911
FXUS63 KLSX 282006
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
306 PM CDT TUE OCT 28 2025
KEY MESSAGES
- WIDESPREAD RAINFALL IS EXPECTED THIS EVENING THROUGH WEDNESDAY
MORNING BEFORE TAPERING OFF FROM NORTHWEST TO SOUTHEAST.
RAINFALL AMOUNTS ARE EXPECTED TO RANGE FROM AROUND 0.25" OVER
WEST- CENTRAL ILLINOIS TO LOCALLY UP TO 2" OVER SOUTHEAST
MISSOURI.
- DRY AND SEASONABLY COOL CONDITIONS ARE FAVORED THROUGH THE
WEEKEND.
SHORT TERM
(THROUGH LATE WEDNESDAY NIGHT)
ISSUED AT 306 PM CDT TUE OCT 28 2025
THE UPPER LEVEL PATTERN FEATURES A RIDGE CENTERED SOUTHEAST OF THE
HUDSON BAY AND A LONGWAVE TROUGH TO THE WEST THAT EXTENDS SOUTHWARD
INTO THE CENTRAL PLAINS. A TANDEM OF SURFACE HIGHS EXTEND OVER THE
NORTHEAST CONUS AND INTERMOUNTAIN WEST. WHILE SURFACE RIDGING
MAINTAINS MOSTLY CLEAR SKIES OVER THEIR RESPECTIVE REGIONS, A BROAD
AND ELONGATED MASS OF CLOUD COVER ENCOMPASSES MUCH OF THE
MISSISSIPPI RIVER VALLEY WITH A COLD FRONT DRAPED NORTH TO SOUTH
ACROSS THE EASTERN PLAINS.
SHORT AND MEDIUM RANGE GUIDANCE SHOWS AN UPPER LEVEL SHORTWAVE
ROUNDING THE BASE OF THE WESTERN TROUGH, GIVING RISE TO SURFACE
CYCLOGENESIS OVER EASTERN TEXAS. THE INCREASING PRESSURE GRADIENT
OVER THE PLAINS IS EXPECTED TO SUPPORT A STRENGTHEN UPPER LEVEL JET,
RESULTING IN A DIGGING UPPER TROUGH AND DEEPENING SYSTEM TONIGHT
INTO WEDNESDAY. THE SYSTEM CURVES NORTHEAST FROM EAST TEXAS INTO
THE LOWER MISSISSIPPI RIVER VALLEY, BECOMING STACKED AS IS PASSES
OVER THE MISSOURI BOOTHEEL. MID-LEVEL MOISTURE TRANSPORT VECTORS
SHOW MOISTURE INITIALLY CARRIED INTO ILLINOIS BEFORE WRAPPING BACK
INTO THE NORTH SIDE OF THE SYSTEM AS IT DEEPENS TO OUR SOUTH.
RAP SOUNDINGS SHOW LOW LEVEL SATURATION (SFC-750MB) DEEPENING
FROM EAST TO WEST AS MOISTURE IS WRAPPED INTO AND AROUND THE NORTH
SIDE OF THE SYSTEM TONIGHT INTO EARLY WEDNESDAY MORNING. SHOWERS
ARE EXPECTED TO BECOME MORE NUMEROUS THIS EVENING. THERE ARE A
COUPLE OF THINGS TO NOTE WITH THE PLACEMENT OF HIGHER RAINFALL
POTENTIAL AND QPF TOTALS THROUGH WEDNESDAY. FIRST, THE UPPER LEVEL
RIDGE AND SURFACE HIGH TO THE NORTHEAST WILL HAVE SOME PLAY ON
THE NORTHEAST EXTEND OF THE BETTER RAINFALL. SECOND, THE SOUTHERN
TRACK OF THE SYSTEM WILL KEEP THE BEST LIFT OVER THE SOUTHERN
SECTIONS OF THE CWA. AS THE UPPER LEVEL SHORTWAVE TRACKS SOUTHEAST
AND THE SURFACE SYSTEM DEEPENS, THE NORTHEAST TURN WILL PLACE
MUCH OF SOUTHEAST MISSOURI UNDER THE PIVOT, WHICH EQUATES TO
LONGER DURATION OF SOAKING RAIN. AS WE WORK NORTHWARD FROM THE
SYSTEM, SCATTERED SHOWERS LINING THE COLD FRONT WILL BE IMPEDED BY
EASTERLY FLOW THAT WRAPS BETWEEN THE RIDGE AND THE SYSTEM OVER
WEST-CENTRAL ILLINOIS AND NORTHERN MISSOURI LATE TONIGHT INTO
WEDNESDAY.
WITH THE ONGOING DROUGHT, THIS WILL BE ANOTHER WELCOME RAINFALL,
ESPECIALLY FOR LOCATIONS IN SOUTHEAST MISSOURI. HREF ENSEMBLES
INDICATE THE HIGHEST PROBABILITY (80-100%) FOR 1" QPF ROUGHLY
SOUTHEAST OF I-44, SOUTH OF FESTUS THROUGH SOUTHERN ILLINOIS.
