971
FXUS63 KIND 061959
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
259 PM EST Sat Dec 6 2025

.KEY MESSAGES...

- Cloudy this evening

- Chances for flurries or freezing drizzle late tonight and Sunday
  morning. Minimal measurable precipitation expected.

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

&&

.SHORT TERM (This evening through Sunday)...
Issued at 258 PM EST Sat Dec 6 2025

Surface analysis early this afternoon shows a frontal boundary
across NRN Illinois and NRN MO. The front was extending from low
pressure found over South Dakota. Westerly flow was in place across
Indiana amid broad cyclonic flow. Un-organized high pressure was in
place across the deep south. GOES19 shows stratus across Indiana.
Aloft, broad and cold cyclonic flow was in place across the much of
the northern half of the country, due to deep and large low pressure
over Hudson Bay. Water vapor showed Pacific moisture flowing over
the Rockies and Plains states.

Tonight and Sunday morning...

A weak short wave within the flow aloft is expected to pass across
Indiana and the Ohio valley tonight. Forcing appears quite limited
with this feature. Meanwhile within the lower levels the weak
frontal boundary to the north is expected to sag southward across
Central Indiana as the surface low over the South Dakota approaches,
taking a south southeast trajectory. Models suggest plenty of dry
air continues to be available this evening, but as the front and low
arrive in the area overnight, forecast soundings suggest top down
saturation. However, the lower levels appear to fail to become
completely saturated. Moisture is limited as only Pacific moisture
is available due to the blocking high to the south. Thus due to the
limited forcing and moisture along with incomplete lower level
saturation, the ongoing forecast trend for some light freezing
drizzle or flurries, minimally measurable, appears on track. Best
window for this precipitation appears to be late tonight, after
08Z- 10Z through mid morning Sunday. It is during this window that
the best forcing will pass as the surface low pushes across
southern Illinois and KY.

Regarding temperatures clouds and minimal temperature advection will
allow for minimal temperature drops. Lows should fall to the upper
20s to around 30.

Sunday afternoon...

In the wake of the passed surface low and weak upper short wave
subsidence appears to begin as forecast soundings begin to trend
toward a top-down drying. Lower level moisture looks to linger
through much of the day. A strong area of high pressure over the
upper midwest will then begin to settle across Indiana on Sunday
afternoon, leading to ongoing cold air advection and cold north
winds.

Thus we should expect cloudy skies on Sunday afternoon with
temperatures mainly steady in the middle 30s. Colder lows will be
expected on Sunday night.

&&

.LONG TERM (Sunday night through Saturday)...
Issued at 258 PM EST Sat Dec 6 2025

Sunday night through Tuesday...

Broad zonal trough occupying North America...that has brought recent
light to significant snowfalls, and a couple very cold mornings for
the northern Midwest courtesy its lingering snow pack...will allow
at least a brief respite through the early workweek.  Quasi-split
upper flow facilitated by embedded, yet offset short waves
concurrently tracking over southeastern Canada and the Mid
South...will allow surface high pressure to drift east across the
Great Lakes and Midwest through Monday...this, when coupled with a
pause in upstream energy, will promote overall dry conditions
through Tuesday.  Although can not rule out very light mixed
precipitation, trending from rain to flurries, lingering Sunday
night over far southern zones.

Monday will be the visually nicer day with mostly clear skies for
most locations, albeit with temperatures climbing from the teens
into the 20s...with light breezes dropping wind chills down to
around zero north of I-70 early in the day.  Deepening low pressure
across the north-central CONUS will provide a southern Chinook
starting late Monday night, with gusts to around 20 mph only
allowing readings to fall about 10 degrees, yet producing wind
chills down into the single digits for many northern counties.

South-southwesterly wind gusts to increase to 20-30 mph Tuesday as
990 mb surface low spins into the Upper Midwest...bringing a long-
awaited return to low 40s readings for much of the local region
under considerable cloudiness.  If Indianapolis does not exceed 39
degrees through Tuesday...it will tie the second-longest November-
early December period held below 40*F (13 days, last recorded in
1903).

Tuesday night through Saturday...

Mainly light precipitation associated with the northern system`s
cold frontal passage is expected Tuesday night through at least
Wednesday with chances increasing from north to south as the
supporting vort`s tail plunges across the Midwest Wednesday.  Rain
precip type is expected for most of this lighter episode, with
mixing or changeover to light snow/flurries possible as the system
exits east. Attention should be paid to ground temperatures north of
I-70 Tuesday night into Wednesday which may be subfreezing to start
despite air temps approaching 40F.

A transition back to the colder pattern favoring snow/mixed
precipitation types will occur around the Wednesday night timeframe,
with heights dropping ahead of the next, more southern short wave,
that should strengthen while crossing the central US Thursday.  Some
model disagreement on organization/intensity of corresponding
surface low...but appears so far a good shot of light accumulating
snowfall for much of the region Thursday into Thursday night...with
rain possibly mixing over southern zones.  Both snow/mix line and
amount of precipitation may be mostly dependent on proximity of
downstream H500 trough over Quebec, whose wobbling will influence
track and tilt of the central US system.

Workweek to most likely end with a few flurries amid brisk WNW
surface flow holding readings below freezing and wind chills
between zero and 20 degrees. However, bigger story will be the
potential bitter cold to follow through the weekend...with arctic
air under 520 dm H500 low capable of producing widespread single
digits at night, mainly teens maximums....and possibly criteria
wind chill values.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1217 PM EST Sat Dec 6 2025

Impacts:

- MVFR Cigs expected to become IFR during the TAF period.

- Ceilings improving this afternoon and evening near HUF/BMG.

Discussion:

GOES19 shows stratus deck with MVFR cigs across the TAF sites.
Clearing was found over southern IL along with a pocket of clearing
over northern Indiana. These features may impact LAF...HUF and BMG
briefly late this afternoon.

A slow moving cold front will slowly push across Central Indiana
late this afternoon and evening. Time heights suggest saturation
within the lower levels overnight as the front lingers with weak and
limited forcing. This may result in some FZDZ or flurries across the
TAf sites, but the main impact will be continue MVFR to IFR cigs.

IFR cigs will continue on Sunday morning in the wake of the front as
lower level moisture lingers across Indiana.

&&

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

$$

SHORT TERM...Puma
LONG TERM...AGM
AVIATION...Puma