037
FXUS63 KLSX 281737
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1237 PM CDT TUE OCT 28 2025
KEY MESSAGES
- RAIN WILL OVERSPREAD THE AREA FROM LATE THIS AFTERNOON INTO THIS
EVENING. RAIN IS EXPECTED TO END FROM NORTHWEST TO SOUTHEAST ON
WEDNESDAY.
- FORECAST RAINFALL AMOUNTS RANGE FROM AROUND 4/10 OF AN INCH IN
WEST CENTRAL ILLINOIS TO ROUND 1 3/4 INCHES IN SOUTHEAST
MISSOURI.
- DRY WEATHER WITH SEASONABLY COOL TEMPERATURES IS EXPECTED FOR
THE REST OF THE WEEK.
SHORT TERM
(THROUGH WEDNESDAY NIGHT)
ISSUED AT 329 AM CDT TUE OCT 28 2025
A STRONG NEGATIVELY TILTED SHORT WAVE TROUGH IS DIGGING INTO THE
GREAT PLAINS THIS MORNING. THE OPEN WAVE IS FORECAST TO CLOSE OFF
OVER THE EAST CENTRAL PLAINS LATE THIS AFTERNOON OR EARLY THIS
EVENING. AS THIS HAPPENS IT WILL FORCE LOW LEVEL CYCLOGENESIS OVER
THE LOWER AND MID MISSISSIPPI VALLEY RESULTING IN A CLOSED LOW
DEVELOPING IN THE VICINITY OF THE MISSOURI BOOTHEEL BY AROUND 06Z
TONIGHT. THE STACKED LOW PRESSURE SYSTEM WILL THEN MOVE SLOWLY
EASTWARD INTO THE TENNESSEE VALLEY WEDNESDAY AND PHASE WITH ANOTHER
TROUGH OVER THE MID ATLANTIC AND NORTHEASTERN U.S.
THIS ALL BOILS DOWN TO ANOTHER PERIOD OF RAIN FOR THE FORECAST AREA.
THERE MAY BE A FEW SPRINKLES OR AREAS OF LIGHT RAIN THIS MORNING.
GUIDANCE SHOWS THE DEVELOPING LOW WILL PRODUCE WEAK LOW LEVEL
MOISTURE CONVERGENCE, MAINLY EAST OF THE MISSISSIPPI RIVER DURING
THE MORNING. MOISTURE CONVERGENCE WILL STRENGTHEN THIS AFTERNOON
AND EVENING AS THE CLOSED LOW DEEPENS PRODUCING STEADIER AND MORE
WIDESPREAD RAIN ACROSS THE AREA. MODELS SHOW A STEADY STREAM OF LOW
LEVEL MOISTURE WRAPPING INTO THE SYSTEM, FIRST FROM THE GULF TO THE
SOUTH TODAY, AND THEN FROM THE EAST TONIGHT AND WEDNESDAY AS THE LOW
LEVEL COLD FRONT MOVES THROUGH THE LOWER MISSISSIPPI VALLEY INTO THE
GULF. RAIN WILL END FROM NORTHWEST TO SOUTHEAST ON WEDNESDAY AS THE
LOW MOVES EAST, AWAY FROM THE AREA AND DRIER LOW LEVEL AIR IS PULLED
IN FROM THE NORTH BEHIND IT. THIS WILL BE ANOTHER PERIOD OF
BENEFICIAL RAIN DESPITE IT LASTING FOR AS MUCH AS 18-24 HOURS
ACROSS PARTS OF SOUTHEAST MISSOURI AND SOUTHWEST ILLINOIS. RAINFALL
RATES ARE NOT EXPECTED TO BE EXCESSIVE, AND ACCUMULATIONS ARE NOT
EXPECTED TO EXCEED 1 INCH IN ANY 6 HOUR PERIOD (IN MOST CASES WELL
UNDER THAT). TEMPERATURES THROUGH THE PERIOD WILL REMAIN COOL DUE TO
CLOUDS AND PRECIP WITH HIGHS TODAY AND WEDNESDAY MAINLY IN THE MID
TO UPPER 50S AND LOWS IN THE MID TO UPPER 40S TODAY, DROPPING TO THE
35-40 DEGREE RANGE WEDNESDAY NIGHT BEHIND THE COLD FRONT.
