274
FXUS63 KIWX 171747
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
147 PM EDT WED JUN 17 2026
KEY MESSAGES
- TWO ROUNDS OF STORMS ARE EXPECTED TODAY (1-5PM EDT AND
5PM-12AM EDT). THERE IS A LOW CHANCE OF SEVERE WEATHER WITH
THE FIRST ROUND AND A MUCH HIGHER CHANCE WITH THE SECOND
ROUND.
- ALL HAZARDS WILL BE POSSIBLE ACROSS THE ENTIRE AREA WITH ROUND
2 INCLUDING STRONG TORNADOES, LARGE HAIL, DAMAGING WINDS AND
FLOODING. A FLOOD WATCH IS IN EFFECT FOR AREAS ALONG AND NORTH
OF US-24.
- QUIET WEATHER IS EXPECTED THURSDAY THROUGH SATURDAY.
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 THROUGH LATE TONIGHT FOR INZ005>009-012>015-017-
018-020-022>025-103-104-116-203-204-216.
BEACH HAZARDS STATEMENT FROM LATE TONIGHT THROUGH THURSDAY
EVENING FOR INZ103.
OH...FLOOD WATCH THROUGH LATE TONIGHT FOR OHZ001-002-004-005-015.
MI...FLOOD WATCH THROUGH LATE TONIGHT FOR MIZ078>081-177-277.
BEACH HAZARDS STATEMENT FROM LATE TONIGHT THROUGH THURSDAY
EVENING FOR MIZ177-277.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THURSDAY FOR LMZ043-046.
DISCUSSION...AGD/COBB
AVIATION...COBB
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