681
FXUS63 KLOT 161112
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
612 AM CDT TUE SEP 16 2025
KEY MESSAGES
- WARM AND DRY CONDITIONS PERSIST THROUGH THE WORK WEEK.
- PERIODIC SHOWER AND THUNDERSTORM CHANCES RETURN THIS WEEKEND
INTO EARLY NEXT WEEK (20-40%).
DISCUSSION
ISSUED AT 305 AM CDT TUE SEP 16 2025
EXPANSIVE SURFACE HIGH PRESSURE ACROSS THE BROADER GREAT LAKES
REGION EARLY THIS MORNING HAS LED TO CONTINUED MOSTLY CLEAR
SKIES AND LIGHT AND VARIABLE TO CALM WINDS. RADIATIONAL COOLING
ACROSS INTERIOR NORTHERN ILLINOIS MAY LEAD TO PATCHY SHALLOW FOG
DEVELOPMENT THROUGH DAYBREAK BUT COVERAGE SHOULD REMAIN MUCH
LOWER THAN SEEN OVER THE WEEKEND GIVEN OVERALL DRIER LOW-LEVELS.
A BLOCKY UPPER-LEVEL FLOW PATTERN ACROSS THE EASTERN CONUS WILL
CONTINUE TO SUPPORT QUIET WEATHER CONDITIONS ACROSS OUR AREA
THROUGH THE WORK WEEK. MOSTLY CLEAR SKIES EACH DAY WILL FOSTER
UNSEASONABLY WARM TEMPERATURES, WITH INLAND HIGHS IN THE 80S TO
NEAR 90 (WARMEST TOWARD WESTERN AND CENTRAL ILLINOIS) THROUGH
THE REMAINDER OF THE WORK WEEK. CLOSER TO THE LAKE, RELATIVELY
WEAK SURFACE FLOW WILL ALLOW LAKE BREEZES TO PUSH INLAND EACH
AFTERNOON. THIS WILL THUS RESULT IN COOLER TEMPERATURES (MAINLY
IN THE 70S) NEAR THE LAKE MICHIGAN LAKESHORE.
WHILE QUIET AND DRY WEATHER WILL PERSIST IN THIS BLOCKED
PATTERN THROUGH THE REST OF THE WORK WEEK, THE UPPER LEVEL RIDGE
BEGINS TO BREAK DOWN HEADING INTO THE WEEKEND AS A WESTERN
TROUGH (AND/OR POTENTIAL CUT-OFF LOW) BEGINS TO SLIDE EASTWARD
TOWARDS THE GREAT LAKES. THIS WILL LEAD TO INCREASING CHANCES
FOR PERIODIC SHOWERS AND THUNDERSTORMS OVER THE WEEKEND INTO
EARLY NEXT WEEK.
PETR/KJB
AVIATION /12Z TAFS THROUGH 18Z WEDNESDAY/
ISSUED AT 612 AM CDT TUE SEP 16 2025
PATCHY FOG HAS DEVELOPED ACROSS PORTIONS OF FAR NORTHERN AND
NORTHEAST IL THIS MORNING WITH SOME LOCALIZED VISIBILITIES DOWN
TO A QUARTER MILE. THIS FOG WILL REMAIN OUTSIDE OF THE TERMINALS
AND SHOULD BEGIN TO ERODE BY 13-14Z THIS MORNING. OTHERWISE,
ANOTHER TRANQUIL FORECAST PERIOD IS EXPECTED AS HIGH PRESSURE
REMAINS IN CONTROL OVERHEAD. WINDS WILL BECOME MORE EAST-
NORTHEAST TOWARDS MIDDAY WITH SPEEDS REMAINING IN THE 5-7 KT
RANGE BEFORE BECOMING LIGHT AND VARIABLE AGAIN TONIGHT. AS FOR
THE SKIES, EXPECT MOSTLY CLEAR CONDITIONS ASIDE FROM A PASSING
CIRRUS CLOUD.
YACK
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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