099
FXUS63 KLOT 162320
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
620 PM 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 233 PM CDT TUE SEP 16 2025
QUIET CONDITIONS WILL PERSIST THROUGH AT LEAST THURSDAY AS A
SOMEWHAT BLOCKED LARGE-SCALE PATTERN WITH A STRONG RIDGE OVER
THE GREAT LAKES BEGINS TO BREAK DOWN. CLOUD COVER WILL REMAIN
QUITE LOW WITH ONLY SOME CIRRUS FILTERING OVER THE AREA FROM A
PAIR OF UPPER-LEVEL LOWS SITUATED WELL TO THE WEST AND SOUTHEAST.
MEANWHILE, THE SOUTHWEST EXTENT OF A SURFACE RIDGE WILL REMAIN
ENTRENCHED OVER THE AREA THROUGH WEDNESDAY BEFORE ANOTHER RIDGE
NOSES SOUTHWARD TOWARD THE AREA ON THURSDAY. THIS WILL FAVOR AN
EXTENDED PERIOD OF GENERALLY E TO NE WINDS.
TEMPS WILL CONTINUE TO GRADUALLY WARM EACH DAY WITH INLAND
LOCATIONS EXPERIENCING HIGHS IN THE MID 80S AND LOWS IN THE MID
TO UPPER 50S. CLOSE TO THE LAKE, REINFORCEMENT OF LAKE-MODIFIED
AIR WILL RESULT IN HIGHS IN THE MID 70S AND LOWS IN THE 60S.
WHILE PRECIP IS UNLIKELY DURING THIS PERIOD, THE LONGER NIGHTS,
LIGHT WINDS, AND MOSTLY CLEAR SKIES COULD SUPPORT SHALLOW FOG
(PRIMARILY TONIGHT) GIVEN MARGINALLY FAVORABLE DEW POINTS IN
THE MID 50S. HAVE INCLUDED PATCHY FOG LATE TONIGHT THROUGH
SUNRISE FOR AREAS ALONG THE NORTH OF THE ILLINOIS RIVER AND
WEST OF THE I-294/94 CORRIDOR IN THE CHICAGO METRO.
KLUBER
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.
KJB
AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 620 PM CDT TUE SEP 16 2025
VFR WITH EASTERLY WINDS UNDER 10 KNOTS THIS EVENING. WINDS WILL
BECOME LIGHT OVERNIGHT. THE ONLY REAL IMPACT THAT IS BEING
MONITORED IS THE POTENTIAL FOR LOCALIZED FOG DEVELOPING
OVERNIGHT. CHANCES ARE BETTER TOWARD DAYBREAK AND CLOSER TO
LAKE MICHIGAN, BUT THERE IS SOME UNCERTAINTY WITH JUST HOW LIGHT
THE WINDS GET (MORE WINDS REDUCES FOG CHANCES). WITH GUIDANCE
TRENDING TOWARD VIS REDUCTIONS, INTRODUCED A TEMPO AT ORD/MDW
FOR THE CHANCE FOR AT LEAST HIGH MVFR WITH TRENDS MONITORED
THROUGH THE OVERNIGHT. ADDITIONALLY, MAINTAINED THE REDUCED VIS
AT RFD/DPA/GYY.
VFR AGAIN ON WEDNESDAY WITH EASTERLY WINDS UP TO 10 KNOTS.
DK
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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