422
FXUS63 KLSX 291751
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1251 PM CDT WED OCT 29 2025
KEY MESSAGES
- RAINFALL WILL END FROM NORTHWEST TO SOUTHEAST TODAY.
- DRY WEATHER AND TEMPERATURES NEAR, TO SLIGHTLY BELOW NORMAL IS
EXPECTED FOR THE REMAINDER OF THE FORECAST PERIOD.
SHORT TERM
(THROUGH LATE TONIGHT)
ISSUED AT 309 AM CDT WED OCT 29 2025
LOW PRESSURE NEAR THE MISSOURI BOOTHEEL BEING DRIVEN BY A CLOSED LOW
ALOFT, IS BRINGING WIDESPREAD RAIN TO THE REGION THIS MORNING. THE
CLOSED, STACKED SYSTEM WILL DRIFT EAST INTO THE TENNESSEE VALLEY
TODAY. SHORT RANGE GUIDANCE IS IN GOOD AGREEMENT THIS MORNING,
PULLING DRIER AIR IN FROM THE NORTHEAST BETWEEN 12-15Z. THIS SHUTS
THE RAIN OFF NORTHWEST OF A LINE FROM JEFFERSON CITY TO GREENFIELD
ILLINOIS BY 16-17Z. THE ENDING OF THE PRECIP OVER THE REST OF THE
AREA WILL BE SLOWER, DEPENDING MORE ON THE SLOW EASTWARD PROGRESSION
OF THE LOW THROUGH THE AFTERNOON AS MOISTURE CONTINUES WRAP BACK
INTO EAST CENTRAL AND SOUTHEAST MISSOURI AS WELL AS SOUTHERN
ILLINOIS. CURRENT INDICATIONS ARE THAT RAIN WILL LINGER WELL INTO
THE AFTERNOON ALONG AND EAST OF I-44 IN MISSOURI AND I-70 IN
ILLINOIS, FINALLY TAPERING OFF AND ENDING IN MOST LOCATIONS BY 00Z
THIS EVENING. CLOUDS AND RAIN WILL KEEP TEMPERATURES COOL TODAY
WITH ONLY AROUND 10 DEGREES OF DIURNAL RISE ACROSS CENTRAL AND
NORTHEAST MISSOURI INTO WEST CENTRAL ILLINOIS WHERE THE RAIN ENDS
EARLY. EXPECT 0-5 DEGREES OF WARM UP WHERE RAIN LINGERS TODAY.
NORTHERLY FLOW BEHIND THE STORM WILL BRING COLDER AIR INTO THE AREA
TONIGHT. WOULDN'T BE SURPRISED TO SEE SOME PATCHY FROST, MAINLY
ALONG AND WEST OF THE MISSISSIPPI RIVER WITH TEMPERATURES
DIPPING INTO THE MID 30S AND WHERE THE WIND WILL BE LIGHTEST.
CARNEY
LONG TERM
(THURSDAY THROUGH TUESDAY)
ISSUED AT 309 AM CDT WED OCT 29 2025
THE LONG WAVE PATTERN REMAINS AMPLIFIED ACROSS THE CONUS WITH
RIDGING OVER THE WEST AND TROUGHING OVER THE EAST. THE DEGREE OF
AMPLIFICATION CHANGES DAY-TO-DAY, BUT THE OVERALL PATTERN PERSISTS.
THE TROUGH OVER THE EASTERN US WILL KEEP THE MID MISSISSIPPI VALLEY
IN NORTHWEST FLOW FOR THE MAJORITY OF THE PERIOD. THIS WILL KEEP
TEMPERATURES WITHIN 5-7 DEGREES OF SEASONAL NORMALS, MOSTLY ON THE
COOL SIDE. SATURDAY STILL LOOKS LIKE THE COOLEST DAY OF THE MEDIUM
RANGE AS ANOTHER STRONG SHORT WAVE DROPS THROUGH THE UPPER MIDWEST
INTO THE MID MISSISSIPPI VALLEY. THIS WILL PUSH ANOTHER COLD FRONT
THROUGH THE FORECAST AREA WITH CLOUDS AND POTENTIALLY A LITTLE RAIN.
THE DETERMINISTIC GFS PRINTS OUT SOME LIGHT QPF AS THE SHORT WAVE
MOVES ACROSS MISSOURI AND ILLINOIS AND CLOSES OF LATE SATURDAY INTO
SUNDAY. HOWEVER THE ECMWF IS DRY, AND KEEPS THE WAVE OPEN UNTIL IT
REACHES THE LOUISIANA COAST LATE SUNDAY. ANYTHING BELOW THE 90TH
PERCENTILE IN THE LREF IS DRY, SO WILL KEEP A DRY FORECAST THROUGH
THE WEEKEND. MODELS ARE SUGGESTING THAT THE LONG WAVE PATTERN WILL
BECOME LESS AMPLIFIED AND BEGIN SHIFTING EASTWARD EARLY NEXT WEEK.
500MB HEIGHT EOF PATTERNS IN THE LREF CLUSTER ANALYSIS HIGHLIGHT
FIRST THE AMPLITUDE AND THEN POSITION OF THE TROUGH EXITING TO THE
EAST, AND THEN THE POSITION FIRST AND AMPLITUDE SECOND OF THE
UPSTREAM RIDGE. WHILE A BUILDING UPPER LEVEL RIDGE SHOULD BRING THE
REGION WARMER TEMPERATURES, THE UNCERTAINTY IMPLIED IN THE EOF
PATTERNS DOES NOT PROVIDE HIGH CONFIDENCE IN THE FORECAST.
CONSEQUENTLY THE INTERQUARTILE RANGE FOR HIGHS MONDAY AND TUESDAY IS
5 TO 7 DEGREES IN MOST LOCATIONS. AT THIS POINT, THE DETERMINISTIC
NBM WARMS TEMPERATURES BACK INTO THE LOW TO MID 60S MONDAY AND
TUESDAY, WHICH MATCHES WELL WITH LREF MEANS, SO THIS SEEMS
REASONABLE AT THIS TIME.
CARNEY
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1246 PM CDT WED OCT 29 2025
FLIGHT CONDITIONS HAVE BEEN IMPROVING MORE RAPIDLY THAN EXPECTED
AND THIS IS REFLECTED IN THE LATEST TAFS. THIS IS LARGELY DUE TO
THE PERSISTENT NORTHWESTERLY WINDS THAT HAVE BEEN ADVECTING MUCH
DRIER LOW LEVEL AIR INTO THE REGION. THESE WINDS SHOULD CONTINUE
THROUGH THE AFTERNOON, AND GUIDANCE IS IN STRONG CONSENSUS THAT
THIS QUICKER IMPROVEMENT WILL CONTINUE. ADDITIONALLY, THERE IS A
HIGH LIKELIHOOD (90% CHANCE) THAT THESE IMPROVED FLIGHT
CONDITIONS REMAIN IN PLACE AT THE TERMINALS THROUGH THE NIGHT,
THANKS AGAIN TO A FAIR BIT OF DRYNESS IN THE LOW LEVELS.
BSH
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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