Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 310419
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1119 PM CDT SUN AUG 30 2015

.SHORT TERM: (THROUGH TONIGHT)
ISSUED AT 253 PM CDT SUN AUG 30 2015

WEAK SFC BOUNDARY REMAINS STRETCHED ACROSS THE REGION. LATEST
GUIDANCE CONTINUES TO SUGGEST ISOD TO WIDELY SCT TSRA WILL BE
POSSIBLE...MAINLY ACROSS SRN PORTIONS OF THE CWA. WHAT TSRA DO
DEVELOP SHUD DISSIPATE THRU THE EARLY EVENING HOURS.

CLOUDS SHUD DISSIPATE THIS EVENING AS WELL. WITH LIGHT WINDS TONIGHT
AND A CLEAR SKY...ANTICIPATE FG DEVELOPMENT AGAIN TONIGHT FOR AREAS
ALONG AND N OF THE BOUNDARY. THE UNCERTAINTY REMAINS WHERE THE
BOUNDARY WILL BE THRU THE NIGHT AS GUIDANCE SUGGESTS IT WILL LIFT
SLOWLY NWD LATE TONIGHT. HAVE ADDED MENTION OF PATCHY FG ACROSS CNTL
MO WHERE MORE BODIES OF WATER EXIST AND SHUD BE NEAR THE BOUNDARY.
ACROSS THE SRN HALF OF THE CWA...WINDS ARE EXPECTED TO REMAIN SLY
AND HELP PROMOTE MIXING LIMITING ANY DEVELOPMENT. WHATEVER FG DOES
DEVELOP...EXPECT IT TO LINGER INTO MON MORNING FOR A COUPLE OF HOURS
AS THE SFC BOUNDARY LIFTS NWD OUT OF THE REGION.

TILLY

.LONG TERM:  (MONDAY THROUGH NEXT SUNDAY)
ISSUED AT 253 PM CDT SUN AUG 30 2015

(MONDAY THROUGH WEDNESDAY)

KEPT WITH A DRY FORECAST THROUGH THIS PERIOD AS UPPER LEVEL SHEAR
AXIS CURRENTLY OVER THE AREA WILL SHIFT JUST SOUTHEAST OF THE CWA BY
TOMORROW.  IN ADDITION THE GFS/NAM ARE BOTH SHOWING LESS DEEP
MOISTURE AND ASCENT ASSOCIATED WITH THE SHEAR AXIS EACH DAY WHICH
LOWERS THE CHANCES FOR THUNDERSTORMS.  IT WILL BE A WARM PERIOD WITH
HIGHS AROUND 90 GIVEN FORECAST DEEP MIXING INTO THE 850-800MB LAYER
AND 850MB TEMPERATURES NEAR +20C.

(THURSDAY THROUGH SUNDAY)

THE BEGINNING OF THE HOLIDAY WEEKEND PROMISES TO BE A DRY AS THE
MEAN UPPER LEVEL RIDGE AXIS BUILDS OVER THE AREA.  SURFACE HIGH WILL
STILL DOMINATE THE AREA AS IT MOVES OFF TO THE EAST OF THE AREA.
STILL LOOKS LIKE TEMPERATURES WILL BE ABOVE NORMAL WITH 850MB
TEMPERATURES STAYING AROUND +20C.

BRITT

&&

.AVIATION:  (FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1107 PM CDT SUN AUG 30 2015

WEAK SURFACE FRONT/TROF FROM CENTRAL TO NORTHEAST MO WILL DRIFT
AROUND AND DISSIPATE BY MONDAY AFTERNOON. WIDELY SCATTERED
THUNDERSTORMS POPPED UP LATE SUNDAY AFTERNOON AND HAVE DIED AFTER
SUNSET. QUITE A BIT OF FOG FORMED OVERNIGHT SATURDAY NIGHT ACROSS
CENTRAL TO NORTHEAST MO/WEST CENTRAL IL. ATMOSPHERE IS NOT MUCH
DIFFERENT SO SEE NO REASON WHY IT WILL NOT FORM AGAIN. HOWEVER,
TEMP/DEW POINT SPREAD AT UIN IS SEVERAL DEGREES MORE TONIGHT THAN
LAST NIGHT. THUS FOG MAY BE SLOWER TO FORM. WILL BACK OFF A BIT
FROM THE PREVIOUS FORECAST FOR COU AND UIN. SUS COULD BE AN ISSUE
TONIGHT AS IT HAS 6SM BR AT 73/72. THE MET MOS GUIDANCE HAS ALSO
BACK OFF ON THE EXPECTED VISIBILITY. OTHERWISE THE FORECAST WILL
STAY VFR WITH LIGHT SOUTHERLY WINDS MONDAY.

SPECIFICS FOR KSTL: WIDELY SCATTERS THUNDERSTORMS HAVE PRETTY MUCH
DISSIPATED EXCEPT FOR A STORM NEAR THE MONROE/ST. CLAIR COUNTY,
BUT IT IS DYING. VFR FORECAST WITH LIGHT SOUTHERLY WINDS.

JPK

&&

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

$$

WFO LSX



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