968
FXUS63 KLSX 272324
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
524 PM CST MON JAN 27 2025
KEY MESSAGES
- DRY WEATHER WITH ABOVE-NORMAL TEMPERATURES IS FORECAST THROUGH
WEDNESDAY.
- WIDESPREAD RAINFALL IS FORECAST THURSDAY-FRIDAY. MOST LOCATIONS
ARE LIKELY (50-90+%) TO SEE AT LEAST A HALF INCH OF RAIN.
SHORT TERM
(THROUGH LATE TUESDAY NIGHT)
ISSUED AT 223 PM CST MON JAN 27 2025
A WEAK "COLD" FRONT WILL BE MOVING THROUGH THE REGION OVERNIGHT
TONIGHT. HOWEVER, THIS IS A PACIFIC FRONT WITH NO REAL CHANGE IN THE
AIR MASS. IN FACT, TEMPERATURES TONIGHT AND TUESDAY WILL ACTUALLY BE
WARMER THAN THE PAST 24 HOURS. CONTINUED WEST/SOUTHWEST WINDS WILL
PROVIDE LOW-LEVEL WARM AIR ADVECTION. THIS COMBINED WITH PLENTY OF
SUNSHINE AND SOME DOWNSLOPE OFF OF THE OZARK PLATEAU WILL COMBINE TO
YIELD HIGHS IN THE UPPER 40S TO MID 50S FROM NORTH TO SOUTH. GIVEN
THESE FAVORABLE CONDITIONS, LEANED CLOSE TO THE 90TH PERCENTILE OF
AVAILABLE MODEL GUIDANCE FOR HIGHS. LOWS TONIGHT ARE EXPECTED TO BE
IN THE MID 20S TO LOW 30S, WITH LOW TO MID 30S FORECAST TUESDAY
NIGHT.
GOSSELIN
LONG TERM
(WEDNESDAY THROUGH NEXT MONDAY)
ISSUED AT 223 PM CST MON JAN 27 2025
(WEDNESDAY - WEDNESDAY NIGHT)
THERE IS VERY LITTLE CHANGE IN THE SYNOPTIC PATTERN ACROSS THE CONUS
INTO WEDNESDAY AS A WEAK SURFACE RIDGE MOVES QUICKLY ACROSS THE MID-
MISSISSIPPI VALLEY. THERE IS WEAK LOW-LEVEL COLD AIR ADVECTION, BUT
850-HPA TEMPERATURES THEMSELVES REMAIN ABOVE NORMAL. ANOTHER SUNNY
DAY IS ALSO EXPECTED, SO WE ARE LOOKING AT ANOTHER DAY WITH HIGHS
MAINLY IN THE UPPER 40S TO MID 50S.
(THURSDAY - FRIDAY)
DETERMINISTIC MODELS AND ENSEMBLE GUIDANCE ARE IN GOOD AGREEMENT
WITH RESPECT TO THE NEXT WEATHER SYSTEM APPROACHING THE AREA EARLY
THURSDAY. THE CLOSED, CUTOFF LOW IS FINALLY EXPECTED TO MOVE
EASTWARD INTO THE SOUTH-CENTRAL PLAINS ON THURSDAY. STRONG MID/UPPER
LEVEL DIFFLUENCE AHEAD OF THIS FEATURE COMBINED WITH INCREASING LOW-
LEVEL MOISTURE ADVECTION IS EXPECTED TO YIELD WIDESPREAD RAIN ACROSS
THE AREA ON THURSDAY. THE RAIN SHOULD MOVE INTO PARTS OF SOUTHEAST
MISSOURI FIRST (LIKELY DURING THE MORNING HOURS), THEN SPREAD NORTH
AND EASTWARD ACROSS THE REMAINDER OF THE BI-STATE AREA DURING THE
DAYLIGHT HOURS. THE RAIN SHOULD BE HEAVIEST AND MOST CONSISTENT IN
PARTS OF SOUTHEAST MISSOURI AND SOUTHWEST ILLINOIS THROUGH THURSDAY
NIGHT, BUT A DRY SLOT SHOULD MOVE INTO THESE AREAS TOWARD EARLY
FRIDAY MORNING. THE FOCUS SHOULD SHIFT THEN FOR THE STEADIER RAIN TO
BE MORE CENTERED ACROSS NORTHEAST MISSOURI AND WEST-CENTRAL ILLINOIS
ON FRIDAY WITHIN THE DEFORMATION ZONE. THERE REMAINS HIGH CONFIDENCE
IN ALL OF THIS EVENT BEING RAIN, WITH TEMPERATURES EVEN ON FRIDAY IN
OUR NORTHERN COUNTIES WELL ABOVE FREEZING NOT ONLY AT THE SURFACE
BUT ALSO UP TO AT LEAST 925 HPA.
THIS WILL BE THE FIRST WIDESPREAD PRECIPITATION EVENT IN NEARLY 3
WEEKS. MOST LOCATIONS SHOULD SEE AT LEAST A HALF INCH OF RAIN, WITH
PROBABILITIES ON THE LATEST LREF ABOVE 50% EVERYWHERE. HIGHEST ODDS
(80-90+%) ARE IN PARTS OF SOUTHEAST MISSOURI AND SOUTHWEST ILLINOIS.
THIS IS ALSO WHERE 1+" TOTALS ARE MOST LIKELY (30-60%).
(FRIDAY NIGHT - NEXT MONDAY)
THE MID/UPPER LEVEL FLOW ACROSS THE CONUS IS MAINLY ZONAL, WITH A
FAST JET STREAM ACROSS THE PACIFIC OCEAN. THIS MEANS A RETURN TO
MILD AND DRY CONDITIONS FOR THIS UPCOMING WEEKEND HEADING INTO NEXT
WEEK.
GOSSELIN
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 519 PM CST MON JAN 27 2025
VFR CEILINGS/VISIBILITIES ARE EXPECTED THROUGHOUT THE 00Z TAF
PERIOD. GUSTY SOUTHWEST WINDS WILL DIMINISH GRADUALLY THIS
AFTER SUNSET, BUT STRONG WINDS ALOFT WILL PERSIST FOR SEVERAL MORE
HOURS. THIS MAY LEAD TO A 3-6 HOUR WINDOW FOR MARGINAL LOW LEVEL
WIND SHEAR THIS EVENING AND OVERNIGHT, BUT CONFIDENCE IS LOW
REGARDING THIS POTENTIAL. THIS IS BECAUSE CONFIDENCE IS LOW THAT
SURFACE WIND SPEEDS WILL DIMINISH FAST ENOUGH TO MEET LLWS
CRITERIA, AND ALSO BECAUSE WINDS WILL LIKELY BE BLOWING FROM THE
SAME DIRECTION AT ALL LEVELS (~230-260 DEGREES). THESE TRENDS WILL
BE MONITORED, AS WEAK SURFACE WINDS MAY REQUIRE AN AMENDMENT FOR
LLWS IN THE TAF. ALL LOCAL TERMINALS COULD POTENTIALLY BE IMPACTED
IF THIS OCCURS.
BRC
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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