533
FXUS63 KIWX 171826
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
226 PM EDT FRI APR 17 2026
KEY MESSAGES
- A LINE OF STRONG TO SEVERE STORMS IS EXPECTED TO MOVE IN
LATER THIS EVENING AND SPREAD EAST OVERNIGHT. THE GREATEST
SEVERE THREAT WILL EXIST WEST OF INTERSTATE 69 WITH DAMAGING
WINDS AND POSSIBLY A TORNADO OR 2 THE MAIN CONCERN.
- SOME HYDRO CONCERNS WILL EXIST TONIGHT AS LOCALLY HEAVY RAIN
ACCOMPANIES THE LINE OF STORMS. OVERALL QPF AMOUNTS AND
EXPECTED DURATION SHOULD LIMIT ADDITIONAL IMPACTS, BUT SOME
AREAS COULD SEE LOCALIZED FLOODING ISSUES. THEREAFTER, NO
ADDITIONAL SIGNIFICANT RAIN CHANCES ARE EXPECTED INTO NEXT
WEEK.
- MUCH COOLER TEMPERATURES ARRIVE AND PERSIST INTO EARLY NEXT
WEEK WITH CHANCES FOR NEAR OR BELOW FREEZING TEMPS SUNDAY AND
MONDAY MORNING.
- RAIN CHANCES MAY RETURN TOWARDS THE END OF NEXT WEEK.
DISCUSSION
ISSUED AT 226 PM EDT FRI APR 17 2026
PRIMARY FORECAST FOCUS IS ON THE WELL ADVERTISED STRONG TO
SEVERE STORM THREAT THIS EVENING INTO THE OVERNIGHT HOURS IN
ASSOCIATION WITH A STRONG COLD FRONT AND PLENTIFUL UPPER LEVEL
SUPPORT. DRY CONDITIONS ARE EXPECTED THROUGH THE REMAINDER OF
THE AFTERNOON AND MOST LIKELY TO NEAR OR JUST AFTER 00Z. NUMEROUS
THUNDERSTORMS ARE EXPECTED TO DEVELOP UPSTREAM (SOME ALREADY
UNDERWAY FROM MINNESOTA TO NE MISSOURI) IN A STRONGLY FAVORABLE
ENVIRONMENT FOR ALL MODES OF SEVERE. AS THESE STORMS RACES ENE,
THEY SHOULD CONGEAL INTO 1 OR MORE LINES AND MOST LIKELY
ESTABLISH STRONG COLD POOLS AS THEY MOVE ACROSS IL AND
EVENTUALLY INTO PORTIONS OF INDIANA. IT REMAINS TO BE SEEN JUST
HOW STRONG THEY ARE AS THEY ARRIVE LATER THIS EVENING, BUT
CONCERNS HAVE INCREASED SOME THAT THEY MAKE IT ROUGHLY HALF WAY
THROUGH THE AREA BEFORE WEAKENING SOMEWHAT. THIS IS DEPICTED BY
SOME EXPANSION EAST OF THE SLIGHT AND MARGINAL RISK AREAS IN THE
DY1 OUTLOOK. BY THIS POINT, HAIL SHOULD NOT BE A CONCERN, WITH
AREAS OF WIND DAMAGE (60 TO 70 MPH) AS WELL AS SOME BRIEF
TORNADOES WILL BE THE MAIN CONCERN. THE MAIN SEVERE THREAT
SHOULD WRAP UP IN THE 6-8Z TIME FRAME WITH LINGERING STRATIFORM
RAIN BEHIND THE MAIN LINE. POPS HAVE BEEN ADJUSTED FOR A
SOMEWHAT FASTER TREND GIVEN THE IMPACTS OF THE COLD POOL PUSHING
THE LINE ALONG SOONER THAN PREVIOUS INDICATIONS. WITH REGARDS
TO HYDRO ISSUES, A FLOOD WATCH WAS CONTEMPLATED GIVEN THE
POTENTIAL FOR 0.5" TO 1" OF RAIN (LOCALLY HIGHER POSSIBLE), BUT
WITH THE LINE BEING SO PROGRESSIVE FEEL THE CONCERNS WILL BE
RATHER LIMITED AND CAN JUST BE HANDLED BY FLOOD ADVISORIES OR
WARNINGS AS NEEDED.
THE FRONT WILL STALL OUT SOME SATURDAY AS ANOTHER WAVE MOVES
ALONG IT. THE SEVERE THREAT SHOULD REMAIN TO OUR EAST BUT SOME
SHOWERS AND MAYBE A STORM ARE STILL POSSIBLE IN SE AREAS,
ESPECIALLY EARLY. AFTER THAT, WE ENTER A LESS ACTIVE PERIOD INTO
AT LEAST THE MIDDLE OF NEXT WEEK WITH THE ONLY CONCERN BEING THE
MONITORING OF COLDER TEMPERATURES AND FROST/FREEZE POTENTIAL
SUNDAY AND MONDAY MORNING. WILL SORT THAT OUT AFTER WE GET THIS
SYSTEM OUT OF HERE.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 126 PM EDT FRI APR 17 2026
VFR CONDITIONS THIS AFTERNOON AND EVENING WITH HIGH CLOUDS
MOVING IN AHEAD OF NEXT SYSTEM. SOUTHERLY WINDS ARE STARTING TO
INCREASE WITH GUSTS AROUND 20 KTS EXPECTED THROUGH THE EVENING.
AN APPROACHING COLD FRONT FROM THE WEST WILL INCREASE
PRECIPITATION CHANCES IN THUNDERSTORMS OF WHICH A FEW MAY
BECOME STRONG TO SEVERE AFTER 02Z TONIGHT, AND SPREAD EASTWARD
INTO SATURDAY MORNING BRINGING MVFR CIGS/VSBYS WITHIN
THUNDERSTORMS AND POST FRONTAL RAIN. CONDITIONS WILL IMPROVE
SATURDAY AFTERNOON BUT GUSTY NORTHWEST WINDS WILL PERSIST.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 2 AM EDT SUNDAY
FOR LMZ043-046.
DISCUSSION...FISHER
AVIATION...COBB
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