273
FXUS63 KLSX 121756
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
1255 PM CDT THU MAR 12 2026
KEY MESSAGES
- A WIND ADVISORY IS IN EFFECT FOR TONIGHT INTO FRIDAY MORNING
ACROSS PARTS OF NORTHEAST MISSOURI AND WEST CENTRAL/SOUTHWEST
ILLINOIS. WIND GUSTS UP TO 45 MPH ARE EXPECTED IN THE ADVISORY
AREA.
- MILD AND DRY WEATHER IS EXPECTED THROUGH SATURDAY.
- A STRONG COLD FRONT WILL BRING ANOTHER ROUND OF RAIN AND
THUNDERSTORMS TO THE AREA SUNDAY. TEMPERATURES WILL DROP BACK TO
WINTRY COLD BEHIND THE FRONT AND PRECIPITATION MAY END AS SNOW
SUNDAY NIGHT INTO MONDAY MORNING.
SHORT TERM
(THROUGH LATE FRIDAY AFTERNOON)
ISSUED AT 433 AM CDT THU MAR 12 2026
HIGH PRESSURE OVER THE GREAT PLAINS WILL DRIFT SOUTHEAST TODAY. THE
RIDGE AXIS WILL PASS ACROSS THE MID MISSISSIPPI VALLEY BY MID-LATE
MORNING AND LOW LEVEL FLOW WILL TURN BACK TO THE SOUTHWEST. THE
SOUTHWEST FLOW ALONG WITH A MOSTLY SUNNY SKY WILL PRODUCE A 20+
DEGREE TEMPERATURE RISE FROM LOWS AROUND 30 THIS MORNING TO HIGHS IN
THE MID TO UPPER 50S THIS AFTERNOON.
A STRONG CLIPPER-TYPE SYSTEM WILL MOVE FROM THE NORTHERN PLAINS INTO
THE UPPER MIDWEST FROM LATE THIS AFTERNOON INTO TONIGHT. THE
PRESSURE GRADIENT BETWEEN THIS CLIPPER TO OUR NORTH AND THE HIGH
PRESSURE SYSTEM TO MOVING ACROSS THE GULF COAST INTO THE
SOUTHEASTERN U.S. WILL STRENGTHEN QUICKLY DURING THE EVENING. EXPECT
SUSTAINED WINDS OF 15-25+ MPH WITH GUSTS OF 35-45 MPH, AND THE NBM
MEAN 24HR MAXIMUM WIND GUST IS INDICATING THERE COULD BE GUSTS TO
50+ MPH. THE HIGHER END OF THESE RANGES WILL BE ACROSS NORTHEAST
MISSOURI INTO WEST CENTRAL AND SOUTH CENTRAL ILLINOIS. HAVE
THEREFORE ISSUED A WIND ADVISORY FOR THESE AREAS STARTING THIS
EVENING AND CONTINUING INTO FRIDAY MORNING. TEMPERATURES TONIGHT
WILL REMAIN RELATIVELY MILD IN THE 40S DUE TO THE SOUTHWEST FLOW
AHEAD OF THE COLD FRONT ASSOCIATED WITH THE CLIPPER.
LOW LEVEL MOISTURE WILL BE BOTTLED UP WELL SOUTH OF US DUE TO THE
BLOCKING RIDGE ALONG THE GULF COAST, SO NO PRECIP IS EXPECTED AS THE
CLIPPER'S COLD FRONT MOVES THROUGH THE FORECAST AREA ON FRIDAY.
FORECAST SOUNDINGS ARE SHOWING THE POTENTIAL FOR ONLY SOME MID-HIGH
LEVEL CLOUDS, LIKELY THIN AND SCATTERED. THERE SHOULD THEREFORE BE
GOOD INSOLATION, AND COLD ADVECTION BEHIND THE COLD FRONT ISN'T
PARTICULARLY STRONG. THESE FACTORS ALONG WITH A WARMER START TO
FRIDAY MORNING SHOULD PRODUCE HIGHS AT LEAST AS WARM AS THURSDAY'S
IN THE MID TO UPPER 50S, WITH EVEN WARMER TEMPERATURES IN THE 60S
ACROSS SOUTHEAST MISSOURI INTO SOUTHERN ILLINOIS AS THESE AREAS
WON'T SEE FROPA UNTIL LATE MORNING OR EARLY AFTERNOON.
