986 
FXUS63 KIND 210002
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
702 PM EST Thu Nov 20 2025

.KEY MESSAGES...

- Fog development expected again tonight; greatest coverage across 
  the north where there is increasing potential for dense fog

- Drizzle possible at times overnight with increasing coverage of 
  showers late tonight into Friday

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

&&

.SHORT TERM (This evening through Friday)...
Issued at 249 PM EST Thu Nov 20 2025

Continued dreary conditions can be expected through the period as a 
persistent subsidence inversion aloft and warm air advection beneath 
it allows a low-level stratus deck to remain in place. Latest 
observations show ceilings and visibilities have improved gradually 
through the day as temperatures have slowly warmed. Unfortunately, 
this improvement will only be short-lived as ceilings and 
visibilities drop again overnight. 

Latest guidance has trended drier overnight especially across the 
northern half of the area. Forecast soundings show the subsidence 
inversion strengthening over the north slightly with winds becoming 
very light or even calm at times. This and very small dewpoint 
depressions will quickly promote fog development into the overnight, 
potentially dense. Patchy drizzle is also possible thanks to 
marginal forcing. Guidance shows subsidence slowly increasing aloft 
overnight across the south as well. However, greater PBL moisture 
and slightly stronger forcing supports better chances for drizzle 
and the development of light showers. The higher chances for light 
precipitation over southern counties leads to lower confidence in 
coverage or duration of fog overnight. 

Model guidance depicts the aforementioned subsidence inversion 
weakening with increasing isentropic ascent during the day Friday. 
This will lead to greater coverage of showers as the day goes on. 
Showers should help clear out fog through the morning. Cannot rule 
out fog lingering through midday across the north if showers move in 
later than expected. Blended guidance has been far too warm with the 
stratus deck overhead which has limited the diurnal temperature 
swing significantly. High temperatures today and tomorrow were 
trended lower than the NBM. Look for lows to generally range from 
the mid 40s to near 50F tonight while highs Friday mostly remain in 
the low 50s.

&&

.LONG TERM (Friday night through Thursday)...
Issued at 249 PM EST Thu Nov 20 2025

Upper-level analysis shows a progressive split flow jet pattern over 
the CONUS. Flow tends to split over the west coast before converging 
again over the Midwest. This broad upper-level convergence, in 
tandem with surface high pressure pushing southward, will lead to 
broad subsidence Friday night into Saturday. Model trends have shown 
this subsident atmosphere edging southward, and have shown less 
rainfall compared to previous runs. We will trim PoPs a bit across 
our north while maintaining likely to categorical PoPs from Indy 
southward. We lowered total expected rainfall amounts as well, 
especially further north. Further reductions may be needed.

The system responsible for Friday's rain will depart eastward on 
Saturday. Surface high pressure arrives along with a dry continental 
polar air mass from the north. With a drying trend shown in guidance 
it now appears likely that we'll finally see some sunshine beginning 
on Saturday. Clear to partly cloudy skies should then continue 
through the weekend. Larger diurnal temperature swings are expected 
due to clearing skies, with highs in the 50s/low 60s and lows in the 
30s. Patchy overnight fog is possible at times this weekend due to 
recent rainfall and ideal radiative cooling during the overnights.

Quiet weather continues into the new week, but is not expected to 
last long. A storm system, currently over southern California, looks 
to eject eastward out of the Rockies on Monday. Guidance shows this 
system remaining quite weak while potentially merging with a system 
moving eastward over the US/Canadian border. Guidances diverges at 
this point, with various models handling the potential interaction 
differently. Regardless, rain appears likely as the southern system 
moves northeastward on Tuesday. How much rainfall and exact timing 
will come down to how the interaction with the northern stream 
evolves.

A trend towards colder weather appears increasingly likely late in 
the week or next weekend. The aforementioned split flow pattern looks 
to consolidate into a single stream with broad troughing over the 
central and eastern US. Timing and magnitude of the initial push of 
cold air may again depend on the interaction of the early-week storm 
systems. A stronger resultant low may allow for a quicker/stronger 
push of cold air southward, and vice versa.

Day 8-14: Taking a peek towards the end of the month / early 
December. Ensemble guidance hints at continued troughing over the 
northern US with repeated shots of arctic air (whether these make it 
to Indiana is unknown as of now). Additionally, ensemble guidance 
hints at troughing shifting westward which may allow for a more 
active storm track over the Midwestern US.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 640 PM EST Thu Nov 20 2025

Impacts:

- Widespread IFR/LIFR conditions overnight

- Drizzle or light showers moving in tonight into Friday morning

Discussion: 

Widespread low stratus and fog continue across the area with 
IFR/LIFR conditions. Some light drizzle has been reported at times 
as well.

Drizzle or light showers will move in during the overnight hours 
with visibilities deteriorating to IFR or worse. The lowest 
visibilities are expected at KLAF and KIND with the emergence of some 
1/2-2SM MIFG.

Widespread rain will arrive tomorrow, with greatest coverage at 
KBMG. Tempo groups or shorter from groups may be more appropriate 
for KIND, KHUF and KLAF tomorrow as confidence increases in rainfall 
timing.

&&

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

$$

SHORT TERM...Melo
LONG TERM...Eckhoff
AVIATION...Updike