Lafayette, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

423
FXUS63 KIND 020539
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
139 AM EDT Thu Jul 2 2026

.KEY MESSAGES...

- Heat index values between 105 to 110 daily through Friday

- Extreme Heat Warning in effect through Friday evening

- Thunderstorm chances will increase Friday through the holiday
  weekend

&&

.DISCUSSION (Today through Wednesday)...
Issued at 138 AM EDT Thu Jul 2 2026

Overview.

An intense heat wave will peak across central Indiana through
Friday, maintaining dangerously hot and humid conditions with
afternoon heat index values pushing up to 110 degrees. The upper-
level ridge will begin to suppress southward this weekend, allowing
a transition to a more active, convective pattern with daily chances
for scattered showers and thunderstorms alongside a gradual cooling
trend into next week.

Today through Friday night.

The synoptic pattern through the end of the work week will be
characterized by the persistence of a robust, highly anomalous 594
dm sub-tropical ridge centered over the Ohio Valley. Intense large-
scale subsidence and strong mid-level thermal capping manifested by
700 mb temperatures remaining between +12C and +14C will continue to
inhibit deep vertical moist convection through Thursday and much of
Friday. A persistent low-level southwesterly wind component will
maintain a steady tap into rich Gulf moisture, anchoring surface dew
points in the mid to upper 70s across the forecast area. When
combined with strong diabatic solar heating, maximum afternoon
ambient temperatures in the low to mid 90s will yield dangerous peak
heat index values ranging from 105 to 110 degrees.

Consequently, Excessive Heat Warnings remain in effect through
Friday evening. By late Friday afternoon, subtle height falls on the
northern periphery of the retreating ridge axis, combined with
intense boundary layer destabilization, may support isolated
convective initiation along localized mesoscale boundaries, though
widespread storm development will remain heavily suppressed by the
lingering cap.

Saturday through Wednesday.

Medium-range and ensemble guidance show a transition in the upper-
level pattern beginning Saturday as the sub-tropical ridge
deamplifies and suppresses further into the Deep South. In its wake,
a progressive northwest flow regime will establish itself across the
Great Lakes and Ohio Valley. This transition will open the door for
a series of migratory mid-level shortwave troughs and embedded
convective impulses to traverse central Indiana, interacting with an
unseasonably moist and unstable airmass. Precipitable water values
hovering near or above 2.0 inches will fuel high afternoon CAPE
values each day from Saturday through Monday.

Given the lack of robust deep-layer vertical wind shear, the primary
convective mode through the weekend will favor pulse-type storms or
loosely organized multicell clusters capable of producing localized
downbursts and torrential rainfall rates. By Tuesday into Wednesday,
long-range guidance depicts a more potent northern stream shortwave
digging out of south-central Canada into the Great Lakes region,
propelling a surface cold front across the state. This boundary will
provide a focus for more organized convective development before
introducing a much cooler, drier Canadian airmass. Significant cold
air advection in the wake of the front will finally suppress
temperatures back to near or slightly below seasonal levels by the
conclusion of the forecast period.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 138 AM EDT Thu Jul 2 2026

Impacts:

- Chance of brief MVFR/IFR vsbys in patchy fog within 09Z-12Z this
morning

Discussion:

VFR conditions expected through the TAF period outside of patchy fog
from 09Z to 12Z with winds near calm and dewpoint depressions near
zero. Mostly clear skies expected through the remainder of the TAF
period after fog dissipates with diurnally driven cu looking a bit
more widespread today compared to yesterday. Winds will generally be
southerly at 7-12kts through tonight outside of the near calm winds
this morning.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 8 PM EDT Friday for INZ021-028>031-
035>049-051>057-060>065-067>072.

&&

$$

AVIATION...White
DISCUSSION...White