317
FXUS63 KIND 190524
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1224 AM EST Wed Nov 19 2025

.KEY MESSAGES...

- Low clouds, patchy fog and drizzle overnight into tomorrow

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

&&

.FORECAST UPDATE...
Issued at 956 PM EST Tue Nov 18 2025

Behind the passing wave, low stratus have moved in across the
area. Observed on satelitte is also a more stationary area of
stratus currently aiding in the formation of patchy dense fog and
drizzle across the SW third of central Indiana.

Low lying fog will likely continue throughout the night but
should remain patchy due to lack of significant diurnal cooling
beneath stratus and a weak NE wind. Patchy drizzle may also be
possible within the stratus layer be should be very light.

&&

.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 (06Z TAF Issuance)...
Issued at 1223 AM EST Wed Nov 19 2025

Impacts:

- Widespread IFR or worse conditions to persist or develop through
  the night into Wednesday morning before improving to MVFR in
  the afternoon all but BMG

Discussion:

Cool and stable northeasterly flow across the area north of an
elongated area of weak low pressure and boundary to our south will
promote continued deterioration of flight conditions overnight into
Wednesday morning. Widespread IFR with periods of LIFR or VLIFR is
expected, with improvement to low end MVFR Wednesday afternoon save
for BMG, where IFR conditions should persist much of the day if not
continue into tomorrow night.

Fluctuations are likely, particularly in visibilities, with
primarily MVFR visibilities at the TAF sites occasionally dropping
into IFR.

Winds will generally be northeasterly, becoming more easterly during
the day on Wednesday, less than 10KT throughout.

&&

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

&&

$$

UPDATE...Updike
SHORT TERM...CM
LONG TERM...Puma
AVIATION...Nield