115
FXUS63 KIWX 090501
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
101 AM EDT Sun Aug 9 2026

.KEY MESSAGES...

- An active pattern brings periodic chances for thunderstorms
  Sunday afternoon through the middle of the upcoming week.
  Some storms could be severe and may also result in flash
  flooding, especially Sunday night through Monday night.

- Seasonable temperatures are expected to persist.

&&

.DISCUSSION...
Issued at 203 PM EDT Sat Aug 8 2026

A cold front will sag southeast through northeast IN and northwest
OH this afternoon. This front will have up to near 2000 j/kg of
MLCAPE to work with. However, lacking deep forcing/moisture, and
only 15-20 kts of effective shear, should keep any convection sub-
severe and isolated (10-30%) along the front. Drier air then briefly
settles in post-frontal tonight and Sunday morning, with the
potential for patchy fog early Sunday as winds go light/calm under a
mainly clear sky.

The aforementioned frontal boundary will lift back northeast toward
the MI state line Sunday afternoon into Sunday night on the nose of
increasing low level west-southwest flow. This will allow very
muggy/unstable air to advect back into the lower Great Lakes. This
will set the stage for a prolonged, convectively active period
across the region through midweek as several low amplitude
shortwaves send convective complexes through on the southern fringes
of developing west-northwest flow aloft.

Chances for convection will enter the picture Sunday afternoon into
early Sunday evening with the initial theta-e surge and some
semblance of an incoming MCS from the west. The bulk of the area may
see this feature in a weakening, more elevated state, though
could see a few cells rooted in the surface (potentially severe)
into northwest IN, depending on the timing/intensity of
convection, and the positioning of the sfc warm front. 12z CAMs
did come into better agreement on another subtle impulse
invigorating a cluster of convection along the frontal slope
later Sunday night over mainly northern zones, possibly sinking
south over the area through mid morning Monday. Flooding appears
to be the primary risk, though a low end wind threat could
emerge if a decent cold pool becomes established.

Forecast specifics become increasingly uncertain with time Monday
through Wednesday as where the next several convective clusters
track will depend on how the previous convective cycle played out,
and how any cold pools modulate where mesoscale composite outflow
boundaries set up for renewed diurnally driven thunderstorm
activity. It is worth noting that shear/instability/moisture
profiles will support the potential for severe thunderstorms and
flooding, particularly late Monday afternoon into Monday night.
Otherwise, given the low confidence, held close to NBM guidance for
PoPs and temps in what could be a fairly active period.

Models overall continue to support some suppression by Thursday and
Friday as troughing into the Northeast US likely forces the
boundary and associated humidity/moisture off to the south.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1253 AM EDT Sun Aug 9 2026

Pockets of stratus and fog are noted on RGB satellite over
Central Indiana and northern Ohio. Dew point depressions are
variable over the area and there are still enough indications
to suggest BR/FG this morning.

A developing thunderstorm complex over the ND- SD state line
will be worth watching this morning. Embedded within west-
northwest flow, this feature is anticipated to track into
Illinois and Indiana by the afternoon. Significant timing and
strength differences remain in the high resolution forecast
guidance, thus, confidence is low in how this evolves. However,
there is enough agreement to suggest the inherited PROB30 at
KSBN for TSRA is worth keeping and slowing down by 2 hours. This
first round of TSRA still appears to miss KFWA due to the
anticipated weakening trend.

A second complex of storms is in the cards early Monday
morning, but given low confidence in the first round, how
anything evolves around 04z Monday is questionable.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Steinwedel
AVIATION...Brown