682
FXUS63 KIWX 171932
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
332 PM EDT Thu Jul 17 2025

.KEY MESSAGES...

- Highs through Monday will be seasonably warm in the 80s.
  Humidity levels will vary with tonight through Friday being
  the most pleasant.

- The best chances for showers and thunderstorm should remain
  south of the area until Saturday.

- Heat and humidity return for the second half of next week
  with heat indicies possibly reaching 100 degrees or higher.

- A Beach Hazards Statement remains in effect for the beaches
  along southeastern Lake Michigan into this evening. Waves of 4
  to 6 feet will create dangerous currents.

&&

.DISCUSSION...
Issued at 303 PM EDT Thu Jul 17 2025

A nice change of pace in today`s weather with lower dew points
and cooler temperatures. Dew points tonight will be in the
upper 50s and lower 60s. The drier airmass will remain in place
through Friday. As stated in previous discussions this break
from all the heat and humidity will unfortunately be rather
short. As Saturday, we get a northward return of moisture into
the area due to a quasi-stationary boundary that will waver
north and south in the next several days. This boundary is in
place with a zonal flow aloft over the area and separates the
hot and humid airmass over the southeastern CONUS from the
cooler drier air over southern Canada.

As this boundary shifts northward over our area we will see
a slight uptick in high temperatures and increased moisture
push northward along with an increase in chances for
showers/thunderstorms. SPC has currently has a majority of our
area under a marginal severe thunderstorm risk for Saturday. WPC
also has the entire area under a slight risk for exceeding
flash flood guidance due to the moist airmass influx and slow
storm propagation. When this boundary shifts a bit back
southward Sunday into Monday we will see a reduction in both the
moisture and convective chances especially for the northern
half of the CWA. Temperatures at least remain in the lower to
mid 80s through Tuesday.

However, on Tuesday the southeastern CONUS ridge begins to push
back northward a bit more stoutly and we will see humidity
levels jump back into the mid to upper 70s across the area
Tuesday through at least Thursday, most likely longer. This will
be also accompanied by much warmer temperatures in the lower to
mid 90s from Wednesday into the end of the week. This will
amount to heat indices above 100 degrees. Will need to monitor
this in the coming days as it is likely some heat products will
become necessary.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 140 PM EDT Thu Jul 17 2025

A drier airmass has followed the front that moved through the
area earlier today. Ceilings have been improving at KFWA since
sunrise today while KSBN remains MVFR. Expect KSBN to remain
MVFR overnight before becoming sctd around 12Z and KFWA
primarily VFR. Winds will remain northwest overnight before
turning more east southeast Friday morning as surface high
pressure drifts east across the Great Lakes.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement until 1 AM CDT Friday for INZ103.
OH...None.
MI...Beach Hazards Statement until 2 AM EDT Friday for MIZ177-277.
MARINE...Small Craft Advisory until 2 AM EDT Friday for LMZ043-046.

&&

$$

DISCUSSION...Andersen
AVIATION...Frazier