724
FXUS63 KIND 280502
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1202 AM EST Sun Dec 28 2025

.KEY MESSAGES...

- Above normal temperatures continue through the weekend with near
  record highs Sunday

- Strong front with wind gusts possibly over 50 mph Sunday night
  into Monday morning along with a few thunderstorms

- Rapidly falling temperatures into the 20s on Monday with wind
  chill values near zero at times

- Much colder weather through next week with highs at or below
  freezing

&&

.FORECAST UPDATE...
Issued at 921 PM EST Sat Dec 27 2025

Slight changes to the overnight forecast, mostly surrounding fog
coverage and potential for isolated thunder over far NE central
Indiana. The frontal boundary is currently over far SW central
Indiana as of 02Z, and will push northward quickly overnight. This
will put NE central Indiana in an advantageous set up for patchy
dense fog to develop over the next several hours. This said,
easterly winds north of the front will increase as the low to the
northwest deepens, likely mixing out some of this fog later tonight
into the morning hours. Additional fog is possible over NW central
Indiana where calming winds on a stalled portion of the front is
possible between 08-13Z.

As mentioned, there could be isolated thunder potential over NE
Indiana tonight due to increasing elevated instability. This likely
will remain north of central Indiana, but an isolated rumble of
thunder cant be ruled out over places like Muncie and Anderson.

&&

.SHORT TERM (This evening through Sunday Night)...
Issued at 108 PM EST Sat Dec 27 2025

Rest of Today and Tonight.

The primary focus for the short term period will be tracking a
potent system Sunday into Sunday night which will bring showers and
storms, strong gradient winds, and a 40+ degree temperature drop
over 6 to 9 hours. Through the rest of today, stubborn low-level
moisture will remain trapped beneath a persistent subsidence
inversion which will help to keep widespread cloud clover locked in
place. Satellite imagery shows a broad expanse of low stratus across
central Indiana, though a high-pressure system passing to our north
is beginning to introduce some slightly drier air aloft . This
should allow the inversion to weaken enough to permit some scattered
breaks in the cloud deck by late afternoon or evening. However, this
recovery will be brief as a deep upper-level low organizes over the
Northern Plains which will help to bring increasing strong warm air
advection to the area. This moisture surge will help to bring a
return to nearly saturated temperatures in the low levels and could
bring some drizzle or light fog by daybreak Sunday.

Sunday and Sunday Night.

Sunday will feature a significant synoptic transition as central
Indiana enters the warm sector of a rapidly deepening mid-latitude
cyclone. A powerful LLJ of 45 to 55 knots will pump an anomalously
moist airmass into the region, with moisture content values
approaching 1.25 inches. Temperatures will soar into the mid-to-
upper 60s with these values at or above records. The forecast high
for Indianapolis is currently 68 which is 3 degrees above the record
set in 1984. While there may be some daytime precipitation,
especially in the northwest ahead of the arrival of better forcing,
much of the precipitation looks to be at or after sunset. The
overall threat for organized severe weather remains low with
extensive cloud cover and poor lapse rates helping to limit surface-
based instability and keeping much of the instability elevated. That
being said, a line of showers and storms looks increasingly likely
which could help to mix down some of the jet level winds and bring a
few thunderstorm wind gusts of 50-60 mph. Total QPF with the event
will range from around 0.25" to 0.5" in the south to around 0.5" to
0.75" in the north.

Outside of storms, strong gradient winds will also occasionally mix
down with gusts of 35 to 45 mph. Confidence in the strongest winds
will be across the northeastern counties where the LLJ will be
maximized. A Wind Advisory may be needed, but with uncertainty as to
the extent of 45+ mph winds will hold off at this time.

After the frontal passage another window for impacts arrives late
Sunday night. A sharp non-diurnal temperature curve will see values
crash from the 60s into the 20s in around six hours. This presents a
risk for a flash freeze. While strong post-frontal winds will help
evaporate some surface moisture, any residual standing water on
untreated surfaces, particularly bridges and overpasses, will likely
freeze rapidly before it can dry along with areas where water had
ponded earlier in the night. There also may be a brief period of
snow on the backend of the system as temperatures fall, but this
increasingly looks brief with only very minor snow accumulations.

&&

.LONG TERM (Monday through Saturday)...
Issued at 108 PM EST Sat Dec 27 2025

Monday Through Tuesday.

Monday will be a day of transition into a more traditional winter
pattern. Central Indiana will reside firmly within a cold air
advection regime as the aforementioned surface low departs toward
the Great Lakes. Tight pressure gradients will maintain blustery
northwest winds with gusts continuing to reach 40 mph through the
morning. When combined with ambient temperatures struggling to reach
the mid-20s, wind chill values will likely drop to near or slightly
below zero. Within the cyclonic flow on the backside of the system,
wrap-around moisture will interact with the arrival of the cold air
to produce scattered snow showers and flurries. The best chances for
minor accumulations will be focused north of the Interstate 70
corridor, where deeper moisture and better lift are expected.

Wednesday Through Saturday.

The middle of the week features a period of relative quiet as a
large polar high-pressure system slides across the Midwest. This
will keep temperatures well below seasonal averages on Wednesday,
though the airmass will be significantly drier, leading to more
sunshine. The main concern for midweek will be the potential for
some lake-effect cloudiness or a stray flurry to drift into our
northernmost counties, though the fetch across Lake Michigan appears
unfavorable for any significant inland penetration.

Looking toward the end of the year, New Years Eve is shaping up to
be frigid but dry. Clear skies and light winds associated with the
center of the high pressure will facilitate efficient radiational
cooling, likely dropping overnight lows into the lower teens for the
midnight celebrations. A weak clipper-like system may approach the
region by Friday or Saturday, potentially bringing a return of light
wintry precipitation. However, there is significant ensemble
divergence regarding the timing and strength of this system, so for
now, the forecast reflects only low-end chances for light snow or
rain to kick off the first weekend of 2026.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1202 AM EST Sun Dec 28 2025

Impacts:

- Low stratus at IFR/MVFR levels through late day
- A few light showers in the predawn hours then rain returning late
  day
- A narrow axis of heavier rain and thunder with wind gusts
  near 40kts expected early Sunday evening with the cold front
- Southwest winds gusts peaking at 25-30kts this afternoon, veering
  to westerly tonight and increasing to 40kts

Discussion:

Low stratus continued across the region early this morning as a warm
front lifts north through southern Indiana. Winds north of the front
are E/SE but will veer to southerly once the front lifts north over
the next few hours. A few light showers are possible through
daybreak.

As the front shifts north of the terminals after daybreak...
southwest winds will become gusty with ceilings remaining at or
below 1500ft. Other than lingering showers at KLAF through mid
morning...much of today will be dry. A powerful cold front will
arrive early this evening with a narrow convective line impacting
the terminals between 23Z and 01Z. Along the line...visibilities
will drop to a mile with the potential for winds to gust up to 40kts
if not a bit higher. Rain will quickly shift east with the cold
front this evening as winds veer to westerly with frequent gusts at
30-40kts continuing.

&&

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

&&

$$

UPDATE...Updike
SHORT TERM...White
LONG TERM...White
AVIATION...Ryan