383
FXUS63 KLSX 110340
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
1040 PM CDT THU OCT 10 2024
KEY MESSAGES
- ABOVE NORMAL TEMPERATURES IN THE 80S WILL CONTINUE INTO SATURDAY.
- A DRY COLD FRONT WILL TREK ACROSS THE REGION ON SUNDAY AND BRING
A MUCH COLDER AIR INTO THE REGION NEXT WEEK. FROST IS LIKELY
TUESDAY AND WEDNESDAY MORNINGS WITH THE POTENTIAL FOR MORE
SHELTERED LOCATIONS TO SEE THEIR FIRST FREEZE OF THE SEASON.
SHORT TERM
(THROUGH SATURDAY)
ISSUED AT 241 PM CDT THU OCT 10 2024
DEPARTING SURFACE HIGH PRESSURE AND WEAK FORCING ALOFT WILL CONTINUE
TO BE THE MAIN CATALYST FOR OUR DRY WEATHER AND ABOVE NORMAL
TEMPERATURES THROUGH SATURDAY. WITH ANOTHER DAY OF CUMULATIVE
INSOLATION, TEMPERATURES TODAY ARE A FEW DEGREES WARMER THAN
YESTERDAY. FRIDAY'S HIGH TEMPERATURES WILL BE A FEW DEGREES WARMER
THEN TODAY AS SURFACE HIGH BEGINS TO SHIFT TO THE SOUTHEAST,
PROMOTING SOUTHWESTERLY LOW-LEVEL FLOW AND WARM AIR ADVECTION INTO
SATURDAY. MEAN ENSEMBLE 850-MB TEMPERATURES (APPROXIMATELY 18C) ON
SATURDAY CONTINUE TO TREND ABOVE THE 90TH PERCENTILE OF CLIMATOLOGY.
SHOULD WE MIX OUT UP TO 850-MB, WE ARE NEAR RECORD DAILY HIGH
TEMPERATURES AT KSTL (89F) AND KUIN (88F)(SEE CLIMATE SECTION).
HOWEVER, CURRENT GUIDANCE IS INDICATING AN INCREASE IN HIGH CLOUDS
ON SATURDAY AS WELL AS A WEAK STATIONARY FRONT ACROSS THE NORTHERN
MOST PARTS OF THE CWA. EITHER OF THESE TWO THINGS COULD LIMIT HOW
WARM WE GET ON SATURDAY.
MMG/PFAHLER
LONG TERM
(SUNDAY THROUGH NEXT THURSDAY)
ISSUED AT 241 PM CDT THU OCT 10 2024
THERE REMAINS CONSENSUS AMONG ENSEMBLE GUIDANCE THAT AN UPPER-LEVEL
TROUGH WILL BEGIN DIGGING ACROSS THE UPPER MIDWEST AND PUSH A STRONG
COLD FRONT ACROSS THE REGION SUNDAY MORNING. THERE IS SOME
UNCERTAINTY AS TO HOW QUICKLY THE POST-FRONTAL COLDER AIRMASS MAKES
IT INTO THE REGION, ULTIMATELY AFFECTING SUNDAY'S HIGH TEMPERATURES
AND THIS IS REFLECTED IN A 7 DEGREE SPREAD IN THE NBM INTERQUARTILE
RANGE. THE CURRENT FORECAST SUPPORTS THE COLDER AIR ARRIVING TO THE
NORTHERN HALF OF THE CWA BY SUNDAY AFTERNOON. THE COLD FRONT IS
EXPECTED TO BE DRY WITH THE GREATEST UPPER-LEVEL SUPPORT AND
MOISTURE REMAINING TO OUR NORTHEAST.
THE INITIAL BRUNT OF THE COLDER AIRMASS WILL BE FELT ON MONDAY
WITH MUCH COOLER TEMPERATURES BUT THE PRIMARY QUESTIONS ARE COOL
WE GET AT NIGHT AND HOW LONG THE COOLER TEMPERATURES WILL STAY.
SHOULD THE CORE OF THE COLDER AIRMASS (SURFACE HIGH PRESSURE) BE
CENTERED OVER THE REGION DURING THE NIGHTTIME HOURS, WE CAN EXPECT
THE COLDEST LOW TEMPERATURES TUESDAY AND WEDNESDAY MORNINGS.
CURRENT NBM PROBABILITIES OF <=32F ARE 50-60% IN MISSOURI WHICH
WOULD SUPPORT A FREEZE, WHEREAS PROBABILITIES OF <=36 ARE UP TO
75% AREA WIDE. TEMPERATURES <=36F WOULD BRING CHANCES OF
WIDESPREAD FROST. ANOTHER UNCERTAINTY IS HOW LONG THE SURFACE HIGH
REMAINS IN PLACE OVER US BEFORE SHIFTING EAST AND LOW-LEVEL
SOUTHERLY FLOW RETURNS. CURRENT DETERMINISTIC GUIDANCE MEMBERS ARE
IN AGREEMENT THAT THE SURFACE HIGH WILL BE IN PLACE THROUGH MID-
WEEK.
MMG/PFAHLER
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1038 PM CDT THU OCT 10 2024
CONFIDENCE REMAINS HIGH IN DRY AND VFR FLIGHT CONDITIONS AT ALL
LOCAL TERMINALS THROUGH THE FORECAST PERIOD. FOG CAN'T COMPLETELY
BE RULED OUT AT KJEF, KSUS, AND KCPS, THOUGH WITH TEMPERATURES
TRENDING WARMER TONIGHT COMPARED TO THE LAST COUPLE OF NIGHTS,
CONFIDENCE IN FOG DEVELOPING AND IMPACTING THESE TERMINALS REMAINS
LOW.
ELMORE
CLIMATE
ISSUED AT 220 PM CDT WED OCT 9 2024
OCTOBER 12TH RECORD DAILY HIGH TEMPERATURES:
KSTL: 89 IN 1890
KCOU: 94 IN 1899
KUIN: 88 IN 1975
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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