449
FXUS63 KIWX 172255
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
655 PM EDT WED JUN 17 2026
KEY MESSAGES
- HEAVY RAIN AND AN ISOLATED SEVERE THUNDERSTORM ARE POSSIBLE
THIS EVENING.
- A TORNADO WATCH WAS ISSUED SOME COUNTIES SOUTH OF US 24 WHERE
THERE IS THE GREATEST CHANCE FOR SEVERE THUNDERSTORMS.
- QUIET WEATHER IS EXPECTED THURSDAY THROUGH SATURDAY.
UPDATE
ISSUED AT 655 PM EDT WED JUN 17 2026
THE OVERALL SEVERE WEATHER RISK APPEARS TO BE GRADUALLY
DIMINISHING OVER NORTHERN INDIANA, YET WE REMAIN VIGILANT OVER
THE TORNADO WATCH AREA.
AN UPPER- LEVEL TROUGH AND COLD FRONT REMAIN TO OUR WEST, WHILE
OUR NEAR TERM ENVIRONMENT REMAINS LIMITED DUE TO STEADY RAIN
AND CAPPING. DESPITE THIS, A SMALL AREA OF EMBEDED
THUNDERSTORMS PERSISTS ALONG THE INDIANA TOLL ROAD, PERHAPS ON
THE CUSP ON A LINGERING MCV FROM MORNING ACTIVITY. CONVECTION
THERE HAS BEEN SHALLOW WITH A STRONG WIND FIELD ALOFT. YET, TO
THIS POINT, HEAVY RAIN HAS BEEN THE OBSERVED IMPACT. BEHIND THIS
AREA OF RAIN, THE IN- HOUSE WARN ON FORECAST SUGGEST THE BEST
INSTABILITY WILL QUICKLY FADE SOUTH, LIMITING ANY RENEWED
CONVECTION RISK AFTER THIS CURRENT PERIOD OF HEAVY RAIN AND
THUNDER.
FARTHER SOUTH, TOWARD WHITE COUNTY, SHOWERS HAVE CONTINUED TO
PERCOLATE IN THE VICINITY OF A 60-JET 850MB JET. WITH STRONG
LOW-LEVEL FLOW, WE REMAIN ALERT FOR AN SEVERE THUNDERSTORM
DEVELOPMENT WITHIN THE TORNADO WATCH AREA, AS GUIDANCE
CONTINUES TO OFFER GLIMPSES THAT RENEWED CONVECTION THERE IS
POSSIBLE. TIME IS RUNNING OUT, AND THUS IF ANY SEVERE STORMS
OCCUR, THEY OUGHT TO DEVELOP PRIOR TO SUNSET.
LASTLY, A WIND ADVISORY WAS HOISTED FOR WHAT APPEARED TO BE A
DEVELOPING WAKE LOW OVER CHICAGO'S AREA EARLIER IN THE
AFTERNOON. (GUSTY WINDS WERE OBSERVED AND INSTANCES OF DAMAGER
AND POWER OUTAGES WERE NOTED). THIS HAS FAILED TO MATERIALIZE
ANY FURTHER AND WILL LIKELY RESULT IN THE WIND ADVISORY BEING
CANCELED EARLIER THAN ADVERTISED.
DISCUSSION
ISSUED AT 120 PM EDT WED JUN 17 2026
AN MCS MOVING IN FROM ILLINOIS IS CURRENTLY MOVING INTO THE
REGION AND ACTING TO HOLD THE WARM FRONT AND BETTER INSTABILITY
SOUTH OF THE AREA. HOWEVER, AS THIS WEAKENS THIS AFTERNOON, A
STRONG SURGE OF WARM/MOIST AIR ADVECTION WILL PUSH NORTHWARD.
