563
FXUS63 KLSX 081919
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
219 PM CDT SUN MAR 8 2026
KEY MESSAGES
- NEAR RECORD HIGH TEMPERATURES ARE POSSIBLE ON MONDAY AND TUESDAY.
- WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED LATE TUESDAY
THROUGH WEDNESDAY MORNING. SOME OF THESE STORMS MAY BE STRONG TO
SEVERE, MAINLY DURING THE LATE AFTERNOON/EVENING HOURS ON
TUESDAY.
SHORT TERM
(THROUGH LATE MONDAY NIGHT)
ISSUED AT 218 PM CDT SUN MAR 8 2026
MILDER TEMPERATURES ARE IN STORE TONIGHT AS SOUTHERLY SURFACE
WINDS REMAIN IN THE 5-10 MPH RANGE OVERNIGHT. THE EXCEPTIONS COULD
BE SOME SHELTERED VALLEY TERRAIN ACROSS PARTS OF SOUTHEAST
MISSOURI. WINDS STILL MAY BE ABLE TO DECOUPLE IN THESE ISOLATED
LOCATIONS, WHICH WOULD HELP LEAD TO COOLER TEMPERATURES THAN
SURROUNDING AREAS VIA ENHANCED RADIATIONAL COOLING. SOME SPOTTY
UPPER 30S ARE POSSIBLE IN THESE LOCATIONS. ELSEWHERE, LOOK FOR
TEMPERATURES TO ONLY DROP BACK INTO THE LOW TO MID 40S FOR THE
MOST PART, WHICH WOULD BE ABOUT 15 DEGREES ABOVE NORMAL FOR THE
DATE.
ALL REMAINS ON TRACK FOR THE FIRST OF TWO UNSEASONABLY WARM DAYS ON
MONDAY. LOW-LEVEL WARM AIR ADVECTION CONTINUES TO STRENGTHEN DURING
THE DAY, WITH 850-HPA TEMPERATURES PUSHING +16C (>99TH PERCENTILE OF
CLIMATOLOGY) ALONG/WEST OF THE MISSISSIPPI RIVER. THIS ANOMALOUSLY
WARM AIR MASS COMBINED WITH PLENTY OF SUNSHINE AND A SOUTHWEST
SURFACE WIND ARE EXPECTED TO YIELD RECROD-THREATENING HIGH
TEMPERATURES. READINGS ARE EXPECTED TO CLIMB WELL INTO THE 70S, WITH
SOME SPOTS NEAR THE 80 DEGREE MARK POSSIBLE IN CENTRAL/EAST CENTRAL
MISSOURI WHERE THERE IS A DOWNSLOPE WIND OFF OF THE OZARK PLATEAU.
FOR MORE INFORMATION ON DAILY RECORDS FOR BOTH MONDAY AND TUESDAY,
PLEASE SEE THE CLIMATE SECTION BELOW.
VERY MILD TEMPERATURES ARE IN STORE ON MONDAY NIGHT WITH CONTINUED
SOUTHERLY FLOW AROUND 5-10 MPH AND AT LEAST SOME INCREASE IN
MID/HIGH LEVEL CLOUDINESS. LOWS ARE ONLY FORECAST TO DROP BACK INTO
THE MID 50S TO NEAR 60 DEGREES. THOSE VALUES WOULD BE SOME 25-30
DEGREES ABOVE NORMAL.
GOSSELIN
LONG TERM
(TUESDAY THROUGH NEXT SUNDAY)
ISSUED AT 218 PM CDT SUN MAR 8 2026
(TUESDAY - WEDNESDAY)
TUESDAY'S HIGH TEMPERATURES LIKELY WILL BE A BIT WARMER THAN MONDAY,
MAINLY DUE TO STARTING OFF ~15 DEGREES WARMER IN THE MORNING. AS
NEARLY ALWAYS, CLOUDS ARE A CONCERN AND DETERMINISTIC RH PLOTS DO
SHOW THICKER MID/HIGH LEVEL CLOUDS TRYING TO MOVE IN BY AFTERNOON.
WHILE I DO NOT SEE MUCH POTENTIAL FOR THESE CLOUDS TO SIGNIFICANTLY
ALTER THE HIGH TEMPERATURES TUESDAY AFTERNOON, THEY COULD HELP MUTE
HIGHS BY A FEW DEGREES ROUGHLY. THE CURRENT FORECAST OF UPPER 70S TO
LOWER 80S SITS AT ABOUT THE 75TH PERCENTILE OF AVAILABLE MODEL
GUIDANCE GIVEN THE ANOMALOUSLY WARM AIR MASS IN PLACE AND WARM START
TO THE DAY. HOWEVER, HIGHS MORE IN THE MID TO UPPER 70S ARE POSSIBLE
IF THE CLOUDS ARE THICKER EARLIER IN THE DAY.
