636
FXUS63 KIWX 162313
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
713 PM EDT TUE JUN 16 2026
KEY MESSAGES
- A SLIGHT RISK FOR SEVERE WEATHER EXISTS FOR THIS AFTERNOON AND
EVENING WITH DAMAGING WINDS AND HAIL THE MAIN THREATS, BUT A
TORNADO CANNOT BE RULED OUT.
- A MODERATE RISK FOR SEVERE WEATHER EXISTS FOR WEDNESDAY INTO
WEDNESDAY NIGHT. DAMAGING WINDS, LARGE HAIL, AND TORNADOES,
AND LOCALIZED FLOODING ARE ALL POTENTIAL THREATS.
- A MODERATE SWIM RISK FOR SOUTHEAST LAKE MICHIGAN BEACHES IS
PRESENT TODAY AND A HIGH SWIM RISK APPEARS LIKELY FOR
THURSDAY.
- DRY WEATHER RETURNS FOR FRIDAY AND SATURDAY.
DISCUSSION
ISSUED AT 1225 PM EDT TUE JUN 16 2026
PRETTY ACTIVE PERIOD OVER THE NEXT 36 HOURS OR SO IN TERMS OF
STRONG TO SEVERE THUNDERSTORMS. FOR TODAY'S PORTION OF EVENTS
THERE WILL BE TWO SPURTS. THE FIRST ONE WILL CONSIST OF SHOWERS
AND EMBEDDED THUNDERSTORMS ACCOMPANYING A SHORTWAVE WITH A WEAK
QUASI-BOUNDARY WHICH ARE CURRENTLY PUSHING EASTWARD ACROSS THE
AREA. THE MAIN IMPACT UP TO THIS POINT HAS BEEN SHOWERS WITH A
FEW RUMBLES OF THUNDER. THE SECOND PART WILL BE SCATTERED
THUNDERSTORMS DEVELOPING MAINLY IN THE WAKE OF THE FIRST BURST
WITH INCREASE SOLAR INSOLATION BEHIND THIS FIRST BAND. THIS WILL
HELP TO INCREASE THE SB CAPE VALUES TO AROUND 1200 J/KG. THE ONE
THING TO MONITOR WILL BE WEAK LAKE BREEZE BOUNDARIES AND A
DEVELOPING WARM FRONTAL BOUNDARY APPROACHING FROM THE WEST THAT
WILL HELP PROVIDE STORMS WITH INCREASED SHEAR AND HELICITY.
SHEAR VALUES AROUND 25 TO 45 KNOTS AND HELICITY VALUES AROUND
100 TO 150 M2/S2 WILL BE POSSIBLE AND SUFFICIENT TO ALLOW FOR
STRONG TO SEVERE STORMS TO DEVELOP. MID LEVEL LAPSE RATE VALUES
OF 7 TO 7.5 DEG/KM WILL BE AVAILABLE. A LIMITING FACTOR WILL BE
THE LACK OF A STRONGER FORCING MECHANISM AND WILL LEAD TO A
MORE SCATTERED NATURE IN THE STORMS. GUSTY WINDS AND HAIL WILL
BE THE MAIN THREATS BUT THERE IS STILL THE POSSIBILITY FOR A
TORNADO OR TWO.
FOR TOMORROW, WARM AIR ADVECTION WILL CONTINUE AND WILL SEE
INCREASING DEW POINTS FROM THE 50S TO THE 60S. A WARM FRONTAL
BOUNDARY WILL BE PUSHING NORTH AND EASTWARD AND PUTTING US IN
THE WARM SECTOR. AS THIS BOUNDARY PUSHES NORTHWARD SHOWERS WILL
BE ON THE INCREASE WITH EVEN A FEW EMBEDDED THUNDERSTORMS AFTER
AROUND 10 AM EDT. A FEW OF THE STORMS IN THIS TIME PERIOD COULD
BECOME STRONG TO SEVERE BUT SHOULD REMAIN FAIRLY TAME. BY THE
AFTERNOON, A COLD FRONT WILL BE PUSHING EASTWARD ACROSS IA/IL/WI
AND APPROACH OUR WESTERN PARTS OF THE CWA AFTER 3-4 PM EDT AND
WILL PUSH EASTWARD THROUGH THE AREA BY 2 AM EDT. THIS WILL BE
THE MAIN EVENT.