THUNDERSTORMS OVER CENTRAL ILLINOIS WILL THEN STREAM IN FROM THE
SOUTHWEST AROUND 20Z. THIS WILL BE THE BEGINNING OF WHAT WE HAVE
PREVIOUSLY BEEN REFERRING TO AS "ROUND 2" OF STORMS WITH A
SIGNIFICANT SEVERE POTENTIAL, ESPECIALLY DAMAGING WINDS AND
TORNADOES. THE GREATEST THREAT FOR SEVERE WEATHER WILL
GENERALLY BE SOUTH OF US-30 AS A STRONG COLD FRONT COMES IN
22-23Z. THIS WILL BE ACCOMPANIED BY EXTREME WIND SHEAR AND
EFFECTIVE SRH ON THE ORDER OF 900 M2/S2. IT WILL BE IMPORTANT TO
REMAIN VIGILANT GIVEN THE POTENTIAL FOR STRONG TORNADOES. ALSO,
WHILE THE HIGHEST TORNADO PROBABILITIES REMAIN SOUTH OF US-30
AND WEST OF I-69 WHERE BETTER INSTABILITY RESIDES, WITH THE WARM
FRONT APPROACHING THE MICHIGAN BORDER WHERE THE BETTER HELICITY
EXISTS, THE TORNADO THREAT COULD BE JUST AS HIGH OR HIGHER IF
ANY MINOR INSTABILITY DEVELOPS THERE. IN ADDITION TO THE TORNADO
THREAT, WILL ALSO HAVE TO WATCH POTENTIAL FOR WAKE LOW
DEVELOPMENT WHICH COULD BRING DAMAGING WINDS BEHIND THE LINE OF
STORMS INTO THE LATE EVENING. REGARDLESS OF WAKE LOW
DEVELOPMENT, IT WILL BE BREEZY INTO THE OVERNIGHT AND ON
THURSDAY. HAIL THREAT IS A BIT LOWER TODAY GIVEN POOR LAPSE
RATES BUT ANY ORGANIZED SUPERCELL WILL STILL BE CAPABLE OF
GENERATING SOME LARGE HAIL.
ALSO OF CONCERN IS THE POSSIBILITY OF HEAVY RAIN/FLOODING GIVEN THE
POTENTIAL FOR MULTIPLE ROUNDS OF CONVECTION TRAINING EAST-WEST
ACROSS THE AREA TODAY. PW VALUES REACH OR EXCEED 2 INCHES WITH A
VERY MOIST PROFILE THROUGHOUT THE COLUMN. WARM CLOUD LAYERS AND MBE
VELOCITIES ARE ON THE MARGINAL SIDE FOR A SIGNIFICANT FLOODING
THREAT AND STORM MOTIONS WILL BE FAST. HOWEVER, STILL SEE POTENTIAL
FOR A QUICK 2-3 INCHES IN SOME LOCATIONS (PARTICULARLY IN OUR NW)
AND THIS WILL BE CAPABLE OF AT LEAST ISOLATED POCKETS OF FLOODING
AND IMPACTS. HAVE THEREFORE MAINTAINED A FLOOD WATCH FOR AREAS
ALONG AND NORTH OF US-24. (FLOOD RISK APPEARS A BIT LOWER SOUTH
OF 24).
OUTSIDE OF SOME GUSTY WINDS TOMORROW, NO WEATHER CONCERNS FOR
THURSDAY-SATURDAY. ANOTHER SYSTEM APPEARS POSSIBLE ON SUNDAY BUT
FOCUS REMAINED ON TODAY'S HAZARDS.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 120 PM EDT WED JUN 17 2026
WIDESPREAD RAIN IS CURRENTLY OVERTAKING THE AREA. EMBEDDED
THUNDERSTORMS ARE ALSO POSSIBLE THIS AFTERNOON AND EVENING. THE
BEST CHANCES FOR THUNDER STILL APPEAR TO BE WITH THE COLD FRONT
DURING THE EVENING HOURS BETWEEN 21Z AND 02Z. STRONG WINDS AND
BRIEF IFR CONDITIONS ARE LIKELY WITH THESE STORMS. RETURN TO VFR
EXPECTED OVERNIGHT BUT BREEZY CONDITIONS WILL PERSIST THROUGH
THURSDAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...FLOOD WATCH UNTIL 2 AM EDT /1 AM CDT/ THURSDAY FOR INZ005>009-
012>015-017-018-020-022>025-103-104-116-203-204-216.
WIND ADVISORY UNTIL 11 PM EDT /10 PM CDT/ THIS EVENING FOR
INZ005>009-012-014-017-018-103-104-116-203-204-216.
BEACH HAZARDS STATEMENT FROM 1 AM CDT THURSDAY THROUGH
THURSDAY EVENING FOR INZ103.
OH...FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR OHZ001-002-004-005-015.
WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR OHZ001-002-004-
005-015-016.
MI...FLOOD WATCH UNTIL 2 AM EDT THURSDAY FOR MIZ078>081-177-277.
WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MIZ078>081-177-
277.
BEACH HAZARDS STATEMENT FROM 2 AM EDT THURSDAY THROUGH
THURSDAY EVENING FOR MIZ177-277.
MARINE...GALE WARNING UNTIL 8 PM EDT THIS EVENING FOR LMZ043-046.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THURSDAY FOR LMZ043-046.
UPDATE...BROWN
DISCUSSION...COBB
AVIATION...COBB
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