186
FXUS63 KIWX 210557
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
157 AM EDT WED OCT 21 2026
KEY MESSAGES
- DENSE FOG POSSIBLE EARLY WEDNESDAY MORNING, ESPECIALLY ALONG AND
EAST OF I-69.
- TRANQUIL FALL WEATHER CONTINUES WITH MILD TEMPERATURES AND
SUNSHINE THROUGH THIS WEEK INTO THE WEEKEND.
DISCUSSION
ISSUED AT 1245 PM EDT TUE OCT 20 2026
WITH HIGH PRESSURE OVER SOUTHERN ONTARIO AND PROMINENT UPPER LEVEL
RIDGING OVER THE CENTRAL CONUS EXPECTED TO BUILD INTO THE GREAT
LAKES OVER THE NEXT SEVERAL DAYS, A TRANQUIL WEEK IS AHEAD. EXPECT
LOTS OF SUNSHINE, LIGHT WINDS, AND HIGHS GENERALLY IN THE UPPER 60S
TO LOW 70S EACH DAY. LITTLE TO NO RAINFALL IS EXPECTED OVER THE NEXT
7 DAYS AND MAINLY DRY CONDITIONS LOOK TO CONTINUE THROUGH AT LEAST
THE END OF THE MONTH. WE MAY SEE SOME SHOWERS OUT OF A COLD FRONTAL
PASSAGE EARLY NEXT WEEK BUT FOR NOW CHANCES REMAIN VERY LOW (15% OR
LESS).
DESPITE SOME CLOUDS OVER NORTHWEST OHIO AND NORTHEAST INDIANA
OVERNIGHT WITH A WEAK BACKDOOR COLD FRONT FROM LAKE ERIE,
PATCHY TO WIDESPREAD DENSE FOG IS POSSIBLE OVERNIGHT INTO
WEDNESDAY MORNING. LIGHT EASTERLY FLOW MAY ALLOW FOR ADVECTION
FOG TO DEVELOP, ESPECIALLY ALONG AND EAST OF I-69. FORECAST
SOUNDINGS INDICATE POTENTIAL FOR SMALL DEWPOINT DEPRESSIONS AS
TEMPERATURES AND DEWPOINTS ARE BOTH EXPECTED TO BE IN THE LOW TO
MID 40S TONIGHT. THE BEST TIMEFRAME FOR DENSE FOG WILL BE
BETWEEN 3 AM TO 9 AM EDT WEDNESDAY, WITH THE LOWEST VISIBILITIES
AT OR JUST BEFORE DAYBREAK. CURRENT NBM PROBABILITIES ARE ABOUT
20-30% FOR VISIBILITIES LESS THAN 3 MILES WHILE HREF GUIDANCE
SUGGESTS VISIBILITIES MAY GO DOWN TO LESS THAN 1 MILE ESPECIALLY
IN NW OHIO; GIVEN THAT THERE ARE STILL UNCERTAINTIES AND THAT
FOG CAN BE QUITE FICKLE TO FORECAST, FUTURE SHIFTS MAY NEED TO
HOIST AN SPS OR EVEN A DENSE FOG ADVISORY DEPENDING ON HOW LOW
VISIBILITIES DROP.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 150 AM EDT WED OCT 21 2026
THE PRIMARY AVIATION WEATHER FORECAST ISSUE WILL BE ON THE
POTENTIAL OF DENSE FOG AT KFWA THIS MORNING. SATELLITE IMAGERY
AND SFC OBSERVATIONS EARLY THIS MORNING ARE DEPICTING AN
EXPANDING AREA OF LOW CLOUDS AND DENSE FOG ACROSS NORTHWEST
OHIO, WITH A SLOW WESTWARD TRANSLATION OVER PAST HOUR. WEAK
NORTHEAST FLOW ASSOCIATED WITH EASTERN PERIPHERY OF LOW LEVEL
ANTICYCLONE WILL CONTINUE TO SUPPORT WESTWARD EXPANSION OF THESE
LOW CLOUDS/DENSE FOG FROM THE EASTERN GREAT LAKES THIS MORNING,
POSSIBLY AFFECTING KFWA AS EARLY AS 10Z. THE TIME PERIOD OF
GREATEST POTENTIAL OF DENSE FOG AT KFWA APPEARS TO BE IN THE
11Z-14Z TIMEFRAME. WILL MAINTAIN VFR CONDITIONS AT KSBN WITH
EXPECTATION BULK OF DENSE FOG WILL BE ROUGHLY ALONG AND EAST OF
THE I-69 CORRIDOR. A SHORT WAVE TRACKING ACROSS THE GREAT LAKES
REGION WILL ALLOW FOR LOW LEVEL ANTICYCLONE TO REFOCUS
WESTWARD LATER TODAY WITH WEAK LOW LEVEL NORTHEAST FLOW OFF THE
EASTERN GREAT LAKES AGAIN TONIGHT. THIS COULD SET UP ANOTHER
NIGHT OF PATCHY FOG LATE WEDNESDAY NIGHT AT KFWA, ALTHOUGH WITH
THE NE TRAJECTORIES, BEST CHANCES MAY BE SOUTH OF KFWA>
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR OHZ001-002-
004-005-015-016-024-025.
MI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MIZ081.
MARINE...NONE.
DISCUSSION...JOHNSON
AVIATION...MARSILI
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