285
FXUS63 KLSX 060900
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
400 AM CDT SUN JUL 6 2025
KEY MESSAGES
- SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED
THIS AFTERNOON INTO EARLY EVENING ACROSS CENTRAL AND EASTERN
MISSOURI INTO SOUTHWEST AND WEST CENTRAL ILLINOIS. SOME STORMS
COULD PRODUCE LOCALLY HEAVY DOWNPOURS AND GUSTY WINDS.
- SEASONABLY WARM AND HUMID WEATHER WILL CONTINUE INTO THE WORK-
WEEK WITH A CHANCE FOR MAINLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS.
SHORT TERM
(THROUGH LATE TONIGHT)
ISSUED AT 357 AM CDT SUN JUL 6 2025
ONGOING CONVECTION IS BEING FUELED BY MOISTURE CONVERGENCE DRIVEN BY
A WEAK LOW LEVEL JET AHEAD OF A COLD FRONT WHICH IS MOVING INTO
MISSOURI THIS MORNING. THE FRONT WILL CONTINUE TO SAG SOUTHEAST
TODAY, DRIVEN BY A SHORT WAVE TROUGH MOVING MOVING THROUGH THE
MIDWEST. THIS FRONT WILL CONTINUE TO BE A FOCUS FOR CONVECTION TODAY
AND TONIGHT AS IT DRIFTS SOUTHEAST INTO THE FORECAST AREA. GUIDANCE
IS SOMEWHAT DIVIDED ON CONVECTIVE TRENDS THIS MORNING, WITH SOME
MODELS SHOWING STORMS DISSIPATING BY 12-14Z, AND OTHERS SHOWING
ISOLATED TO WIDELY SCATTERED SHOWERS AND STORMS CONTINUING THROUGH
THE MORNING HOURS. HOWEVER, THERE IS CONSENSUS IN INCREASING
COVERAGE THIS AFTERNOON ALONG AND AHEAD OF THE COLD FRONT ACROSS
CENTRAL AND SOUTHEAST MISSOURI INTO SOUTHWEST AND SOUTH CENTRAL
ILLINOIS. THE 60-70 POPS IN THE GOING FORECAST CONTINUE TO LOOK GOOD
FOR THIS AFTERNOON, WITH DECREASING POPS IN THE EVENING AS DIURNAL
HEATING WANES. SHORT RANGE GUIDANCE SHOWS THE FRONT STALLING
TONIGHT SOMEWHERE BETWEEN I-70 AND I-44 IN MISSOURI, AND JUST SOUTH
OF I-70 IN ILLINOIS. ISOLATED TO WIDELY SCATTERED SHOWERS AND
STORMS WILL LIKELY CONTINUE OVERNIGHT DUE TO LOW LEVEL MOISTURE
CONVERGENCE IN THE VICINITY OF THE FRONT. LOCALIZED HEAVY DOWNPOURS
AND POSSIBLE WET MICROBURSTS CONTINUE TO BE POSSIBLE WITH THESE
STORMS. TEMPERATURES THIS AFTERNOON SHOULD BE A FEW DEGREES COOLER
THAN SATURDAY DUE TO MORE CLOUD COVER AND AFTERNOON STORMS.
CARNEY
LONG TERM
(MONDAY THROUGH SATURDAY)
ISSUED AT 357 AM CDT SUN JUL 6 2025
THERE'S BEEN LITTLE CHANGE TO THE FORECAST FOR MONDAY THROUGH NEXT
SATURDAY. THE FRONT REMAINS NEARLY STATIONARY NEAR OR JUST SOUTH OF
I-70 FOR MUCH OF THE DAY. HOWEVER THE POSITION OF THE EFFECTIVE
BOUNDARY WILL MOST LIKELY BE CONTROLLED BY CONVECTION/OUTFLOWS
THROUGH THE DAY. WHILE CONVECTION IN THE VICINITY OF THE FRONT ON
MONDAY, THE COVERAGE IS QUESTIONABLE WITH SOME MODELS SHOWING
WIDESPREAD QPF ALONG AND SOUTH OF THE FRONT, AND OTHERS (INCLUDING
MOST CAMS) KEEPING COVERAGE MORE IN THE 20-50% RANGE. CURRENTLY
LEANING TOWARD THE 20-50% RANGE GIVEN THE UNCERTAINTY IN FRONTAL
POSITION, BUT THIS MAY NEED TO BE INCREASED IN SUBSEQUENT FORECASTS.