CARNEY
LONG TERM
(THURSDAY THROUGH MONDAY)
ISSUED AT 329 AM CDT TUE OCT 28 2025
THE REMAINDER OF THE FORECAST LOOKS RELATIVELY QUIET. THE OVERALL
WEATHER PATTERN REMAINS HIGHLY AMPLIFIED AT LEAST THROUGH THE
WEEKEND WITH LONG WAVE TROUGHING OVER THE EASTERN 1/2 OF THE CONUS
AND RIDGING OVER THE WEST. THIS WILL KEEP OUR SEASONABLY COOL
STREAK GOING WITH TEMPERATURES NEAR, TO A FEW DEGREES BELOW NORMAL.
ANOTHER SHORT WAVE TROUGH WILL DROP FROM THE NORTHERN PLAINS INTO
THE MID MISSISSIPPI VALLEY FRIDAY NIGHT INTO SATURDAY. THE SURFACE
COLD FRONT ASSOCIATED WITH THE WAVE PUSHES THROUGH EARLY SATURDAY
MORNING, AND COLD ADVECTION FROM LOW LEVEL NORTHWEST FLOW WILL
PRODUCE ANOTHER DAY WITH HIGHS 5 OR MORE DEGREES BELOW NORMAL,
LIKELY THE COOLEST DAY OF THE MEDIUM RANGE. LREF INTERQUARTILE RANGE
OF HIGHS AT STL ON SATURDAY IS ONLY 3 DEGREES (52-55) SO CONFIDENCE
IN THESE COOL TEMPERATURES IS HIGH. STRONG PVA AND MODEST MID-LEVEL
FRONTOGENESIS ASSOCIATED WITH THE WAVE MAY PRODUCE SOME VERY LIGHT
RAIN OR SPRINKLES, THOUGH CURRENT INDICATIONS ARE THAT MID-LEVEL
MOISTURE WILL BE LACKING. INDEED, LESS THAN 20% OF THE LREF MEMBERS
PRODUCE ACCUMULATING PRECIP WITH THIS WAVE. HOWEVER, A 15-20 PERCENT
CHANCE IS WARRANTIED AS THE WAVE PASSES SATURDAY NIGHT GIVEN THE
UNCERTAINTIES THIS FAR OUT. TEMPERATURES MODERATE A BIT SUNDAY AND
MONDAY AS COLD ADVECTION CEASES AND A CLEARER SKY ALLOWS FOR MORE
INSOLATION DURING THE DAY.
CARNEY
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1235 PM CDT TUE OCT 28 2025
LOW PRESSURE IS EXPECTED TO STRENGTHEN AS IT PROGRESSES FROM THE
SOUTHERN PLAIN OVER THE MISSOURI BOOTHEEL TONIGHT INTO WEDNESDAY.
A BROAD AREA OF CLOUD COVER EXTENDS OVER THE MISSISSIPPI RIVER
VALLEY WITH MVFR/IFR CEILINGS AND ISOLATED SHOWERS.
SHOWERS ARE EXPECTED TO INCREASE IN COVERAGE OVER CENTRAL MISSOURI
AND METRO TERMINALS AS THE DAY APPROACHES SUNSET. STEADY LIGHT TO
MODERATE RAIN IS EXPECTED TO ACCOMPANY IFR CEILINGS TONIGHT INTO
EARLY THURSDAY WITH VISIBILITY RESTRICTIONS IN THE 2-5SM RANGES.
RAIN IS THEN TAPER OFF FROM MID TO LATE MORNING WITH OCCASIONAL
SPRINKLES OR BRIEF, SCATTERED LIGHT RAIN SHOWERS THROUGH EARLY
AFTERNOON. DRIER AIR IS THEN EXPECTED TO WRAP IN BEHIND THE SYSTEM
WITH IMPROVEMENT LATER IN THE PERIOD (THURSDAY AFTERNOON).
IFR/MVFR IS FAVORED THROUGH MUCH OF THE PERIOD WITH VFR GRADUALLY
WORKING THROUGH THE REGION FROM NORTHWEST TO SOUTHEAST BEYOND 16Z
THURSDAY.
AS RAIN BEGINS TO LIGHTEN/TAPER OFF THURSDAY, NORTHEASTERLY WINDS
WITH GUSTS AROUND 25 KNOTS THROUGH THE DAY.
MAPLES
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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