Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 010831
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
331 AM CDT TUE SEP 1 2015

.SHORT TERM:  (THROUGH LATE THIS AFTERNOON)
ISSUED AT 330 AM CDT TUE SEP 1 2015

PRIMARY CONCERN FOR TODAY IS THUNDERSTORM CHANCES THROUGHOUT THE
DAY.  SHORT RANGE GUIDANCE CONTINUES TO WANT TO BREAK OUT ISOLATED
TO WIDELY SCATTERED CONVECTION THIS MORNING ALONG A LINE FROM NEAR
WEST PLAINS MISSOURI TO SALEM ILLINOIS.  THIS IS IN THE VICINITY OF
A MID-UPPER LEVEL VORTICITY CHAIN STRETCHING UP FROM EAST TEXAS
THROUGH ARKANSAS AND SOUTHEAST MISSOURI INTO INDIANA.  RAP SHOWS
SOME WEAK LOW LEVEL WARM ADVECTION AND MOISTURE CONVERGENCE UNDER
THE VORT CHAIN THROUGH MID MORNING AND LATEST IR SAT-PICS SHOW WHAT
LOOKS LIKE ALTO-CUMULUS BREAKING OUT IN THE VICINITY OF THE
AFOREMENTIONED LINE.  INDEED...SURFACE OBS SHOW DEVELOPING CEILINGS
BETWEEN 8000-10,000 FT AND AN ISOLATED CELL HAS RECENTLY POPPED UP
ON RADAR IN CENTRAL ILLINOIS.  SHOULD SEE THIS ACTIVITY CONTINUE TO
PERCOLATE THROUGH MID MORNING BEFORE WANING.  THINK THERE WILL BE
SOME REDEVELOPMENT THIS AFTERNOON IN THE VICINITY OF THAT VORT CHAIN
WHERE THE MID LEVEL CAPPING AND UPPER LEVEL SUBSIDENCE WILL BE
WEAKEST.  COVERAGE WILL LIKELY BE WIDELY SCATTERED AT BEST.  WITH
RELATIVELY STAGNANT PATTERN IN PLACE, EXPECT HIGHS TO BE SIMILAR TO
YESTERDAY`S...PERHAPS A DEGREE OR TWO WARMER.

CARNEY

.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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1105 PM CDT MON AUG 31 2015

WEAK UPPER LOW/SHEAR AXIS WILL BECOME CENTERED OVER INDIANA BY
MIDDAY TUESDAY. SUSPECT THAT WILL KEEP MOST OF THE TSRA DEELOPMENT
EAST OF THE TERMINALS. WHILE A ISOLATED STORM POSSIBLE, NO REASON
TO PUT IT IN THE FORECAST. PATCHY FOG OVERNIGHT, BASICALLY A
PERSISTENCE FORECAST.

SPECIFICS FOR KSTL: VFR DRY FORECAST CONTINUES. HIGH PRESSURE
BEGINS BUILDING THUS THE THE ISOLATED AFTERNOON THUNDERSTORMS WILL
BECOME EVEN MORE ISOLATED. WOULD NOT BE SURPRISED TO SEE SOME
MORNING FOG/HAZE START APPEARING THE NEXT COUPLE OF DAYS.

JPK

&&

.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS     91  78  92  78 /  10  10   5   5
QUINCY          90  70  91  70 /   5   5   5   5
COLUMBIA        90  69  91  69 /  10  10   5   5
JEFFERSON CITY  91  69  92  70 /  10  10   5   5
SALEM           89  71  90  70 /  20  10  10   5
FARMINGTON      88  68  91  69 /  20  20  10   5

&&

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

$$

WFO LSX


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