874
FXUS63 KIND 181500
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1000 AM EST Tue Nov 18 2025

.KEY MESSAGES...

- Occasional showers through this evening; a few thunderstorms will
  be possible, primarily across southern portions of the area. A
  stray strong storm with hail cannot be ruled out

- Areas of fog with patchy dense fog possible tonight

- Seasonable temperatures through next weekend with another round of
  rain expected Thursday into Friday

&&

.FORECAST UPDATE...
Issued at 1000 AM EST Tue Nov 18 2025

The wet and dreary forecast is playing out as expected across
Central Indiana this morning as satellite and radar show widespread
showers and thunderstorms ongoing.

A frontal boundary extends eastward through South Central Indiana
from an area of low pressure in Missouri while a strong 45 kt low
level jet advects ample moisture northward into the state. Local
soundings show a strong low level inversion in place as the LLJ
brings a warmer airmass in aloft while the denser cooler air remains
stuck at the surface. Soundings at both KIND and KSDF indicate steep
enough mid level lapse rates and sufficient shear to support
continued elevated thunderstorm activity along and south of the I-70
corridor through the rest of the morning and into the afternoon.

Satellite and radar imagery show the back edge of this first wave of
precipitation nearing the IL/IN border and quickly moving east with
a dry slot and partial clearing not far behind. While the low levels
remain very stable, still watching for the potential for additional
showers and storms to develop early this afternoon along the quasi-
stationary warm front as the area of low pressure tracks along the
Ohio River. With the low tracking east-southeast, confidence is
higher that a secondary round of convective activity will be
confined to South Central Indiana, closer to the front and warm
sector. Storms will remain elevated as the deep stable layer near the
surface remains in place across the region, keeping the threat of
strong winds fairly low. Any thunderstorm this afternoon does have
the potential to produce small hail and lightning.

Further north across Central and North Central Indiana, the stable
airmass north of the warm front should keep moisture trapped near
the surface, keeping low clouds around through tonight. While the
the heaviest precipitation will be to the south the latter half of
the day, drizzle and light rain may persist for much of Central
Indiana with temperatures stuck in the 40s.

&&

.SHORT TERM (Today and tonight)...
Issued at 302 AM EST Tue Nov 18 2025

Weak low pressure will slide east-southeastward today and tonight
from the mid Missouri Valley into the Ohio Valley, producing
plentiful opportunity for showers and perhaps a few thunderstorms,
along with cloudy and dreary conditions and a fairly strong
temperature gradient across the area as the effective warm front
nudges into southern portions of the area late.

Forecast soundings do depict some modest elevated instability that
may briefly become near surface based in the far south late in the
day. SPC has outlined a marginal risk roughly southwest of a Terre
Haute to North Vernon line, and this is not entirely unreasonable,
though most hail should likely remain small given modest instability
progs depicted.

Any lingering precipitation should clear the area relatively quickly
by the late evening tonight, leaving low clouds and potentially some
fog trapped beneath a substantial low level subsidence inversion
building into the area north of the lingering front to our south.
Given the expected rainfall and cool/stable northeasterly flow, very
low clouds and at least patchy dense fog will be on the table.

NBM appears far too aggressive with northeastward progress of the
surface warm front today and have tempered this and enhanced the
surface temperature gradient a bit as the blend tends to wash this
out at times - highs will range from the low 40s northeast to near
60 in the far southwest, with cool advection overnight bringing lows
back down into the upper 30s to mid 40s.

&&

.LONG TERM (Wednesday through Monday)...
Issued at 302 AM EST Tue Nov 18 2025

Wednesday Through Saturday.

Precipitation is expected to end by Wednesday morning outside of a
low-end chance for some lingering light rain/drizzle with widespread
cloud cover expected to persist through much of the middle of the
week. Polar air will remain locked to the north which will keep
temperatures near normal through Thursday. Focus then will shift to
a low pressure system exiting the Four Corners Region. Models
continue to hone in on this system being on the weaker end due to a
stronger low to the northeast suppressing its northeasterly push and
weakening the overall cyclogenesis within the system.

Confidence continues to increase that central Indiana will be to
the north of the warm front associated with the system which will
limit the threat for thunderstorms, but still allow for appreciable
rainfall of around a half inch through Saturday.

Sunday Through Monday.

Seasonable temperatures and quiet weather are then expected for the
remainder of the weekend into early next week with weak southerly
flow across Indiana as the jet stream remains locked to the north.
Rain chances will gradually begin to increase going further into
next week but details remain very uncertain at this time on the
development of a more significant upper level low across the
Southern states.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 603 AM EST Tue Nov 18 2025

Impacts:

- Occasional showers and possibly a few thunderstorms through this
  evening

- MVFR or worse ceilings developing and persisting much of the period

Discussion:

As low pressure continues to approach the region this morning,
showers have overspread the sites. This will continue periodically
through the day, with ceilings gradually deteriorating to MVFR where
they have not already, and continuing to deteriorate to IFR or worse
most sites late today into tonight, along with some potential for
areas of fog, perhaps dense. Dense fog will be most likely nearest
the boundary in the south.

Thunderstorms will be possible today, but given continued
uncertainty with respect to timing and location, will keep explicit
mention out.

Winds will be easterly or southeasterly much of today, gradually
shifting as the low passes late in the period to more northeasterly.
This cool, stable northeast flow will keep low clouds trapped below
an inversion, and may produce fog as well.


&&

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

$$

UPDATE...CM
SHORT TERM...Nield
LONG TERM...White
AVIATION...Nield