Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 070503
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1203 AM CDT TUE JUL 7 2015

.SHORT TERM:  (THROUGH LATE TONIGHT)
ISSUED AT 320 PM CDT MON JUL 6 2015

TRANQUIL WEATHER HAS COME TO AN END. HEATING OF THE VERY MOIST
AIR MASS HAS PRODUCED SBCAPE OF 3000-4000 J/KG WHICH ALONG WITH A
WEAK UPPER DISTURBANCE TRACKING INTO EASTERN MO HAS GENERATED
SCATTERED THUNDERSTORMS ACROSS THE SOUTHEAST HALF OF THE CWA. PWS
OF 1.6-1.8 INCHES IS RESULTING IN HEAVY DOWNPOURS WITH STORMS,
AND PRESENCE OF SUFFICIENTLY STEEP LOW LEVEL LAPSE RATES AND
PRECIPIP LOADING IS ALSO AIDING IN PROMINENT OUTFLOWS AND GUSTY
SURFACE WINDS. SOME OF THIS ACTIVITY WILL LINGER INTO THE EARLY
EVENING PRIMARILY FROM ST. LOUIS EAST, BUT THE MAIN SHOW WILL BE A
GROWING EXTENSIVE BAND OF SHOWERS AND THUNDESTORMS CURRENTLY
EXTENDING FROM NORTHWEST MO INTO EASTERN KS. THIS ACTIVITY WILL
MOVE EAST AND SINK SOUTH WITH TIME TONIGHT. THE GREATEST THREAT OF
HEAVY RAIN WILL BE CENTERED IN NORTHEAST MO AND WEST CENTRAL IL
TRAILING INTO CENTRAL MO AND MAINLY THIS EVENING. THE CURRENT
FLASH FLOOD WATCH HAS THIS WELL COVERED. THE SEVERE WEATHER
THREAT WILL OCCUPY THE SAME GENERAL REGION AND TIME SPACE AND WILL
LARGELY BE DRIVEN BY THE AFOREMENTIONED INSTABILITY WITH MARGINAL
DEEP LAYER SHEAR SUPPORTING A MULTICELL MODE AND WIND DAMAGE
THREAT.

GLASS

.LONG TERM:  (TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 320 PM CDT MON JUL 6 2015

THE SCENARIO HAS CHANGED LITTLE TUESDAY INTO WEDNESDAY WITH THE
FRONT GRADUALLY MOVING SOUTHWARD AND BECOMING STATIONARY ACROSS
SOUTHERN ILLINOIS AND SOUTHEAST MISSOURI BY TUESDAY EVENING, AND
THEN WAVERING BACK NORTH LATE TUESDAY NIGHT-WEDNESDAY WITH THE
MOVEMENT AND PASSAGE OF A SURFACE LOW MIGRATING ALONG THE FRONT.
BROAD DEEP LOW LEVEL CONVERGENCE ATTENDANT WITH THE FRONTAL ZONE
ALONG WITH AMPLE INSTABILITY AND ABUNDANT MOISTURE /PWS IN EXCESS
OF 2 INCHES/ SUPPORT THE FORECAST OF WIDESPREAD SHOWERS AND
THUNDESTORMS WITH A HEAVY RAINFALL THREAT. THE CURRENT FLASH FLOOD
WATCH COVERS THIS PERIOD WITH MULTIDAY RAINFALL TOTALS OF 2-4
INCHES EXPECTED AND LOCALLY HIGHER TOTALS. ULTIMATELY THE WATCH
MAY NEED TO BE EXTENDED INTO WEDNESDAY NIGHT-THURSDAY NIGHT PERIOD
WITH ANOTHER AND THE FINAL SURFACE WAVE MOVING ALONG THE FRONT.

THE FRONT FINALLY PUSHES NORTH OF THE AREA BY EARLY FRIDAY PUTTING
AN END TO THE PRECIPITATION FOR SEVERAL DAYS. SUMMER HEAT AND HUMIDITY
IS ON TAP FOR NEXT WEEKEND AS HEIGHTS RISE ALOFT AND A PROMINENT
UPPER RIDGE BUILDS THROUGH THE NATIONS MIDSECTION.

GLASS
&&

.AVIATION:  (FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1150 PM CDT MON JUL 6 2015

COLD FRONT IS SOUTH OF KUIN AND KCOU AND WILL CONTINUE MOVING
THROUGH SOUTH. THE FRONT WILL BE SOUTH OF THE TAF SITES BY MIDDAY
ON TUESDAY. IN THE MEANTIME, CIGS TO DROP DOWN TO MVFR/IFR WITH
SHOWERS/ISOLATED THUNDERSTORMS. PRECIPITATION TO TAPER OFF BY MID
MORNING ALL LOCATIONS. COULD STILL SEE SOME LINGERING ACTIVITY,
BUT DON`T WANT TO KEEP 12+ HOURS OF PRECIPITATION. CIGS TO LIFT TO
MVFR/VFR TOWARDS END OF FORECAST PERIOD. AS FOR WINDS, SOUTH WINDS
TO VEER TO THE WEST TO NORTHWEST WITH FRONTAL PASSAGE, THEN TO THE
NORTH AS FRONT SETTLES SOUTH.

SPECIFICS FOR KSTL:
COLD FRONT IS SOUTH OF KUIN AND KCOU AND WILL CONTINUE MOVING
THROUGH SOUTH. THE FRONT WILL BE SOUTH OF THE METRO AREA BY
14Z TUESDAY. IN THE MEANTIME, CIGS TO DROP DOWN TO MVFR/IFR WITH
SHOWERS/ISOLATED THUNDERSTORMS. PRECIPITATION TO TAPER OFF BY MID
MORNING. COULD STILL SEE SOME LINGERING ACTIVITY, BUT DON`T WANT
TO KEEP 12+ HOURS OF PRECIPITATION. CIGS TO LIFT TO MVFR/VFR
TOWARDS END OF FORECAST PERIOD. AS FOR WINDS, SOUTH WINDS TO VEER
TO THE WEST TO NORTHWEST WITH FRONTAL PASSAGE, THEN TO THE NORTH
AS FRONT SETTLES SOUTH.

BYRD
&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...FLASH FLOOD WATCH THROUGH WEDNESDAY EVENING FOR AUDRAIN MO-BOONE
     MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-GASCONADE MO-
     JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN MO-MARION MO-MONITEAU
     MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS MO-SHELBY
     MO-ST. CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO-
     WASHINGTON MO.

IL...FLASH FLOOD WATCH THROUGH WEDNESDAY EVENING FOR ADAMS IL-BROWN
     IL-CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN IL-MADISON IL-
     MONROE IL-PIKE IL-ST. CLAIR IL.

&&

$$
WFO LSX


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