PROBABILITIES SHOW 0.50" IS LIKELY (GREATER THAN 60%) WEST OF THE
MISSISSIPPI RIVER WITH THE SHARPEST CUTOFF TO AMOUNTS NORTHEAST OF I-
70, EAST OF THE MISSISSIPPI RIVER. THIS PROVIDES THE BEST EXAMPLE OF
THE IMPACT OF THE DRY, EASTERLY FLOW THAT CUTS INTO QPF OVER THE FAR
NORTHEAST QUADRANT OF THE CWA, WHERE HREF SHOWS ABOUT 50% OF THE
MEMBERS SUPPORT 0.25" OF TOTAL QPF BY WEDNESDAY AFTERNOON.
AS THE SYSTEM DEPARTS INTO THE OHIO VALLEY WEDNESDAY, IT DRAWS THE
COLD FRONT SOUTHWARD WITH MUCH DRIER AIR BEING WRAPPED IN BEHIND THE
SYSTEM. THE TIGHTENING PRESSURE GRADIENT WILL INDUCE GUSTY WINDS
TROUGH THE DAY WEDNESDAY WITH SOME GUST APPROACHING 30 MPH AT TIMES.
RAIN IS EXPECTED TO TAPER OFF FROM NORTHWEST TO SOUTHEAST WITH
COOLER AIR IN UNDER CLEARING SKIES WEDNESDAY NIGHT.
TONIGHT'S LOWS WILL FALL INTO THE MID/UPPER 40S. HIGH TEMPERATURES
WEDNESDAY WILL BE IN THE LOW/MID-50S AND OVERNIGHT LOWS WILL FALL
INTO THE MID-30S TO LOW-40S.
MAPLES
LONG TERM
(THURSDAY THROUGH NEXT TUESDAY)
ISSUED AT 306 PM CDT TUE OCT 28 2025
MUCH OF THE COUNTRY WILL BE UNDER SOME INFLUENCE OF A BROAD,
LONGWAVE UPPER LEVEL TROUGH BY THURSDAY MORNING. THE PATTERN WILL
RESULT IN NORTHWEST FLOW ALOFT THAT WILL BE THE STEERING MECHANISM
FOR A SERIES OF SHORTWAVES/UPPER LOWS TO TRACK SOUTHEAST THROUGH THE
CENTRAL PART OF THE COUNTRY.
THURSDAY, WE WILL BE SPENT IN BETWEEN THE FEATURES - ONE WILL BE
DEPARTING TO THE EAST (LATE TUES./WED. SYSTEM) AND ANOTHER UPPER
LEVEL SHORTWAVE WILL BE POISED TO SINK SOUTHEASTWARD FROM THE
NORTHERN PLAINS. AS WE TUCK BETWEEN THE TWO SYSTEMS, DRY AND
SEASONABLY COOL CONDITIONS ARE EXPECTED THURSDAY. BY LATE THURSDAY
INTO FRIDAY, AN UPPER LOW WILL TRACK FROM THE NORTHERN PLAINS INTO
THE MIDWEST WITH ANOTHER SHORTWAVE AT THE SOUTHWESTERN PERIPHERY OF
THE LONGWAVE TROUGH. THE SHORTWAVE AT THE BASE OF THE TROUGH LOOKS
LIKE IT WILL BE FAR ENOUGH TO THE SOUTHWEST TO HAVE LITTLE IMPACT
LOCALLY. THE UPPER LOW THAT TRACKS OVERHEAD HAS VERY LITTLE MOISTURE
TO WORK WITH, AS IT NEVER TRULY RECOVERS AFTER THE MIDWEEK SYSTEM.
NBM GUIDANCE ONCE HINTED AT SLIGHT CHANCE POPS SATURDAY, BUT HAS
SINCE BACKED OFF. TEMPERATURES COOL SLIGHTLY BEHIND THE FRONT WITH
DRY CONDITIONS NOW FAVORED FOR SATURDAY.
AS GET FURTHER OUT INTO THE LONG TERM PERIOD, ENSEMBLE SPREAD
INCREASES WITH TROUGHING OVER THE EASTERN PORTION OF THE CONUS AND
RIDGING TO THE WEST. LONG RANGE GUIDANCE VARIES WITH THE AMPLITUDE
OF THE RIDGE AND SMALLER SCALE FEATURES THAT PLAY OUT IN BETWEEN.
WHILE GENERAL TRENDS MODERATE TEMPERATURES SOME, HOW FAR WE END UP
ON EITHER SIDE (TROUGH/RIDGE) OF THE PATTERN WILL BE THE PRIMARY
DRIVER IN TEMPERATURE TRENDS. CONSIDERING THE IQR (25TH/75TH
PERCENTILE) SPREADS OUT FROM 5-7 DEGREES SUNDAY TO 10-12 DEGREES
EARLY NEXT WEEK, THERE IS LESS CONFIDENCE IN THE LATER PORTION OF
THE FORECAST.
MAPLES
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1240 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 (WEDNESDAY 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 WEDNESDAY, 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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