640
FXUS63 KLSX 220527
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1227 AM CDT MON JUN 22 2026
KEY MESSAGES
- DAMAGING WINDS AND TORNADOES ARE POSSIBLE THROUGH THIS EVENING
ACROSS EAST CENTRAL AND SOUTHEAST MISSOURI INTO SOUTHWEST ILLINOIS.
- LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE THROUGH EARLY TONIGHT.
- SEASONABLY COOL CONDITIONS ARE FORECAST THIS WORK WEEK.
SHORT TERM
(THROUGH LATE TONIGHT)
ISSUED AT 9 PM CDT SUN JUN 21 2026
THE TORNADO WATCH HAS BEEN CANCELED FOR ALL OF MISSOURI AND WEST
CENTRAL ILLINOIS.
THERE ARE CURRENTLY TWO LINES OF SHOWERS AND THUNDERSTORMS ACROSS
THE AREA. THE FIRST LINE BEING NORTH OF ST. LOUIS AND THE SECOND
BEING ACROSS A CRAWFORD TO WASHINGTON TO RANDOLPH COUNTY LINE. THE
NORTHERN LINE IS IN ASSOCIATION WITH A SURFACE COLD FRONT, WHILE
THE SOUTHERN LINE IS IN ASSOCIATION WITH A MUCH WEAKER FRONTAL
ZONE. THE NORTHERN LINE IS EXPECTED TO REMAIN RATHER WEAK AND
LIGHTNING DEFICIENT, WHILE THE SOUTHERN LINE OF STORMS IS
FORECAST TO BE STRONGER. THIS IS DUE TO THE NORTHERN LINE BEING
DIRECTLY UPSTREAM OF THE DEPARTING MCV (WEAK UPPER LEVEL
SUBSIDENCE), AND LESS OVERALL INSTABILITY. THE SOUTHERN LINE HAS
LESS SURFACE CONVERGENCE, BUT STORMS HAVE MUCH MORE INSTABILITY TO
WORK WITH (UPWARDS OF 2000 J/KG OF MLCAPE IN PLACES). THE PRIMARY
THREATS FOR THE SOUTHERN STORMS WILL BE LARGE HAIL, DAMAGING WIND
GUSTS, AND A TORNADO OR TWO.
THE SURFACE COLD FRONT WILL SWEEP THROUGH CENTRAL MISSOURI AND
WEST-CENTRAL ILLINOIS TONIGHT WITH TEMPERATURES AND DEWPOINTS
FALLING. SKIES WILL REMAIN OVERCAST TO BROKEN THOUGH WITH
CEILINGS LOWERING TO LESS THAN 1000 FT BY EARLY MONDAY MORNING.
EXPECT LOW TEMPERATURES IN THE LOWER 60S.
BAH
LONG TERM
(MONDAY THROUGH NEXT SUNDAY)
ISSUED AT 324 PM CDT SUN JUN 21 2026
(MONDAY - MONDAY NIGHT)
COOLER WEATHER ALONG WITH NORTHERLY WINDS AND CLOUDS ARE
EXPECTED ON MONDAY. HIGH TEMPERATURES ARE ONLY EXPECTED TO REACH
INTO THE MID 70S, OR ABOUT 10 DEGREES BELOW NORMAL FOR THE DATE.
LOWS MONDAY NIGHT ARE FORECAST TO DROP INTO THE MID 50S TO NEAR THE
60 DEGREE MARK.
(TUESDAY - NEXT SUNDAY)
NOT MUCH HAS CHANGED WITH RESPECT TO THE WORK WEEK FORECAST WITH
BROAD NORTHWEST FLOW ALOFT ACROSS THE MISSISSIPPI VALLEY. THERE IS
HIGH CONFIDENCE IN SEASONALLY COOL TEMPERATURES WITH MOSTLY DRY
WEATHER EXPECTED OUTSIDE OF A COLD FRONTAL PASSAGE
WEDNESDAY/WEDNESDAY NIGHT.
MODERATING TEMPERATURES ARE FORECAST HEADING INTO NEXT WEEKEND WITH
FLOW ALOFT BECOMING MORE ZONAL. THAT MEANS INCREASING
MOISTURE/INSTABILITY AS WELL AND INCREASING CHANCES OF SHOWERS AND
THUNDERSTORMS.
GOSSELIN
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1227 AM CDT MON JUN 22 2026
A COLD FRONT HAS CLEARED ALL TERMINALS TO THE SOUTHEAST WITH
NORTHERLY SURFACE WINDS AROUND 10KTS AND WIDESPREAD LOW MVFR/IFR
STRATUS ACROSS THE AREA WITHIN THE POST-FRONTAL AIRMASS. THESE LOW
CEILINGS WILL CONTINUE TO IMPACT ALL TERMINALS OVERNIGHT AND INTO
MONDAY MORNING. CONFIDENCE IS LOWER IN THE DURATION OF THE LOW
CEILING IMPACTS AFTER THE MORNING TIMEFRAME WITH UNCERTAINTY
REGARDING WHEN IMPROVEMENTS MAY START. THE GENERAL TREND THROUGH THE
LATE MORNING INTO THE AFTERNOON APPEARS TO BE A SCATTERING OF THESE
LOWER CEILINGS FROM NORTHWEST TO SOUTHEAST. BY TOMORROW EVENING, ALL
TERMINALS ARE FORECAST TO HAVE VFR AND DRY FLIGHT CONDITIONS WITH
LIGHT AND VARIABLE SURFACE WINDS MONDAY NIGHT.
PEINE
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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