663
FXUS63 KIWX 170418
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1218 AM EDT THU SEP 17 2026
KEY MESSAGES
- A ROUND OF SHOWERS AND THUNDERSTORMS EXPECTED THIS MORNING. HEAVY
RAIN AND ASSOCIATED FLOODING POTENTIAL ARE THE GREATEST
CONCERN, ESPECIALLY IN AREAS THAT EXPERIENCED HEAVY RAIN OVER
THE PAST 24 HOURS. FLOOD WATCH IN EFFECT FOR PARTS OF NORTHERN
INDIANA
- DRY AND LESS HUMID CONDITIONS ON FRIDAY FOLLOWED BY RENEWED
OPPORTUNTIES FOR RAIN AND STORMS THIS WEEKEND.
DISCUSSION
ISSUED AT 212 PM EDT WED SEP 16 2026
A SMALL WINDOW OF DRIER CONDITIONS SHOULD UNFOLD FOR THE NEXT 6 TO 9
HOURS FOR MANY AREAS IN THE WAKE OF THE DEPARTING MCV AND ASSOCIATED
PRECIP. UPSTREAM ACROSS IL A FEW SHOWERS ARE DEVELOPING AND CAN'T
RULE OUT WIDELY SCATTERED SHOWERS AND STORMS LATER TODAY INTO THIS
EVENING IN AREAS THAT SEE LIMITED CLEARING (MAINLY SE). SPC HAS
MAINTAINED THE MARGINAL RISK FOR SEVERE IN OUR SE WITH A LOW CHANCE
FOR SOME LOCALLY GUSTY WINDS FROM ANY MORE ORGANIZED STORMS THAT
PRODUCE WET MICROBURSTS, MUCH LIKE YESTERDAY.
THE GREATER CONCERN LIES WITH FLOODING POTENTIAL LATER TONIGHT INTO
THURSDAY. MOST AREAS ACROSS N INDIANA AND TO A LESSER EXTENT NW OHIO
HAVE EXPERIENCED MULTIPLE ROUNDS OF SHOWERS AND STORMS AND ALL SIGNS
POINT TOWARDS ANOTHER ROUND OVERNIGHT DEVELOPING UPSTREAM AND MOVING
ESE ALONG THE QUASI STATIONARY BOUNDARY THAT WILL BE DRAPED ACROSS
THE AREA. PWATS CONTINUE AROUND 2" AND PROBABLY EVEN HIGHER WITH NO
MAJOR CHANGE IN AIR MASS EXPECTED UNTIL LATER THURSDAY INTO FRIDAY.
WPC HAS ALL BUT OUT MI COUNTIES IN A SLIGHT RISK FOR EXCESSIVE
RAINFALL, WHICH IS VERY REASONABLE GIVEN THE SETUP. WHILE CONFIDENCE
IS SOMEWHAT HIGHER ON AT LEAST PARTS OF THE AREA BEING IMPACTED,
SOME CAMS (ESPECIALLY THE HRRR) DEVELOP 2 ROUNDS WITH ONE SHORTLY
AFTER 6Z ACROSS SOUTHERN AREAS AND THEN THE UPSTREAM DEVELOPMENT
ARRIVING TOWARDS 12Z THU. WHILE A FLOOD WATCH COULD BE EASILY
JUSTIFIED GIVEN THE WET CONDITIONS AND POTENTIAL FOR ANOTHER 1 TO AS
MUCH AS 3 INCHES IN SOME SPOTS, CONFIDENCE ON TIMING AND LOCATION OF
THE HEAVIEST PRECIP REMAINS LOW ENOUGH TO HOLD OFF ON ANY HEADLINES.
POPS HAVE BEEN ADJUSTED TO REFLECT TRENDS WITH A LARGER,
BROADBRUSHED LIKELY AREA LATE TONIGHT INTO THURSDAY MORNING WITH
PRECIP THEN ENDING FROM WEST TO EAST.
LATE THURSDAY INTO FRIDAY IT STILL APPEARS THAT MUCH, IF NOT ALL OF
THE AREA SHOULD SEE A BREATHER IN RAIN CHANCES ALONG WITH SOMEWHAT
LOWER HUMIDITY. LATE FRIDAY NIGHT INTO SAT THIS CHANGES AS YET
ANOTHER WAVE MOVES TOWARDS THE REGION WHICH FORCES THE FRONT BACK
NORTH AND BRINGS RAIN CHANCES WITH IT. HYDRO CONCERNS WILL LIKELY
REMAIN GIVEN THE SMALL WINDOW OF DRYING.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1218 AM EDT THU SEP 17 2026
WARM ADVECTION INTO A STALLED FRONTAL ZONE WILL ALLOW SHOWERS
AND FEW EMBEDDED STORMS TO INCREASE IN COVERAGE THIS MORNING,
GREATEST COVERAGE/CHANCES IN THE 10-16Z WINDOW. THE BULK OF THE
MORNING WILL GENERALLY FEATURE IFR TO LOW MVFR CONDITIONS AND
LIGHT WINDS, WITH PERIODS OF LIFR ALSO POSSIBLE GIVEN THE MOIST
CONDITIONS. DRYING AND IMPROVEMENT BACK INTO MAINLY MVFR OR VFR
WITH TIME THEN THIS AFTERNOON AS THE FRONTAL ZONE FINALLY
BEGINS TO SHIFT OFF TO THE SOUTH.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FLOOD WATCH THROUGH THIS AFTERNOON FOR INZ026-027-032>034.
OH...NONE.
MI...NONE.
MARINE...NONE.
UPDATE...FISHER
DISCUSSION...FISHER
AVIATION...STEINWEDEL
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