206
FXUS63 KIND 202248
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
548 PM EST Sat Dec 20 2025

.KEY MESSAGES...

- Moderating pattern through the middle of next week with
  unseasonably mild conditions expected Wednesday-Friday

- Near record high temperatures in the 60s possible on Christmas Day.

&&

.SHORT TERM (This evening through Sunday)...
Issued at 207 PM EST Sat Dec 20 2025

Overall pattern through the short term will be transient with a
shift from the northwest flow, that brought the recent cold air and
snow, with high pressure progged to slide in overnight into Sunday.
Then the longwave pattern will see the large ridge across the
pacific northwest relax, which will allow the robust southwest flow
to arrive and usher in much warmer air just in time for Christmas.

Tonight... frontal boundary will be sweeping in from the northwest
and with high based clouds overhead and then some clearing on the
lee-side of the surface ridge. Winds will shift to the northwest
this evening and allow more cold air advection to flow into Central
Indiana and drop temperatures tonight into the upper teens to lower
20s.

Sunday/Sunday Night... Surface ridge will dominant the day with
light northerly flow, but with the upper level pattern still
progressive and transitioning, the surface ridge will push east by
the evening hours. This will allow surface winds to turn
southwesterly by late Sunday night. Temps will generally be in the
30s for much of the day, but then the warmth kick-in for Monday.

&&

.LONG TERM (Sunday night through Saturday)...
Issued at 207 PM EST Sat Dec 20 2025

Monday through Saturday... Upper level ridge axis will have shifted
to the east of the Ohio Valley, as the region enters into a
persistent isentropic ascent for parcels, essentially allowing for
a warmer air push lifting into the Ohio Valley for the upcoming
week. By Mon afternoon 850mb flow will have been solid from the
southwest, helping to kick-off the robust warm-air advection and
steady moisture transport with thickening clouds and some patchy
drizzle or sprinkles. Tuesday the llvl jet upstream in the plains
will be allowing continued northward push of moisture into the
region, which will inhibit any potential for nocturnal cooling and
overnight lows likely well into the 30s  to perhaps even 40 degrees
in the southern portions of the forecast area.

Christmas Eve... If anyone had desired a White Christmas, well, this
isn`t going to the the year for that. Deep longwave trough will be
digging into the Western US, which means a strong and robust
southerly flow for Ohio Valley. Ensembles have been in solid
agreement with this holiday setup, and isn`t just a one cycle or a
couple, this has been consistent for almost a week now that the
abnormally warm setup is going to coincide with Christmas. Current
indications are that 850mb thermal ridge overhead for Christmas eve
will be progged at 2 to 3 standard deviations above climo. Which may
flirt with record warm temperatures if not Christmas Eve, possibly
Christmas Day.

Christmas Day through Friday... Similar setup for Christmas Day, as
the teeth of the thermal ridge will be overhead. Current indications
are that highs for the day will be in the low to perhaps mid 60s,
and overnight lows possibly not dipping below the mid 50s. Again
this goes along with the robust 850mb southerly flow. Turning
towards Friday and Saturday the ensembles do being to diverge, with
some solutions indicating the ridging may begin to breakdown as a
potential flattening to the longwave flow into a faster zonal
setup.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 547 PM EST Sat Dec 20 2025

Impacts:

- Winds becoming W/NW early

- Near LLWS conditions this evening

Discussion:

A cold front will continue passing through the sites early in the
period, shifting winds to west and northwest. Some mid and high
level clouds will continue into the night. Sunday will just see a
few high clouds.

Stronger winds off the surface this evening will produce conditions
near low level wind shear thresholds, but believe that odds are low
enough of reaching them to leave mention out of the TAFs.

&&

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

$$

SHORT TERM...Beach
LONG TERM...Beach
AVIATION...50