430
FXUS63 KLSX 181710
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1210 PM CDT WED JUN 18 2025
KEY MESSAGES
- SEVERE THUNDERSTORMS REMAIN POSSIBLE THIS AFTERNOON AND
EVENING, PARTICULARLY OVER SOUTHEAST MISSOURI AND SOUTHWEST
ILLINOIS.
- HEAT INDEX VALUES MAY CLIMB ABOVE 100 DEGREES STARTING FRIDAY
AND LAST INTO EARLY NEXT WEEK.
SHORT TERM
(THROUGH LATE THURSDAY AFTERNOON)
ISSUED AT 258 AM CDT WED JUN 18 2025
LATEST RADAR MOSAIC IS SHOWING SCATTERED THUNDERSTORMS DEVELOPING
OVER CENTRAL MISSOURI WITH AN ORGANIZED MCS MOVING EAST ACROSS
SOUTHERN MISSOURI AND NORTHERN ARKANSAS. WHILE THE CAMS HAVE THE
MCS STAYING SOUTH OF THE CWA, THEY DO SHOW A MCV MOVING NORTHEAST
THAT WILL HELP GENERATE ADDITIONAL SHOWER AND THUNDERSTORMS, MAINLY
ACROSS CENTRAL AND NORTHEAST MISSOURI INTO WEST ILLINOIS EARLY THIS
MORNING BETWEEN 5 AND 9 AM. THE OUTFLOW FROM THIS ACTIVITY MAY
VERY WELL EITHER PUSH INTO THE EASTERN AND SOUTHERN PARTS OF THE
CWA THIS MORNING, OR PERHAPS OUT OF THE CWA ALTOGETHER DEPENDING
ON THE STRENGTH OF THE OUTFLOW BOUNDARY. IF THE BOUNDARY DOES STAY
IN THE THE CWA, IT WILL ACT AS A FOCUS FOR ADDITIONAL
THUNDERSTORM ACTIVITY AS LATEST RUNS OF THE HRRR IS SHOWING SOME
ADDITIONAL DEVELOPMENT OVER THE EASTERN CWA LATE THIS MORNING IN
THE FORM OF DISCRETE CELLS. FORECAST SOUNDINGS FROM THE RAP AT SLO
AND FAM THIS AFTERNOON ARE SHOWING MLCAPES OF 1000-2000 J/KG WITH
DEEP LAYER SHEAR 30-40 KNOTS WHICH WILL BE ENOUGH TO SUPPORT
ORGANIZED MULTI-CELLS AND PERHAPS SUPERCELLS, WITH THE MAIN
THREAT BEING DAMAGING WINDS WITH LARGE HAIL AND TORNADOES ALSO
POSSIBLE.
THE CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME TO AN END FROM
NORTHWEST TO SOUTHEAST AS FRONT CURRENTLY EXTENDING FROM IOWA INTO
NEBRASKA WILL MOVE SOUTHEAST ACROSS THE AREA TONIGHT. DRY WEATHER
IS EXPECTED ON THURSDAY AS AN UPPER RIDGE BEGINS TO BUILD IN FROM
THE PLAINS.
BRITT
LONG TERM
(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 258 AM CDT WED JUN 18 2025
THE LREF HAS THE AFOREMENTIONED RIDGE BUILDING OVER THE MIDWEST
BRINGING DRY AND WARM WEATHER LATE WEEK INTO THE WEEKEND. THE NBM
IS SHOWING IQR OF ONLY 2-4 DEGREES AT STL FROM FRIDAY THROUGH
MONDAY WITH HIGHS IN THE LOWER TO MIDDLE 90S. WITH DEWPOINTS
FORECAST IN THE 70S, HEAT INDICES CLIMBING ABOVE 100 DEGREES SEEM
REASONABLE WITH THE LREF PROBABILITIES AOA 50% OVER PARTS OF THE
AREA ON SATURDAY AND SUNDAY AFTERNOONS.
BRITT
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1205 PM CDT WED JUN 18 2025
THE THREAT FOR THUNDERSTORMS DURING THE FIRST FEW HOURS OF THE TAF
PERIOD HAS SHIFTED EAST OF THE TERMINALS. SCATTERED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON INTO EVENING, THOUGH
CHANCES ARE LOW (20-30%) SO HAVE INCLUDED A MENTION ONLY IN A
PROB30 GROUP. CONFIDENCE IN IF AND WHERE THUNDERSTORMS DEVELOP IS
LOW AT THIS POINT. THUNDERSTORMS WILL DIMINISH TONIGHT, LEAVING
VFR CONDITIONS FOR THE REMAINDER OF THE FORECAST PERIOD.
DELIA
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page