Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 070010
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
710 PM CDT MON JUL 6 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 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 702 PM CDT MON JUL 6 2015

STORMS THAT DEVELOPED OUT AHEAD OF FRONT HAVE DISSIPATED, SO WILL
SEE A BRIEF BREAK IN ACTIVITY. KUIN AND KCOU SHOULD SEE SHOWERS
AND STORMS MOVE IN AFTER 01Z-02Z TIMEFRAME, WHILE IT WILL NOT MAKE
IT TO STL METRO AREA TIL AFTER 06Z TUESDAY. ONCE STORMS MOVE IN
WILL SEE MVFR CONDITIONS WITH TEMPO IFR CONDITIONS TIL COLD FRONT
MOVES THROUGH. THEN MVFR CONDITIONS TO PERSIST BEHIND BOUNDARY
THROUGH REST OF FORECAST PERIOD WITH RAIN TAPERING OFF BY MID
MORNING ON TUESDAY. AS FOR WINDS, SOUTH TO SOUTHWEST WINDS TO VEER
TO THE WEST AFTER FRONTAL PASSAGE, THEN TO THE NORTH TO NORTHEAST
LATER IN THE FORECAST PERIOD.

SPECIFICS FOR KSTL:
STORMS THAT DEVELOPED OUT AHEAD OF FRONT HAVE DISSIPATED, SO WILL
SEE A BREAK IN ACTIVITY. SHOWERS AND STORMS WILL NOT MAKE IT TO
STL METRO AREA TIL AFTER 06Z TUESDAY. ONCE STORMS MOVE IN WILL SEE
MVFR CONDITIONS WITH TEMPO IFR CONDITIONS TIL COLD FRONT MOVES
THROUGH AROUND 12Z TUESDAY. THEN MVFR CONDITIONS TO PERSIST
BEHIND BOUNDARY THROUGH REST OF FORECAST PERIOD WITH RAIN TAPERING
OFF BY 20Z TUESDAY. DID PUT IN VCTS/VCSH MENTION AFTER 20Z TUESDAY
AS FRONTAL BOUNDARY WILL STALL OUT ALONG I-70 CORRIDOR. AS FOR
WINDS, SOUTH TO SOUTHWEST WINDS TO VEER TO THE WEST AFTER FRONTAL
PASSAGE, THEN TO THE NORTHWEST LATER IN THE FORECAST PERIOD.

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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