761
FXUS63 KLOT 082309
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
609 PM CDT THU OCT 8 2026
KEY MESSAGES
- SCATTERED SHOWERS AND A FEW EMBEDDED THUNDERSTORMS TOMORROW.
- UNSEASONABLE WARMTH ON SATURDAY FOLLOWED BY A PERIOD OF
SHOWERS SATURDAY NIGHT AND SUNDAY MORNING MAINLY NEAR AND
SOUTHEAST OF I-55.
DISCUSSION
ISSUED AT 220 PM CDT THU OCT 8 2026
IT'S BEEN ANOTHER PLEASANT EARLY OCTOBER DAY OUT THERE TODAY
WITH TEMPERATURES EARLY THIS AFTERNOON IN THE LOWER AND MIDDLE
70S AND ONLY A FEW PASSING HIGH LEVEL CLOUDS OVERHEAD.
CONDITIONS WILL REMAIN QUIET THROUGH THE NIGHT AS TEMPERATURES
DROP INTO THE UPPER 40S AND LOWER 50S BY EARLY FRIDAY.
A PROMINENT CENTER OF HIGH PRESSURE IS PARKED OVER THE OZARK
PLATEAU THIS AFTERNOON AND WE FIND A REGION OF WARM ADVECTION
DEVELOPING OVER THE NORTH-CENTRAL PLAINS AS THE HIGH HELPS TO
PUMP MILD SOUTHERLY FLOW INTO THE REGION. THIS WARM ADVECTIVE
WING WILL FOCUS INTO IOWA THIS EVENING. DEEP ISENTROPIC ASCENT
AND A CORRIDOR OF FRONTOGENETIC FORCING WILL FOSTER AN AREA OF
PRECIP TO OUR WEST TONIGHT. THIS FEATURE WILL SHARPEN AS IT GETS
SHUNTED EAST ACROSS NORTHERN IL TOMORROW MORNING INTO
AFTERNOON. SCATTERED SHOWERS ARE EXPECTED IN OUR AREA FOR MUCH
OF THE DAYTIME BEGINNING AS EARLY AS PREDAWN NEAR AND WEST OF
I-39. HIGHEST COVERAGE THROUGH THE DAY IS GENERALLY FAVORED NEAR
AND NORTH OF THE KANKAKEE RIVER VALLEY ALONG A THETA-E GRADIENT
THAT LOOKS TO DEVELOP ON THE NORTHERN PERIPHERY OF THE WARM
ADVECTIVE PUSH, ALTHOUGH RAIN WILL BE POSSIBLE ANYWHERE AROUND
THE AREA. HAVE BOOSTED POPS IN THE FORECAST AND EXPANDED TO NOW
BRING AT LEAST SLIGHT CHANCES TO THE WHOLE AREA THROUGH THE DAY.
AS THE LOW LEVELS CONTINUE TO WARM, MID LEVEL LAPSE RATES WILL
STEEPEN THROUGH THE DAY SUCH THAT SOME EMBEDDED ELEVATED
THUNDERSTORMS WILL ALSO BE POSSIBLE, ESPECIALLY AFTER MID-
MORNING. THERE REMAINS SOME UNCERTAINTY IN HOW MUCH INSTABILITY
CAN BUILD ATOP THE AREA. THE MAIN POOL OF INSTABILITY WILL
REMAIN WEST OF THE MISSISSIPPI WHILE MODELS GENERALLY TOP OUT
BELOW 1,000 JOULES OF ELEVATED CAPE ACROSS NORTHERN IL BY THE
AFTERNOON. THE GENERAL LACK OF INSTABILITY SHOULD HINDER A
STRONG STORM THREAT, BUT 30 TO 40 KT OF EFFECTIVE SHEAR MAY
ALLOW SOME CORES TO ORGANIZE. COVERAGE SHOULD MOSTLY EXIT THE
CWA BY THE END OF THE AFTERNOON. MODELED QPF IS LARGELY ON THE
ORDER OF ONE TO TWO TENTHS OR LESS, BUT MANY CAMPS, ESPECIALLY
THE CONVECTIVE-ALLOWING CAMPS, SUGGEST MORE NOTEWORTHY AMOUNTS
ARE POSSIBLE ON AN ISOLATED BASIS WITH THE POTENTIAL FOR POCKETS
OF HEAVIER RAIN AND THUNDERSTORMS.
