539
FXUS63 KIWX 161848
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
248 PM EDT Wed Apr 16 2025

.KEY MESSAGES...

- Trending warmer and breezy into Thursday and Friday with highs
  near 80F Friday.

- Showers and thunderstorms are likely Friday night. Some of these
  storms could be strong to severe.

- There are periodic chances for rain this weekend.

&&

.DISCUSSION...
Issued at 248 PM EDT Wed Apr 16 2025

An elongated, narrow, low level ridge from western Ontario south
through WI/IL will move east through the local area tonight with
quiet weather and light winds. Southerly winds then pick up a bit on
Thursday resulting in warmer temps. Elevated convection develops
over portions of MO/IA/western IL late tonight into Thursday morning
on the nose of developing low-mid level southwest flow. This
activity decays as it outruns more favorable convergence into a dry
airmass, though a few lingering showers/sprinkles could survive into
mainly northern/western zones late Thursday into Thursday evening
along the leading elevated theta-e gradient.

Southwest flow deepens and lifts a warm front through Friday morning
with renewed nocturnal/elevated convection possibly clipping far
northern portions of the forecast area. Becoming breezy and warm
otherwise post-frontal with an impressive EML keeping a lid on
convection on Friday. Showers and storms are still on target to
develop into Friday night as weak height falls overspread in
advance of a Hudson Bay to Four Corners upper trough, with the
associated cold front and low amplitude shortwave the forcing
mechanisms to finally break the strong capping inversion. Deep
layer shear magnitudes and the EML support a severe threat
Friday night, though unfavorable diurnal timing (stabilizing
boundary layer) and modest forcing appear to be limited factors
for a higher end event.

The aforementioned upper trough axis fractures this weekend with one
piece tracking east-northeast into the northern Great Lakes and
southeast Canada, and the leftover Four Corners wave eventually
ejecting out and sending a developing sfc low through the Midwest
Sunday-Sunday night. At the surface, an active frontal boundary will
try to settle south toward the OH River Saturday-Saturday night
before returning north with the emerging sfc low late Sunday-Sunday
night. Ample Gulf moisture into this oscillating baroclinic zone
will result in periods of rain within the frontal slope. However,
confidence in placement of the boundary and timing of embedded
southwest flow shortwaves remains low at this point given
lingering model spread. River and lowland flooding could become
a concern if wetter solutions verify. Seasonable temps and
trending drier otherwise into early next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1221 PM EDT Wed Apr 16 2025

VFR this period as sfc ridge works east across the terminals.
Briefly gusty northwest winds this afternoon will slacken and
veer southeasterly by daybreak.

&&

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

&&

$$

DISCUSSION...Steinwedel
AVIATION...T