Lafayette, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

244
FXUS63 KIND 221734
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
134 PM EDT Fri May 22 2026

.KEY MESSAGES...

- Rain spreads north across much of central Indiana today with
  continued below normal temperatures. Some potential for
  localized flooding in SE portions of central Indiana this
  evening and tonight.


- Rain chances continue through the holiday weekend into next week,
  but temperatures will become above normal for much of the period.

&&

.DISCUSSION (This evening through Friday)...
Issued at 128 PM EDT Fri May 22 2026

Today and Tomorrow...

For this weekend, central Indiana will be within an active
portion of a subtropical jet streak, of which will aid in the
development of shortwaves and therefor multiple chances for
rainfall. The first of which is passing through today and tonight.
This particular shortwave is ejecting out of the Gulf with
abundant moisture throughout. The enhanced diabatic processes of
this gulf low will aid in low level pressure depletion over the
next 12-24 hours, resulting in a more mature surface low late
today and tonight.

Initial rainfall is expected to be associated with weak frontal
convergence in the 850-700mb layer as dry NE flow interacts with
very moist SE flow over the Ohio Valley. Current radar and IR
imagery showcase this well with widespread rain along the OH/IN
border quickly surging northward. This rain is expected to be in
the Indianapolis area around 2PM Friday afternoon. Consistent
light to moderate rainfall is expected to be the norm for most of
the afternoon and early evening over the SE half of cenral Indiana
with the one exception being a low chance for thermodynamically
enforced convection over far southern central Indiana. However,
late this evening and tonight, slantwise instability in the front
right quadrant of the advancing low will aid upward lift, likely
promoting a period of moderate to heavy rainfall and isolated
lightning production.

When all is said and done, total rain amounts will vary across the
region, but generally those S/E of I-69 are expected to get 0.5-1.5"
with lesser amounts to the N/W. The CSI banding potential overnight
could lead to narrow corridors of 2-3 inches, of which will create
a low end flooding threat given already saturated soils from
prior rainfall.

A quasi stationary boundary will linger north of central Indiana
following the passage of the wave. Along and south of this boundary,
there will be enough moisture and instability for isolated
convection to occur, but the only forcing will likely be
associated with microscale fluctuations and weak synoptic lift
within the entrance region of the subtropical jet. The current
expectation is for a large majority of central Indiana to remain
dry tomorrow, with a few areas seeing a brief shower or storm in
the morning to early afternoon.

Sunday...

The next shortwave will arrive from the West late Saturday night
through Sunday. Moisture with this wave passage will not be as
abundant, but with antecedent dew points already in the mid to upper
60s, there should be enough instability for convective initiation to
occur as the wave passes through. High resolution guidance is mixed
on wave timing as of 12Z Friday. Specifically for Indianapolis there
is a range from 15-18Z start time and a 20-00z end time for storm
chances. Given weak shear within the passing wave along with 500-
1000 J/kg of SBCAPE, isolated strong to severe thunderstorms can
also not be ruled out during this timeframe. After the wave passes
through Sunday late afternoon/evening modest subsidence should
quickly reduce rain chances with dry weather expected Sunday evening
and night.

Temperatures will likely be slightly warmer Sunday with weak
southerly flow returning, but will greatly depend on where
convection and related cloud cover occurs. General expectation is
for afternoon highs in the upper 70s.

Memorial Day onward...

Following Sunday`s wave passage, amplified ridging will start to
build over the Southern Appalachia to the Ohio Valley regions
decreasing upper level forcing. However, in the lower levels, a
stagnant boundary is expected to develop near the Ohio River. Weak
forcing and remnant moisture along the boundary will likely induce a
scattered showers Monday through Tuesday over this same area. Areas
to the north (a majority of central Indiana) are expected remain
dry. Temperatures look to be slightly above normal with some
influence from the ridging to the east expected.

Forecast confidence decreases significantly Wednesday onward as
ensembles introduce another wave entering the region from the
west. Generally, this will increase PoPs for Wednesday, but
specifics for this wave passage are still highly variable.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 128 PM EDT Fri May 22 2026

Impacts:

- Conditions deteriorate to IFR at most sites this afternoon
- Showers spread north this afternoon
- Wind gusts around 20kt at KLAF today

Discussion:

Moisture will continue to increase today, with gradually lowering
ceilings. As low pressure approaches from the south this afternoon,
showers will spread north across the sites. By 21Z, IFR ceilings and
showers will be common. KLAF will take longer to reach IFR and will
have the lowest chances for showers.

Isolated thunderstorms are possible this afternoon and evening, but
coverage will be too low to mention in the TAFs. Best chances for
thunder will be at KBMG. Low ceilings will persist into Saturday
morning. Winds will stay easterly throughout the evening and tonight
before quickly switching to westerly tomorrow morning.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for INZ071-072.

&&

$$

AVIATION...50/Updike
DISCUSSION...Updike