Area Forecast Discussion
Issued by NWS St. Louis, MO

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000
FXUS63 KLSX 011739
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1239 PM CDT SAT AUG 1 2015

.SHORT TERM: (THROUGH TONIGHT)
ISSUED AT 340 AM CDT SAT AUG 1 2015

SCATTERED THUNDERSTORMS HAVE RECENTLY DEVELOPED OVER NORTHEAST
MISSOURI AND WEST CENTRAL ILLINOIS IN AN SMALL AREA OF LOW LEVEL
MOISTURE CONVERGENCE.  RECENT RUNS OF THE RAP SHOW THIS FORCING
ERODING AROUND 12Z.  ATMOSPHERE WILL BECOME UNSTABLE AGAIN THIS
AFTERNOON...HOWEVER THERE WILL BE LITTLE IN THE WAY OF FORCING FOR
IT TO ACT ON.  HAVE KEPT CHANCE POPS OVER NORTHEAST MISSOURI AND
WEST CENTRAL ILLINOIS...PARTICULARLY OVERNIGHT AS A SHORTWAVE TROUGH
WILL MOVE THROUGH THE UPPER MIDWEST WHICH WILL LIKELY PUSH A MCS
ALONG A FRONTAL BOUNDARY OVER IOWA INTO INTO THE NORTHERN CWA.

SHOULD BE ANOTHER WARM DAY ACROSS THE AREA WITH 850MB TEMPERATURES
BETWEEN 18-20C.  HIGH TEMPERATURES SHOULD CLIMB BACK INTO THE LOW-
MID 90S WITH MIXING UP TO 850MB.

BRITT

.LONG TERM: (SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT AUG 1 2015

(SUNDAY AND MONDAY)

WILL CONTINUE THE CHANCE OF THUNDERSTORMS ON SUNDAY AS THE COLD
FRONT MOVES DOWN INTO THE AREA.  CHANCES WILL BE LOWER ON SUNDAY
NIGHT AND MONDAY AS CONVERGENCE WEAKENS ALONG THE FRONT AS IT MOVES
TO THE SOUTHWEST UNDER NORTHWESTERLY FLOW ALOFT.  BOTH DAYS WILL
CONTINUE TO BE WARM WITH MOS TEMPERATURES IN THE LOW-MID 90S AND
850MB TEMPERATURES REMAINING NEAR 20C.

(TUESDAY THROUGH FRIDAY)

IT STILL LOOK LIKE MID TO LATE NEXT WEEK WILL BE UNSETTLED WITH A
CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS IN NORTHWEST FLOW
ALOFT.  BEST CHANCE WILL BE TUESDAY INTO WEDNESDAY WHEN BOTH THE GFS
AND ECMWF SHOW A NOTABLE TROUGH MOVING THROUGH MISSOURI AND
ILLINOIS.  TEMPERATURES WILL FALL BACK BELOW NORMAL AS 850MB
TEMPERATURES ARE FORECAST TO BE AROUND 15C.

BRITT

&&

.AVIATION:  (FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1231 PM CDT SAT AUG 1 2015

SPECIFICS FOR KUIN: INITIALLY LIGHT/VARIABLE WINDS WILL BECOME
SOUTHERLY THEN TURN SOUTHWESTERLY LATE IN THE TAF PERIOD. A
DISTURBANCE MOVING THROUGH IA IS EXPECTED TO SUPPORT A
THUNDERSTORM CLUSTER IN SOUTHERN IA OVERNIGHT. IF THE THUNDERSTORM
COMPLEX DEVELOPS, THEN SH/TS COULD REACH KUIN AFTER 02/06Z.

SPECIFICS FOR KCOU: INITIALLY LIGHT/VARIABLE WINDS WILL BECOME
SOUTHERLY THEN TURN SOUTHWESTERLY LATE IN THE TAF PERIOD AROUND
THE BACK SIDE OF A DEPARTING HIGH PRESSURE CENTER. SCATTERED
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON INVOF A SURFACE BOUNDARY
WHICH WAS LOCATED ACROSS CENTRAL MO AT TAF ISSUANCE.

SPECIFICS FOR KSTL, KSUS, KCPS: INITIALLY LIGHT/VARIABLE WINDS
WILL BECOME SOUTHERLY THEN TURN SOUTHWESTERLY LATE IN THE TAF
PERIOD AFTER A HIGH PRESSURE CENTER HAS MOVED OFF TO THE
SOUTHEAST. A PERIOD OF LIGHT TO NEARLY CALM WINDS MAY OCCUR
OVERNIGHT AT SOME LOCATIONS, ESPECIALLY KSUS IN THE RIVER VALLEY.
THE REMNANTS OF OVERNIGHT CONVECTION TO THE NORTH COULD REACH
KSTL/KSUS/KCPS AFTER 02/10Z HOWEVER CONFIDENCE IS TOO LOW TO
INTRODUCE VCTS IN THE TAF ATTM.

KANOFSKY

&&

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

$$

WFO LSX


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