167
FXUS63 KIWX 170523
AFDIWX

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

.KEY MESSAGES...

- 20 to 40% chance of showers and thunderstorms tonight,
  primarily south of US 24. Confidence is low.

- 20% chance of showers on Wednesday.

-Cooler, less humid and dry through the end of the week.

&&

.DISCUSSION...
Issued at 311 PM EDT Tue Jul 16 2024

A cold front is gradually dropping south into extreme northern
Illinois as of this midday writing. Ahead of it, dew points are well
into the 70s or at least upper-60s. This, paired with temperatures
near 80 is resulting in plentiful CAPE. However, low stratus
over northwest Indiana and high clouds approaching from a MCS
across southwest Illinois is complicating our local environment.
CAMs continue to advertise scattered thunderstorms ahead of
this cold front this afternoon and even well into the overnight,
despite a cap noted on forecast soundings. Upper- level forcing
is far removed from the cold front as it drifts south such that
the cold front really is our only forcing mechanism . The cold
front thus far has struggled to produce more than a few showers
and shallow cumulus over southern Michigan and southern
Wisconsin. Overall, I`ll maintain the inherited forecast through
early tonight, thus keeping 20-40% POPs around.

Later tonight, there are indications showers and thunderstorms might
develop along an outflow boundary or MCV across my southern two rows
of counties. Confidence is low, and I have some concern this MCS
passing through southern IN could have a negative impact on our
storm chance overnight. I`ve blended my POPs as best as I could with
NWS Indy.

A large upper-level trough drops in through the Great Lakes tomorrow
presenting a low chance of showers and perhaps a thunderstorms.
This, as dew points remain somewhat elevated in the mid-60s, until
falling through the afternoon. In the days that follow, absolutely
beautiful weather (and a welcome break from very active weather) is
expected through at least Sunday, perhaps into Monday. During this
time, more sun that clouds and below-normal temperatures; highs
generally in the 70s to round out the week before gradually warming
to the low-80s for Sunday. This warming trend occurs as return flow
from the Gulf brings warm air advection and eventually the chance
for showers and storms by Tuesday and Wednesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 112 AM EDT Wed Jul 17 2024

Isolated showers had developed near a diffuse cool front along
with weak upper level support. According to the latest surface
analysis, the front had dipped just south of the Michigan line
with light winds over the entire area. Fog was developing in the
very humid airmass with Plymouth already down to 2SM. Given the
latest obs and trends, decided to go with IFR fog at SBN,
although cloud cover may limit the lower visibilities.
Otherwise, skies should gradually clear from the northwest as
drier air spreads over the area.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...Skipper