FXUS63 KIWX 151241
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
841 AM EDT Wed Apr 15 2026

.KEY MESSAGES...

- Multiple rounds of showers and thunderstorms will continue
  through today, though the potential for severe weather remains
  uncertain with intensity dependent on how previous activity
  evolves.

- Additional chances for showers and thunderstorms exist
  Thursday through Saturday, with potential for severe weather
  dependent on the previous thunderstorm activity.

- A Flood Watch remains in effect through this evening as swaths
  of locally heavy rain is expected on already saturated grounds
  and high river and lake levels.

&&

.UPDATE...
Issued at 841 AM EDT Wed Apr 15 2026

Quick update to the forecast to increase pops into early
afternoon.

Small cluster of storms across far southern MI this morning has
moved northeast with some occasional light returns further south
into N Indiana. Looking back to the SW, radar and sfc obs
indicate a MCV in west central IL with an area of showers and
storms trying to expand while moving NE. Several of the models
suggest this continues NE reaching the area in a few hours and
lingering into the early afternoon. HRRR is the more robust with
maybe some stronger storm potential. Plenty of shear is in place
with instability on the lower side (500-1000 J/KG of MUCAPE) per
SPC Mesoanalysis and 12Z KILX sounding. While some increase in
temps is expected through the morning, extensive cloud cover
will limit overall heating. Will be monitoring trends over the
next couple of hours for maybe a "marginal" threat of stg-svr
storms. Given the trends, felt it was warranted to keep likely
pops for many areas into early afternoon vs the taper off to chc
that was in place.

Flood watch remains in effect across the northern half. May need
to expand southward depending on evolution of the morning
convection as well as trends for afternoon/evening storms as
PWATs remain in the 1.25 to 1.4" range and depth of warm layer
shy of 12,000 ft all point towards a continued heavy rain
threat.

&&

.DISCUSSION...
Issued at 1257 AM EDT Wed Apr 15 2026

While a primary trough will lift out of the Rockies into the
central plains over the coming 12-18 hours, multiple embedded
waves ahead of this trough through the active flow aloft will
continue to produce periods of shower and thunderstorm activity
across the region today. Forecast soundings depict fairly
saturated atmospheric profiles with precipitable water values
exceeding 1.2-1.4 inches, which will aid in producing heavy
rainfall rates with any thunderstorm that develops. A Flood
Watch remains in effect through this evening for the northern
half of the forecast area given the potential for heavy rain,
though a flooding threat cannot be ruled out further south.

The severe thunderstorm threat remains complicated today with
instability looking more difficult to come by as early morning
convective debris and intermittent shower activity will limit
CAPE values. That said, strong mid- level flow with 40-50 knots
of 0-6km shear will be more than sufficient for organized
convection if adequate surface heating and subsequent
destabilization occurs. For now the severe threat today looks
conditional but worth watching.

A sharper trough moves through the area on Thursday bringing
additional chances for showers and thunderstorms. Strong shear
and adequate instability should bring another day of at least a
marginal severe threat. Attention will then turn to the likely
arrival of a much deeper trough by this weekend, which has
triggered an early highlight by SPC for severe weather potential
on Saturday. A sharp cool-down and gusty winds behind the
associated cold front is likely on Sunday, with a moderation in
temperatures through the first half of next week.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 603 AM EDT Wed Apr 15 2026

MVFR/IFR vsbys and MVFR cigs in scattered thunderstorms today
for both sites mainly between 16z-21z Wed for both TAF sites
and again between 06z-08z Thu for KSBN. Southwesterly winds
around 10 kts with stronger gusts around 25kts with thunderstorm
outflows.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch until 8 PM EDT /7 PM CDT/ this evening for
     INZ005>009-012-014-103-104-116-203-204-216.
OH...Flood Watch until 8 PM EDT this evening for OHZ001-002-004-005.
MI...Flood Watch until 8 PM EDT this evening for MIZ078>081-177-277.
MARINE...None.

&&

$$

UPDATE...Fisher
DISCUSSION...Edwards
AVIATION...Andersen