511
FXUS63 KLSX 271721
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1221 PM CDT FRI MAR 27 2026
KEY MESSAGES
- AFTER RECORD BREAKING TEMPERATURES THURSDAY, TEMPERATURES WILL
BE MUCH COOLER TODAY AND SATURDAY BEFORE WARMING NEXT WEEK.
- ELEVATED FIRE DANGER IS POSSIBLE ACROSS CENTRAL, EAST- CENTRAL,
AND SOUTHEAST MISSOURI SATURDAY AFTERNOON.
SHORT TERM
(THROUGH LATE TONIGHT)
ISSUED AT 215 AM CDT FRI MAR 27 2026
AS OF 215 AM, THE SURFACE COLD FRONT HAS JUST CLEARED REYNOLDS,
IRON, AND MADISON COUNTIES. AT 250MB, BROAD ANTICYCLONIC FLOW WAS
LOCATED OVER WESTERN TEXAS WITH THE REMNANT UPPER LEVEL LOW (THAT
WAS SOUTHWEST OF CALIFORNIA ON WEDNESDAY) OVER NORTHERN OKLAHOMA.
THERE APPEARS TO BE JUST ENOUGH LEFT OVER UPPER LEVEL DIVERGENCE
WHICH HAS ALLOWED CONVECTIVE INITIATION TO OCCUR, WITH A CLUSTER
OF SHOWERS AND THUNDERSTORMS OVER KANSAS HEADING EAST INTO CENTRAL
MISSOURI. ANOTHER KEY FEATURE IN THE UPPER LEVELS IS THE MODEST
AMPLIFICATION IN THE UNITED STATES WHICH HAS ELONGATED THE SLOPED
FRONTAL ZONE WITH ELEVATED CONVECTION FIRING OVER NORTHERN
MISSOURI AND CENTRAL ILLINOIS. THIS LINE OF SHOWERS AND
THUNDERSTORMS CONTINUE TO WEAKEN THIS MORNING THOUGH AS THEY
BECOME REMOVED FROM THE BEST UPPER LEVEL FORCING. THE OTHER MAIN
QUESTION THIS MORNING IS HOW FAR EAST WILL THE SHOWERS AND
THUNDERSTORMS OVER KANSAS BE ABLE TO HOLD TOGETHER AS THE UPPER
LEVEL DIVERGENCE FADES. THE MOST LIKELY SCENARIO APPEARS TO BE
THAT CONVECTION APPROACHING ST. LOUIS FROM THE NORTH WILL WEAKEN
AS WELL AS THE CONVECTION ENTERING MISSOURI FROM KANSAS. NEAR
SUNRISE THIS MORNING, THE CONVECTION WILL LIKELY BE LIMITED TO
SHOWERS OR JUST RAIN AS THE FRONTAL SURFACE AROUND 800 MB
APPROACHES CENTRAL MISSOURI AND ILLINOIS. THROUGH THE MORNING INTO
THE EARLY AFTERNOON, SHOWERS WILL CONTINUE TO WEAKEN AND PROGRESS
SOUTH WITH THE FRONTAL SURFACE. BEHIND THE COLD FRONT, DRY AIR
WILL BE SLOW TO FILTER IN, ESPECIALLY IN THE MID AND UPPER LEVELS.
THIS MEANS CLOUDS WILL LIKELY HOLD ON THROUGH THE MORNING AND
SOME OF THE AFTERNOON (ESPECIALLY IN REYNOLDS, IRON, AND MADISON
COUNTIES). GIVEN THE FILTERED CLOUD COVER AND COOLING THERMAL
PROFILES, HIGH TEMPERATURES WILL LIKELY REMAIN IN THE LOWER 50S
TODAY. ONE OTHER CONCERN FOR THIS AFTERNOON IS THE POTENTIAL FOR
RELATIVE HUMIDITY VALUES TO FALL BELOW 35% WITH SUSTAINED WINDS AT
OR ABOVE 10 KTS. TAKING A LOOK AT THE HREF, THE GREATEST
PROBABILITY OF THIS OCCURRING WILL BE OVER NORTHEAST MISSOURI AND
WEST-CENTRAL ILLINOIS. HOWEVER, THIS IS ALSO WERE UP TO 1" OF
RAINFALL (ACCORDING TO MRMS) HAS FALLEN WITH FUELS BECOMING
SATURATED. AS SUCH, THERE ISN'T CONCERN TODAY FOR ANY ELEVATED
FIRE DANGER.
LATE THIS EVENING, THE LAST REMAINING CLOUD COVER OVER SOUTHEAST
MISSOURI WILL ADVECT SOUTH AS SURFACE HIGH PRESSURE APPROACHES
FROM THE NORTH. TEMPERATURES WILL QUICKLY FALL INTO THE UPPER 30S.
