712
FXUS63 KIND 182144
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
444 PM EST Tue Nov 18 2025

.KEY MESSAGES...

- Showers and thunderstorms continue through this evening. A few
storms may be strong with hail as the primary threat south of I-70

- Low clouds, patchy fog and drizzle overnight into tomorrow

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

&&

.MESOSCALE UPDATE...
Issued at 444 PM EST Tue Nov 18 2025

The surface boundary remains just north of the Ohio River, but strong
WAA within WSW flow has created a strong inversion around 5-7kft. In
return, there is a modest layer of elevated CAPE of around 1000-1500
J/kg, fueling our on going thunderstorms. The primary threat with
these thunderstorms remains small hail, with the freezing level at
only 10kft and strong updrafts pushing will into a highly sheared
region. Current estimated effective shear is around 35-40kt, plenty
for sustain updraft growth.

Typically, a strong 3000ft inversion would be enough to mitigate
severe wind gusts. However, dual-pol signature are identify
significant melting of hail, of which, through thermodynamically
induced cooling, could allow for a strong enough cold pool to push
through this inversion and produce isolated severe wind gusts. Hail
cores should remain below 1 inch in most storms but given a freezing
layer below 13kft, there could be a long enough exposure for smaller
hail to congeal together for some isolated severe hail as well. This
was seen in prior storms over Jackson County.

&&

.SHORT TERM (This evening through Wednesday)...
Issued at 154 PM EST Tue Nov 18 2025

Main focus in the short term period will be the stubborn low clouds
and patchy drizzle or fog overnight tonight. For information on the
thunderstorm threat this afternoon/evening, refer to the mesoscale
discussion.

For this evening and tonight, a surface low tracks eastward along
the Ohio River, keeping a very moist and stable environment across
all of Central Indiana. Local soundings today show a strong
inversion from 0.5 to 1.5 km agl which will keep the boundary layer
near saturation through the night. The best forcing for ascent and
deep moisture advection for rainfall will be east of the state
tonight as the main system all progresses eastward; however enough
moisture will be leftover in the boundary layer to support
widespread low clouds, drizzle, and patchy fog at times. Higher
confidence exists in low stratus and drizzle, while there is greater
uncertainty regarding fog development as low level winds remain
elevated and little to no clearing is expected to take place.
Although some locations across South Central Indiana may still
report patchy fog as the stable boundary layer nears saturation
through the night. Despite northeasterly flow behind the low
pressure system, there`s not much cold air advecting into the state,
so expect temperatures to remain fairly steady in the low to mid 40s
tonight.

Low clouds will likely stick around for much of the day tomorrow as
the lower sun angle this time of year usually is not strong enough
to heat the boundary layer enough to break the inversion. Keeping a
more pessimistic forecast through the day with mainly cloudy skies
and temperatures barely rising out of the mid to upper 40s. Went
well below guidance for highs, near the NBM10th percentile, as
guidance tends to have a warm bias in these types of patterns.

&&

.LONG TERM (Wednesday night through Tuesday)...
Issued at 154 PM EST Tue Nov 18 2025

Wednesday Night through Saturday...

Models suggest weak zonal flow aloft during this time with a quick
but weak moving upper disturbance passing on Thursday, while a more
organized short wave looks to arrive on Friday night and pass on
Saturday. The first system will be relatively moisture starved as
deep moisture appears unavailable and forcing is weak. Indiana will
be under the influence of weak high pressure at the surface on
Thursday, before a weak frontal boundary passes on Thursday night.
Time heights continue to show saturation in place at the surface but
not much aloft. Thus as the weak cusp passes on Thursday night, very
light rain cannot be ruled out. Confidence for rain is low but is
high for clouds.

Better chances for rain will be on Friday night as the more
organized short wave aloft arrives and passes through Saturday.
Here, models show deep moisture available. Also the lower levels
appear to be more organized as a trailing area of low pressure
becomes organized and passes across KY on Saturday. This will place
much of the southern half of Indiana in a favorable sector for wrap
around rain. Thus confidence for rain will be highest on Friday
night and into Saturday as this surface low passes.

Sunday through Tuesday...

Models suggest quick west-northwest flow in place across Indiana
during this period with little in the way of forcing passing aloft.
The quick WNW flow will keep polar air well north, and seasonal
temperatures will continue. Within the lower levels, high pressure
looks to remain across the area on Sunday, followed by a dry looking
trough on Monday, followed by yet another surface high on Tuesday.
Thus with no clear signal here for strong, developed forcing, mainly
a dry forecast will be expected.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1231 PM EST Tue Nov 18 2025

Impacts:

- Showers and few thunderstorms through this evening

- MVFR to IFR cigs and vis deteriorate even further overnight due to
low stratus, drizzle, and fog

Discussion:

Low pressure over Central Missouri tracks eastward near the Ohio
River over the next 12 to 24 hours, keeping rain and low cigs/vis
around through much of the period.

Satellite and radar imagery show the first round of precipitation
exiting to the east with additional scattered showers and
thunderstorms developing and pushing into Central Indiana along and
south of the I-70 corridor. Best chance for any TSRA will be at KHUF
and KBMG before 22z with brief periods of IFR or worse conditions
possible. Kept mention of thunder for KIND as the northern edge of
the thunderstorm threat will be right around there and confidence is
high enough based on trends today. Expect cigs and vis to bounce
between MVFR and IFR through the evening, then widespread IFR cigs
develop for the overnight hours and into tomorrow morning as
abundant moisture becomes trapped under a strong near surface
inversion. Patchy drizzle and fog persist overnight as well lowering
vis at times...confidence is low in how much vis will deteriorate
overnight as it could widely vary among TAF sites. Currently have
cigs rising to 1500 ft agl by 15z tomorrow, but confidence on that
is also low as cigs may remain below 1000 ft much of the day in this
type of pattern during the late Fall.

Southeasterly winds around 10-15 mph with periodic gusts to 20 mph
continue through the afternoon hours before becoming northeasterly
at 5-10 mph overnight.


&&

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

$$

MESOSCALE...Updike
SHORT TERM...CM
LONG TERM...Puma
AVIATION...CM