THE INGREDIENTS LOOK TO BE WELL IN PLACE AND A VERY HEARTY MID-
LEVEL FLOW AROUND 60 KNOTS WITH A LOW LEVEL JET EXPECTING TO
STRENGTHEN INTO THE EVENING. THIS REALLY IS A RARE TYPE SET-UP
ESPECIALLY FOR THIS TIME OF THE YEAR WITH THAT MUCH MID-LEVEL
FLOW IN THIS SYNOPTIC PATTERN. SB CAPE VALUES PROGGED AROUND
1500 J/KG WITH BULK SHEAR VALUES OF 50 TO 60 KTS. LAPSE RATES OF
8 DEG/KM AND PWATS AROUND 2 INCHES. THE FORECASTED HELICITY
VALUES WILL BE PRETTY MUCH OFF THE CHARTS AT A 500-600 M2/S2.
EFFECTIVE LAYER STP VALUES OF 10 TO 11. WOW. ALL THREATS ARE ON
THE TABLE AND SPC CURRENTLY HAS OUR AREA UNDER A MODERATE TO
SLIGHT RISK FOR SEVERE THUNDERSTORMS AND A TORNADO THREAT AROUND
15%. THE MAIN THREATS WILL BE VERY STRONG GUSTY WINDS AND LARGE
HAIL OF AROUND 2 INCHES IN DIAMETER AND OF COURSE TORNADOS,
SOME BECOMING LONG- LIVED POSSIBLE. ALSO, A THREAT OF LOCALIZED
FLOODING WILL BE POSSIBLE WITH THE VERY EFFICIENT RAINFALL WITH
THE ELEVATED PWATS, EVEN CONSIDERING THE FAST MOVING NATURE OF
THE STORMS. SO THIS IS A POTENTIALLY VERY DANGEROUS SITUATION
AND ONE WOULD BE WISE TO USE CAUTION AND STAY VERY WEATHER AWARE
TOMORROW. MAKE SURE TO HAVE MULTIPLE MEANS OF RECEIVING
WARNINGS AND KEEP YOUR CELL PHONES CHARGED UP AND A FRESH SET OF
BATTERIES IN YOUR WEATHER RADIOS IN CASE OF POWER OUTAGES.
IN THE WAKE OF THIS COLD FRONT DRIER CONDITIONS WILL ARRIVE
WITH THURSDAY THROUGH SATURDAY MAINLY PRECIPITATION FREE. COOLER
TEMPERATURES WILL ALSO CONTINUE WITH HIGHS IN THE 70S.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 713 PM EDT TUE JUN 16 2026
THE -TSRA RISK AS KSBN HAS ENDED FOR THE NEAR-TERM. A BULK OF
THE REMAINING -TSRA WILL PASS SOUTH OF KFWA.
IN THE WAKE OF SHOWERS AND THUNDERSTORMS THIS EVENING, DRY
WEATHER IS ANTICIPATED OVERNIGHT WITH DECREASING CLOUDS. A ROBUST
SEVERE THUNDERSTORM ENVIRONMENT IS BEING MONITORED CLOSELY FOR
WEDNESDAY. HIGH RESOLUTION GUIDANCE IS IN STRONG AGREEMENT A
DECAYING LINE OF THUNDERSTORMS AFTER 12Z WILL EVOLVE INTO A
RENEWED LINE OF STORMS. ALL HAZARDS WILL BE POSSIBLE, ESPECIALLY
AT KFWA. PERHAPS ONLY SLIGHTLY LESS CONFIDENT AT KSBN WHERE NEW
CONVECTION COULD DEVELOP JUST SE OF KSBN.
ADDITIONALLY, LATE IN THE PERIOD, SOME GUIDANCE HAS HINTS OF A WAKE
LOW DEVELOPING.THIS WOULD CAUSE A PERIOD OF 40+ KNOT WIND GUSTS BEHIND
ANY LINE OF STORMS.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ043-
046.
DISCUSSION...ANDERSEN
AVIATION...BROWN
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