THERE'S QUITE A BIT OF SPREAD IN TEMPERATURE GUIDANCE TOMORROW
WITH UNCERTAINTY IN THE EXACT NORTHWARD EXTENT OF THE WARM
ADVECTION. MOST OF THE AREA IS FAVORED IN THE 70S BUT COULD BE
STUCK IN THE 60S NEAR AND NORTH OF I-80. SATURDAY SHOULD BE MUCH
WARMER WITH HIGHS PROGGED IN THE LOWER 80S AREA-WIDE AND MOSTLY
SUNNY SKIES INTO THE AFTERNOON. CLOUD COVER LOOKS TO BUILD
LATER IN THE DAY AS THE REMNANTS OF HURRICANE ISAIAS WORK THEIR
WAY UP INTO THE REGION.
THE CORE OF THE STORM WILL STAY TO OUR SOUTH AND SOUTHEAST AS
IT TRACKS ACROSS THE TENNESSEE AND OHIO VALLEYS, BUT IT'S STILL
UNCLEAR HOW FAR NORTHWEST LAYER MOISTURE WILL STRETCH THAT CAN
SUPPORT PRECIP SATURDAY NIGHT INTO SUNDAY. THESE REMNANTS WILL
BE CLASHING WITH A NOTABLY DRY AIRMASS OVER THE MIDWEST AND THE
BETTER SYNOPTIC FORCING WILL ALSO FOCUS TO OUR SOUTH AND EAST.
IN THE FORECAST, MAINTAINED SLIGHT CHANCE POPS AS FAR NORTHWEST
AS THE I-55 CORRIDOR DURING THE OVERNIGHT AND MORNING PERIODS
WITH LOW-END CHANCES EAST OF I-57 AND INTO NORTHWEST IN.
ADDITIONAL OPPORTUNITIES FOR RAIN ARE IN THE FORECAST NEXT WEEK
INCLUDING ALONG A COLD FRONT MONDAY-NIGHT INTO TUESDAY AND WITH
ANOTHER LARGE SYNOPTIC SYSTEM FAVORED TO TRAVERSE THE REGION IN
THE WEDNESDAY TO THURSDAY WINDOW. PRIOR TO THAT COLD FRONT,
MONDAY WILL BE ANOTHER UNSEASONABLY WARM DAY WITH HIGHS PROGGED
IN THE UPPER 70S AND LOWER 80S. MORE SEASONABLE TEMPERATURES ARE
THEN FAVORED INTO LATE WEEK.
DOOM
AVIATION /00Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 609 PM CDT THU OCT 8 2026
KEY AVIATION MESSAGES FOR THE CURRENT TAF PERIOD:
- SHOWERS AND A CHANCE FOR THUNDERSTORMS LATE FRIDAY MORNING
THROUGH THE AFTERNOON
A WEAK LAKE BREEZE IS CURRENTLY PASSING THROUGH THE CHICAGO
TERMINALS. BOTH THE NORTHWEST WINDS WEST OF THE LAKE BREEZE AND
NORTHEAST WINDS ON THE EAST SIDE HAVE GENERALLY BEEN LIGHT AND
LESS THAN 8 KNOTS. THIS LAKE BREEZE IS EXPECTED TO WASH OUT
AFTER 00Z AS THE SUN SETS WITH LIGHT AND VARIABLE WINDS EXPECTED
OVERNIGHT.
WINDS ARE EXPECTED TO BE OUT OF THE SOUTHEAST THROUGH MOST OF
FRIDAY. MODELS REMAIN IN FAIRLY GOOD AGREEMENT WITH SCATTERED
SHOWERS MOVING IN MID MORNING AROUND KRFD AND LATE MORNING FOR
THE CHICAGO TERMINALS, AND REMAINING THROUGH MOST OF THE
AFTERNOON. CONFIDENCE IS LOWER ON THE EXACT COVERAGE OF ANY
EMBEDDED THUNDER AS MODELS ARE SHOWING A WEAKENING TREND IN THE
INSTABILITY AS IT MOVES THROUGH. THAT BEING SAID, THERE SHOULD
BE ENOUGH INSTABILITY TO KEEP THE CHANCE FOR THUNDER IN THE TAFS
AND MAKE NO CHANGES TO THE PROB30 AT THIS TIME. DRIER
CONDITIONS ARE EXPECTED AFTER 00Z AS THE RAIN EXITS TO THE
EAST-NORTHEAST. WINDS WILL DIMINISH AND BECOME MORE SOUTHERLY
DURING THE EVENING (IF NOT FLOP OVER TO THE SOUTHWEST TOWARD
06Z).
DK
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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