921
FXUS63 KIND 191136
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
636 AM EST Fri Dec 19 2025

.KEY MESSAGES...

- Slick/icy spots early this morning as temperatures drop quickly to
  well below freezing.

- Snow showers at times into the early morning hours with
  accumulations up a half inch possible.

- Wind chills near zero degrees possible this morning.

- Moderating pattern Monday through Christmas Day with well above
  normal temperatures most likely for the late week

&&

.SHORT TERM (Today and tonight)...
Issued at 319 AM EST Fri Dec 19 2025

An arctic front passed through central Indiana between 04-07z, with
a quick drop in temperatures and changeover to snow. Snow has been
fairly steady for the past hour or two with up to half an inch in
some areas. Snow should become more showery as large-scale forcing
lifts northeastward, leaving only shallow instability in its place.
A few heavier snow showers are possible but these will be widely
scattered. An additional few tenths to a half an inch could be
possible especially under one of these heavier bands. All snow
shower activity should come to an end around 12z, though stratus
could linger through most of the day.

Temperatures in the low 20s are already being reported in
northwestern portions of our area as of 07z, with teens upstream
across Illinois. Continued strong cold air advection will bring most
of central Indiana into the low 20s/teens by morning. Wind chills
near zero degrees are expected. Additionally, the combination of
rapidly cooling temperatures and snow should will lead to slick/icy
spots on area roadways. A Special Weather Statement has been issued
to address this possibility.

Winds are currently out of the west-northwest between 15-25kt
gusting to 30-40kt. A gradual shift to more westerly direction is
anticipated along with a slow decrease in speeds/gustiness. Winds
decrease more quickly after about 21z as surface ridging advances
eastward into Indiana. A period of light and variable winds is
possible by sunset, which may allow for a quick drop in temperature
early in the night. However, winds quickly reverse and become
southeasterly as surface ridging passes east by around 06z.
Southeasterly winds increase to between 10-15kt as the MSLP gradient
tightens in advance of a trough over the northern Plains. Therefore,
lows probably occur early in the night before warming through the
20s as morning approaches.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 319 AM EST Fri Dec 19 2025

The so-far early winter will continue its proactive trend...as the
long term period oversees a passive regime change into an early
January thaw.  An overall upper zonal pattern will shift from late
weekend troughiness to what should be a broad subtropical ridge
building north over much of the CONUS, and bringing anomalously mild
conditions to the local region by Christmas Day.

The short term`s arctic surface high pressure will already be
positioned along the eastern US by Saturday morning, as the next
strong surface low begins to cross Ontario.  Resultant robust
southerly wind gusts will provide moderation, with most areas
climbing 20-25 degrees, and low 50s expected along the Ohio Valley.
Weaker cold frontal zone extending south of the Ontario system will
pass Indiana late Saturday/Saturday night without precipitation...
with the subsequent polar ridge maintaining seasonably cold
overnights through the remaining weekend, and another chillier day
Sunday where 30s will be the rule despite slackening northwest
breezes and ample sunshine.

The workweek will see broad surface high pressure expand over much
of the eastern half of North America, which will most often promote
moderate southerly to southwesterly breezes over the Hoosier state.
Steady moderation is expected to bring at least low 50s to most
zones by Tuesday...perhaps 60 to the lower Wabash Valley by
Wednesday...and a current forecast of widespread low to mid-60s
across the CWA for Christmas Day.  Occasional low chances of rain
showers to accompany this trend, although location and timing to
depend on weak warm/stationary frontal boundary near the Ohio
Valley, which will in turn be influenced by progression of any
northern-stream surface ridge riding the retracted upper flow along
the Canadian border.  Low chances in any appreciable precipitation
for any single location from Monday night into the late week.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 636 AM EST Fri Dec 19 2025

Impacts:

- Snow showers through 14z, brief reductions in visibility possible.

- Gusts up to around 40kt at times this morn, gradually diminishing
  after 18z.

- MVFR ceilings persisting into the afternoon.

- Gusty SSW winds on Saturday between 25-30kt.


Discussion:

A strong arctic front passed through central Indiana last night, and
all rain has transitioned to snow. Snow showers are expected to
continue on and off through 14z, with brief reduction in visibility
possible.

MVFR stratocumulus will likely persist into the afternoon hours as
well, gradually retreating from south to north. Stratus should
completely lift northward by 03z.

West-northwesterly winds between 15-25kt gusting to 40kt are
expected this morning into the early afternoon. Winds gradually
diminish this afternoon, becoming light and variable for a time
after 00z. However, winds pick up again after about 03z from the
southeast as surface high pressure quickly moves eastward. After
sunrise Saturday, an approaching trough will allow gusty winds to
return from a south-southwesterly direction.

&&

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

$$

SHORT TERM...Eckhoff
LONG TERM...AGM
AVIATION...Eckhoff