623
FXUS63 KLSX 270406
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1106 PM CDT THU MAR 26 2026
KEY MESSAGES
- GUSTY SOUTHWEST WINDS AND LOW HUMIDITY WILL MAINTAIN ELEVATED
FIRE WEATHER CONDITIONS THE REMAINDER OF THE AFTERNOON. PERIODS
OF ELEVATED FIRE WEATHER WILL ALSO BE POSSIBLE IN PLACES
TOMORROW THROUGH THE WEEKEND.
- SHOWERS AND A FEW THUNDERSTORMS, ALONG WITH BREEZY NORTH WINDS,
ARE EXPECTED BEHIND A COLD FRONT THIS EVENING AND OVERNIGHT.
MARGINALLY SEVERE HAIL (1") IS THE MOST LIKELY HAZARD WITH
STRONGER STORMS.
- A 30-40 DEGREE TEMPERATURE DROP IS EXPECTED BY TOMORROW, BUT A
STEADY WARMUP WILL BRING VERY WARM TEMPERATURES BACK BY MID-
WEEK. SHOWER/THUNDERSTORM CHANCES ALSO RETURN BY MID-WEEK.
SHORT TERM
(THROUGH LATE FRIDAY NIGHT)
ISSUED AT 306 PM CDT THU MAR 26 2026
THERE ARE TWO PRIMARY ITEMS OF CONCERN DURING THE SHORT TERM PERIOD
OF THE FORECAST, INCLUDING ELEVATED FIRE WEATHER AND NEAR-RECORD
TEMPERATURES THIS AFTERNOON, FOLLOWED BY A SHARP COLD FRONT AND A
ROUND OF SHOWERS AND THUNDERSTORMS OVERNIGHT. THERE IS ALSO A
LIMITED POTENTIAL FOR A FEW SEVERE THUNDERSTORMS AS WELL, WITH LARGE
HAIL BEING THE PRIMARY THREAT.
AS OF NOON, TEMPERATURES HAVE ALREADY SOARED WELL INTO THE 80S UNDER
PERSISTENT SOUTHWESTERLY LOW LEVEL FLOW, WITH A BOOST FROM
DOWNSLOPING OFF THE OZARKS. WITH A FEW HOURS LEFT OF HEATING TO GO,
ALONG WITH PERHAPS A BRIEF BOOST FROM COMPRESSIONAL WARMING AHEAD OF
THE ADVANCING COLD FRONT LATER THIS AFTERNOON, TEMPERATURES ARE
LIKELY TO REACH INTO THE LOW 90S IN SEVERAL LOCATIONS. IN FACT, WE
HAVE ALREADY SET DAILY RECORD HIGHS AT ALL THREE LOCAL CLIMATE
STATIONS (ST. LOUIS, COLUMBIA, AND QUINCY) PARTIALLY DUE TO THE FACT
THAT THE LOCAL RECORDS FOR TODAY ARE A BIT ON THE LOW SIDE, BUT EVEN
STILL, THERE IS A REASONABLE POTENTIAL TO REACH ALL-TIME RECORD
MAXIMUMS FOR THE ENTIRE MONTH OF MARCH AS WELL.
MEANWHILE, DEWPOINTS HAVE RISEN INTO THE UPPER 50S TO LOW 60S ACROSS
THE AREA, AND WHILE THIS MOISTURE ADVECTION IS HELPING TO KEEP TRULY
"CRITICAL" FIRE WEATHER CONDITIONS IN CHECK, THE VERY WARM
TEMPERATURES WILL OFFSET THIS ENOUGH TO DROP HUMIDITY VALUES INTO
THE 25-40% RANGE BY THE WARMEST PART OF THE DAY. WHEN COUPLED WITH
SUSTAINED SOUTHWEST WINDS OF 15 TO 20 MPH AND GUSTS TO 30, ALONG
WITH DRY VEGETATION, THESE CONDITIONS WILL SUPPORT ERRATIC FIRE
BEHAVIOR NONETHELESS.
