194
FXUS63 KIWX 131045
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
645 AM EDT Mon Oct 13 2025

.KEY MESSAGES...

- Areas of dense fog are expected this morning, especially along
  and east of IN-15. Visibilities of one quarter to one half
  mile in dense fog. A dense fog advisory is in effect for
  portions of the area.

- Highs in the 70s are expected into Tuesday and again Friday
  into Saturday, with more seasonable temperatures in the 60s in
  between as well as for the weekend.

- Chances for showers and possibly thunderstorms (30 to 55%)
  arrive for the weekend.


&&

.UPDATE...
Issued at 511 AM EDT Mon Oct 13 2025

Vsbys rapidly dropping in the NE third to half of the area,
warranting issuance of a Dense Fog Advisory. High clouds are
moving in from the west and north which may limit westward
extent of the fog and could erode the lower vsbys on the western
edge of the headlines (generally SR 15/US 131). Still went
ahead and included these areas. Much like yesterday, anticipate
improvement in the 13-14Z time frame, so ended the advisory at
14Z. Otherwise, no changes to the forecast.

&&

.DISCUSSION...
Issued at 252 AM EDT Mon Oct 13 2025

Weak NE flow is once again advecting in a moist, shallow marine
layer with shallow ground fog already in place in portions of NW
Ohio. Grids in decent shape with fog mention already, but will
monitor obs for possible Dense Fog Advisory. Any fog will quickly
burn off by 13-14Z as temperatures climb into the low to mid 70s as
upper level ridging takes hold for the next couple of days.

The ridge axis will flatten Tuesday night, then rebuild back to the
west of the region as a weak trough passes to our NE. A cold front
will drop into the area late Tuesday night, but majority of any
precip (which will still be light) looks to fizzle as it arrives in
our NW counties late Tuesday night, encountering a dry low level
airmass. Model blends still holding onto slgt chc to chc pops in
these area, which will be left alone for now. Temperatures will
settle back to seasonable levels in the mid 60s Wed and mid 60s NE
to low 70s SW as the heights begin to increase once again.

The ridge axis will shift overhead Friday and then east Saturday
with an increasing SW flow aloft allowing highs back into the low to
mid 70s. As this flow continues, low level moisture will begin to
increase as a longwave trough and series of waves attempt to bring
shower and thunderstorm chances back into the forecast. Model blend
introduced some low end likely pops in NW areas Sat into Sat
evening, likely keying in on the more aggressive GFS with a
stronger wave moving into the area vs majority of the trough
still to the west on the ECMWF. Although this may be overdone,
will leave it in as it is likely to keep changing in the coming
days. Additional chances for rain will linger through the end of
the period.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 629 AM EDT Mon Oct 13 2025

LIFR to VLIFR conditions at KFWA this morning, then improving to
VFR by late morning. Dense fog/VV002 developed shortly after 9z
this morning, and will linger through 14Z before improving to
IFR/MVFR. Expect increasing high clouds otherwise, with light
E-SE flow becoming variable by late afternoon into the evening.

KSBN will also begin at LIFR conditions and improve to VFR
through the afternoon. As of 1025z, KSBN dropped to 4SM/BKN002
as they are on the edge of developing lower stratus/fog as seen
on satellite. KEKM is reporting around 1/2SM and BKN002, so have
a tempo for 1/2SM BKN through 14z for now. It`s possible we see
VLIFR conditions briefly based on KPPO/KOXI/KC65 obs, but
confidence wasn`t high enough further north to go anything below
1/2SM.

There is potential for MVFR/BR conditions Tuesday morning at
both KFWA/KSBN but it won`t be until after 6z. Confidence is
low so did not include at this time.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Dense Fog Advisory until 10 AM EDT this morning for INZ005>009-
     017-018-024>027-033-034-116-216.
OH...Dense Fog Advisory until 10 AM EDT this morning for OHZ001-002-
     004-005-015-016-024-025.
MI...Dense Fog Advisory until 10 AM EDT this morning for MIZ079>081.
MARINE...None.

&&

$$

UPDATE...Fisher
DISCUSSION...Fisher
AVIATION...MCD