CARNEY
LONG TERM
(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 433 AM CDT THU MAR 12 2026
A STRONG MID-UPPER LEVEL TROUGH WILL MOVE ACROSS THE ROCKIES AND
INTO THE GREAT PLAINS SATURDAY INTO SUNDAY MORNING. LOW LEVEL
CYCLOGENESIS OVER THE PLAINS AHEAD OF THE TROUGH WILL PUSH THE FRONT
BACK TO THE NORTH ACROSS MISSOURI SATURDAY AFTERNOON, RESULTING IN
ANOTHER MILD TO WARM DAY WITH HIGHS MAINLY IN THE 60S. THERE ARE
SOME MODEL DIFFERENCES IN HOW QUICKLY THE LOW OVER THE PLAINS WILL
STRENGTHEN, AND THEREFORE HOW FAR NORTH THE FRONT WILL MOVE ON
SATURDAY. SATURDAY'S HIGH TEMPERATURE IQRS IN THE NBM ARE AS MUCH AS
10 DEGREES. HOWEVER THE DETERMINISTIC GFS AND ECMWF ARE GENERALLY
IN GOOD AGREEMENT WITH THE FRONT MOVING TO NEAR OR JUST NORTH OF THE
I-70 CORRIDOR.
THE SURFACE LOW CONTINUES TO STRENGTHEN SATURDAY NIGHT AND MOVES
INTO THE MIDWEST ON SUNDAY. CURRENT INDICATIONS ARE THAT THE ENTIRE
AREA WILL BE IN THE WARM SECTOR AHEAD OF THE SYSTEM ON SUNDAY.
DETERMINISTIC GUIDANCE IS SHOWING AS MUCH AS 300-500 J/KG MLCAPE
AHEAD OF THE FRONT, AND THE EC ENSEMBLE'S MEAN MUCAPE IS 200-400
J/KG. THEREFORE, THE CHANCE FOR THUNDERSTORMS IN SUNDAY'S FORECAST
CONTINUES TO LOOK GOOD. 0-6KM SHEAR IS FORECAST TO BE IN THE 40-
60KT RANGE AHEAD OF THE FRONT AS WELL, SO SEVERE STORMS CANNOT BE
RULED OUT.
THE UPPER LEVEL TROUGH WILL CONTINUE TO DEEPEN AS IT MOVES EAST
THROUGH THE MISSISSIPPI VALLEY SUNDAY NIGHT INTO MONDAY. THIS
CONTINUES TO STRENGTHEN THE LOW LEVEL SYSTEM WHICH DRAGS THE COLD
FRONT THROUGH THE AREA SUNDAY AFTERNOON INTO THE EVENING. THE DEEP
THROUGH WILL OPEN THE DOOR FOR AN ARCTIC BLAST FROM THE NORTH BEHIND
THE FRONT. THERE'S STILL SOME QUESTION AS TO HOW COLD IT WILL GET.
THIS LATEST SET OF GFS DETERMINISTIC MOS GUIDANCE IS COLDER THAN THE
PAST FEW RUNS. LREF TEMPERATURE IQRS ARE 5 TO 10 DEGREES SUNDAY
NIGHT AND MONDAY. THESE DIFFERENCES WILL GREATLY AFFECT THE PRECIP
TYPES BEHIND THE FRONT ON SUNDAY NIGHT. AS THE MODELS HAVE TRENDED
COLDER, THE CHANCE FOR SNOW BEHIND THE FRONT HAS INCREASED. BOTH
THE GFS AND ECMWF ARE SHOWING IT WILL COOL OFF FAST ENOUGH FOR RAIN
TO CHANGE TO SNOW SUNDAY NIGHT, AND THE MAJORITY OF LREF MEMBERS
SHOW SNOW, MAINLY ALONG AND NORTH OF I-70, BUT AT LEAST 40% SHOW
SNOW AS FAR SOUTH AS FARMINGTON. REGARDLESS, I WOULD LIKE TO SEE
MORE CONSISTENCY WITH THE LOW TRACK AND STRENGTH OF COLD ADVECTION
BEFORE INCREASING CHANCES FOR SNOW TOO MUCH.
