Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 011731
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
ISSUED BY NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1231 PM 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:  (TONIGHT THROUGH MONDAY)
ISSUED AT 355 AM CDT TUE SEP 1 2015

EXPECT ANY THUNDERSTORMS THAT DEVELOP THIS AFTERNOON TO QUICKLY
DISSIPATE EARLY THIS EVENING AS WE LOSE DAYTIME HEATING.  WHILE THE
SHEAR AXIS/VORTICITY CHAIN IN THE MID AND UPPER LEVELS WILL STILL BE
IN THE VICINITY OF THE AREA TONIGHT AND WEDNESDAY, IT LOOKS LIKE IT
WILL BE WEAKENING WITH TIME AS WELL AS DIPPING FURTHER SOUTH ACROSS
FAR SOUTHEAST MISSOURI, NORTHEAST ARKANSAS, TENNESSEE, AND KENTUCKY.
I CAN`T TOTALLY RULE OUT AN ISOLATED SHOWER OR THUNDERSTORM
TONIGHT INTO WEDNESAY, BUT THINK PRECIP CHANCES ARE LOW ENOUGH IN
OUR CWFA TO KEEP POPS BELOW MENTIONABLE LEVELS AT THIS TIME.

THE REST OF THE FORECAST AT LEAST THROUGH THE WEEKEND LOOKS PRETTY
UNEVENTFUL.  LATE SUMMER-LIKE PATTERN WITH STRONG RIDGING THROUGH
THE DEPTH OF THE TROPOSPHERE SHOULD KEEP THE AREA HOT AND DRY
THROUGH THE WEEKEND.  HIGHS LOOK TO BE IN THE LOW TO MID 90S WITH
LOWS GENERALLY IN THE LOW TO MID 70S.  DEWPOINT TEMPERATURES SHOULD
STAY IN THE UPPER 60S TO LOW 70S ACROSS THE AREA THOUGH THE PERIOD.
WHILE THIS WILL FEEL WARM AND HUMID, CURRENT THINKING IS THAT HEAT
HEADLINES WILL NOT BE NEEDED.  A PATTERN SHIFT WITH SOME COOLER
TEMPERATURES MAY BE IN THE FORECAST NEXT WEEK, BUT GFS AND ECMWF
AREN`T EXACTLY IN GOOD AGREEMENT ON THIS.  REGARDLESS...THE SHIFT
(IF IT OCCURS) WILL LIKELY BE TOWARD THE MIDDLE OF THE WEEK; SO HAVE
KEPT WARM TEMPERATURES GOING THROUGH MONDAY.

CARNEY

&&

.AVIATION:  (FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM CDT TUE SEP 1 2015

VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE FORECAST PERIOD
ACROSS THE MAJORITY OF THE REGION. SCATTERED CUMULUS WITH BASES
AROUND 5 KFT WILL CONTINUE TO DEVELOP THROUGHOUT THE SOUTHERN HALF
OF THE FORECAST AREA...AND COULD EVEN SEE A FEW POP UP SHOWERS OR
ISOLATED THUNDERSTORMS THIS AFTERNOON MAINLY SOUTH OF THE TERMINALS.
CLOUD COVER AND ANY POTENTIAL FOR PRECIPITATION WILL DISSIPATE AROUND
01Z-02Z...LEAVING BEHIND CLEAR SKIES AND LIGHT SOUTHERLY WINDS.

SPECIFICS FOR KSTL: VFR CONDITIONS EXPECTED. A FEW ISOLATED SHOWERS
OR THUNDERSTORMS COULD DEVELOP SOUTH OF KSTL AND WILL MONITOR CLOSELY
IN CASE THESE ENCROACH ON THE VICINITY OF THE TERMINAL...BUT FOR NOW
THE PROBABILITY IS TOO LOW FOR MENTION IN THE TAF. WINDS WILL VARY
BETWEEN 210 AND 230 DEGREES AT SPEEDS AROUND 7 TO 8 KTS THROUGH EARLY
EVENING...THEN WILL BACK TO THE SOUTH AND DECREASE TO SPEEDS AROUND 5
KTS.

LAFLIN

&&

.PRELIMINARY POINT TEMPS/POPS:
SAINT LOUIS     93  78  92  78 /  10  10   5   5
QUINCY          93  69  91  70 /   5   5   5   5
COLUMBIA        93  69  92  70 /  10  10   5   5
JEFFERSON CITY  93  69  92  70 /  10  10   5   5
SALEM           90  70  90  70 /  20  10  10   5
FARMINGTON      90  68  91  69 /  20  20   5   5

&&

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

$$

WFO LSX



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