Lafayette, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

182
FXUS63 KIND 171317
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
917 AM EDT Wed Jun 17 2026

.KEY MESSAGES...

- Severe weather is likely most areas today with one round of
  marginally severe storms in the afternoon and more widespread
  severe weather towards the evening. All modes of severe weather
  are possible

- Below normal temperatures will continue for much of the period

&&

.FORECAST UPDATE...
Issued at 917 AM EDT Wed Jun 17 2026

The synoptic pattern remains highly anomalous for mid-June,
characterized by a deep mid-level trough and a robust 130+ kt jet
streak translating into the southern Great Lakes. Surface analysis
reveals a deepening low to our northwest with an advancing cold
front that will serve as the primary focus for convective initiation
this evening. High-resolution guidance, including the 06Z and latest
HRRR runs, confirms a significant severe weather threat, with a
heightened concern for discrete supercellular development across
west-central Indiana with the 2nd round of storms. The environment
is undergoing a rapid, efficient moisture surge, with dew points
already rising into the low 60s towards southwestern Indiana. This
influx of high-theta-e air is expected to compensate for any
lingering morning cloud cover or convective inhibition, providing
sufficient buoyancy for surface-based convection. The 13Z Day 1
outlook expanded the Moderate risk further to the south which looks
very reasonable based on the expected location of the warm front.

Of primary meteorological concern is the highly anomalous kinematic
environment. Model soundings continue to depict elongated, highly
curved low-level hodographs with backed surface winds and nearly 70
kt flow at 1 km, creating an environment favorable for significant,
long-lived tornadoes if the cells can remain discrete. Current CAM
consensus suggests that west-central Indiana remains the primary
corridor for potential tornadogenesis, as storms here will be best
positioned to interact with maximized low-level helicity and
localized outflow boundaries before upscale growth into a more
linear mode occurs. While the potential for discrete, supercellular
cells is the immediate priority, the transition to a bowing line
segment later this evening brings an increasing risk of destructive
straight-line winds, potentially enhanced by wake low development.
Flash flooding also remains a secondary but serious hazard, as high
PWAT values and potential training of convective elements may lead
to rapid, localized rainfall accumulations. The situation remains
highly dynamic and warrants close monitoring of convective
initiation timing and the exact positioning of the surface warm
front as the afternoon progresses.

In the near term, confidence is increasing that the ongoing
convection crossing into northwestern Illinois will be able to
maintain its intensity as it moves further into Illinois and
approaches western Indiana. Timing overall remains fairly similar to
previous thoughts with convection arriving as early as 12PM, but
more likely closer to 1PM with damaging winds as the main threat.
With the strong moisture advection, even if the system holds
together better than models show, still think a higher-end severe
threat is on the table for later this evening.

&&

.DISCUSSION (Today through Tuesday)...
Issued at 253 AM EDT Wed Jun 17 2026

...SEVERE WEATHER LIKELY LATER THIS AFTERNOON INTO TONIGHT...

Early This Morning...

Patchy fog will continue to develop, mainly across areas that saw
rain on Tuesday. Fog may be locally dense.

Today and Tonight...

An anomalously strong system (with many variables exceeding
climatological maxima for mid-June) will likely bring severe weather
to central Indiana, mainly later this afternoon into the early
overnight.

An initial upper wave will develop a complex of thunderstorms across
Iowa and Illinois this morning, and this will spread east into
central Indiana this afternoon. Increasing southwest winds thanks to
a warm front moving north will bring in moisture and instability.
With strong wind fields, some severe storms may be possible with
this complex this afternoon, especially north near the surface warm
front.

The highest PoPs will be across the northern half of the area, where
better forcing will exist. The far southern forecast area may remain
dry.

The strong wind field will allow a quick recovery behind this first
complex. Dewpoints will rise into the 65-70 degree range. Aloft, the
850mb jet will increase to 50-60kt by 21Z. The strong wind fields
will continue even farther up, creating very high shear values. As
noted by the Storm Prediction Center, 0-3km shear may exceed 60kt.

Given this environment, expect supercells to develop upstream of the
forecast area mid to late afternoon, and these will move into the
area late afternoon into the evening hours. Some CAMs congeal these
into a line, but uncertainty exists on whether this will happen
given the strong shear profiles. Regardless, damaging to destructive
winds, large hail, and tornadoes (some strong) are all possible with
these storms.

Excellent moisture transport with this system will also lead to
threat of excessive rainfall and localized flash flooding.

The storms should exit the forecast area to the south in the early
overnight hours.

The wind fields will lead to near Wind Advisory criteria for much of
central Indiana this afternoon and potentially into early evening.
Wind gusts around 40 mph are likely, with some gusts near 45 mph
possible.

Highs today will range from the upper 70s in the north where clouds
and rain will be more of a factor this afternoon, to the middle 80s
south where more sunshine is expected. Lows tonight will be in the
60s.

Thursday into Saturday...

A cold front just south of the area on Thursday may allow a stray
shower to reach the extreme southern forecast area. Otherwise, high
pressure will build in and provide dry conditions for Friday and
Saturday. Some guidance does try to create some light QPF Saturday
with an upper wave, but confidence is not high enough to include.
Highs will near normal to below normal.

Sunday and Monday...

Models agree that a larger upper wave along with a surface low
pressure system will move through the area in this time frame, but
they disagree on the timing. Will keep the blended guidance`s PoPs
for now which peak around Sunday night, but confidence is lower than
normal. High temperatures will depend on the timing of the rain, but
expect near normal to below normal readings.

Tuesday and Wednesday...

Surface high pressure is expected to dominate in this period. With
continued northwest flow aloft, near normal to below normal
temperatures look to persist.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 640 AM EDT Wed Jun 17 2026

Impacts:

- Showers and thunderstorms this afternoon and then again this
  evening and overnight.

- Wind gusts over 30kt this afternoon. LLWS tonight.

Discussion:

Fog should be gone by or not long after valid time, so didn`t put
it in the TAFs.

Otherwise, expect a complex of showers and thunderstorms to move
east across most sites 18-22Z, followed by a line of convection
moving from the northwest from about 23Z-06Z. IFR and worse
conditions are possible, along with severe convection.

Outside of convection winds will increase this afternoon with gusts
over 30kt likely. These may diminish in the evening, allowing LLWS
to exist as strong winds continue aloft.


&&

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

$$

UPDATE...White
AVIATION...50
DISCUSSION...50