516
FXUS63 KIND 160128
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
928 PM EDT Sun Mar 15 2026

.KEY MESSAGES...

- Showers and thunderstorms expected late today, with severe storms
  possible mainly from 7 PM to 2 AM EDT

- High Wind Warning until 8pm, then Wind Advisory from 8pm today
  to 8am Monday. Wind gusts between 50-60 mph possible today, then
  up to 45 mph overnight.

- Snow showers likely on Monday with up to an inch possible

- Much colder air early this week, wind chills near zero Tuesday
  morning

&&

.MESOSCALE UPDATE...
Issued at 928 PM EDT Sun Mar 15 2026

QLCS with a LEWP structures has recently moved into far western
portions of central Indiana. Wind gusts withing this QLCS to the
west in Illinois have measured between 44 and 51 kts at ASOS sites
just west of Indiana, although other reports of wind gusts from 60-
70 mph have been reported in central Illinois. Instability just
ahead of the line remains very marginal for a tornado threat with 0-
3KM CAPE between 25-40 J/KG. Low level shear however has recently
intensified with 0-1 KM SRH from the KIND VWP upwards of 350-400
m2/s2. Therefore an isolated tornado can not be ruled out in areas
of enhanced low level vorticity on the northern edges of any bowing
structures.

Several pronounced north-south oriented bowing structures exist
along this LEWP, with one in particular moving towards the NW
portions of central Indiana including the Lafayette and Kokomo areas
in the next hour. Given modest low level lapse rates combined with
50-60kts at 925 mb (2kft AGL), the severe threat will continue to
favor damaging wind gusts in these bowing structures within the
line.

With the line motion averaging between 35-40 kts, the expectation is
for the line and severe threat to move across the Indy Metro area
between 10 and 11 PM.

&&

.SHORT TERM (This evening through Monday)...
Issued at 310 PM EDT Sun Mar 15 2026

Surface low pressure continues to strengthen over northern Illinois
as a vort max amplifies significantly over the Great Plains. The low
will then track northeastward into the Great Lakes tonight, dragging
a strong cold front through Indiana between 00z-06z. As of 2pm,
Indiana lies firmly within the system`s warm sector. Temperatures
have surged into the 70s as strong mass response promotes continued
warm air advection. Additionally, a tightening MSLP gradient has
lead to strong gusty winds with numerous observations of gusts
between 50 to 60 mph. A High Wind Warning is in effect until 8pm,
with a Wind Advisory from 8pm today to 8am Monday.

Turning our attention to the system`s cold front, this feature will
act as a focal point for thunderstorm initiation this afternoon over
Illinois. Moisture advection ahead of the front is modest, with dew
points currently into the mid 40s to low 50s. High-resolution
guidance suggests a last-minute surge of slightly higher moisture
content immediately ahead of the front, which may impact severe
weather potential this evening.

TONIGHT`S SEVERE WEATHER THREAT

As mentioned above, tonight`s threat depends on available moisture
and therefore low-level instability. First, we`ll discuss the
available dynamics, which certainly are not lacking. A strong low-
level jet from the south between 50-70kt (925mb-850mb layer) is
expected to develop this evening. This will result in highly
elongated and curved hodographs, signifying abundant speed and
directional shear. ACARS soundings show a deep elevated mixed layer
from 850mb to 650mb, which will act to mitigate open warm sector
convection. As such, forcing looks to be confined to the front
itself. With a largely southwesterly shear profile, a nort-south
oriented boundary, and a focused region of forcing...a linear mode
is preferred for tonight`s convection.

Regarding hazards, the linear convective mode combined with the
potency of the low-level jet will favor severe (60-70mph) to
significantly severe (70-80mph) wind gusts as the primary threat.
However, with such a strongly sheared low-level environment,
indicated by the long curved hodographs mentioned above, a QLCS
tornado threat is also present. This threat is contingent on near-
surface moisture/instability. Greater moisture and near surface
lapse rates, and thus lower LCLs would increase the QLCS tornado
threat with the inverse also true. QLCS spin up potential should be
maximized in line segments that become perpendicular to the
effective shear vector within the lowest kilometer of the
atmosphere. This would allow for greater rear inflow jet (RIJ) surge
potential and vertical shearing vorticity that could then be
stretched by updrafts.

