389
FXUS63 KIWX 160959
AFDIWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
559 AM EDT TUE JUN 16 2026
KEY MESSAGES
- A MARGINAL RISK FOR SEVERE WEATHER EXISTS FOR TODAY 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 305 AM EDT TUE JUN 16 2026
AFTER ENDING THE DAY MONDAY WITH DEW POINTS IN THE 40S, ESPECIALLY
IN AREAS EAST OF IN-15, DEW POINTS ARE EXPECTED TO RISE INTO THE 50S
TODAY. SHORT RANGE MODELS HAVE TWO LINES OF CONVECTION MOVING
THROUGH THE AREA TODAY. THE FIRST IS ALONG THE RETURN MOISTURE PLUME
AND THE SECOND IS BACK WITH THE COLD FRONT. THIS FIRST OF SHOWERS
AND STORMS SWINGING IN AROUND 17 OR 18Z IS EXPECTED TO HAVE ONLY
AROUND 500 J/KG OF CAPE WITH RELATIVELY WEAK SHEAR (BETTER SOUTH
THAN NORTH) IN THIS INVERTED-V TYPE ENVIRONMENT SO IT COMES WITH
LESS CONFIDENCE IN ANY SEVERE WEATHER OCCURRING, BUT IF SHEAR IS
SLIGHTLY HIGHER, IT'S POSSIBLE A GUSTY TO DAMAGING WIND EVENT IS
OBSERVED. THE SECOND LINE OF STORMS, ASSOCIATED WITH THE COLD FRONT,
SWINGING IN AROUND 21Z IS EXPECTED TO HAVE BETTER INSTABILITY
(AROUND 1500 J/KG) AND AROUND 25 TO 30 KTS OF SHEAR, WHICH WOULD
POINT TO A BETTER ENVIRONMENT FOR DAMAGING WINDS AND PERHAPS
SOME HAIL. THIS SECOND LINE'S INSTABILITY IS CONTINGENT ON ANY
CLOUD DEBRIS FROM THE FIRST LINE BEING REMOVED THOUGH. THERE IS
ENOUGH LOW LEVEL TURNING OF THE WIND AND LOW ENOUGH LCLS THAT A
TORNADO CANNOT BE RULED OUT FROM THE LINE OF CONVECTION
ASSOCIATED WITH THE COLD FRONT. ALSO, GUSTY WINDS 25 TO 35 MPH
WILL BE POSSIBLE TODAY AS A LOW LEVEL JET SWINGS THROUGH.
THE EVENTUAL LOCATION OF THE COLD FRONT TUESDAY NIGHT IS FORECAST
DOWN IN MO, BUT THE FRONT'S LOCATION LATER IN THE DAY AND INTO THE
OVERNIGHT HAS BEEN TRENDING NORTHWARD OVER THE LAST COUPLE OF THE
GFS RUNS. EVEN THE HRRR ATTEMPTS TO PUSH THE WARM FRONT INTO THE
AREA STARTING AROUND 22Z WEDNESDAY EVENING. HOWEVER, BOTH THE HRRR
AND THE NAM ATTEMPT TO PUSH WHAT APPEARS TO BE AN MCS INTO THE AREA
AROUND MIDDAY AS A VORT MAX DEVELOPS OVERHEAD. IF THIS PUTS OUT A
COLD POOL, IT MAY BE TOUGH GET DESTABILIZATION/RECOVERY AHEAD OF THE
FOLLOWING COLD FRONT. IF WE DO, THE LOW LEVEL JET IS VERY STRONG AND
LOW LEVEL TURNING APPEARS VERY CONDUCIVE TO A DAMAGING WIND AND
TORNADO ENVIRONMENT. BUT AGAIN, TRYING TO GET PARCELS UP INTO THE
BETTER SHEAR WITH LIMITED INSTABILITY MAY BE DIFFICULT. GIVEN THE
MCS AND THEN SQUALL LINE EVOLUTION, THIS MAY BE ENOUGH TO GET HEAVY
RAIN ACROSS THE AREA. WE'VE BEEN SO DRY SO THAT WE CAN PROBABLY TAKE
SOME RAIN INTO THE SOILS. MODELS HAVE ABOUT A 20 TO 40 PERCENT
CHANCE OF 2 INCHES OF RAIN IN 24 HOURS ENDING 12Z THURSDAY, WHICH IS
HELPED ALONG BY THE PWATS REACHING 2 INCHES WEDNESDAY EVENING AS THE
THETA-E PLUME SWINGS THROUGH.
ONE OTHER ASPECT OF THIS IS THAT THERE IS A 17 MB PRESSURE FALL IN
6 HRS OVER THE AREA WEDNESDAY EVENING, WHICH APPEARS TO BE AS
THE FIRST MCS IS LEAVING THE AREA. USUALLY MODELS DISPLAY THE
POSSIBILITY OF A WAKE LOW BY INDICATING SUBSIDENCE IN MODEL
SOUNDINGS, BUT THAT DOESN'T APPEAR TO BE THE CASE IN HRRR
SOUNDINGS. THIS MAY MAY BE AN INDICATION IT DOESN'T HAPPEN.
SOMETHING TO KEEP AN EYE ON.
GIVEN THE STRENGTH OF THE WAVE AND ITS PATH ACROSS LK MI, THERE
COULD BE SOME RAIN THAT ATTEMPTS TO FORM THURSDAY. THE NAM HAS
500 J/KG OF SBCAPE WITHIN THIS AREA SO IT WOULD PROBABLY JUST
LEAN SHOWERS AND, AT BEST, NON-SEVERE STORMS.
FRIDAY AND SATURDAY ARE DRY AS MID LEVEL RIDGING AND SURFACE HIGH
PRESSURE PASS THROUGH. THE NEXT CHANCE FOR SHOWERS AND PERHAPS A FEW
THUNDERSTORMS COMES SUNDAY AS THE NEXT WAVE EJECTS OFF THE
ROCKIES.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 529 AM EDT TUE JUN 16 2026
TWO OPPORTUNITIES FOR SHOWERS AND STORMS OCCUR TODAY AS TWO
CONVECTIVE LINES SWING THROUGH, THE SECOND ALONG A COLD FRONT. THERE
IS SOME QUESTION ABOUT THE SEVERITY AND SOUTHERN EXTENT OF THE FIRST
LINE, BUT THE SECOND LINE LOOKS TO HAVE THE MOST CONFIDENCE TO BE
THE STRONGER OF THE TWO. GIVEN THIS, WILL GO WITH A PROB30 GROUP FOR
MVFR CONDITIONS WITH BOTH LINES INDIVIDUALLY, BUT LOWER FOR THE
SECOND LINE. DAMAGING WIND AND HAIL ARE THE MAIN THREATS, BUT A
TORNADO CANNOT BE RULED OUT.
ADDITIONALLY, SOUTHWEST GUSTS TO 25 TO 30 KTS WILL BE POSSIBLE
THROUGH THE DAY TODAY.
IWX WATCHES/WARNINGS/ADVISORIES
IN...NONE.
OH...NONE.
MI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 10 PM EDT THIS
EVENING FOR LMZ043-046.
DISCUSSION...ROLLER
AVIATION...ROLLER
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