434
FXUS63 KIND 121015
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
615 AM EDT Thu Mar 12 2026

.KEY MESSAGES...

- Wind Advisory on Friday from 5 AM through 8 PM for much of
  central Indiana

- Showers and storms return Sunday, low end chance for severe weather

- Much colder air early next week, lows in the teens Tuesday

&&

.SHORT TERM (Today through Friday)...
Issued at 211 AM EDT Thu Mar 12 2026

Today Through Friday.

The primary focus in the short will be the potential high wind event
late tonight into Friday. The cold front that brought convection
Wednesday has now fully exited central Indiana with strong CAA
ongoing. Upstream satellite and surface obs show a broad area of mid-
level stratus beneath a strengthening subsidence inversion. Expect
these clouds to linger through much of the night before high
pressure building in from the west allows for some clearing toward
dawn.

By late tonight, a highly dynamic northern stream shortwave will
dive out of central Canada, deepening a sub-990mb surface low as it
tracks across the northern Great Lakes. While the best moisture and
forcing remain displaced to our north, the associated pressure
gradient and low-level wind field are impressive. Forecast soundings
for Friday morning show a 55-65kt LLJ at 850mb overspread by
steepening low-level lapse rates as the diurnal cycle begins.
Efficient mixing within the post-frontal environment even in a non-
typical diurnal timeframe will likely tap into these higher momentum
winds. Deterministic GFS and some of the higher resolution models
remain in good agreement of surface gusts exceeding 40-45 mph across
much of central Indiana, with potential for localized 50+ mph gusts
across the northern tier of counties. These winds will be strongest
during the pre-dawn to morning hours with the strongest gusts coming
to an end by mid to late afternoon as the pressure gradients and
associated LLJ begin to relax.

Based on coordination with neighbors, will be issuing a Wind
Advisory for much of central Indiana with the potential that some of
the northern portion could get upgraded to a High Wind Warning.
There will be at least a low-end chance for a few rain showers late
tonight across the northern counties, but that threat is low with
the main focus being on the wind threat.

&&

.LONG TERM (Friday Night through Wednesday)...
Issued at 211 AM EDT Thu Mar 12 2026

Friday night Through Late Sunday.

Surface high pressure briefly drifts across the Ohio Valley
Saturday, providing a transient period of tranquil weather. However,
the pattern remains highly progressive as a vigorous longwave trough
begins to organize over the Rockies. There may be a few showers
Saturday night with weak isentropic lift, though the bulk of the
initial saturation will be fighting a lingering dry layer.

Focus for the next round of precipitation centers on Sunday into
early Monday. Global ensembles depict a deepening surface reflection
moving into the Great Lakes by Sunday evening, dragging a strong
cold front into the region. Guidance continues to suggest a narrow
but high-quality moisture tongue with dewpoints surging back into
the 50s or even low 60s ahead of the boundary. Given the strength of
the kinematics with 0-6km bulk shear values likely exceeding 50kts
we will need to monitor for the severe threat Sunday afternoon and
evening, provided the warm sector can sufficiently destabilize.
Surface temperatures are expected to rise well into the 60s and
potentially into the 70s, but poor lapse rates currently look to
limit instability values to around 500 J/kg. Heavy rain also remains
a concern as PWATs climb toward 1.25 inches, which is well above the
90th percentile for mid-March.

Monday Through Wednesday.

Behind this system, a significant airmass change is on the horizon.
A deep polar lobe is progged to settle over eastern Canada, opening
the gates for a modified Arctic airmass to spill into the Midwest
with a 30+ degree drop likely Sunday night. Light snow accumulations
are possible on the backend of the system Sunday night, but models
often overdo this backend snow as the lift usually exits ahead of
the arrival of colder air.

850mb temperatures are forecast to plummet to -12C to -15C by Monday
morning. This will result in high temperatures on Monday and Tuesday
struggling to reach the freezing mark, a stark contrast to the
preceding weekend. Scattered snow showers or flurries are possible
into the day on Monday in the cold advection regime, though
accumulation is not expected at this time due to the lack of deeper
moisture.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 614 AM EDT Thu Mar 12 2026

Impacts:

- A few westerly gusts to 20kts this afternoon at IND and LAF
- Wind shift to the southwest after 00Z, gusts up to 40kts after 08Z

Discussion:

VFR conditions expected through the TAF period with the last of the
low VFR clouds clearing. Mostly clear skies will continue with only
passing cirrus is expected through much of the day before higher
level clouds begin to fill back in after 00Z. Westerly winds will
occasionally gust up to 20kts at IND and LAF through the afternoon
hours. These gusts will briefly come to an end during the early
overnight tonight with winds  shifting to more southerly to
southwesterly after 00Z. Gusts upwards of 40kts will be possible at
times at IND, LAF, and HUF after 09Z into much of Friday.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 5 AM to 8 PM EDT Friday for INZ021-028>031-
035>049-051>057-060>065.

&&

$$

SHORT TERM...White
LONG TERM...White
AVIATION...White