586
FXUS63 KIWX 070924
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
424 AM EST Sun Dec 7 2025

.KEY MESSAGES...

- Snow today 3 AM EST to 1 PM EST, amounts 1 to 4 inches.

- Cold wind chills tonight and Monday night, -15F to +5F.

- Snow and rain mix Tuesday & Wednesday.

- Turning very cold late this week with highs in the teens.

&&

.DISCUSSION...
Issued at 421 AM EST Sun Dec 7 2025

Snow was just reaching the area west of Highway 31 early this
morning at 4 AM EST. Upstream visibilities were generally 3/4SM
to 2SM with locally 1/4SM +SN over the northern 1/3rd of IL.
Given the latest surface observations, INDOT data, radar
indications, observed snowfall amounts upstream, model forecast
and the latest trends, made a couple of generally minor updates
to the forecast including slightly higher snowfall amounts and a
slightly more northern track. The heaviest snow amounts will
fall north of Highway 30 and west of Highway 31. Northern
Laporte is expected to receive around 4 inches of snow. Lighter
amounts are expected east and south of this area. Have handled
this system with a Special Weather Statement.

Otherwise, much colder air will spread back into the area behind
the snow. Winds should remain under 10 mph through Monday with
wind chills falling below zero tonight and around zero Monday
night. Temperatures should recover above freezing Tuesday and
Wednesday before another surge of cold air brings wind chills as
low as -15F Friday and Saturday nights . Chances for light snow
will continue through the end of the week.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1252 AM EST Sun Dec 7 2025

Initially MVFR conditions will deteriorate to IFR/LIFR overnight
into Sunday as a weak clipper system moves through our
area/south of our area. This low will drift eastward and weaken
through Sunday. A stationary front that extends from Lake Erie
into southern Lake MI/IL/IA has brought us predominantly MVFR
ceilings and a few areas of BR reported, with generally
light/variable winds (with the exception of KSBN which is
southwest at around 8kts). The low is currently situated over MO
with warm air advection/isentropic ascent leading to areas of
mainly light to moderate snow in SW WI/NW IL/IA (sparse heavy
snow reports and couple of mixed precip reports near the
deformation zone on north/west side). Ceilings/visibility will
drop as snow moves in first at KSBN sometime between 6-9z before
progressing to KFWA closer to 10-12z. For now have the lower
visibilities at KSBN given the system is stronger initially and
the deformation zone will be over the terminal, dropping to
around 3/4SM between 10-14z. Ceilings may drop below 600 ft, but
confidence is not high enough to include at this point. KFWA
still have ceilings dropping to around 500ft 12-15z, with
visibility around 1SM as the def. band moves through-but most
models suggest it weakens. I suspect we could see a period of
visibility less than 1SM but will wait until next issuance to
provide greater details based on radar/ob trends.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory from 2 PM this afternoon to 4 AM EST
     Monday for LMZ043-046.

&&

$$

DISCUSSION...Skipper
AVIATION...MCD