346
fxus63 kiwx 131834
afdiwx
area forecast discussion
national weather service northern indiana
134 pm est sat dec 13 2025
.key messages...
- a period of accumulating snow (1-3", locally higher far south)
for areas mainly along and south of us 30 in in, and areas
south of us 24 in nw oh, through the early evening.
- 1-3" of lake effect snow expected tonight into sunday morning in
northwest in and southwest mi.
- below zero wind chills tonight and sunday night, with values
of -15 to -20 south of us-30 tonight.
- warmer temperatures by tuesday and wednesday.
&&
.discussion...
issued at 133 pm est sat dec 13 2025
accumulating snow moving through the southern half of the area
this afternoon into early this evening. a mid level perturbation
and associated corridor of pacific moisture is driving this
swath of snow, with noted baroclinic enhancement within the
right entrance region of a ~140 kt upper level jet. these
features are phasing with an impressive polar vort lobe flirting
with the northern shores of lake superior. the quick clipper
movement likely holds snow totals to 1-3" for the southern half
of the forecast area, with locally 3-5" up against our bordering
counties with ind. sfc temps in the mid-upper teens will make
for slick travel into the early evening.
arctic air fully wraps in tonight into sunday with dangerous wind
chills and les in our northwest flow snow belts. strong dry
advection from the upper midwest and a low dgz favor small flake
size within the le plume despite impressive delta t magnitudes,
though there could be a period later this evening into early sunday
morning where better flake size will be possible. overall
expectations remain unchanged with snow amounts generally in the 1-
3" range in the south bend area and southwest mi. reduced
visibilities and snow covered roads will create hazardous travel
in spots. this lake plume likely keeps wind chills from
reaching advisory criteria (15 below or colder) for most
locations along and north of us 30, with areas to the south in
in experiencing wind chills as cold as -20f sunday am with no
changes to the cold weather advisory.
a warm advection regime develops sunday night and continues
through mid week as sfc high pressure settles off to the
southeast under flattening flow aloft. with that said, sub-zero
wind chills will persist into sunday night and monday morning as
the near sfc arctic wedge is slow to erode with increasing
southwest winds. probs for advisory or colder wind chills by
this time are relatively low per href/nbm probs, but any minor
adjustments to temps and winds could easier push values to -15f
or colder for a time. dry otherwise as waa induced snow likely
bypasses northeast later sun night-monday.
&&
.aviation /18z tafs through 18z sunday/...
issued at 1245 pm est sat dec 13 2025
snow has overspread much of northern indiana this afternoon,
largely in response to the activation of a mid/upper level
frontal zone by an upstream short wave. latest observational and
short range guidance trends guidance to support kfwa and points
southward for best snowfall accumulations (generally in the 1
to 3 inch range at kfwa). elevated lift and top-down saturation
appears to have favored some seeder-feeder processes at ksbn
with brief redevelopment of lake enhanced snow showers
downstream of the main synoptic system. however, it still
appears ksbn will be on the northern periphery of system snow,
with low confidence in any notable duration periods with
anything lower than mvfr vsbys. system snow will depart to the
east this evening which will be followed by quick transition
late evening/overnight to lake effect snow showers. ksbn should
see some periods of vsby restrictions tonight into early sunday.
cold temperatures in boundary layer and very shallow based dgz
should allow for small flake size that could be more efficient
vsby reducers. some lake effect snow showers are possible at
kfwa overnight for a time, but confidence is too low to include
at this time. inversion heights should sharply drop mid morning
sunday with lake effect snow showers expected to taper quickly.
&&
.iwx watches/warnings/advisories...
in...cold weather advisory from midnight tonight to 1 pm est sunday
for inz013-015-020-022>027-032>034.
winter weather advisory until 7 pm est this evening for inz020-
022-023-032>034.
oh...none.
mi...none.
marine...small craft advisory until 10 pm est sunday for lmz043-046.
&&
$$
discussion...steinwedel
aviation...marsili