SNOWFALL POTENTIAL

Temperatures fall quickly behind the front, which will pass through
the area between 00-09z. By 12z Monday, most of the region likely
falls to around freezing with continued strong cold advection
causing temperatures to drop through the daylight hours Monday.
Steep lapse rates within the cold air mass will promote scattered to
numerous snow showers on Monday. Some of the snow showers could be
briefly heavy, given steep low-level lapse rates, which may reduce
visibility and lead to hazardous travel. Snowfall likely melts on
contact with roadways early but as temperatures drop through the day
some slick spots may develop. Total snowfall accumulations should be
less than an inch on average.

Additionally, continued gusty winds between 30-40 mph throughout the
day Monday combined temperatures falling through the 20s may result
in wind chills in the teens. Even colder wind chills in the single
digits are possible Tuesday night as ambient air temperatures fall
into the teens.

&&

.LONG TERM (Monday night through Sunday)...
Issued at 310 PM EDT Sun Mar 15 2026

Much of the long term will be dominated by NW flow as very strong
CAA from the earlier weak system helps induce high pressure in the
low levels and a deepening trough in the mid to upper levels. In
return, winter-like conditions are expected for Monday night and
Tuesday. The biggest forecast concern for the beginning of the long
term will be cloud coverage. The strong subsidence with an upstream
deep trough could lead to a low stratus layer, but continued surface
mixing and emergence of more broad subsidence through AVA could
produce some breaks. If overcast conditions remain Monday night,
lows will likely only fall into the mid to upper teens; however, if
there is some clearing, pockets of lows near 10 degree or even
lower in the valleys will be possible. For highs on Tuesday, typical
diurnal curves with 850mb temperatures around -15C should lead to
highs in the mid 20s.

The pattern begins to change mid week as 700-600mb wave progresses
eastward. This wave has modest CVA and WAA attached with it, but the
forcing is displaced from the low levels keeping temperatures cold
initially, This should lead to a weak snowfall event Tuesday night
into Wednesday morning with snowfall up to an inch possible over
portions of central Indiana. Following the passage of this wave, low
level high rises and temperature gains will promote a late week warm
up with high back near 60 by Thursday.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 656 PM EDT Sun Mar 15 2026

Impacts:

- South winds with gusts between 40-49kt this evening.
- Thunderstorms and MVFR conditions expected after 00Z ending by 04Z.
- Snow showers with pockets of IFR VIS possible after 08Z.
  Coverage will lower but snow showers remain possible through
  the rest of TAF period.
- Wind gusts remain over 30 kts through tomorrow.

Discussion:

Strong winds will continue through a majority of the TAF period,
generally with sustained around 20kt with gusts between 30-40kt.
There will be a brief period to begin the TAF period at KIND and
KBMG prior to a line of thunderstorms where stronger wind gusts of
up to 50kt will be possible. Scattered rain showers are also
possible in this pre-line environment. Winds will initially be
southerly before becoming westerly following line passage.

A line of thunderstorms will move west to east through the terminals
between 00Z-04Z. Convection may be severe with wind gusts up to
60kt, but in the group its left below 50kt at this time. IFR to LIFR
VIS is likely within convection. After the line passes, MVFR
ceilings will be likely with light rain showers. There will be a few
hours of no precipitation around 08-12Z, before snow showers arrive.
Greatest snow shower coverage will be in the morning and early
afternoon, but the threat will continue through 06Z. Brief IFR vis
will be possible within these snow showers.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 10 PM EDT this evening for INZ021-030-
031-037>042-046>049-054>057-062>065-070>072.

Wind Advisory until 8 AM EDT Monday for INZ021-028>031-035>049-
051>057-060>065-067>072.

&&

$$

MESOSCALE...Crosbie
SHORT TERM...Eckhoff
LONG TERM...Updike
AVIATION...Updike