO OUR AREA AND IGNITES ADDITIONAL
CONVECTION DURING THE LATE MORNING AND AFTERNOON. THIS IS A
FAIRLY MAJOR CHANGE FROM EARLIER SOLUTIONS...AND IS ALSO A MUCH
MORE ROBUST SOLUTION THAN THE 00Z GFS WHICH HINTS AT A THREAT OF
CONVECTION THAT WILL BE MUCH MORE HIT AND MISS. BECAUSE OF THIS
CONSIDERABLE UNCERTAINTY WILL STICK WITH DIURNALLY DRIVEN CU FIELD
FOR NOW...AND LET MID SHIFT MONITOR CONVECTIVE TRENDS OVERNIGHT TO
ASCERTAIN WHETHER THE ADDITION OF TSRA IS WARRANTED IN LATER
FORECASTS.

SPECIFICS FOR KSTL...

GENERALLY CLEAR SKIES EXPECTED OVERNIGHT...GIVING WAY TO FAIR
WEATHER CU AOA 3KFT BY LATE THURSDAY MORNING AND INTO THE
AFTERNOON.  AS MENTIONED ABOVE...WILL NEED TO KEEP AN EYE ON
CONVECTION POTENTIAL THURSDAY AFTERNOON BUT AT THIS TIME IT APPEARS
ANY COVERAGE WILL BE VERY SPOTTY...SO THREAT IN VICINITY OF TERMINAL
WILL BE VERY LOW.  LIGHT EAST WINDS TONIGHT WILL VEER TO THE SOUTH
BY LATE THURSDAY MORNING...WITH SPEEDS INCREASING TO AROUND 8 KTS OR
SO.

TRUETT

&&

.PRELIMINARY POINT TEMPS/POPS...
SAINT LOUIS     90  70  93  71 /  20  10  20  10
QUINCY          88  68  89  70 /  20  20  20  10
COLUMBIA        89  69  91  70 /  20  10  20  10
JEFFERSON CITY  90  69  91  70 /  20  10  30  10
SALEM           87  67  89  70 /  20  10  10  10
FARMINGTON      88  66  89  68 /  20  20  10  10

&&

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

$$

WFO LSX