BEGINNING AT ROUGHLY 5 PM, A VERY SHARP COLD FRONT WILL BEGIN TO
MOVE THROUGH NORTHEAST MISSOURI AND WEST-CENTRAL ILLINOIS, AND WILL
SWEEP THROUGH THE REMAINDER OF THE AREA OVER THE REMAINDER OF THE
EVENING AND OVERNIGHT. SURFACE OBSERVATIONS TO THE NORTH INDICATE
THAT THIS FRONT HAS REACHED DES MOINES, IA, AND BEHIND THIS BOUNDARY
GUSTS TO BETWEEN 30 AND 40 MPH ARE CURRENTLY BEING OBSERVED. THIS
RAPID WIND SHIFT AND INCREASING SPEEDS ARE BOTH EXPECTED TO CONTINUE
AS THE FRONT PASSES THROUGH OUR AREA, AS WELL. TEMPERATURES WILL
ALSO QUICKLY DROP, WITH MORE ON THIS LATER.
MEANWHILE, MODERATE MIXED-LAYER INSTABILITY IS ALSO DEVELOPING
THROUGHOUT THE WARM SECTOR, TO THE TUNE OF AROUND 1000-2000 J/KG OF
CAPE. THIS IS LARGELY INACCESSIBLE, THOUGH, DUE TO A ROBUST LAYER
OF CONVECTIVE INHIBITION (CAP) ASSOCIATED WITH A PRONOUNCED WARM
LAYER ALOFT. WHILE THERE ARE STEEP MID-LEVEL LAPSE RATES ABOVE
THIS WARM NOSE, IT WILL BE VERY DIFFICULT FOR SURFACE-BASED
PARCELS TO TAP INTO THESE LAPSE RATES, EVEN WITH THE VERY STRONG
HEATING AND SHARP COLD FRONT. RATHER, IT REMAINS MORE LIKELY THAT
CONVECTION WILL BE LARGELY POST-FRONTAL AND ELEVATED, WHICH LIMITS
THE MAGNITUDE OF INSTABILITY AVAILABLE AND LIKEWISE THE OVERALL
SEVERE WEATHER THREAT. STILL, WE DO EXPECT WIDESPREAD SHOWERS AND
AT LEAST A FEW THUNDERSTORMS TO DEVELOP THIS EVENING AND OVERNIGHT
BEHIND THE FRONT, AND IF MORE ROBUST CORES CAN REMAIN DISCRETE,
SOME OF THESE MAY BE CAPABLE OF PRODUCING MARGINALLY SEVERE HAIL.
QUARTER-SIZED HAIL APPEARS TO BE MOST REASONABLE WITH THE STRONGER
CORES, BUT YOU DON'T HAVE TO GO FAR TO THE EAST TO FIND AN
ENVIRONMENT THAT IS MORE SUPPORTIVE OF HAILSTONES TO 2".
MEANWHILE, THE ELEVATED NATURE OF THESE STORMS WILL LIMIT THE
DAMAGING WIND AND TORNADO THREATS, ALTHOUGH A FEW STRONGER GUSTS
ARE POSSIBLE. THE POTENTIAL FOR BURSTS OF HEAVY RAIN ALSO EXISTS,
ALTHOUGH WE DO NOT SUSPECT THAT A SUSTAINED LINE OF STORMS OR
REPEATED TRAINING WILL PRODUCE A SIGNIFICANT FLOODING THREAT
LOCALLY.
