432
FXUS63 KIND 211711
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1211 PM EST Fri Nov 21 2025

.KEY MESSAGES...

- Rain will expand across the area from the southwest today

- Additional rainfall early next week with much cooler weather
  likely post-Thanksgiving

&&

.FORECAST UPDATE...
Issued at 951 AM EST Fri Nov 21 2025

Visibilities continue to slowly improve across central Indiana, with
dense fog becoming more isolated. Rain slowly moving in will also
help improve visibility from very low values. Given this, will let
the Dense Fog Advisory expire at the top of the hour (15Z).

Rain will continue to slowly move north and east today as isentropic
lift also shifts north. Adjusted PoPs based on latest trends seen on
radar, but overall the ongoing forecast looks good.

Low clouds will help keep temperatures from rising too much. Left
highs alone for now and will monitor.

&&

.SHORT TERM (Today and Tonight)...
Issued at 301 AM EST Fri Nov 21 2025

Dense fog with visibilities of 1/4-1/2SM has become prevalent across
the northern half of the forecast area early this morning as
moisture remains trapped within the near surface layer under a
shallow inversion. 07Z temperatures had moved little from readings
on Thursday in the mid and upper 40s.

The fog and low ceilings will persist as the primary concern for the
next several hours past daybreak but the approach of low pressure
currently over the central Plains will spread rain across much of
the area through tonight.

Have expanded the Dense Fog Advisory to cover the northern half of
the forecast area through 15Z based on obs and webcams. With near
calm surface winds and model soundings showing no weakening of the
shallow inversion...there is nothing available to offer a mixing
component to the near surface layer through daybreak and potentially
for a good chunk of the morning. The arrival of the broad area of
rain to our southwest currently across the Ozarks east into the
lower Ohio Valley will eventually serve as a catalyst to dissipating
the dense fog but that will take some time as gradually stronger
isentropic lift expands into the region and slowly erodes the dry
layer present in the 850-500mb layer. Rain will move into the lower
Wabash Valley over the next few hours with a slow expansion to the
northeast through the morning as that deeper isentropic lift sets
up. Heaviest rainfall will align across southern portions of the
forecast area immediately north of the warm front by this afternoon
with lighter amounts north of Interstate 70.

Rainfall rates will drop back this evening as deeper moisture shifts
east with a developing wave along the boundary that will become the
primary surface low as it transitions into the mid Atlantic region
by Saturday morning. Model soundings though maintain saturated
conditions below 700mb which combined with the trailing upper level
wave axis set to pass through prior to daybreak Saturday will
support light showers lingering through much of tonight. Light rain
will end prior to daybreak Saturday from northwest to southeast as
drier air and broad subsidence advects into the region in wake of
the upper wave. This will ultimately lead to clearing skies from the
northwest beginning predawn through daybreak Saturday and the return
of sunshine for much of the upcoming weekend.

Temps...the model blend continues to be much too optimistic on
warming for today which will be stunted substantially by the low
clouds and rain. Nudged 3-4 degrees cooler for highs ranging form
the upper 40s to mid 50s. The clearing towards daybreak Saturday
will enable lows to drop into the mid and upper 30s over the
northern half of the forecast area with 40s further south.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 301 AM EST Fri Nov 21 2025

Seasonably mild and dry weather is expected over the weekend as the
recent quasistationary front is finally moved out of the region by
the system expected to bring rain to the area today.

The next rainmaker for the area is the closed low currently over the
West Coast, which will gradually shift northeastward and may phase
with a northern stream upper level disturbance as both promote lee
cyclogenesis over the central Plains, with the resultant surface low
moving quickly into the Great Lakes early to mid next week. This
system will bring another round of rain to the area as late Monday,
with the most significant rain chances Monday night into early
Tuesday.

Depending upon the intensity of the upper low/trough, there will be
some low potential for lingering rain as late as Tuesday night into
Wednesday, but these chances are far more uncertain at this point.

What is more certain is that a fairly substantial cooldown is likely
for Thanksgiving and beyond, though the exact magnitude of the
colder conditions remains to be seen. At the moment, highs in the
30s and lows in the 20s and perhaps upper teens appear likely.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1211 PM EST Fri Nov 21 2025

Impacts:

- Poor flying conditions continue into tonight
- Some improvement possible Saturday morning, more likely
  Saturday afternoon
- Rain at times into tonight

Discussion:

Poor flying conditions will continue into tonight with rain at times
at the TAF sites. Ceilings are likely to bounce around the lower
categories, with visibility varying at times too.

Rain will diminish tonight, but clouds will take longer to exit.
Some questions remain on how fast they will clear out and when the
improvement will occur.

&&

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

$$

UPDATE...50
SHORT TERM...Ryan
LONG TERM...Nield
AVIATION...50