923
FXUS63 KIWX 140552
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
152 AM EDT Tue Oct 14 2025

.KEY MESSAGES...

- Areas of fog possible again tonight, especially east of I-69.

- Near to above normal temperatures through the weekend with
  highs in the 60s and 70s.

- Showers likely, thunderstorms possible Saturday and Sunday.

&&

.UPDATE...
Issued at 755 PM EDT Mon Oct 13 2025

A pronounced low level moisture gradient persists this evening
across the western Great Lakes. Satellite imagery/sfc obs
indicate a 5-8k ft cloud deck along this boundary from far
northwest Indiana into extreme western Lower Michigan. Some
amplification of Mid MS Rvr Valley low/mid level ridging will
allow for some increase in low level north-northwest flow which
should allow this theta-e gradient and associated cloud deck to
make a little eastward progress tonight. Best chance of fog
development once again appears to be for areas east of I-69
corridor which should have less cloud cover for much of tonight.
Near sfc/sfc dew points and cross over values are a bit lower in
comparison to yesterday, but weak northeast flow off Lake Erie
could promote some greater fog potential across NW Ohio and
into far NE Indiana. Greatest potential of dense fog appears to
be across NW Ohio early Tuesday AM, but at least patchy dense
fog potential does appear to be in place across far NE Indiana.

&&

.DISCUSSION...
Issued at 140 PM EDT Mon Oct 13 2025

Showers over northeast IL and WI were weakening and are not
expected to reach the forecast area. Light east flow should
prevail over most areas tonight with a good chance for ground
fog redeveloping east of I-69. Have added patchy fog in this
area for late tonight and early Tuesday. Otherwise, an upper
level ridge should build east help keep high temperatures close
to 15 degrees above normal including the mid to upper 70s into
Friday as as a large positive height anomaly prevails from the
Ohio River to Hudson Bay. Anomalously large diurnal temperature
ranges should accompany this pattern through Friday given the
antecedently dry ground conditions and dry air over the region
with dew points near 50 degrees. Diurnal ranges may exceed 30
degrees until the ridge pattern breaks down late in the week.
Rain is likely over the weekend along with the chance for
thunderstorms. Severe weather is not expected. WPC rainfall for
the forecast area is generally around an inch for the 7 days.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 142 AM EDT Tue Oct 14 2025

Predominantly VFR conditions expected at the TAF Sites, with
KFWA potentially dropping to MVFR between 9-13z. It`s possible
KSBN drops to high end MVFR once clouds clear towards morning,
but initial cloud cover may limit radiational cooling. Dewpoints
are much lower in the west initially as well--it`s unclear how
far the moisture off the lower lakes advects in. Left out of TAF
given low confidence.

KFWA may drop to MVFR between 9-13z, though much of the
guidance that brings visibility down have greatly underestimated
the current cloud cover so I`m skeptical. If we see flow off
the lower lakes like last night we may have a chance for fog
below MVFR, especially if it times with clearing cloud cover.
Otherwise, radiational cooling will be limited.

Otherwise, we could get a few showers or sprinkles at KSBN just
beyond the TAF period tomorrow night. Light and variable winds
will strengthen out of the N-NE through the period.


&&

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

&&

$$

UPDATE...Marsili
DISCUSSION...Skipper
AVIATION...Marsili