THE NEXT UPSTREAM SHORT WAVE MOVE FROM THE PLAINS INTO THE MIDWEST
TUESDAY, WHICH ALONG WITH THE LINGERING FRONT, WILL PRODUCE MORE
THUNDERSTORMS. THE DETERMINISTIC GFS CONTINUES TO LOOK LIKE IT'S
CONTAMINATED WITH CONVECTIVE FEEDBACK, HOWEVER IT'S SHOWING 2300+
J/KG MLCAPE AT 18Z TUESDAY ACROSS PARTS OF WESTERN AND CENTRAL
MISSOURI, AND THIS AGREES WELL WITH LREF MEAN SBCAPE. INVERTED V
FORECAST SOUNDINGS INDICATE THE POSSIBILITY OF WET MICROBURSTS, BUT
THE 0-6KM SHEAR IS ONLY 15-20KTS. WHILE THERE COULD BE A FEW
STRONG/SEVERE STORMS, ORGANIZED SEVERE STORMS ARE UNLIKELY DUE TO
THE LACK OF STRONG DEEP-LAYER SHEAR.
WEAK NORTHWEST TO OCCASIONAL ZONAL FLOW CONTINUES FOR THE REST OF
THE WORK-WEEK AS THE UPPER PATTERN IS FIRST AMPLIFIED BY TUESDAY'S
SHORT WAVE, AND THEN THE SOUTHWEST UPPER RIDGE IS ATTENUATED BY
ANOTHER WAVE WHICH MOVES ACROSS THE NORTHERN 1/2 OF THE CONUS AND
SOUTHERN CANADA FRIDAY AND SATURDAY. SENSIBLE WEATHER AT THE
SURFACE WILL CHANGE LITTLE DURING THIS PERIOD, WITH MOSTLY AFTERNOON
AND EVENING CONVECTION DRIVEN BY DIURNAL HEATING. TEMPERATURES LOOK
SEASONABLY WARM AND HUMID WITH HIGHS MAINLY IN THE UPPER 80S TO LOW
90S. THERE MAY BE SOME RELIEF FROM THE HEAT SATURDAY IF THE
AFOREMENTIONED SHORTWAVE DIGS FARTHER SOUTH INTO THE MIDWEST OR
GREAT LAKES WHICH WOULD PUSH THE ASSOCIATED COLD FRONT FARTHER INTO
THE MISSISSIPPI VALLEY.
CARNEY
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1035 PM CDT SAT JUL 5 2025
SCATTERED THUNDERSTORMS ARE EXPECTED TO ENTER NORTHEAST MISSOURI
SHORTLY, BUT ARE FORECAST TO GRADUALLY WEAKEN AND DISSIPATE
OVERNIGHT. WHILE THE THREAT FOR THUNDERSTORMS IS NOT ZERO VERY LATE
TONIGHT INTO EARLY SUNDAY MORNING, IT IS VERY LOW. COVERAGE OF
STORMS SHOULD INCREASE JUST AFTER MIDDAY ON SUNDAY, WITH THE BEST
CHANCES FROM THE ST. LOUIS METRO AND POINTS SOUTH. ADDED A TEMPO
AT THE METRO TERMINALS FOR THUNDERSTORMS, ROUGHLY BETWEEN 19 AND
23 UTC. ANY STORM THAT DOES DIRECTLY IMPACT A SITE WILL BE CAPABLE
OF HEAVY DOWNPOURS/REDUCED VISIBILITIES AND POTENTIALLY GUSTY
WINDS.
GOSSELIN
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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