605
FXUS63 KLSX 191735
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1135 AM CST THU DEC 19 2024
KEY MESSAGES
- DRY WEATHER IS EXPECTED THROUGH THE WEEKEND BEFORE RAIN RETURNS
TO THE AREA EARLY NEXT WEEK
- TEMPERATURES WILL TREND COOLER THROUGH THE END OF THE WEEK
BEFORE WARMING GRADUALLY NEXT WEEK.
SHORT TERM
(THROUGH LATE FRIDAY AFTERNOON)
ISSUED AT 351 AM CST THU DEC 19 2024
WINDS WILL BE LIGHT ACROSS THE AREA THIS MORNING AS A SURFACE HIGH
WAS CENTERED OVER ILLINOIS WITH A LOW OVER THE CENTRAL PLAINS. THE
WINDS WILL PICK UP OUT OF THE SOUTH LATER THIS MORNING AND THEN TURN
OUT OF THE SOUTHWEST THIS AFTERNOON AS THE HIGH MOVES OFF TO THE
EAST AND THE LOW MOVES INTO THE UPPER MIDWEST. WITH THE SOUTHWEST
WIND AT LEAST SOME SUNSHINE TODAY, TEMPERATURES WILL BE ABLE TO
CLIMB BACK INTO THE 40S AND LOWER 50S THIS AFTERNOON.
A CLIPPER THAT IS CURRENTLY OVER THE NORTHERN PLAINS IS STILL ON
TRACK TO MOVE ACROSS THE MIDWEST TONIGHT ALONG WITH AN ATTENDANT
COLD FRONT. FORECAST SOUNDINGS FROM THE NAM AND GFS ARE SHOWING
THAT THERE WILL BE SOME POST-FRONTAL LOW CLOUDS THAT WILL MOVE INTO
THE AREA LATE TONIGHT INTO FRIDAY MORNING, PRIMARILY ALONG AND EAST
OF THE MISSISSIPPI RIVER. THE MAJORITY OF THE MODELS CONTINUE TO
SNOW NO QPF WITH THIS SYSTEM OVER THE CWA, THOUGH I COULDN'T RULE
OUT A STRAY SPRINKLE/FLURRY OVER ILLINOIS UNDER THE LOW CLOUDS.
IT WILL BE NOTABLY COLDER TOMORROW WITH STRONG COLD AIR ADVECTION
AND WINDS GUSTING UP TO 35 MPH IN THE MORNING AND LOW CLOUDS
PERSISTING OVER THE EASTERN HALF OF THE CWA. HIGHS WILL ONLY BE IN
THE 30S WITH MORNING WIND CHILLS IN THE TEENS.
BRITT
LONG TERM
(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 351 AM CST THU DEC 19 2024
THE FORECAST REMAINS ON TRACK OVER THE WEEKEND INTO NEXT WEEK AS
THERE IS OVERALL AGREEMENT IN THE MODEL GUIDANCE THAT THE
NORTHWESTERLY FLOW OVER THE WEEKEND WILL BE FOLLOWED BY A MORE
ACTIVE PATTERN NEXT WEEK. DRY WEATHER IS STILL EXPECTED ON SATURDAY
AND SUNDAY AS AN UPPER RIDGE WILL BUILD INTO THE MIDWEST AT THE SAME
TIME HIGH PRESSURE MOVES THROUGH THE GREAT LAKES. THEN THE HREF IS
SHOWING A TROUGH DEEPENING OVER THE GREAT PLAINS EARLY NEXT WEEK AT
THE SAME TIME THAT ANOTHER WEAKER COLD FRONT WILL MOVE DOWN INTO
MISSOURI AND ILLINOIS. MOISTURE WILL BE DRAWN UP FROM THE GULF AHEAD
OF THE TROUGH SUPPORTING A CHANCE OF RAIN OVER THE CWA BEGINNING
MONDAY THAT WILL CONTINUE INTO CHRISTMAS DAY. WHILE THE LREF IS
INDICATING THAT THERE ARE DIFFERENCES AMONGST ITS MEMBERS IN THE
TIMING AND THE DEPTH OF THE UPPER TROUGH AND THE PLACEMENT OF THE
SURFACE FRONT, THE MAJORITY OF THE MEMBERS (50-70%) HAVE THE BEST
CHANCE OF RAIN ON TUESDAY AND TUESDAY NIGHT WARRANTING KEEPING THE
LIKELY POPS.
SATURDAY STILL LOOKS SEASONABLY COOLER WITH HIGHS ONLY IN THE 30S
BEFORE TEMPERATURES BEGIN TO MODERATE ON SUNDAY AS WINDS BEGIN TO
TURN OUT OF THE SOUTH BEHIND A RETREATING SURFACE HIGH. THE 850MB
TEMPERATURES WILL CLIMB TO AROUND +5C WHICH IS IN THE 90TH
PERCENTILE FOR MID DECEMBER WHICH SUPPORTS KEEPING HIGHS IN THE 40
AND 50S AND LOWS ABOVE FREEZING. VERY FEW OF THE LREF MEMBERS
(<15%) ARE SHOWING ANY CHANCE OF SNOW NEXT WEEK OVER THE CWA IN THIS
RELATIVELY WARM PATTERN.
BRITT
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1135 AM CST THU DEC 19 2024
SMALL CHANGES WERE MADE SINCE THE LAST UPDATE, PRIMARY CONCERNING
SOUTHERLY WIND GUSTS OVER KJEF/KCOU/KUIN. QUICK CLEARING OF CLOUD
COVER HAS RESULTED IN DEEPER MIXING AND WILL PROVIDE BETTER
SUPPORT FOR GUST POTENTIAL AT THESE LOCATIONS THIS AFTERNOON.
AFTER A BRIEF LULL IN THE GUSTS LATE THIS AFTERNOON INTO EARLY
THIS EVENING, WINDS WILL SHIFT OUT OF THE NORTHWEST BEHIND A COLD
FRONT. GUSTS WILL RETURN LATE THIS EVENING AND LAST THROUGH THE
DAY FRIDAY. GUSTS ARE EXPECT TO PEAK AT 25-30 KNOTS LATE TONIGHT
THROUGH MID-AFTERNOON FRIDAY.
CONDITIONS REMAIN VFR THROUGH TODAY WITH INCREASING CLOUD COVER
TONIGHT. WITH EXCEPTION TO KCOU/KJEF, MVFR CLOUDS WILL MOVE IN
LATE TONIGHT THROUGH FRIDAY MORNING. IMPROVE WILL BE RATHER
GRADUAL WITH VFR RETURNING LATE IN THE PERIOD.
MAPLES
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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