THE INTENSITY OF SHOWERS AND THUNDERSTORMS WILL LIKELY WIND DOWN AS
WE APPROACH THE EARLY MORNING HOURS, BUT AT LEAST SOME SHOWER
ACTIVITY MAY PERSIST SOUTH OF I-70 FOR A FEW HOURS AFTER SUNRISE
BEFORE COMPLETELY DIMINISHING. OTHERWISE, FRIDAY IS EXPECTED TO BE
LARGELY DRY, BUT MUCH COOLER BEHIND THE PASSING COLD FRONT. MOST
AREAS ARE LIKELY TO SEE A 30 TO 40 DEGREE DROP IN TEMPERATURES FROM
TODAY, ALTHOUGH THIS EQUATES TO NEAR OR SLIGHTLY BELOW AVERAGE
TEMPERATURES FOR LATE MARCH. DEWPOINTS WILL ALSO BE MUCH LOWER
TOMORROW, AND CONSIDERING THAT NORTH-NORTHEAST WINDS WILL REMAIN
RATHER BRISK THROUGHOUT THE DAY (10-20 MPH SUSTAINED), SOME
LOCALIZED POCKETS OF ELEVATED FIRE WEATHER WILL BE POSSIBLE ACROSS
NE/C MO AND WEST-CENTRAL IL IF THERE ARE ANY AREAS THAT MISS OUT ON
TONIGHT'S RAINFALL.
19
LONG TERM
(SATURDAY THROUGH NEXT THURSDAY)
ISSUED AT 306 PM CDT THU MAR 26 2026
WHILE THE REMAINDER OF THE WEEKEND WILL FEATURE PRIMARILY HIGH
PRESSURE AND (MOSTLY) TRANQUIL WEATHER, A MORE UNSETTLED PATTERN IS
EXPECTED TO GRADUALLY RAMP UP OVER THE COURSE OF THE WEEK. THIS WILL
BRING BOTH THE RETURN OF SHOWER/THUNDERSTORM CHANCES AND ALSO YET
ANOTHER SUBSTANTIAL WARMUP BY MID-LATE WEEK.
BY EARLY SATURDAY, A LARGE AREA OF HIGH PRESSURE WILL SETTLE ALMOST
DIRECTLY OVERHEAD, RESULTING IN ANOTHER MILD AND DRY DAY. VERY LOW
DEWPOINT AIR (LIKELY IN THE LOW 20S OR EVEN UPPER TEENS) COMBINED
WITH A SLIGHT INCREASE IN AFTERNOON TEMPERATURES WILL VERY LIKELY
YIELD HUMIDITY RANGING FROM THE LOW 20S TO LOW 30S, MAINTAINING
THE POTENTIAL FOR ELEVATED FIRE WEATHER. WE WILL NEED TO KEEP A
CLOSE EYE ON OUR WESTERN AREAS IN PARTICULAR (NE AND C MO), AS
SOUTHERLY WINDS WILL BEGIN TO INCREASE SATURDAY AFTERNOON AS THE
SURFACE HIGH SLIDES OFF TO THE EAST. CURRENT WIND SPEED
PROJECTIONS ARE MARGINAL (SUSTAINED 5 TO 10 MPH), BUT WE DO
APPROACH ELEVATED CONDITIONS IN THE CURRENT FORECAST IN THESE
AREAS. MUCH WILL DEPEND ON HOW MUCH RAIN THESE AREAS RECEIVE
TONIGHT, ALTHOUGH BY SATURDAY THE FINE-DEAD FUELS WILL HAVE HAD A
FULL DAY OF BREEZY WINDS AND LOW HUMIDITY TO DRY BACK OUT.
THIS THREAT MAY ALSO CONTINUE INTO SUNDAY AS WELL, AS SOUTH-
SOUTHWEST FLOW INCREASES SLIGHTLY MORE AND EXPANDS INTO THE
REMAINDER OF THE AREA. ONCE AGAIN WARM/MOIST ADVECTION WILL RESUME,
KICKING OFF YET ANOTHER SUBSTANTIAL WARMING TREND AND ALSO GRADUALLY
ADVECTING HIGHER DEWPOINT AIR INTO THE AREA. EXACTLY HOW QUICKLY
THIS INCREASING MOISTURE ARRIVES SUNDAY WILL LIKELY DETERMINE THE
DEGREE OF FIRE WEATHER THREAT, AS WILL THE DEGREE OF WARMING. THE
COMBINATION OF COOLER TEMPERATURES / HIGHER DEWPOINTS WOULD LEAD TO
A MINIMAL THREAT, WHILE TEMPERATURES ON THE HIGHER END OF THE
ENSEMBLE ENVELOP, AND/OR DEWPOINTS ON THE LOWER END, COULD
REASONABLY RESULT IN WIDESPREAD ELEVATED CONDITIONS YET AGAIN.
