IWX issues Area Forecast Discussion (AFD) at Nov 26, 12:51 AM EST220
FXUS63 KIWX 260551
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
1251 AM EST Wed Nov 26 2025
.KEY MESSAGES...
- Strong westerLy winds will gust 40-50 mph on Wednesday. Remaining
breezy and chilly on Thanksgiving with gusts to 35 mph.
- Lake effect snow showers are likely Wednesday afternoon
through Thursday night, mainly along and north of the Indiana
Toll Road. Reduced visibilities and snow accumulations will
create difficult travel in spots.
- A period of accumulating wet snow is possible late Saturday
into Saturday night, best chances (70%) north of US 24.
Impacts to post-thanksgiving travel possible.
&&
.DISCUSSION...
Issued at 230 PM EST Tue Nov 25 2025
Surface low pressure deepens east-northeast through the northern
Great Lakes tonight into Thursday in response to a robust negatively
tilted upper level wave digging through. This will send a strong
cold front east through the local area later tonight into early
Wednesday (07-12z), accompanied by a narrow line of gusty rain
showers and rapidly falling temperatures. Pressure rises and intense
post-frontal CAA will allow winds to pick up immediately in the
morning, with a tight low level height gradient keeping westerly
winds up through the day on Wednesday. Momentum transfer progs in
model forecast soundings suggest persistent gusts in the 40-50 mph
range on Wednesday. HREF probs for 45 mph or greater or still around
30%, but did opt for a CWA-wide Wind Advisory per collaboration.
This gradient does relax into Thanksgiving, though it will be chilly
and still breezy (gusts 30-35 mph).
The lake effect snow machine will also get going in cold westerly
flow Wednesday afternoon through at least Thursday night, mainly
impacting areas along and north of the Indiana Toll Road. Lake-850
mb temps near 20C with a decent signal for omega and saturation wrt
ice to align in lower portions of the DGZ. However, westerly flow
will be strong, likely limiting parcel residence time and
organization for a higher end LES event in favored wnw flow snow
belts. There likely will be enough snow for reduced visby's and
impacts to travel however, particularly in southwest Michigan
where a Winter Weather Advisory was issued.
Attention over the weekend will then turn to the next upper level
trough to dig out into the central Plains on Saturday, then making
the turn east-northeast into the Great Lakes by Sunday. A broad area
of strong theta-e advection and isentropic lift will develop within
the a leading low level jet. This along with incoming mid level dcva
and upper diffluence allows an expansive area of precipitation to
blossom in advance of the system sfc trough and developing weak sfc
low. Ptype looks to begin as wet snow for most at some point
Saturday into Saturday evening before mixing with or changing to
rain/drizzle Sunday morning as WAA eventually overwhelms the column.
Ensemble probs from the LREF and NBM are for approximately 70% of
the members dropping 3" or more of snow (10:1 ratio) in nw IN and sw
MI, which drops to near 20% in our far southeast (Lima area).
Definitely a system to keep an eye on given the potential for post-
thanksgiving travel impacts.
&&
.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1250 AM EST Wed Nov 26 2025
A strong cold front will continue to push across northwest/north
central Indiana to begin this forecast valid period. Southwest
winds will veer to the west-southwest overnight into early
Wednesday morning as mixed layer deepens in post-frontal
environment. Surface wind gusts to 35 to 40 knots are possible
by mid-late morning and will continue through the afternoon and
evening before somewhat subsiding overnight tonight into early
Thursday morning. A brief period of improved cigs is expected
with dry slot feature for the remainder of the overnight, but
cold advection MVFR stratocu will overspread terminals during
the day with cigs of 1000-2000 ft likely. This cold air will be
accompanied by an increasing lake effect snow potential by later
this morning through tonight, with best chances along/north of
the Toll Road. This fetch will put KSBN on southern fringe of
most favored lake effect snow area with a good deal of
uncertainty in timing of lower vsby/cigs with lake effect snow
bands at KSBN. The period of potential greatest impacts at KSBN
could be this afternoon into early this evening and will carry
TEMPO IFR vsby group for KSBN. Otherwise, a band of pre-frontal
showers/drizzle will impact terminals briefly to begin the
period, but precip amounts will be light.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Wind Advisory from 7 AM EST /6 AM CST/ this morning to 7 PM
EST /6 PM CST/ this evening for INZ005>009-012>015-017-
018-020-022>027-032>034-103-104-116-203-204-216.
OH...Wind Advisory from 7 AM this morning to 7 PM EST this evening
for OHZ001-002-004-005-015-016-024-025.
MI...Wind Advisory from 7 AM this morning to 7 PM EST this evening
for MIZ078>081-177-277.
Winter Weather Advisory from 10 AM this morning to 7 AM EST
Friday for MIZ078-079-177-277.
MARINE...Gale Warning from 4 AM early this morning to 1 AM EST Friday
for LMZ043-046.
&&
$$
DISCUSSION...Steinwedel
AVIATION...Marsili
Source:
IWX issues Area Forecast Discussion (AFD) at Nov 26, 12:51 AM EST---------------
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