ATTENTION TUESDAY AFTERNOON IS ON WHEN/WHERE CONVECTIVE INITIATION
(CI) WILL OCCUR. WHILE SOUNDINGS DO SHOW CAPPING ACROSS THE REGION,
THIS LOOKS TO SERVE MORE TO DELAY CI AS GRADUAL MID/UPPER LEVEL
HEIGHT FALLS AND ASSOCIATED COOLING ALOFT SUGGEST CI BECOMES MORE
LIKELY WITH TIME. MOST OFTEN, DEVELOPMENT OCCURS WHERE NEAR-SURFACE
CONVERGENCE IS STRONGEST, AND THIS LIKELY WILL BE THE CASE AGAIN
TUESDAY AFTERNOON. SURFACE CONVERGENCE TUESDAY AFTERNOON IS
STRONGEST ALONG/NEAR A QUASI-STATIONARY FRONT NEAR THE MISSOURI-IOWA
BORDER. THE EXACT PLACEMENT OF THIS FRONT THEN IS VERY IMPORTANT, AS
A SHIFT SOUTH (NORTH) COULD YIELD MORE (LESS/NONE) CONVECTION IN OUR
REGION. RIGHT NOW, THE BEST THREAT FOR STRONG TO SEVERE CONVECTION
IN OUR APPEARS TO BE ACROSS NORTHEAST MISSOURI AND WEST-CENTRAL
ILLINOIS ROUGHLY FROM 2100 UTC TUESDAY TO 0300 UTC WEDNESDAY.
SUPERCELLS ARE THE EXPECTATION GIVEN ~40 KNOTS OF DEEP-LAYER SHEAR
AND SBCAPE VALUES OF 1500+ J/KG. STEEP MIDLEVEL LAPSE RATES/HIGH
AMOUNTS OF CAPE WITHIN THE HAIL-GROWTH ZONE AND THE CONVECTIVE MODE
SUGGEST LARGE HAIL BEING THE PRIMARY THREAT, WITH SWATHS OF VERY
LARGE HAIL (2.00"+) POSSIBLE IN/NEAR OUR NORTHERN COUNTIES. WHILE
SURFACE WINDS ARE VEERED SOUTH OF THE BOUNDARY, A TORNADIC THREAT
WILL EXIST NEAR THE FRONTAL ZONE. THIS THREAT SHOULD INCREASE
NEAR/AFTER SUNSET, BUT THIS INITIAL ROUND OF CONVECTION MAY HAVE
PUSHED OFF TO THE NORTHEAST BY THAT TIME. FOR AREAS FURTHER SOUTH,
CONVECTIVE INITIATION IS MUCH MORE UNCERTAIN DUE TO WEAKER SURFACE
CONVERGENCE. DEEP-LAYER SHEAR AND INSTABILITY ARE ALSO LESS THAN
THAT FURTHER NORTH, SO IF CONVECTION DOES DEVELOP, IT MAY STAY
LARGELY SUB-SEVERE.
FOR THE OVERNIGHT HOURS, MOSTLY SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED ACROSS THE REGION DUE TO A BROAD LOW-LEVEL JET.
MOISTURE CONVERGENCE ASSOCIATED WITH THIS JET IS NOT PARTICULARLY
FOCUSED OR OVERLY STRONG EITHER. THE HIGHEST COVERAGE OF STORMS IS
MOST LIKELY GOING TO BE ACROSS PARTS OF NORTHEAST MISSOURI/WEST
CENTRAL ILLINOIS WHERE THE LOW-LEVEL FRONTAL ZONE SLOWLY OOZES
SOUTHEASTWARD. WHILE THE SEVERE THREAT SHOULD LESSEN OVERNIGHT DUE
TO WANING INSTABILITY, THE FOCUS MAY TEND TO SHIFT MORE TO THE
POTENTIAL FOR FLASH FLOODING. WHILE THE ENVIRONMENT DOES CERTAINLY
LOOK FAVORABLE FOR EFFICIENT WARM RAINFALL PROCESSES (PWATS > 99TH
PERCENTILE OF CLIMATOLOGY, DEEP WARM CLOUD DEPTHS), THERE ARE SOME
MITIGATING FACTORS. ONE IS THAT THE AFOREMENTIONED LOW-LEVEL
MOISTURE CONVERGENCE, AT THIS TIME AT LEAST, IS NOT MODELED TO BE
THAT STRONG. THE MERIDIONAL COMPONENT (V) OF THE LOW-LEVEL JET IS
EXPECTED TO BE <90TH PERCENTILE FOR REFERENCE. THE HEAVIEST RAINFALL
AMOUNTS ALSO SHOULD TEND TO FOCUS ACROSS NORTHEAST MISSOURI AND WEST-
CENTRAL ILLINOIS. THIS AREA DID NOT RECEIVE NEARLY AS MUCH RAIN OVER
THE PAST 5 DAYS AS THOSE FURTHER SOUTHEAST AND REMAINS IN MODERATE
(D1) TO SEVERE (D2) DROUGHT CONDITIONS. THIS IS REFLECTED IN FLASH-
FLOOD GUIDANCE, WITH 3-HOUR VALUES OF 2.00-2.50". THE TERRAIN IS
ALSO FLATTER IN THAT REGION THAN SAY OF THE EASTERN OZARKS. TRAINING
OF CONVECTION IS THE MAIN CONCERN GIVEN THE FAVORABLE ENVIRONMENT.
