000
FXUS63 KLSX 140446
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1146 PM CDT THU JUN 13 2013

.SHORT TERM...(THROUGH TONIGHT)
ISSUED AT 341 PM CDT THU JUN 13 2013

A RATHER PERSISTENT AREA OF CLOUDCOVER CURRENTLY OVER SOUTHEASTERN
MISSOURI AND SOUTHERN ILLINOIS WILL CONTINUE TO SLOWLY MOVE
SOUTHWARD THIS EVENING...WITH REMAINING CUMULUS DISSIPATING AFTER
SUNSET ALLOWING FOR MOSTLY CLEAR SKIES OVERNIGHT. THE ONLY CONCERN
IS AN AREA OF SHOWERS AND THUNDERSTORMS CURRENTLY OVER NORTHEASTERN
KANSAS AND SOUTHEASTERN NEBRASKA...WHICH ARE PROGGED TO CONTINUE TO
MOVE EAST ACROSS THE MISSOURI/IOWA BORDER THIS EVENING. MODELS
INDICATE GRADUAL WEAKENING OF THE STORMS WITH THE LOSS OF DIURNAL
HEATING...AND CURRENTLY IT APPEARS THAT THE PRECIPITATION WILL
DIMINISH PRIOR TO ENTERING THE NORTHWESTERN PORTION OF THE CWA.
OTHERWISE...SURFACE HIGH PRESSURE AND NORTHWEST FLOW ALOFT WILL
CONTINUE TONIGHT...AND WITH LIGHT WINDS EXPECTED ALONG WITH MOSTLY
CLEAR SKIES THERE WILL BE AMPLE RADIATIONAL COOLING. THUS...LOW
TEMPERATURES WILL RANGE FROM THE UPPER 50S TO LOW 60S ACROSS THE
AREA...NEAR OR SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR.

JP

.LONG TERM...(FRIDAY THROUGH NEXT THURSDAY)
ISSUED AT 341 PM CDT THU JUN 13 2013

(FRIDAY THROUGH SUNDAY)

FOCUS THRU THE PERIOD WILL BE POPS.

MDLS ARE IN GENERALLY GOOD AGREEMENT WITH UPPER RIDGE BUILDING INTO
THE REGION ON FRIDAY AND INTO SAT. MDLS PROG THE ONGOING CONVECTION
OVER ERN NEB/NRN KS TO REDEVELOP OVER CNTL IA ON FRI. WITH THE UPPER
RIDGE IN PLACE...THIS CONVECTION SHUD REMAIN N OF THE CWA WITH ONLY
CLOUDS SPREADING SWD OVER THE REGION. HAVE KEPT SLIGHT CHC ACROSS
THE NRN PORTIONS OF THE CWA AS SOME UNCERTAINTY REMAINS HOW FAR S
TSRA WILL BE ABLE TO DEVELOP. SOME GUIDANCE SUGGESTS BETTER CHANCES
DURING THE AFTERNOON WITH BETTER UPPER LEVEL DIVERGENCE WITH SOME
LOWER LEVEL FORCING.

THE UPPER RIDGE GRADUALLY BREAKS DOWN FRI NIGHT THRU SAT TO BECOME
MORE ZONAL AS A SERIES OF S/W ROUND THE TOP OF THE UPPER RIDGE. MDLS
PROG A WEAK UPPER LOW PULLING A PLUME OF SUBTROPICAL MOISTURE NWD ON
THE WRN FRINGE OF THE UPPER RIDGE. THIS MOISTURE PLUME WILL
GRADUALLY RAISE DEWPOINTS OVER THE AREA TO HELP FEED TSRA THRU THE
WEEKEND.

AS THE RIDGE BREAKS DOWN AND MOISTURE RETURN INCREASES...TSRA
CHANCES WILL INCREASE THRU THE WEEKEND. MDLS DIFFER SLIGHTLY
REGARDING TIMING MAKING PINNING DOWN POPS MORE DIFFICULT. ATTM...SEE
NO REASON THAT TSRA WILL NOT BE DIURNALLY DRIVEN. TSRA CHANCES WILL
LINGER IN THE MORNING HOURS AS THE LLJ DIMINISHES WITH A LULL DURING
MUCH OF THE DAY AND TSRA REDEVELOPING DURING THE AFTERNOON AND INTO
THE EVENING. ANY OUTFLOW BOUNDARIES WILL BE A FOCUS...BUT IS TOO
UNCERTAIN ATTM TO PIN DOWN LOCATION.

(MONDAY THROUGH THURSDAY)

FOCUS THRU THIS PERIOD CONTINUES TO BE POPS.

MDLS CONTINUE TO BE RELATIVELY GOOD AGREEMENT REGARDING MASS FIELDS
THRU THE PERIOD. DIFFERENCES DEVELOP BY MON NIGHT REGARDING CDFNT
PLACEMENT. THE GFS IS A SLOW OUTLIER AMONG THE OPERATIONAL
GUIDANCE...BUT DOES HAVE GOOD SUPPORT FROM THE GEFS. IN
GENERAL...HAVE RAISED POPS WHERE AND WHEN MDLS ARE IN AGREEMENT AND
KEPT LOW CHANCE POPS TO ACCOUNT FOR DIFFERENCES IN TIMING.

PRECIP CHANCES AND CLOUD DEBRIS PRESENT ANOTHER FORECAST PROBLEM IN
THE EXTD. HAVE TRENDED TEMPS A LITTLE COOLER AS THE AREA IS PROGD TO
BE UNDER NW FLOW THRU THE PERIOD AND WITH THE ANTICIPATION OF
CLOUDS.


TILLY

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1141 PM CDT THU JUN 13 2013

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH BOUTS OF HIGH
CLOUDS OVERNIGHT THROUGH FRIDAY. HIGH PRESSURE WILL DOMINATE AT
THE SURFACE WITH LIGHT AND VARIABLE WINDS TONIGHT BECOMING
EASTERLY OR EAST SOUTHEASTERLY FRIDAY MORNING.

SPECIFICS FOR KSTL...

VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD WITH BOUTS OF HIGH
CLOUDS OVERNIGHT THROUGH FRIDAY. HIGH PRESSURE WILL DOMINATE AT
THE SURFACE WITH LIGHT AND VARIABLE WINDS TONIGHT BECOMING
EASTERLY FRIDAY MORNING.

GLASS

&&

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

$$

WFO LSX