Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 312006
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
306 PM CDT MON AUG 31 2015

.SHORT TERM:  (THROUGH LATE TONIGHT)
ISSUED AT 304 PM CDT MON AUG 31 2015

THUNDERSTORMS THAT PRODUCED HEAVY RAINFALL OVER THE EASTERN CWA THIS
MORNING DISSIPATED WITH THE LOSS OF THE WEAK LOW LEVEL MOISTURE
CONVERGENCE ON THE WEST SIDE OF THE UPPER LEVEL LOW CURRENT CENTERED
OVER INDIANA.  MORE RECENTLY...ATMOSPHERE HAS BECOME VERY UNSTABLE
WITH MLCAPES OF 2000-3000 J/KG WITH LITTLE CIN.  SHEAR AXIS HAS
MOVED DOWN INTO SOUTHERN MISSOURI...SO THINK BEST CHANCE FOR
THUNDERSTORMS WILL BE OVER THE EASTERN OZARKS...PARTICULARLY SINCE
THAT IS TRADITIONALLY WHERE OROGRAPHIC LIFT HAS HELPED GENERATE LATE
AFTERNOON/EARLY EVENING THUNDERSTORMS IN THE PAST.  WOULD EXPECT ANY
CONVECTION TO DIMINISH WITH LOSS OF DAYTIME HEATING.

ADDITIONAL THUNDERSTORMS WILL BE POSSIBLE ONCE AGAIN LATE TONIGHT
OVER THE EASTERN CWA AS BOTH THE NAM AND GFS ARE POINTING TOWARD TO
SOME WEAK 925-850MB MOISTURE CONVERGENCE DEVELOPING ONCE AGAIN ON
THE WEST SIDE OF THE UPPER LEVEL LOW.  WILL GO WITH A SLIGHT CHANCE
OF THUNDERSTORMS LATE TONIGHT THROUGH TOMORROW MORNING.

BRITT

.LONG TERM:  (TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 304 PM CDT MON AUG 31 2015

(TUESDAY THROUGH THURSDAY)

PLAN TO GO WITH A DRY FORECAST FROM TUESDAY AFTERNOON THROUGH
THURSDAY AS FORCING FOR THUNDERSTORMS LOOKS WEAK AS UPPER LOW MOVES
EAST AND UPPER RIDGE AXIS BUILDS OVER THE AREA WHICH SHOULD SUPPRESS
THUNDERSTORM DEVELOPMENT.  DON`T EXPECT MUCH CHANCE IN THE WARM AND
HUMID CONDITIONS. BASED HIGHS ON MIXING DOWN 850MB TEMPERATURES
WHICH ARE CLOSE TO +20C.

(FRIDAY THROUGH MONDAY)

FORECAST STILL LOOKS ON TRACK FOR MAINLY DRY WEATHER EARLY ON FOR
THE HOLIDAY WEEKEND AS THE UPPER LEVEL RIDGE AXIS MOVES OVER THE
AREA WHICH WILL SUPPRESS THUNDERSTORMS ACTIVITY ON FRIDAY AND
SATURDAY.  THIS RIDGE AXIS WILL BEGIN TO BREAK DOWN BY SUNDAY...SO
WILL KEEP THE SLIGHT CHANCE OF THUNDERSTORMS OVER NORTHEAST MISSOURI
ON SUNDAY.  WILL GO WITH A WIDER CHANCE OF THUNDERSTORMS ON LABOR
DAY AS BOTH THE GFS AND ECMWF SHOW THE RIDGE AXIS MOVING SOUTH OF
THE AREA AT THE SAME TIME A COLD FRONT ENTERS THE AREA FROM THE
NORTH.  STILL WENT ABOVE NORMAL THROUGH THE HOLIDAY WEEKEND AS WE
WILL STAY IN THE SAME WARM AND HUMID AIRMASS UNTIL THE COLD FRONT
MOVES THROUGH.

BRITT

&&

.AVIATION:  (FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1208 PM CDT MON AUG 31 2015

ISOD TSRA ARE POSSIBLE AGAIN THIS AFTERNOON. HOWEVER...WITH
VERY LOW CHANCES OF IMPACTING A TERMINAL...HAVE KEPT TAFS DRY FOR
NOW. LATEST GUIDANCE SUGGESTS CU FIELD THIS AFTERNOON MAY BECOME
BKN RATHER THAN SCT. WILL CONTINUE TO MONITOR TRENDS. TSRA ARE
POSSIBLE AGAIN AROUND SUNRISE TUES MORNING...BUT ARE CURRENTLY
EXPECTED TO REMAIN E OF UIN/SUS/CPS. OTHERWISE...WINDS WILL BECOME
SWLY TUES MORNING WITH SCT CU FORMING WITH BASES AROUND 5 KFT.

SPECIFICS FOR KSTL: ISOD TSRA MAY DEVELOP THIS AFTERNOON. CU FIELD
MAY BECOME BKN THIS AFTN BUT SUBSIDENCE FROM THIS MORNINGS CONVECTION
MAY LIMIT THIS. TSRA ARE POSSIBLE AGAIN TUES MORNING AROUND
SUNRISE...BUT ARE EXPECTED TO REMAIN E OF TERMINAL.
OTHERWISE...WINDS WILL BECOME SWLY TUES MORNING WITH SCT CU
FORMING WITH BASES AROUND 5 KFT.

TILLY

&&

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

$$

WFO LSX



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