Lafayette, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

309
FXUS63 KIND 091338
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
938 AM EDT Thu Jul 9 2026

.KEY MESSAGES...

- Strong to severe storms possible, mainly this evening into
  tonight, with damaging winds and heavy rain/localized flooding
  the primary threats

- Additional rain possible at times Friday through the weekend with
  localized flooding possible

- Warmer and drier again next week, though with more modest humidity
  than experienced the first week of the month

&&

.FORECAST UPDATE...
Issued at 938 AM EDT Thu Jul 9 2026

A few updates to the forecast this morning. The primary change was
to the ongoing cloud cover and patchy fog this morning. An area of
dense fog progressed NE into the Indianapolis Metro area this
morning, with a few pockets of less than 1/2mi visibility. This has
slowly improved over the last few hours, with some lingering low
level cloud decks still remaining. Increased heat fluxes throughout
the morning should lead to mixing in the PBL and breaks in the sky
cover by 11AM.

The other changes are related to the evening and overnight
thunderstorm chances. CAMs are widely varied on placement and timing
on convection later today leading to a lower confidence level in the
forecast. That said, the forecast currently is focused on the
presence of the nocturnal LLJ as this will be the primary convective
forcing. Conceptual models point towards some substance on the N/NE
side of this LLJ of which should lead to lower shower and storm
coverage north of I-70 this evening, with a quasi-organized line
across southern Indiana. Damaging wind gusts and the potential for
an isolated tornado are still the expected hazards from 8PM through
1AM.

&&

.DISCUSSION (Today through Wednesday)...
Issued at 257 AM EDT Thu Jul 9 2026

TODAY AND TONIGHT -

Aside from some patchy fog in the outlying and favored areas in the
light winds and high humidity airmass, expect generally quiet
weather this morning, with thunderstorm chances ramping up through
the day as the airmass destabilizes and a convectively enhanced
upper level disturbance approaches the area.

CAMs in general are depicting the evolution of one or more clusters
of storms into a linear structure late in the day into the overnight
hours tonight, with primarily a concern for a few damaging wind
gusts. Deep layer shear is modest but sufficient, and may be
enhanced slightly beyond what guidance depicts by the aforementioned
MCV. Diurnal timing is not ideal though moderately strong
instability should remain in place into the overnight hours -
approaching and possibly exceeding MUCAPE values of 2000 J/kg.
Seasonably high wet-bulb zero values will limit hail threat to
primarily small hail in the stronger cores absent any more discrete
convection, which appears unlikely, and while a brief QLCS spin-up
cannot be ruled out, damaging winds in a seasonable setting of a
cold-pool driven MCS will be the primary concern.

Despite precipitable water values approaching 2 inches, well in
excess of the climatological 90th percentile, the (mostly)
progressive CAM solutions do give some optimism that despite
undeniable heavy rain potential, hydrologic threat should be
relatively limited with today and tonight`s convection, though
mesoscale reorientation of the low level environment in the form of
boundaries and the larger scale low to mid level flow will always be
a concern in such setups, and the slight risk for excessive rainfall
day one is certainly reasonable.

Overall, current expectation is for a broken line of storms to
possibly move into central Indiana during the evening hours, perhaps
just prior to nightfall, and push through the area to the
east/southeast - with southwestern portions of the area the most
likely area for both severe and hydrologic concerns.

FRIDAY INTO SUNDAY -

Another upper level wave will move slowly through the region Friday
into Saturday, though models differ in their handling and intensity
of the disturbance. A continued moist airmass will promote at least
moderate destabilization, and one or more clusters of storms will be
possible Friday into Friday night and perhaps on Saturday as well,
though the threat will lessen and shift southward with time, and be
focused primarily along remnant boundaries from previous convection,
lessening the predictability as time goes on.

An isolated strong to severe threat cannot be entirely ruled out,
though hydro concerns will likely be slightly more pressing as the
area has been decently wet in recent weeks, and the aforementioned
plentiful moisture combined with what may be fairly slow storm
motions outside of more organized clusters could present a localized
flash flood threat - WPC excessive rainfall outlooks outline this
well.

NEXT WEEK -

The predominant story next week will be a reassertion of summertime
heat as a brief pseudo-Rex block pattern forms with the western
CONUS ridge sliding back eastward atop weak upper level low pressure
to our south, gradually reconnecting with the Bermuda high over the
southeast. Temperatures will climb back towards the 90 degree mark
in spots, though with slightly more reasonable dewpoints than the
first week of the month, keeping max apparent temperatures still
toasty but far more manageable in the low to mid 90s.

The high pressure aloft and at the surface will keep the area dry
for the most part, though airmass thunderstorms cannot be entirely
ruled out near peak heating many days. That said, these are quite
low predictability days ahead of time and will not merit mentionable
PoPs on most days.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 624 AM EDT Thu Jul 9 2026

Impacts:

- MVFR, TEMPO IFR fog in the first hour or so

- Showers and storms possible at all sites this evening into the
  overnight

Discussion:

As expected, fog has formed at the outlying sites, with visibilities
fluctuating between MVFR and IFR. Conditions should be steadily
improving shortly after valid time, with VFR returning around 13Z in
typical diurnal fashion.

Once fog mixes out, VFR conditions will remain throughout the
majority of the period, the possible exception being this evening
when showers and storms are possible at the sites. Will carry VCSH
for now with a PROB30 group for thunder at all sites.

Winds will be calm to light and variable early, becoming
southwesterly (200-230 degrees) during the day, with a few gusts
into the mid teens range possible at most sites.


&&

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

$$

UPDATE...Updike
AVIATION...Nield
DISCUSSION...Nield