735
FXUS63 KIWX 171059
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
659 AM EDT Wed Jul 17 2024

.KEY MESSAGES...

-Rain showers and isolated thunderstorms are possible today,
 mainly along and south of US 24 this morning into mid
 afternoon. Heavy rain, minor flooding or ponding of water on
 the roads, and lightning are the main threats. Gusty winds are
 possible this afternoon.

-Dry and less humid conditions persist from tonight into early
 Monday, with variable cloud cover and highs in the 70s and low
 80s.

-There is a moderate swim risk on Lake Michigan beaches today
 and Thursday. Breaking waves and currents are expected.

&&

.DISCUSSION...
Issued at 425 AM EDT Wed Jul 17 2024

There could be some patchy fog this morning, with some of the sites
in northern Indiana showing 1 to 3 mile visibility. Expect we`ll see
improvement towards sunrise as we commence daytime mixing. The cloud
cover kept us somewhat limited in the amount of radiational cooling,
and I suspect they will linger just long enough to keep the fog
development from becoming more widespread. That being said, I
wouldn`t be surprised to see a few northern IN sites drop to less
than 1 mile just before sunrise. If this occurs, may end up issuing
an SPS to cover the hazard through around 9 am EDT depending on the
extent. Holding off for now.

Scattered showers and thunderstorms associated with a cold front
(sinking southeast) and a weak surface boundary developed overnight,
generating around 1-2 inches of rain in several areas (near Columbia
City, IN). There was a narrow strip of around 500-700 J/kg of CAPE
that is weakening now as the cold front continues to sink southeast,
as we`re far departed from daytime heating, and low level moisture
has begun to dwindle a bit. Expect some continued scattered to
isolated showers and maybe storms again this afternoon as we get
instability with daytime heating and a weak mid level wave moves
through, but expect this mainly along/south of US 24 once the
morning precipitation dwindles off. Greatest threat in any storms
today will be torrential rainfall and minor flooding/ponding of
water on the road. Gusty winds are also possible, but expect things
to stay below severe limits (gusts to maybe 20-40 mph with DCAPE
around 600 J/kg per the NAM).

Otherwise, expect northwest flow to become more breezy, with a few
gusts around 20-25 mph expected this afternoon. There is a moderate
swim risk on Lake Michigan for breaking waves and current activity
today, which will continue into tomorrow, especially as wave periods
lengthen to 5-6 seconds. Highs will rise into the mid-upper 70s and
low 80s. Lows tonight will be in the 50s.

High pressure will build in at the surface with mid level height
rises Thursday morning into the weekend. Despite several weak waves
moving through in the flow aloft this weekend, the ridging appears
to hold somewhat and keep us dry. The surface high will slowly
meander eastward through IN/MI/OH then wash out somewhat towards
Saturday night and Sunday, though we stay dry through at least
Monday afternoon. During this period we`ll welcome less humidity and
more agreeable temperatures-highs in the mid-upper 70s-low 80s and
lows in the upper 50s-60s.

Another trough will dive into the central CONUS for Mon afternoon-
Tuesday, drifting east through Thursday into our area. A surface low
will lift northward from near TN/KY Monday afternoon into Tuesday
morning, with WAA associated with the warm front bringing some
chances for showers and storms by Monday afternoon. The front stalls
there and provides a focus for rain and storms through Tue/Wed.
Highs will be in the 70s and low 80s.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 656 AM EDT Wed Jul 17 2024

Isolated showers are likely to persist into the morning before
ending this afternoon. Otherwise, VFR conditions will prevaill
with winds under 10 knots.

&&

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

&&

$$

DISCUSSION...MCD
AVIATION...Skipper