MONDAY AND TUESDAY CONTINUE TO LOOK UNSEASONABLY COLD UNDER THE
INFLUENCE OF THE ARCTIC AIRMASS BEHIND THE FRONT. LOWS IN THE TEENS
AND 20S ARE LIKELY MONDAY MORNING, AND EVEN SOME SINGLE DIGITS MAY
CREEP INTO NORTHEAST MISSOURI ON TUESDAY. MONDAY'S HIGHS WILL
LIKELY NOT GET ABOVE FREEZING FOR MUCH OF THE AREA ALONG AND NORTH
OF I-70, AND WILL STRUGGLE INTO THE LOW TO MID 30S FARTHER SOUTH.
THE SURFACE HIGH IS FORECAST TO MOVE EAST OF THE AREA INTO THE OHIO
VALLEY BY LATE TUESDAY WHICH SHOULD BRING TEMPERATURES BACK U PINTO
THE MID 30S TO LOW 40S IN MOST LOCATIONS. SOUTHERLY FLOW ON THE
WEST SIDE OF THE RIDGE CONTINUES TO WARM TEMPERATURES INTO
WEDNESDAY. HOWEVER, LREF CLUSTER ANALYSIS SHOWS DIFFERENCES IN THE
AMPLITUDE AND POSITION OF THE LONG WAVE PATTERN, AND THEREFORE THE
POSITION AND STRENGTH OF THE SURFACE HIGH TOWARD MID-WEEK. WHILE IT
IS LIKELY THE AREA WILL EXPERIENCE WARMER TEMPERATURES BY WEDNESDAY,
LREF HIGH TEMPERATURE IQRS APPROACH 20 DEGREES INDICATING A GOOD DEAL
OF UNCERTAINTY IN THE STRENGTH OF THE WARM UP.
CARNEY
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY MORNING)
ISSUED AT 1255 PM CDT THU MAR 12 2026
VFR CONDITIONS WILL PERSIST AT ALL TAF SITES THROUGH FRIDAY
AFTERNOON. WINDS BECOME STRONGER AND GUSTIER FROM THE SOUTH-
SOUTHWEST LATER THIS AFTERNOON. LOW LEVEL WINDS WILL INCREASE
NOTABLY THIS EVENING AS A LOW LEVEL JET DEVELOPS WITH 60 KT
SOUTHWESTERLY FLOW AT AROUND 3-4 KFT. GIVEN THE HEIGHT OF THE LOW
LEVEL WINDS, LEFT LLWS OUT OF THE TAFS FOR NOW, BUT THE STRONG WINDS
ALOFT MAY CAUSE LOW LEVEL WIND SHEAR CONCERNS IF SURFACE WIND
SPEEDS/GUSTS DECREASE NOTICEABLY OVERNIGHT. THERE ARE SOME
DIFFERENCES AMONG FORECASTS OF LOW LEVEL STABILITY AND THE LOW LEVEL
INVERSION HEIGHT OVERNIGHT, BUT WE CURRENTLY ANTICIPATE WIND SPEEDS
TO REMAIN ENHANCED AT THE SURFACE. A COLD FRONT WILL MOVE INTO
NORTHERN MO/CENTRAL IL LATE TONIGHT, TURNING THE WIND MORE TO THE
WEST BEFORE 12Z FRIDAY.
WFO ILX
LSX WATCHES/WARNINGS/ADVISORIES
MO...WIND ADVISORY FROM 10 PM THIS EVENING TO 11 AM CDT FRIDAY FOR
AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-KNOX MO-LEWIS MO-
LINCOLN MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
PIKE MO-RALLS MO-SHELBY MO.
IL...WIND ADVISORY FROM 10 PM THIS EVENING TO 11 AM CDT FRIDAY FOR
ADAMS IL-BROWN IL-CALHOUN IL-GREENE IL-JERSEY IL-MACOUPIN
IL-MONTGOMERY IL-PIKE IL.
WFO LSX
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