South Bend, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

881
FXUS63 KIWX 180921
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
421 AM EST Thu Dec 18 2025

.KEY MESSAGES...

- Briefly warmer today with scattered showers becoming more
  numerous this afternoon into early evening.

- Windy conditions are expected this afternoon into this
  evening with numerous gusts of 35 to 40 mph. The potential
  exists for gusts of 45 to 50 mph, but confidence is low at
  this time.

- A strong cold front will bring a rapid drop in temperatures
  tonight. Wet roadways could freeze as temperatures fall
  through the 20s, resulting in the potential for some travel
  issues overnight into Friday morning. Highs Friday will be in
  the 20s.

- The bulk of the period from Saturday through Christmas Eve
  will feature above normal temperatures and limited chances for
  precipitation.

&&

.DISCUSSION...
Issued at 421 AM EST Thu Dec 18 2025

Multiple challenges over the next 24 to 36 hours as a series of
fronts associated with deep low pressure passing well north of
the area bring a roller coaster of temperatures, rain changing
to snow and gusty winds.

This morning...
Temperatures are on the rise as strong WAA is underway,
courtesy of 40 to 50 kt LLJ that will only increase further
through the day. A warm front will surge north into the area
this morning and should make it to at least the US-30 corridor
this afternoon. Increasing isentropic lift ahead of the front
should aid in the development of scattered to numerous showers
over the next several hours to our west and south, moving in
towards morning. With low level moisture starting out limited,
the showers won`t produce a lot of QPF (< 0.10"). By noon
temperatures across the area will be well into the 40s with
southern areas likely flirting with 50 degree.

This afternoon into early evening...
As the warm front enters southern areas and the first of 2
strong cold fronts approach from the west, a significant uptick
on precip coverage and intensity will occur for a 2 to 4 hour
period along and behind the front with CAMS consistently
indicating a fine line of somewhat stronger convective elements
that could produce brief heavy rain. Highest pops should occur
in the 22Z Thu to 02Z Fri period. A noticeable increase in winds
and wind gusts will occur this afternoon with medium to high
confidence in frequent gusts of 35 to 40 mph. Handful of CAMs
continue to point towards the potential of 45 to possibly even
50 mph wind gusts despite a strong low level inversion (further
strengthened by the cold ground still attempting to warm). While
the threat cannot be fully dismissed, especially along the warm
front/cold front interface, consensus was to limit gusts to the
above range and monitor upstream trends. Will message concerns
in social media products and HWO. Temperatures will begin to
fall behind the first front but not drop below freezing till
after 03Z. A transition to snow will occur during the evening
hours as the colder air begins to arrive with maybe a dusting in
some areas.

Mid evening into Friday...
Second, much stronger cold front arrives a few hours behind the
first front with temperatures falling 15 to 20 degrees from mid
evening through the overnight hours. This rapid drop will cause
any lingering moisture on roads or light precip falling to
freeze, which may bring some slippery conditions. Gusty winds
will still be underway, which may help in "drying" of surfaces
to limit the icing potential. Lake effect snowshowers will
increase in coverage, but greatest lake response looks to remain
north of the area. Locations in SW Lower MI may see some
accumulations up to an inch before the flow weakens and coldest
air begins to shift away. The cold temperatures and breezy
conditions will bring a cold start to the Fri AM commute with
wind chills either side of 0 degrees.

Remainder of the forecast period...

Forecast for Fri ngt through Christmas eve left relatively
untouched given the short term concerns. One more longwave
trough will move through the northern stream. Temperatures will
warm into the 40s ahead of the system on Sat, but a brief surge
of cold air follows in its wake to drop highs into the upr 20s
to lower 30s Sunday.

From Monday on, a strong upper level ridge will set up along the
gulf states with a more zonal flow setting up which keeps any
northern stream waves well north of the area. As has been
advertised for a while, this will bring a shift to above normal
temperatures for the area which looks to last most likely into
Christmas Day.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1215 AM EST Thu Dec 18 2025

Strong low pressure system and associated cold front moves
through during the TAF period resulting in very windy
conditions and rain. At this hour, numerous observations in the
warm sector (eastern Nebraska, central Kansas) are reporting
wind gusts of 35-40 knots. Along the cold front, wind gusts of
45-55 knots (or more) are noted. High confidence in both sites
seeing at least 36-38 knot wind gusts today with an opportunity
for higher gusts immediately along the cold front.

High confidence in LLWS today amid a modest low-level inversion
and an incredible wind field. Raw model guidance depicts several
hours of 55kt wind around 2kFT; 70 kts at 4k FT.

Antecedent dry air will take some time this morning to
saturate, thus, the start time of rain and falling ceilings has
been delayed with this TAF issuance. As this storm system
quickly exits, there is strong model agreement for ceilings to
rise beyond IFR late in the TAF period.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for LMZ043-
     046.
     Gale Warning from 7 PM this evening to 7 AM EST Friday for
     LMZ043-046.

&&

$$

DISCUSSION...Fisher
AVIATION...Brown