569
FXUS63 KLSX 300346
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1046 PM CDT SAT MAR 29 2025
KEY MESSAGES
- A FEW SEVERE THUNDERSTORMS ARE POSSIBLE LATE TONIGHT AND EARLY
SUNDAY MORNING OVER PARTS OF CENTRAL AND NORTHEAST MISSOURI INTO
WEST CENTRAL ILLINOIS. DAMAGING WINDS WILL BE THE PRIMARY THREAT.
- SEVERE THUNDERSTORMS ARE LIKELY ON SUNDAY AFTERNOON WITH LARGE
HAIL, DAMAGING WINDS, AND A FEW TORNADOES OVER SOUTHEAST AND EAST
CENTRAL MISSOURI AS WELL AS SOUTHWEST AND SOUTH CENTRAL ILLINOIS.
SHORT TERM
(THROUGH LATE SUNDAY NIGHT)
ISSUED AT 249 PM CDT SAT MAR 29 2025
AN AREA OF RAIN HAS BEEN SLOW TO MOVE OUT OF THE CWA THIS AFTERNOON
AHEAD OF A WEAK MID-LEVEL TROUGH MOVING THROUGH THE MID
MISSISSIPPI RIVER VALLEY. THIS TROUGH WILL PROGRESS EASTWARD THIS
LATE AFTERNOON ALLOWING THE RAIN TO EXIT THE AREA. WE WILL THEN
FOCUS TO THE WEST LATE TONIGHT WHEN SEVERE THUNDERSTORMS WILL
LIKELY GROW UPSCALE INTO A LINE AND ENTER CENTRAL MISSOURI AFTER 3
AM. THIS QLCS WILL STILL HAVE THE POTENTIAL TO PRODUCE SOME
DAMAGING WIND GUSTS AS IT ENTERS THE CWA BEFORE IT GRADUALLY
WEAKENS AS IT MOVES TO THE NORTHEAST TOWARD THE MISSISSIPPI RIVER
TOWARD AROUND SUNRISE.
THIS FIRST ROUND OF SHOWERS AND THUNDERSTORMS WILL HAVE AN IMPACT ON
HOW ADDITIONAL THUNDERSTORMS DEVELOP AND HOW SEVERE THEY MAY BE
LATER IN THE DAY ON SUNDAY. IF THE MORNING ROUND OF STORMS LINGER
AROUND LONGER AND PUSHES AN OUTFLOW BOUNDARY FARTHER SOUTH, THEN
LESS OF THE CWA WILL LIKELY SEE ANY SEVERE WEATHER TOMORROW. IF
THIS MORNING ROUND MOVES THROUGH QUICKLY AND AFFECTS LESS OF THE
CWA, THEN THERE WILL BE MORE CHANCE THAT CONVECTIVE INITIATION
WILL OCCUR FARTHER TO THE NORTHWEST AND WILL AFFECT MORE OF THE
CWA INCLUDING THE ST. LOUIS METRO AREA. AT THIS POINT, TWEAKED THE
GOING FORECAST USING A BLEND OF THE LATEST HRRR/HREF FORECAST
WHICH WOULD FAVOR DEVELOPMENT OF THUNDERSTORMS BY EARLY AFTERNOON
OVER PART OF SOUTHEAST AND EAST CENTRAL MISSOURI INTO SOUTHWEST
AND SOUTH CENTRAL ILLINOIS WITH STORMS EXITING THE AREA BY LATE
EVENING. THE CAMS ARE SHOWING A SMALL WINDOW FOR DISCRETE CELLS
INITIALLY OVER THE CWA BEFORE THE STORMS FORM INTO A LINE.
HAZARDS STILL INCLUDE DAMAGING WINDS, LARGE HAIL, AND A FEW
TORNADOES.
DID DROP HIGHS A FEW DEGREES TOMORROW, ESPECIALLY IN THE NORTHWEST
HALF WHERE I EXPECT MORE RAIN AND CLOUDS TO MAKE AN IMPACT ON
TEMPERATURES.
