621
FXUS63 KIWX 061048
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
648 AM EDT Sun Jul 6 2025

.KEY MESSAGES...

- Hot and humid today. Highs around 90 east and south of Ft Wayne
  with heat indices around 90 to the mid 90s.

- Thunderstorms will develop rapidly this afternoon over
  northwest Indiana. Heavy rainfall is likely which could lead
  to local flooding. Severe storms are not expected.

- There is a moderate swim risk for Lake Michigan beaches along
  the coast of Berrien and La Porte counties. A moderate swim
  risk means breaking waves and strong currents are expected.

&&

.DISCUSSION...
Issued at 152 AM EDT Sun Jul 6 2025

A weak cold front will move into northern Indiana this afternoon and
provide the impetus for storm development. At the onset, mid level
lapse rates will be quite stable between 5.0 and 5.5C/Km, but
precipitable water values will be anomalously high with values
around 2.0 inches. In this environment, chances for severe storms
are low, but heavy rainfall is likely which could bring local
flooding. The strongest storms should occur between 4pm EDT and 9pm
EDT.

For this upcoming week, the subtropical ridge over the
southwest CONUS will stay relatively subdued as an abundance of
energy races over the top of the ridge into the Midwest and
Upper Midwest. This pattern will help keep favorable conditions
for thunderstorms over the forecast area for the rest of the
week. While the most conducive diurnal time for thunderstorms
from about 19Z to 01Z (this diurnal time is strongly favored),
storms are also possible outside this window.

As for temperatures, a weak cold front will do little to bring
relief to the hot conditions except for being a few degrees cooler
Monday. Heat indices will be in the 90s this afternoon, but will
stay below advisory criteria. High temperatures the rest of the
week will be near normal in the 80s.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 637 AM EDT Sun Jul 6 2025

VFR conditions expected through at least 16z to 17z Sun when
chances for thunderstorms increase along and ahead of an
easterly moving cold frontal passage which will bring MVFR cigs
and MVFR/IFR vsbys in thunderstorm rains which may become
moderate to heavy at times. At this time kept MVFR conditions in
the TAFs as confidence on the exact placement and timing/occurrence
of the heavier downpours is low. Gusty winds and lightning will
be the primary threats with any storms that develop. Continued
to use the prob 30 groups to highlight the most probable time
frames. South-southwest winds through most of the period,
shifting northwesterly for KSBN after 01z Mon and westerly for
KFWA after about 06z. After 02z Mon, cigs for KSBN look to drop
into the IFR category and after 10z Mon for KFWA with the lower
dew point depressions. There is a possibility for vsbys
lowering into IFR category due to mist for both sites, however
at this time kept vsby categories MVFR as confidence in dropping
further due to mist is low at this time. Definitely will need
to watch as dew point depressions do get smaller with the still
very moist lower levels and some diurnal cooling.

&&

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

&&

$$

DISCUSSION...Skipper
AVIATION...Andersen