385
FXUS63 KLSX 221930
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
230 PM CDT SAT AUG 22 2026
KEY MESSAGES
- PLEASANT AND MOSTLY DRY CONDITIONS ARE EXPECTED THROUGH THE
UPCOMING WEEK.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 230 PM CDT SAT AUG 22 2026
NORTHWEST FLOW CONTINUES ALOFT ACROSS THE REGION. A RIDGE IS
BRINGING HOT WEATHER OUT WEST WHILE A TROUGH OVER THE GREAT
LAKES IS BRINGING CONSIDERABLY COOLER WEATHER IN THE EAST. AT
THE SURFACE, HIGH PRESSURE IS PUSHING SOUTH INTO THE NORTHERN
PLAINS, WITH WINDS OUT OF THE NORTH ACROSS OUR REGION BRINGING
IN DRIER AIR. AS THIS HIGH NUDGES FURTHER SOUTH OVERNIGHT WE'LL
SEE WINDS DIE OFF AND TEMPERATURES DROP IN THE FRESH DRY AIR
MASS. LOWS TONIGHT WILL DIP INTO THE LOW TO MID 60S, WITH SOME
UPPER 50S POSSIBLE IN THE COOLER SPOTS. SUNDAY WILL BE ONE OF
THE COOLEST DAYS OF THIS AIR MASS WITH HIGHS ONLY REACHING INTO
THE LOW 80S. SOME MID AND HIGH LEVEL CLOUD COVER WILL CONTRIBUTE
TO THOSE LOWER TEMPERATURES.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 230 PM CDT SAT AUG 22 2026
THIS WEEK WE CONTINUE IN SOME FLAVOR OF WESTERN RIDGING AND
EASTERN TROUGHING, KEEPING OUR AREA IN THE NORTHWEST FLOW IN
BETWEEN. SHOWERS AND THUNDERSTORMS ROTATING AROUND THE RIDGE
STAY LARGELY WEST OF OUR AREA, KEEPING US MAINLY DRY THROUGH
TUESDAY WITH TEMPERATURES EVENTUALLY MAKING A MODEST REBOUND
BACK INTO THE MID TO UPPER 80S.
THE INITIAL EASTERN TROUGH WEAKENS AND LIFTS INTO THE CANADIAN
MARITIMES BY MIDWEEK, BUT IT GETS REPLACED BY A NEW TROUGH
ARRIVING FROM AROUND THE TOP OF THE RIDGE. IT'S THIS TROUGH
THAT'S PROBABLY THE MOST INTERESTING FEATURE FOR OUR WEATHER
THIS WEEK. IT INITIALLY ARRIVES IN THE PACIFIC NORTHWEST
TOMORROW BUT MOVES INTO THE WESTERN GREAT LAKES ON WEDNESDAY. AS
IT DOES SO, IT WILL SLIDE ANOTHER COLD FRONT SOUTHWARD THROUGH
THE MIDDLE OF THE COUNTRY, PUSHING THROUGH OUR AREA WEDNESDAY OR
WEDNESDAY NIGHT. THIS REPRESENTS OUR BEST CHANCE OF RAIN THIS
WEEK, THOUGH THOSE CHANCES AREN'T PARTICULARLY HIGH AT THIS
POINT. MOST OF THE FORCING FROM THE TROUGH PASSES BY TO OUR
NORTH WHILE THE BETTER MOISTURE AND INSTABILITY REMAINS FURTHER
SOUTH. NBM POP REMAINS QUITE LOW, GENERALLY 20 PERCENT OR LESS,
BUT IF WE LOOK AT THE LOW RESOLUTION ENSEMBLE GUIDANCE WE SEE
THAT 50 TO 60 PERCENT OF THESE MEMBERS PRODUCE MEASURABLE RAIN
IN THE 24 HOURS ENDING WEDNESDAY NIGHT. IT'S THE TIMING AND
LOCATION UNCERTAINTY THAT'S HOLDING POP LOWER AT THIS POINT, BUT
THIS DOES REPRESENT OUR BEST CHANCE OF RAIN LOCALLY THIS WEEK.
WEDNESDAY'S FRONT MAY KNOCK TEMPERATURES BACK A FEW DEGREES, BUT
GUIDANCE IS IN GENERAL AGREEMENT THAT THE WESTERN RIDGE WEAKENS
AND BROADENS LATER IN THE WEEK, NUDGING ITS INFLUENCE EASTWARD.
THIS WOULD NUDGE US BACK TOWARD WARMER TEMPERATURES, BUT NOT AS
EXTREME AS WE'VE SEEN RECENTLY. WE'LL ALSO HAVE A FEW OTHER
OPPORTUNITIES FOR RAIN AS SHORTWAVE TROUGHS ROUND THE EDGE OF
THE RIDGE EVEN AS IT APPROACHES OUR AREA. HOWEVER, CONFIDENCE
IN THE TIMING AND TRACK OF THOSE WAVES IS EVEN LOWER THAN FOR
WEDNESDAY'S TROUGH, SO DAILY RAIN CHANCES REMAIN FAIRLY MINIMAL
IN THE CURRENT FORECAST UNTIL THAT CONFIDENCE CHANGES.
AVIATION /18Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 100 PM CDT SAT AUG 22 2026
VFR CONDITIONS CONTINUE AT ALL SITES. LIGHT WINDS TONIGHT COULD
BRING SOME VALLEY FOG, BUT THIS IS LESS LIKELY DUE TO DRIER AIR
MOVING INTO THE REGION TODAY.
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
SHORT TERM...KIMBLE
LONG TERM...KIMBLE
AVIATION...KIMBLE
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