367
FXUS63 KIWX 222159
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
559 PM EDT Wed May 22 2024

.KEY MESSAGES...

- Cooler and less humid weather settling in through Friday.

- Shower and thunderstorm chances return Friday afternoon and
  evening with a strong storm possible west of Indiana 15/US
  131.

- Saturday into early Sunday appears to be dry with additional
  chances for showers and storms Sunday afternoon into Sunday
  night.

- Lingering showers and storms may impact activities on
  Memorial Day.

&&

.DISCUSSION...
Issued at 235 PM EDT Wed May 22 2024

Drier air continues to filter in behind a pre-frontal trough with
the main cold front working across E Illinois. These 2 features
should scour out the bulk of the low level moisture and keep stable
and quiet conditions in place through Thursday night. Slgt pops were
originally in the forecast for this evening in far SE areas to
address a weak disturbance moving through SE Missouri towards the
Ohio Valley this evening. Showers and storms are active in
eastern MO, but models seem to suggest this will weaken with NE
extent with loss of heating so consensus has been to remove any
mention.

Low pressure will track NW of our area, pushing a warm front across
the region Friday, with the potential for a few showers and storms
along it. A noticeable increase in dewpoints (low to mid 60s) will
accompany the front, setting the stage for the potential for a
greater coverage of showers and storms as we get into Friday night
as a stronger cold front sweeps through the area. While 1000 J/KG or
more of SBCAPE will exist ahead of the front, favorable shear lags
the front somewhat with the main upper level wave well NW of the
area in the Dakotas. In addition, what instability does exist
quickly wanes with loss of heating. SPC has the western portions of
the area in a Marginal risk which is fine at this point with locally
damaging winds and maybe some large hail being the main concerns.
Quick shot of drier air arrives behind the front, allowing much of
Saturday into early Sunday to be dry.

A deeper trough migrates from the Four Corners region Sat morning
northeast into the Great Lakes/Ohio Valley for Sunday. The trough
becomes negatively tilted with a closed upper low taking shape N
IL/S WI Sunday night with the sfc low tracking from Illinois
into southern MI. A stronger warm front will surge north Sunday
with EC/Canadian bringing mid to maybe upper 60 dewpoints into
the area. GFS is the odd ball with low 70 dewpoints across the
southern half of the forecast area. The proximity of these
features and potential instability by Sunday night could set the
stage for showers and storms, some of which could be strong to
severe. SPC DY5 outlook has a 15% risk south of US-24 in Indiana
with much better severe potential further south. Something we
will need to watch not only for the severe concerns, but also
the many outdoor activities over the holiday weekend. Lingering
clouds and precipitation may be around for many of the
ceremonies and parades on Memorial day.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 551 PM EDT Wed May 22 2024

Somewhat cooler and less humid air had spread over northern
Indiana at the start of the TAF period. A surface high pressure
area will help winds become light by early tonight. Winds will
remain light through Thursday with VFR conditions.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ043-
     046.

&&

$$

DISCUSSION...Skipper
AVIATION...Brown