Portage, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

354
FXUS63 KIWX 131810
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
210 PM EDT Wed Aug 13 2025

.KEY MESSAGES...

- There is a slight chance (20%) for isolated showers this afternoon.

- Less humid air moves in tonight through Friday.

- Hot and humid conditions return this weekend.

- Chances for storms (20-40%) return Sunday into early next
  week.

&&

.DISCUSSION...
Issued at 209 PM EDT Wed Aug 13 2025

There may be just enough heating for a few rogue showers (20%) this
afternoon into early this evening. The focus for vertical growth
will be near a lake breeze in the north, and near a differential
heating zone and cold front near and south of the US 24 corridor
where slightly higher instability magnitudes reside. Dry, partly
cloudy and slightly cooler/less humid otherwise into this evening.

Pleasant wx is expected into Thursday as a stable/dry airmass
settles in within the southern fringes of a low level anticyclone
drifting east through Ontario and the Great Lakes. Upper level
ridging does begin to build back in on Friday with slightly warmer
condition as low level trajectories veer more southerly in wake
of sfc high pressure.

Medium range model guidance has continued to support a return to hot
and humid conditions Saturday through Monday as the subtropical
ridge flexes east-northeast into the Ohio Valley and southern Great
Lakes. Peak PM heat indices back in the 90s appear likely in this
regime, with Sunday looking like the warmest (upper 90s to near
100F). How warm it gets will be determined by the track of
convective complexes cresting the upper ridge through the Upper
Midwest and Great Lakes during this time, with cloud debris and
composite outflow boundaries potentially resulting in slightly cooler
temps and non-zero shower/storm chances Saturday night through
Monday. The upper ridge does look to retrograde west by Tuesday or
Wednesday which would likely allow a cold front to drop through with
convection and cooler/less humid conditions.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 125 PM EDT Wed Aug 13 2025

Stratus/fog has finally lifted at both sites with drier air
slowly working in from the NW through the period. Cu will
persist through sunset at KFWA, but lake breeze may allow KSBN
to fully clear out in the next couple of hours. Regardless,
cloud bases are above 3000 ft so no concerns for any flights.

While not reflected in the TAFs, some patchy ground fog is
possible later tonight as a semi moist boundary layer remains in
place and crossover temps are exceeded. For now have left any
mention out, but at least a MVFR tempo may need to be introduced
in the roughly 9 to 13Z time frame.

&&

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

&&

$$

DISCUSSION...Steinwedel
AVIATION...Fisher