BETWEEN MONDAY AND WEDNESDAY, MUCH WARMER TEMPERATURES WILL RESUME
AS A BROAD UPPER RIDGE BUILDS ACROSS THE CENTRAL CONUS, AND SOUTH-
SOUTHWEST FLOW CONTINUES LARGELY UNABATED. BY MONDAY, MEDIAN NBM MAX
TEMPERATURES CLIMB BACK INTO THE MID TO UPPER 80S AREA-WIDE, WITH
NARROW ENSEMBLE SPREAD, AND CONSIDERING THAT THIS FLOW REGIME IS
VERY SIMILAR TO WHAT WE'RE EXPERIENCING NOW, IT WOULD NOT BE A
SURPRISE TO REACH THE 75TH+ PERCENTILE VALUES OF ENSEMBLE MEMBERS
DURING THIS PERIOD. THIS IS ALSO SUPPORTED BY ENSEMBLE MEAN 850 MB
TEMPERATURES FORECAST TO EXCEED THE 97TH PERCENTILE, AND A
RELATIVELY ROBUST ECMWF EXTREME FORECAST INDEX SIGNAL.
GIVEN THESE VERY WARM EXPECTED TEMPERATURES WE WILL ONCE AGAIN NEED
TO KEEP AN EYE ON THE POTENTIAL FOR MARGINAL ELEVATED FIRE
WEATHER, BUT THIS SHOULD BE OFFSET BY THE INCREASING DEWPOINTS.
MEANWHILE, THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS WILL ALSO
STEADILY INCREASE BY MID-WEEK, PARTICULARLY AS SHORTWAVES BEGIN TO
ENCROACH UPON THE BROAD UPPER RIDGE. DAY-TO-DAY DETAILS REMAIN
SPARSE AT THIS TIME, BUT
19
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1103 PM CDT THU MAR 26 2026
A COLD FRONT HAS SHIFTED SOUTH OF ALL TERMINALS THIS EVENING WITH
GUSTY NORTHERLY WINDS LASTING THROUGH THE NIGHT. AN AREA OF
THUNDERSTORMS HAS LAGGED BEHIND THE FRONT AND IS EXPECTED TO
DECREASE IN INTENSITY AS IT MOVES SOUTH TONIGHT. IT'S STILL
UNCLEAR WHETHER THUNDER WILL IMPACT CENTRAL MO OR ST LOUIS AREA
TERMINALS, BUT IF IT DOES SO IT WILL LIKELY BE BETWEEN 7Z AND
12Z. THERE HAVE BEEN SOME POCKETS OF MVFR CEILINGS THIS EVENING,
BUT THEY HAVE BEEN LESS WIDESPREAD THAN EXPECTED AND CONFIDENCE
HAS DECREASED IN ITS OCCURRENCE. IF MVFR DOES DEVELOP, IT WILL
LIFT AND DISSIPATE THROUGH THE MORNING HOURS ON FRIDAY.
KIMBLE
CLIMATE
ISSUED AT 310 AM CDT THU MAR 26 2026
RECORD HIGHS ON MARCH 26:
ST LOUIS 87 IN 1991
COLUMBIA 86 IN 1910
QUINCY 82 IN 1991
ALL TIME MARCH HIGH TEMPERATURE RECORD:
ST LOUIS 92 ON MARCH 24, 1929
COLUMBIA 92 ON MARCH 21, 1907
QUINCY 88 ON MARCH 21, 1907
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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