399
FXUS63 KIWX 202248
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
648 PM EDT SUN SEP 20 2026
KEY MESSAGES
- A FLASH FLOOD WATCH IS IN EFFECT FROM PORTIONS OF NORTHERN
INDIANA AND NORTHWEST OHIO THROUGH LATE TONIGHT. 1-2 INCHES OF
RAIN IS POSSIBLE ALONG AND SOUTH OF US-30. AREAS FURTHER SOUTH
THAT RECEIVED EXCESSIVE RAINFALL THIS PAST WEEK COULD SEE AN
EXACERBATION TO ANY LINGERING FLOODING. ISOLATED THUNDERSTORMS
ARE POSSIBLE.
- LIGHT RAIN CHANCES CONTINUE THROUGH MONDAY AFTERNOON,
DWINDLING TOWARDS THE EVENING. COOLER AND TRENDING DRIER
THROUGH THE WEEK, WITH HIGHS IN THE 60S, LOW 70S AND LOWS IN
THE UPPER 40S AND LOW-MID 50S.
DISCUSSION
ISSUED AT 409 PM EDT SUN SEP 20 2026
OPTED TO EXTEND THE FLASH FLOOD WATCH UNTIL 2 AM EDT FOR AREAS
FURTHER SOUTH AND EAST GIVEN EXPECTED RAINFALL THROUGH LATE TONIGHT-
WHICH IS WHERE MOST OF THE RAIN HAS FALLEN OVER THE PAST WEEK AND
IMPACTS LINGER. ADDITIONAL TOTALS OF 1-2" ARE POSSIBLE THROUGH
MONDAY MORNING AS A SHORTWAVE OR TWO MOVE THROUGH, WHICH COULD
EXACERBATE ANY FLOODING IN THESE AREAS. MUCH OF THE HIGH RES
DEVELOPS HEAVIER RAINFALL WITHIN SOME MORE CONVECTIVE ELEMENTS THIS
EVENING, HOWEVER AS OF THIS WRITING WE ARE PRETTY MEAGER IN TERMS OF
HEAVY RAIN. EXPECT A PERIOD OF ISENTROPIC ASCENT TO CONTINUE THROUGH
AT LEAST THE EVENING AS A LOW PRESSURE SYSTEM DEVELOPS ALONG THE
STATIONARY FRONT WITH THIS FIRST SHORTWAVE. STILL HAVE DECENT WARM
CLOUD DEPTH, PWATS AROUND 2" AND A LLJ OF AROUND 25-30 KNOTS, SO
HEAVY RAIN IS STILL A POSSIBILITY. THUNDERSTORMS ARE ALSO POSSIBLE.
OTHERWISE, EXPECT A DRYING TREND LATE MONDAY INTO THE REST OF THE
WEEK, WITH MAINLY INTERMITTENT LOW CHANCES (20-30%) AS WE SIT ON THE
PERIPHERY OF UPPER LEVEL RIDGE/UPPER LOW, WITH SURFACE HIGH PRESSURE
BELOW (PARTICULARLY THURSDAY INTO THE WEEKEND). IT WILL BE MORE FALL
LIKE, WITH HIGHS IN THE 60S, LOW 70S AND THEN LOWS FALLING INTO THE
UPPER 40S, 50S. BY THE WEEKEND, WE WARM UP INTO THE LOW-MID 70S
(WARMEST SUN).
AVIATION /00Z TAFS THROUGH 00Z TUESDAY/
ISSUED AT 645 PM EDT SUN SEP 20 2026
NUMEROUS SHOWERS ARE MOVING FROM WEST TO EAST ACROSS THE AREA,
WITH THE BACK EDGE OF PRECIPITATION SEEN ON RADAR IN NORTHERN
ILLINOIS. RAIN WILL GRADUALLY COME TO AN END FROM WEST TO EAST
BETWEEN 01Z-04Z TONIGHT. LOW END IFR CEILINGS ARE ONGOING AS
LOW LEVEL STRATUS PERSISTS. IFR CEILINGS WILL GRADUALLY LIFT TO
MVFR BY MONDAY MORNING. STRATUS WILL CONTINUE THROUGHOUT THE DAY
WITH CEILINGS RISING TO LOW END VFR BY MONDAY EVENING. GUSTY
NORTHEAST WINDS WILL CONTINUE THROUGH THE TAF FORECAST PERIOD
WITH SUSTAINED WINDS BETWEEN 12-15 KTS AND SPORADIC GUSTS TO 20
KTS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FLOOD WATCH UNTIL 2 AM EDT MONDAY FOR INZ017-018-023>027-
032>034.
OH...FLOOD WATCH UNTIL 2 AM EDT MONDAY FOR OHZ015-024.
MI...NONE.
MARINE...NONE.
DISCUSSION...MCD
AVIATION...JOHNSON
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