675
FXUS63 KLSX 272323
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
623 PM CDT MON OCT 27 2025
KEY MESSAGES
- WIDESPREAD BENEFICIAL RAIN IS EXPECTED (90 - 100% CHANCE)
TOMORROW THROUGH WEDNESDAY. MOST OF THE AREA HAS A 70 - 80%
CHANCE AT SEEING 0.50" OR MORE RAIN.
- COOL, DRY WEATHER WILL END THIS WEEK.
SHORT TERM
(THROUGH LATE TUESDAY NIGHT)
ISSUED AT 156 PM CDT MON OCT 27 2025
TONIGHT WILL BE THE WARMEST NIGHT THROUGH AT LEAST LATE THIS WEEK AS
LOW CLOUD COVER KEEPS THE REGION INSULATED. MOST LOCATIONS WILL SEE
LOWS IN THE 40S, WHICH, DESPITE FEELING CHILLY, IS ACTUALLY 5 - 10
DEGREES ABOVE AVERAGE FOR LATE OCTOBER. THE NIGHTLY "WARMTH" WON'T
LAST LONG, HOWEVER, AS OUR NEXT SYSTEM WILL USHER IN COOLER AIR AS
WELL AS WIDESPREAD RAIN.
WATER VAPOR IMAGERY SHOWS THE BEGINNINGS OF OUR AFOREMENTIONED NEXT
SYSTEM IN THE FORM OF AN UPPER-LEVEL TROUGH SWIRLING OVER THE
NORTHERN PLAINS AND PACIFIC NORTHWEST. THIS FEATURE WILL DIG INTO
THE CENTRAL PLAINS AND MID-MISSISSIPPI VALLEY OVERNIGHT, WHILE AT
THE SURFACE A COLD FRONT GAINS INTENSITY AND APPROACHES MISSOURI
FROM THE WEST. CYCLOGENESIS ALONG THE FRONT CAUSED BY UPPER LEVEL
DYNAMICS WILL RESULT IN THE FRONT TILTING FROM NEAR VERTICAL TO A
MORE NORTHWESTERLY-SOUTHEASTERLY ORIENTATION AS IT ENTERS THE CWA
LATE TUESDAY AFTERNOON INTO EVENING. THE DEEPENING SURFACE LOW IS
FORECAST TO TRACK EITHER IN OUR SOUTHERN CWA OR JUST SOUTH OF IT,
LEAVING AT LEAST OUR SOUTHERN COUNTIES BELOW THE SYSTEM'S WARM
CONVEYOR BELT BY WEDNESDAY MORNING. IN THIS REGION, THE BETTER
DYNAMICS WILL SUPPORT HEAVIER RAINFALL AND PERHAPS A RUMBLE OF
THUNDER. THE LREF AND NBM ENSEMBLES REFLECT THIS, SHOWING THAT
LOCATIONS WITHIN THE WARM CONVEYOR BELT (DEPICTED AS SOUTH OF I-44,
BUT SUBJECT TO CHANGE BASED ON WHERE THE LOW TRACKS) HAVE UP TO A
50% CHANCE OF SEEING 1.00" OF RAIN OVER A 24 HOUR PERIOD WITH THE
SYSTEM. THOUGH THE PROBABILITIES FOR 1.00" DROP DRAMATICALLY
ELSEWHERE, THE ENTIRE CWA HAS A HIGH CHANCE (70 - 80%) OF SEEING >=
0.50" OF RAIN IN THE 24 HOURS BETWEEN TUESDAY AND WEDNESDAY EVENING.
THIS WILL BE BENEFICIAL CONSIDERING THE VAST MAJORITY OF THE CWA IS
IN MODERATE OR SEVERE DROUGHT.
THE COOLER AIR USHERED IN WITH THE FRONT WON'T BE EXTREMELY POTENT.
850 MB TEMPERATURES ARE ONLY FORECAST TO DROP ABOUT 4C, WHICH WILL
TRANSLATE TO US DROPPING FROM ABOUT 55 - 60 DEGREE HIGHS ON TUESDAY
TO 50 - 55 DEGREE HIGHS ON WEDNESDAY. IT WILL LIKELY FEEL MUCH
COOLER TO ANYONE UNFORTUNATE ENOUGH TO STEP OUTSIDE, HOWEVER, GIVEN
THE COOL RAIN AND GUSTY (25 - 30 MPH) PRESSURE GRADIENT WINDS.
JAJA
LONG TERM
(WEDNESDAY THROUGH NEXT MONDAY)
ISSUED AT 156 PM CDT MON OCT 27 2025
THURSDAY THROUGH SATURDAY ARE FORECAST TO BE DRY AND COOL WITH HIGHS
LARGELY IN THE 50S AND LOWS IN THE 30S. DEPENDING ON HOW A SURFACE
HIGH IN THE PLAINS BEHAVES LATE THIS WEEK INTO THIS WEEKEND, WINDS
MAY BECOME LIGHT ENOUGH AT NIGHT TO SUPPORT FROST AGAIN. THIS IS NOT
WRITTEN IN STONE YET, BUT IS A POSSIBILITY CONSIDERING THE 50 - 60%
NBM PROBABILITIES OF TEMPERATURES LESS THAN 36 DEGREES IN PORTIONS
OF THE AREA EACH MORNING.
ANOTHER COLD FRONT IS FORECAST TO DIVE THROUGH THE REGION THIS
WEEKEND, BUT RAIN CHANCES WITH THIS FRONTAL PASSAGE ARE MINIMAL.
MOST OF THE MOISTURE IN OUR CWA WILL BE SCOURED OUT BEHIND THE MID-
WEEK SYSTEM, LEAVING THIS WEEKEND'S COLD FRONT LITTLE TO WORK WITH.
THE COLD FRONT DOES LOOK TO USHER IN ANOTHER BOUT OF COOL AIR,
THOUGH UNCERTAINTY LIES IN HOW POTENT AND LONG-LASTING IT IS. THIS
IS REFLECTED WELL IN A 10 DEGREE SPREAD IN THE NBM HIGH TEMPERATURE
INTERQUARTILE RANGE FOR SUNDAY.
JAJA
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 621 PM CDT MON OCT 27 2025
WIDESPREAD IFR/MVFR CEILINGS EXIST ACROSS MUCH OF CENTRAL AND
SOUTHEAST MO, THOUGH ST LOUIS METRO TERMINALS HAVE SEEN RECENT
IMPROVEMENT AND SOME VFR CONDITIONS. IT IS EXPECTED THAT THE LOWER
CEILINGS WILL GRADUALLY NUDGE NORTHWARD TONIGHT, BRINGING
WIDESPREAD MVFR OR IFR BACK INTO ST LOUIS METRO AND CENTRAL MO
TERMINALS OVERNIGHT. COULD ALSO SEE SOME LOWER VISIBILITY, BUT
CONFIDENCE IS LOWER ON THIS AS THICK CLOUD COVER PREVENTS SURFACE
COOLING TO GENERATE FOG. CEILINGS STICK AROUND ALL DAY TOMORROW
AND EVEN SPREAD NORTH TO QUINCY WHICH HAS THUS FAR REMAINED OUT OF
THE LOWER CEILINGS. RAIN MOVES IN FROM THE WEST TOMORROW EVENING
WITH IFR CONDITIONS LIKELY INTO TUESDAY NIGHT.
KIMBLE
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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