953
FXUS63 KLSX 291720
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1120 AM CST MON DEC 29 2025
KEY MESSAGES
- AFTER A COLD AND BLUSTERY DAY, WINDS WILL DIE DOWN TONIGHT AND
TEMPERATURES WILL WARM ROUGHLY 10 DEGREES ON TUESDAY.
- NEAR TO BELOW NORMAL TEMPERATURES WILL PERSIST THROUGH THE
WEEKEND, THOUGH UNCERTAINTY IN THE TEMPERATURE FORECAST IS
HIGHER THAN NORMAL.
SHORT TERM
(THROUGH LATE TUESDAY AFTERNOON)
ISSUED AT 213 AM CST MON DEC 29 2025
WINDS CONTINUE TO GUST INTO THE 30S TO 40S AREA WIDE THIS MORNING AS
THE SURFACE PRESSURE GRADIENT REMAINS TIGHT. THE SURFACE PRESSURE
GRADIENT WILL SLACKEN THROUGH THE MORNING AS YESTERDAY'S SURFACE LOW
PUSHES EASTWARD AND A SURFACE HIGH SPILLS INTO THE AREA. WHILE WINDS
WILL REMAIN ELEVATED, GUSTING INTO THE 30S, THROUGH MUCH OF THE DAY,
THEY WILL DECREASE IN SPEED THROUGH TONIGHT.
STRONG COLD AIR ADVECTION IN THE WAKE OF YESTERDAY'S FRONT WILL
CONTINUE TODAY, RESULTING IN HIGH TEMPERATURES IN THE 20S ACROSS
MOST OF THE AREA. BY TUESDAY THE SURFACE HIGH WILL SINK SOUTH OF THE
FORECAST AREA, AND SUBSEQUENT WESTERLY WINDS WILL HELP TO ADVECT
WARMER TEMPERATURES INTO THE REGION. THE WAA COMBINED WITH INCREASED
SUNSHINE WILL RESULT IN TUESDAY'S HIGHS NEARLY 10 DEGREES WARMER
THAN TODAY.
DELIA
LONG TERM
(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 213 AM CST MON DEC 29 2025
THE WARMING TREND WILL CONTINUE WEDNESDAY, FINALLY PUSHING OUR
TEMPERATURES BACK TO NEAR NORMAL. MEANWHILE, A MID-LEVEL LOW WILL
CHURN OVER SOUTHEASTERN CANADA WEDNESDAY, WITH A MID-LEVEL RIDGE
OVER THE FOUR CORNERS REGION, LEAVING THE MID-MISSISSIPPI VALLEY IN
NORTHWEST FLOW BETWEEN THE TWO. DURING THE DAY, THE SURFACE LOW OVER
SOUTHEAST CANADA ASSOCIATED WITH THE MID-LEVEL LOW WILL SEND A COLD
FRONT SOUTHWARD INTO THE UPPER MISSISSIPPI VALLEY. THE DRY COLD
FRONT WILL SINK INTO THE FORECAST AREA OVERNIGHT INTO THURSDAY,
BRINGING A SHOT OF COOLER AIR TO THE REGION. UNCERTAINTY STILL
EXISTS IN IF THIS FEATURE WILL MOVE THROUGH THE ENTIRE CWA, HOW COLD
IT WILL BE, AS WELL AS HOW QUICKLY IT MOVES NORTHWARD AS A WARM
FRONT. THIS RESULTS IN UNCERTAINTY IN TEMPERATURES FROM THURSDAY
THROUGH THE END OF THE WEEKEND, ROUGHLY 10-15 DEGREES IN THE
INTERQUARTILE SPREAD. DESPITE THIS, THE 25TH PERCENTILE OF THE
INTERQUARTILE SPREAD FOR HIGH TEMPERATURES DURING THIS PERIOD IS
ONLY ABOUT 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR, INCREASING
CONFIDENCE THAT THIS SURGE OF COLD AIR WILL BE LESS INTENSE THAN
TODAY'S.
BY FRIDAY THE MID-LEVEL LOW WILL LIFT NORTHWARD INTO THE HUDSON BAY
REGION, LEAVING ROOM FOR A SHORTWAVE TO MOVE THROUGH THE SOUTHERN
STREAM OF THE MID-LEVEL FLOW, THROUGH THE MID TO LOWER MISSISSIPPI
VALLEY. WHILE CURRENT ENSEMBLE GUIDANCE KEEPS A MAJORITY OF THIS
PRECIPITATION SOUTH OF THE FORECAST AREA AND KEEPS THE EXTENDED
FORECAST DRY FOR NOW, CHANGES IN THE TRACK OF THIS SYSTEM COULD
RESULT IN INCREASING PRECIPITATION CHANCES ACROSS THE SOUTHERN
FORECAST AREA.
DELIA
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1112 AM CST MON DEC 29 2025
A POCKET OF STRATUS IS MOVING ACROSS THE REGION CURRENTLY,
IMPACTING ALL LOCAL TERMINALS. THE BASE HEIGHT OF THIS STRATUS HAS
BEEN DIFFICULT TO TRACK, AS THE DIURNAL TEMPERATURE CURVE HAS BEEN
ATTEMPTING TO RAISE IT WHILE THE COLD AIR ADVECTING INTO THE
REGION HAS BEEN WORKING TO LOWER IT. WHERE THIS BATTLE IS GOING TO
BE MOST IMPACTFUL IS AT KSUS, KSTL, AND KCPS WHERE CEILINGS MAY
BOUNCE AROUND THE MVFR/VFR THRESHOLD THROUGH THE FIRST FEW HOURS
OF THE TAF PERIOD BEFORE STRATUS CLEARS THE AREA. WITHIN THIS
STRATUS AT THESE THREE TERMINALS, THERE IS ALSO A LOW CHANCE FOR
FLURRIES. ONCE STRATUS CLEARS THE LOCAL TERMINALS, VFR FLIGHT
CONDITIONS ARE EXPECTED THROUGH THE REMAINDER OF THE PERIOD AS
WINDS WEAKEN AND BEGIN TO SHIFT TO OUT OF THE WEST-SOUTHWEST.
ELMORE
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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