485
FXUS63 KIWX 311829
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
229 PM EDT Thu Jul 31 2025

.KEY MESSAGES...

- Cooler and less humid weather Friday into this weekend.

- Dangerous swim conditions are expected along the beaches of
  southeastern lake Michigan primarily in LaPorte county into
  Friday morning.

&&

.DISCUSSION...
Issued at 224 PM EDT Thu Jul 31 2025

The last edge of rainfall was sliding southeast across the forecast
area this morning spelling the return of drier air. The northerly
winds also allows for an increase in smoke from Canadian wildfires
into the area. This smoke has been reducing visibility in WI
(where the smoke was particularly thick) and MI and the HRRR
smoke model does have some near surface units of smoke. As a
result and after collaboration with neighbors, have added haze
and smoke to the grids into this evening. There is still an air
quality alert for our Michigan counties until midnight tonight.
One interesting note pointed out by the previous shift is that
the mid 50s in the forecast for lows tonight is the first time
we`ve had those temperatures since the first part of June. So
that will be welcome relief and indicates how long this higher
humidity airmass that we`ve retained has lasted: around 50 days.
The highs in the 70s and lows in the 50s continues through the
weekend before a slow warm trend occurs early next week and 80s
begin to creep in across the area. It looks like an attempt at
60 to 70 degree dew points may be made early next week.

The nearly 1030 mb high pressure system pokes into the area
beginning today and has its center move through the area Saturday
and Saturday night before departing east by Sunday morning. As a
result, drying east winds will keep the area precipitation-devoid
until at least Monday at the earliest. Some connection to a
southeasterly low level jet and better theta-e airmass coming in
from the south may help to advect better air in here to support that
precip chance as a shortwave digs across the central and southern
Plains. This does beg the question, though, about how quickly that
wall of dry air will be able to move out of the area. The ECMWF has
500 to 1000 J/kg of MUCAPE modeled for during the afternoon Monday.
So pop showers/storms may be possible with the increased dew points,
but a lack of shear may limit their severity. Given this fight over
dry and moist airmasses, it could end up just an afternoon
shower/storm chance Monday through Wednesday despite NBM PoPs.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1214 PM EDT Thu Jul 31 2025

Rapid clearing through this aftn in wake of upper disturbance
lifting out through nrn OH attm with VFR expected.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Air Quality Alert until midnight EDT /11 PM CDT/ tonight for
     INZ005-012>015-022-023-103-104-116-203-204-216.
     Beach Hazards Statement through late tonight for INZ103.
OH...None.
MI...Air Quality Alert until midnight EDT tonight for MIZ078>081-
     177-277.
MARINE...Small Craft Advisory until 5 AM EDT Friday for LMZ046.

&&

$$

DISCUSSION...Roller
AVIATION...T