246
FXUS63 KIND 061149
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
649 AM EST Sat Dec 6 2025

.KEY MESSAGES...

- Mostly cloudy and dry today, low chance for flurries or patchy
  drizzle this morning across north-central IN

- Chances for snow late tonight and Sunday over northern areas with
  minor accumulations, predominately rain across the south

- Additional rain chances are expected Tuesday night through
  Wednesday

&&

.SHORT TERM (Today and tonight)...
Issued at 302 AM EST Sat Dec 6 2025

Current satellite imagery shows mid-level clouds streaming into the
area. These clouds are associated with an approaching subtle wave
aloft which is expected to continue increasing clouds through the
morning. Greater cloud cover has limited diurnal cooling. Current
temperatures generally range from the upper 20s to low 30s with only
gradual cooling anticipated over the next several hours.

Mostly quiet weather conditions are expected across central Indiana
today. The aforementioned subtle upper wave and a weak frontal
boundary moving through today will promote mostly cloudy conditions
today, but limited moisture return and forcing should prevent any
measurable precipitation. Forecast soundings do depict a shallow
saturated layer near the surface and marginal forcing for ascent
though which may support some flurries or patchy drizzle. The
the potential appears low given the shallow depth of low-level
moisture. Clouds will limit daytime heating today. Look for highs
generally in the 30s. Far southwestern portions of the area may
reach the upper 30s to possibly even low 40s as some drier air
could help provide breaks in the clouds today.

A stronger system will approach central Indiana tonight bringing the
chance for advection fog and precipitation towards daybreak Sunday.
Expect increasing warm air advection through the overnight period.
While snowpack has greatly decreased across the area, a sufficient
frost depth remains which could support advection fog. Light
precipitation is also expected to begin very late tonight and towards
daybreak with increasing dynamics from the approaching system and
deeper moisture moving in.

Measurable precipitation should mostly be confined to
north/northwest portions of central IN where forcing is strongest.
Thermal profiles support mostly snow in these area. Further south,
weaker forcing and a more shallow saturated layer suggest
predominately freezing drizzle or drizzle is possible. Little to no
impact is expected from any freezing drizzle since surface
temperatures are marginal and will be warming up gradually
overnight.

&&

.LONG TERM (Sunday through Friday)...
Issued at 302 AM EST Sat Dec 6 2025

The synoptic pattern in the long term has remaining consistent with
strong ridging over the eastern Pacific and a robust subtropical jet
over the SE CONUS. This set up typically leads to quickly developing
shortwaves in the divergent region of supergeostrophic jet streaks
which will likely lead to a succession of wave passages across the
Great Lakes region Saturday night through Wednesday. Past Wednesday,
a more amplified western ridge and East Coast trough will likely
lead to surges of cold air later in the week, but with increasing
uncertainty on the location of any low level disturbances.

The initial wave is expected to reach central Indiana late Saturday
night into Sunday morning. This wave will begin to weaken some as it
encounters upper level convergence near the aforementioned
subtropical jet, but will still have enough lift for widespread
precipitation across Indiana; albeit lighter overall QPF than areas
upstream. There are two uncertainties with this initial wave, the
first being a low level dry column of air, that may remove some ice
nuclei over southern Indiana Sunday morning. In return, this would
favor freezing drizzle for a brief period before greater saturation
and a transition back to snow or a rain/snow mix. This leads into
the second uncertainty, the location of the rain/snow transition
line. A modest baroclinic zone resides over the region leading to an
isothermal layer that is near the freezing point. This should lead
to an initial period of snow Sunday morning, but as daytime heating
and greater WAA occurs, a transition to rain. Trends have been
towards a slightly warmer warm sector, and a sharper cutoff in QPF
across the state. This is currently resulting in potential snow fall
totals ranging from T to 1 inch Sunday morning into the afternoon
along and north of I-70.

The mid week clippers are expected to pass to the north with 80-90%
of the ensemble solutions favoring this northern track. This
northern track would put central Indiana mostly in the "warm"
sector, keeping any precipitation during the day on Tuesday and
Wednesday as rain. That said, strong CAA and steepening surface
lapse rates Wednesday night could lead to scattered snow showers.
Some ensemble members are introducing a third wave late Thursday and
Thursday night, but there is still very high uncertainty on how this
wave will strengthen and move. For now chance PoPs have been added to
signify the potential for snowfall.

Temperatures: Each of these clippers will have a positive tilt but
should have enough frontogenetic forcing along the baroclinic zone
for modest temperature swings as they pass. This should lead to
pendulum of highs in the in low to upper 30s Sunday, Tuesday and
Wednesday; Whereas highs are likely to remain below freezing Monday,
Thursday and Friday in the wakes of these clippers. During the
colder stretches of Monday, Thursday, and Friday, lows in the single
digits along with a light breeze will likely lead to near zero wind
chills each morning.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 649 AM EST Sat Dec 6 2025

Impacts:

- MVFR Cigs expected to become IFR later this morning near IND/LAF.

- Ceilings improving this afternoon and evening near HUF/BMG,
  possibly improving near IND/LAF briefly

- Widespread MVFR cigs return tonight with IFR or worse conditions
  expected late tonight into Sunday morning

Discussion:

MVFR cigs have arrived across the area. IFR conditions are possible
later this morning, primarily near LAF/IND. Cigs will generally
remain IFR or MVFR through much of the day for these two sites while
BMG/HUF may improve to VFR during the afternoon. Widespread MVFR
cigs return tonight with IFR or worse conditions possible at a few
sites late tonight into Sunday morning.

Light snow is possible near LAF late tonight with the potential for
visibility reductions. Further south, reduced visibilities are
possible from fog or light drizzle late tonight. Winds will shift
from southwesterly to westerly later this morning before backing to
more south-southeasterly tonight.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...Melo
LONG TERM...Updike
AVIATION...Melo