580
FXUS63 KIND 090150
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
850 PM EST Mon Dec 8 2025

.KEY MESSAGES...

- Increasing clouds tonight and not as cold. Warmer on Tuesday and
  Wednesday.

- Rain chances are expected Tuesday night through Wednesday,
  transitioning to snow showers at times Wednesday evening through
  Friday

- Arctic outbreak expected this weekend with low temperatures in the
  single digits and potentially dangerous sub-zero wind chills

&&

.FORECAST UPDATE...
Issued at 849 PM EST Mon Dec 8 2025

Fairly quiet night tonight for the forecast area, with gradually
shifting and increasing winds from E-SE to S-SW with gusts
increasing to near 20 mph by sunrise. These increasing winds along
with increasing cloud cover in WAA regime south of clipper system
over the Great Lakes will lead to min temps being realized between
05-08Z.

Sufficient moistening of the lower levels (020-050) will lead to
the potential for isolated snow showers moving southeast through
northern Indiana and possibly a glancing the far north part of
central Indiana after 07Z. Have added low pops (20 percent) to this
area for this time period and an updated HWO with this mention as
well.

&&

.SHORT TERM (This evening through Tuesday)...
Issued at 328 PM EST Mon Dec 8 2025

Surface analysis early this afternoon shows a broad area of high
pressure stretching from the Great Lakes across IL to OK and TX.
GOES16 shows some stratus still lingering over southern Indiana and
the Ohio River, while the Central and northern parts of Indiana were
under mainly clear skies. A few cirrus were found there due to the
quick flow aloft. Aloft, quick northwest flow was in place aloft and
a weak shortwave over EKY and OH was exiting quickly. Temperatures
have risen to the upper 20s.

Tonight...

Models suggest the large surface high pressure system to the west
will push across and east of Indiana tonight. This will allow the
mostly clear skies as seen across Indiana as well as upstream to
reside across the state through much of the evening. Overnight, warm
air advection is expected to begin and models suggest a mid level
cloud deck passing through the night. Forecast soundings show lower
levels remaining very dry and overall forcing is limited, thus
precipitation is not a concern. Thus mostly clear this evening with
increasing clouds overnight. Given the expected cloud cover and warm
air advection, lows should be slightly warmer, reaching mainly the
lower and middle 20s.

Tuesday...

Models on Tuesday continue to suggest a quick northwest flow in place
aloft, streaming from western Canada across the northern plains and
into Indiana and the Ohio Valley. Little in the way of forcing
dynamics appears present, so just some mid and high clouds passing
within the quick flow aloft are expected. Within the lower levels,
low pressure moving through the western Great lakes is expected to
provide SSW surface flow to Indiana and continued warm air advection.
Forecast soundings show dry air within the lower levels along with
saturation aloft. This will lead to just partly to mostly cloudy
skies. Given our southwest flow highs should reach into the lower
40s.

&&

.LONG TERM (Tuesday night through Monday)...
Issued at 328 PM EST Mon Dec 8 2025

The long term period will start off near normal, and feel warmer
than we have been experiencing, then quickly turn cold again with
the potential for highs in the teens this weekend. There will also
be a few chances for precipitation through the long term as a few
upper waves pass by.

Central Indiana will be on the warm side of a weak system exiting
the Great Lakes Wednesday, allowing highs in the 40s. Light
precipitation is expected with this system mainly across the NE half
of the forecast area; should fall mainly as rain, but some snow
mixing in will be possible. Winds will also likely be a factor due
to tight gradients around the surface low. At this time, sustained
winds around 20 mph and gusts in excess of 30 mph are likely, which
should start during the early morning hours Wednesday and last
through the afternoon.

Behind the initial system, temperatures will again turn colder
with the return of generally NW flow. Models show additional
passing waves for the end of the week into the weekend that each
have the potential for light snow as it doesn`t take much energy
to produce snow at colder temps. By Saturday and Sunday, highs in
the teens and lows in the single digits will be possible for parts
of the forecast area. Confidence is high in the well below normal
temperatures but just how cold it will be this weekend is still
unknown as models keep going back and forth on the spatial extent
of the surge of arctic air this weekend. It does appear that
somewhere nearby will likely be the furthest reach of the highs
being in the teens. In our favor, the snow pack will likely melt
away midweek with the warmer temperatures, so that could make it
harder for the extreme cold to be realized. Either way, apparent
temperatures this weekend will range from around -10 to near 0 so
bundle up if you must spend time outside.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 642 PM EST Mon Dec 8 2025

Impacts:

- Mixed precip possible late tonight at KLAF.

- MVFR ceilings lowering to IFR tomorrow at KLAF.

- MVFR ceilings developing elsewhere tomorrow morning.

- Gusty winds from the SW at 20-23 kts developing between 12-16Z at
  at all terminals.

 Discussion:

Ahead of a storm system moving through the Great Lakes, winds will
increase aloft late tonight. Speeds will generally be between 25-30
kts only 1kft AGL, not quite sufficient for LLWS. With the increase
in winds will come increasing warm/moist advection and increasing
clouds. Forecast soundings indicate ceilings falling to lower end
MVFR during the morning hours at all terminals with IFR conditions
expected to develop at KLAF. Despite the presence of cloud cover,
sufficient mixing of the winds is expected to develop towards the
surface during the morning hours with gusts from 20-23 kts until
late afternoon.

In addition to the increase in cloud cover, sufficient moistening
will support some scattered precip developing near KLAF, with a
rain/snow mix possible between 08-12Z. Another round of precip is
expected to develop later tomorrow evening, just in time for the
freighter push at KIND. Soundings indicated ceilings will be just
above IFR for IND at this time.


&&

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

$$

UPDATE...Crosbie
SHORT TERM...Puma
LONG TERM...KF
AVIATION...Crosbie