BRITT
LONG TERM
(MONDAY THROUGH NEXT SATURDAY)
ISSUED AT 249 PM CDT SAT MAR 29 2025
THE ACTIVE PATTERN WILL CONTINUE INTO NEXT WEEK AS MODEL GUIDANCE IS
SHOWING ANOTHER STRONG TROUGH MOVING THROUGH THE MIDWEST ON
WEDNESDAY. THE CLUSTER ANALYSIS IS STILL POINTING AT SOME TIMING
DIFFERENCES BETWEEN THE ENSEMBLE SOLUTIONS AT THIS POINT, BUT THERE
REMAINS ENOUGH AGREEMENT TO KEEP 70-90% POPS FOR SHOWERS AND SOME
THUNDERSTORMS TUESDAY NIGHT INTO WEDNESDAY NIGHT. WE WILL NEED TO
CONTINUE TO MONITOR WEDNESDAY FOR A FEW STRONG TO SEVERE
THUNDERSTORMS AS THE LREF HAS JOINT PROBABILITIES OF MUCAPE >500
J/KG AND 0-500MB BULK SHEAR OF >30 KTS BETWEEN 30-50%. THE RAIN
POTENTIAL WILL NOT CLEAR OUT LATE WEEK AS THE UPPER PATTERN WILL
TURN WEST-SOUTHWESTERLY BEHIND THE UPPER TROUGH. THIS WILL CAUSE THE
ATTENDANT COLD FRONT TO HOLD UP JUST SOUTH OF THE CWA THURSDAY INTO
NEXT SATURDAY KEEPING A CHANCE (30-60%) OF ADDITIONAL SHOWERS AND
THUNDERSTORMS DURING THIS PERIOD.
MONDAY AND TUESDAY ARE EXPECTED TO BE COOLER BEHIND SUNDAY'S FRONT
WITH HIGHS ONLY IN THE 50S AND 60S WITH WARMUP ON WEDNESDAY AHEAD OF
THE COLD FRONT WITH TEMPERATURES WARMING BACK INTO THE 70S. I HAVE
FAIRLY GOOD CONFIDENCE IN THE TEMPERATURES ON MONDAY AND TUESDAY AS
THE NBM IQR AT ST. LOUIS IS ONLY 5 DEGREES BEFORE INCREASING TO 8-10
DEGREES THE REST OF THE WEEK GIVEN THE UNCERTAINTY IN THE UPPER FLOW
PATTERN.
BRITT
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1036 PM CDT SAT MAR 29 2025
MULTIPLE ROUNDS OF THUNDERSTORMS CONTINUE TO BE THE MAIN CONCERN
FOR IMPACTS THIS TAF PERIOD AT ALL LOCAL TERMINALS. ROUND ONE WILL
COME VIA A STORM COMPLEX MOVING INTO THE REGION FROM THE WEST
EARLY THIS MORNING, LIKELY WEAKENING AS IT DOES SO. BEFORE THE
COMPLEX WEAKENS TOO MUCH, KCOU AND KJEF ARE CURRENTLY EXPECTED TO
TAKE THE BRUNT OF IT. AS THE COMPLEX TRAVELS FURTHER EASTWARD
THROUGH THE MID MORNING, IT IS EXPECTED TO WEAKEN QUICKLY, LEADING
TO A LOW CHANCE OF LESS SIGNIFICANT IMPACTS AT KUIN, KSUS, KSTL,
AND KCPS. THE STRENGTH AND EXACT TIMING AND PLACEMENT OF THIS
FIRST ROUND WILL IMPACT THE TIMING AND PLACEMENT OF THE SECOND
ROUND DURING THE LATE MORNING AND EARLY AFTERNOON. A STRONGER
FIRST ROUND MAY LEAD TO THE SECOND ROUND ONLY IMPACTING KSUS,
KSTL, AND KCPS OR EVEN FORMING WELL EAST OF THESE TERMINALS. A
WEAKER FIRST ROUND MAY LEAD TO THE SECOND ROUND FORMING SOONER AND
IMPACTING ALL LOCAL TERMINALS. THIS SECOND ROUND HAS THE
POTENTIAL TO BRING GUSTY WINDS, LARGE HAIL, AND POSSIBLY A TORNADO
TO THE LOCAL TERMINALS THAT ARE DIRECTLY IMPACTED. RAIN CHANCES
WILL END AND CEILINGS WILL GRADUALLY IMPROVE THROUGH THE EVENING
AS A COLD FRONT PASSES THROUGH THE REGION AND DRY AIR MOVES IN.
ELMORE
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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