IF HIGH RAINFALL RATES ASSOCIATED WITH CONVECTION OCCURS OVER THE
SAME AREAS, AT LEAST ISOLATED INSTANCES OF FLASH FLOODING COULD
OCCUR. IN THE ABSENCE OF TRAINING HOWEVER, THE FLASH FLOOD THREAT
LIKELY WOULD STAY ON THE LOWER END OF THE SPECTRUM.
THE AREA OF SHOWERS AND THUNDERSTORMS SHOULD SHIFT SOUTHEASTWARD
LATE TUESDAY NIGHT INTO WEDNESDAY MORNING AS THE COLD FRONT BEGINS
TO ACCELERATE EQUATORWARD. THE RAIN IS LIKELY TO BECOME MORE
STRATIFORM IN NATURE WITH EMBEDDED THUNDERSTORMS AS INSTABILITY
CONTINUES TO DECREASE AND MID/UPPER LEVEL FORCING FOR ASCENT
INCREASES. RAIN MAIN CONTINUE INTO THE EARLY AFTERNOON HOURS IN
PARTS OF SOUTHEAST MISSOURI/SOUTHWEST ILLINOIS BENEATH THE RIGHT-
ENTRANCE REGION OF AN UPPER-LEVEL JET STREAK AND DOWNSTREAM OF A
SOUTHERN STREAM MIDLEVEL SHORTWAVE TROUGH. SIMILAR TO THIS PAST
SATURDAY, STRONG LOW-LEVEL COLD AIR ADVECTION IS FORECAST BEHIND THE
SYNOPTIC COLD FRONT. LOOK FOR A RAPID DROP IN TEMPERATURES INTO THE
40S/LOW 50S. THOSE TEMPERATURES WOULD BE SOME 35 DEGREES COLDER THAN
TUESDAY AFTERNOON. GIVEN NORTHWEST WINDS NEAR 20 MPH, IT MAY FEEL
MORE LIKE 40-45 DEGREES COLDER.
(WEDNESDAY NIGHT - NEXT SUNDAY)
MORE SEASONABLE TEMPERATURES ALONG WITH DRY WEATHER ARE FORECAST
WEDNESDAY NIGHT AND THURSDAY. FORECAST UNCERTAINTY INCREASES FRIDAY
THROUGH NEXT WEEKEND, MOSTLY IN TERMS OF TEMPERATURE TRENDS. THERE
APPEARS TO BE TWO COLD FRONTAL PASSAGES DURING THIS TIME FRAME, BUT
EXACTLY WHEN AND HOW COOL THE AIR MASS IS BEHIND EACH BOUNDARY ARE
OPEN QUESTION MARKS. THE SPREAD BETWEEN THE 25TH/75TH PERCENTILES OF
THE NBM INCREASES WITH EACH DAY, AND IS GENERALLY ON THE ORDER OF 20-
25 DEGREES FOR NEXT WEEKEND.
GOSSELIN
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1204 PM CDT SUN MAR 8 2026
DRY/VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD ALONG WITH A
MOSTLY CLEAR SKY. SOUTHWEST WINDS WILL WEAKEN SLIGHTLY BY EARLY
THIS EVENING BEFORE RESTRENGTHENING LATE MONDAY MORNING. GUSTS
LOOK LIKELY AREAWIDE ON MONDAY, MAINLY IN THE 20-25 KNOT RANGE.
GOSSELIN
CLIMATE
ISSUED AT 211 PM CST SAT MAR 7 2026
DAILY RECORD HIGH TEMPERATURES MAY BE THREATENED BOTH ON MONDAY 3/9
AND TUESDAY 3/10. BELOW ARE THE RECORDS FOR EACH DAY FROM OUR
OFFICIAL CLIMATE SITES:
MONDAY 3/9 TUESDAY 3/10
KSTL 80F (1925) 86F (1955)
KCOU 80F (1986) 82F (1955)
KUIN 75F (1986) 79F (1955)
GOSSELIN
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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