499
FXUS63 KIND 071129
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
629 AM EST Sun Dec 7 2025

.KEY MESSAGES...

- Snow with patchy freezing drizzle and rain through this
  morning. Snow accumulation is expected to be minimal

- Additional rain chances are expected Tuesday night through
  Wednesday...with light snow possible Thursday

- Increasing confidence in widespread single digit lows with
  potentially dangerous sub-zero winds chills Friday and Saturday
  night

&&

.SHORT TERM (Today and tonight)...
Issued at 233 AM EST Sun Dec 7 2025

The synoptic pattern this weekend is highlighted by 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, the first
of which is arriving this morning and passing throughout the day.
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 precipitation over northern portions of central
Indiana.

This wave has a multitude of characteristics that is making
the forecast challenging, the first being a low level dry column of
air, that will likely remove some ice nuclei over portions of
central Indiana this morning. In return, this would favor freezing
drizzle for a brief period before greater saturation and a
transition back to snow or a freezing rain/snow mix. This leads into
the second forecast challenge, the location of the freezing
rain/snow transition line. A modest baroclinic zone resides over the
region leading to an isothermal layer that is near the freezing
point. Upstream observations are showing a narrow corridor where a
weak warm nose is allowing for some freezing rain, but the remainder
of the precipitation is falling as snow. As daytime heating and
greater WAA occurs, a transition to rain is possible, but most of
the measurable precipitation should be out of the area by 10AM
limiting any rain if it does occur

Trends have been continuing towards a sharper cutoff in QPF on the
southern edge of this system due to low level dry air, and this is
showcased in the forecast with most of central Indiana now at T to
0.1 inches for expected snowfall. In far northern regions (including
Lafayette and Kokomo) deeper saturation should allow for greater
accumulation with current expectations of 0.2-0.5 inches. Any ice
accumulation is expected to be very light, but could be enough for a
very thin glaze in isolated areas. This could create patchy slick
conditions on untreated surfaces.

The residual boundary following the shortwave passage will slowly
meander southward today. Along it, low stratus with reduced
visibilities of 2-5SM and patchy drizzle is expected. This boundary
will continue to move south until it interacts with an approaching
low level wave from the south this evening and overnight. This
should allow for some weak deformation and greater forcing over
southern Indiana late today and tonight with narrow bands of snow
likely forming. There is still a wide range in potential outcomes
with tonights snowfall, but the 00Z suite is showing greatest
confidence in T-1" of snowfall over far SE portions of central
Indiana including Greensburg and Seymour. Best chance for
accumulating snow tonight will be between 8PM and 1AM before the
forcing moves into N KY and W OH.

$$

&&

.LONG TERM (Monday through Saturday)...
Issued at 233 AM EST Sun Dec 7 2025

Monday through Tuesday...

Quiet weather conditions are expected at the beginning of the period
as surface higher settles over the region along with a colder
airmass. Single digit wind chills are expected near or north of I-70
Monday morning. The cold start along with lingering clouds early
will help keep daytime highs generally in the mid 20s to mid 30s
despite increasing sunshine in the afternoon.

Guidance depicts a weak system passing to the north of the area
Monday night into Tuesday promoting greater cloud cover.
Precipitation is not expected due to forcing remaining well to the
north and limited moisture return. Increasing warm air advection by
Monday night will start to trend temperatures warmer. Lows Monday
night are likely going to range from the mid teens to low 20s.
Strengthening southwesterly flow will help to warm temperatures into
the upper 30s to mid 40s on Tuesday. A tight pressure gradient along
with at least some diurnal mixing could promote gusts up to 30mph.

Tuesday night through Saturday...

Models suggest another shortwave quickly moves in Tuesday night into
Wednesday. Deeper moisture return and more favorable alignment of
forcing supports increasing chances for precipitation. It does
appear the strongest forcing should be to the north again resulting
in light QPF amounts. Predominately rain is expected with continued
warm air advection keeping temperatures above freezing. Snow briefly
mixing in with rain cannot be ruled out late Wednesday though as
colder air filters in behind the departing cold front. A strong
pressure gradient will likely promote breezy or windy conditions
through Wednesday.

Expect temperatures to trend colder late this week, especially
Friday into the weekend with another shot of colder air behind
another system Thursday and Thursday night. This system brings the
potential for snow Thursday and Thursday night with light
accumulations possible. Portions of south-central Indiana may see
more of a rain/snow mix depending on the strength of warm air
advection. Light snow showers or flurries could linger into Friday
as weak forcing and low-level moisture appear to remain over the
area.

Confidence is increasing in the potential for widespread single
digit temperatures with potentially dangerous sub-zero wind chills
Friday night into Saturday morning and Saturday night into Sunday
morning. Look for highs generally in the 20s Friday followed by
colder highs in the teens Saturday.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 629 AM EST Sun Dec 7 2025

Impacts:

- MVFR to IFR CIGS; LIFR within SN/DZ through 19Z
- Winds shifting to NW/N following frontal passage
- Occasional gusts to 18kt after 20Z
- Light snow possible at KBMG overnight

Discussion:

Cigs will continue to fall across the terminals through 15Z when IFR
conditions will become more frequent. Snow is likely towards LAF as
through 13Z. An extended period of IFR to LIFR is this expected at
all TAF sites with occasional DZ. 3-5SM BR is also likely during
this time. After the front passes, VSBY and CIGs should improved
some with winds shifting to the N/NNW. Winds will also strengthen
with occasional gusts to 18kt.

Additional snow may arrive at KBMG overnight with deteriorating
conditions. All other sites should transition to VFR overnight.

&&

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

$$

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