BAH
LONG TERM
(SATURDAY THROUGH THURSDAY)
ISSUED AT 215 AM CDT FRI MAR 27 2026
SATURDAY AND SUNDAY: A FREEZE WILL LIKELY OCCUR ACROSS MOST OF
THE AREA SATURDAY MORNING AS SURFACE HIGH PRESSURE MOVES DIRECTLY
OVERHEAD AND WINDS GO CALM. THE LATEST RUN OF THE NBM SHOWS A 50 -
80% OF TEMPERATURES FALLING TO OR BELOW 32 DEGREES F ACROSS THE
REGION. THIS COOL DOWN WILL BE SHORT LIVED THOUGH AS THE LONG WAVE
TROUGH AXIS OVER THE CENTRAL UNITED STATES MOVES EAST TAKING THE
SURFACE HIGH PRESSURE EAST (OR AWAY FROM MISSOURI AND ILLINOIS)
WITH IT. EXPECT HIGHS ON SATURDAY GENERALLY IN THE MID 50S WITH
HIGHS AROUND 70 DEGREES BY SUNDAY. NO PRECIPITATION THROUGH THE
PERIOD IS FORECAST. ONE OTHER ITEM OF NOTE IS THAT THIS PART OF
THE FORECAST IS HIGH CONFIDENCE WITH THE NBM IQR OF THE HIGH AND
LOW TEMPERATURES BEING AROUND 5 DEGREES.
MONDAY THROUGH THURSDAY: THIS IS WHEN MODEL GUIDANCE STARTS TO
RAPIDLY DIVERGE (ESPECIALLY BY WEDNESDAY AND THURSDAY) WITH NBM
IQR BALLOONING TO 25 DEGREES. FOR MONDAY, GUIDANCE LOOKS IN FAIRLY
GOOD AGREEMENT WITH HIGH TEMPERATURES IN THE MID 80S AND LITTLE
IN THE WAY OF PRECIPITATION THANKS TO THE MID-LEVEL RIDGE
OVERHEAD. FOR TUESDAY AND WEDNESDAY, THE WPC ENSEMBLE SENSITIVITY
ANALYSIS (ESA) AND CLUSTER ANALYSIS GUIDANCE SHOWS THE SPREAD IN
THE ENSEMBLES COMES FROM A SHORTWAVE THAT IS FORECAST TO MOVE EAST
OVER BRITISH COLUMBIA MONDAY. SOME OF THE CLUSTERS SHOW A
STRONGER MID-LEVEL RIDGE ACROSS THE CENTRAL UNITED STATES WHILE
SOME SHOW A LESS AMPLIFIED RIDGE. THIS MEANS THAT SOME ENSEMBLES
PUSH A COLD FRONT THROUGH THE REGION WEDNESDAY WHILE OTHERS DO
NOT. GIVEN THAT THE ESA SHOWS MOST OF THE VARIANCE STARTING ON THE
29TH (SUNDAY), THE EXPECTATION IS FOR MODEL SPREAD TO REMAIN
LARGE FOR WEDNESDAY ONWARD UNTIL AT LEAST SUNDAY.
BAH
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1219 PM CDT FRI MAR 27 2026
VFR CONDITIONS ARE EXPECTED FOR THE MAJORITY OF THE 18Z TAF
PERIOD. SOME SCATTERED TO BROKEN MVFR CUMULUS HAS DEVELOPED THIS
AFTERNOON AND MAY BRIEFLY REDUCE CATEGORIES AT ANY OF OUR LOCAL
TERMINALS, BUT THIS IS NOT EXPECTED TO LAST LONG. SKIES WILL
GRADUALLY CLEAR COMPLETELY BY LATE AFTERNOON/EARLY EVENING, AND
BRISK NORTHERLY WINDS WILL WEAKEN AS WELL. CLEAR SKIES AND LIGHT
WINDS WILL CARRY OUT THE REST OF THE PERIOD.
BRC
LSX WATCHES/WARNINGS/ADVISORIES
MO...FREEZE WARNING FROM 1 AM TO 9 AM CDT SATURDAY FOR AUDRAIN MO-
BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-
GASCONADE MO-IRON MO-JEFFERSON MO-KNOX MO-LEWIS MO-LINCOLN
MO-MADISON MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-
OSAGE MO-PIKE MO-RALLS MO-REYNOLDS MO-SAINT CHARLES MO-
SAINT FRANCOIS MO-SAINTE GENEVIEVE MO-SHELBY MO-WARREN MO-
WASHINGTON MO.
FROST ADVISORY FROM 1 AM TO 9 AM CDT SATURDAY FOR SAINT LOUIS
CITY MO-SAINT LOUIS MO.
IL...FREEZE WARNING FROM 1 AM TO 9 AM CDT SATURDAY FOR ADAMS IL-BOND
IL-BROWN IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-
JERSEY IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-
MONTGOMERY IL-PIKE IL-RANDOLPH IL-SAINT CLAIR IL-WASHINGTON
IL.
WFO LSX
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