Lafayette, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

040
FXUS63 KIND 052236
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
636 PM EDT Fri Sep 5 2025

.KEY MESSAGES...

- Isolated to scattered very light showers over the southeast half
  of central Indiana tonight and early Saturday

- Dry and cooler through early next week with multiple nights with
  lows in the 40s

- Slow warming trend back to the 80s by later next week

- Beyond early Saturday, no chance for rain across central Indiana
  through the end of next week

&&

.SHORT TERM (This Evening through Saturday)...
Issued at 223 PM EDT Fri Sep 5 2025

Central Indiana is enjoying a breezy but comfortable Friday
afternoon in the wake of a cold front that passed through the
forecast area this morning. A smoky haze courtesy of the fires in
the Pacific Northwest remains across much of the area although
visible satellite does show the axis of smoke gradually sinking
southeast. High clouds increase just to our west associated with an
upper level wave over Kansas and Oklahoma. 18Z temperatures ranged
from the upper 60s to mid 70s.

The aforementioned front is already in the process of clearing the
Ohio River and as the upper level energy to the west catches up to
it later today into this evening...expect convection to develop from
the Tennessee Valley northeast into the central Appalachians
continuing into the overnight. Moisture aloft however will expand
north into the Ohio Valley and despite the presence of dry air below
750mb...may have just enough lift to squeeze out a few hundredths
from very light showers tonight. Drier and cooler weather then takes
hold on Saturday and will continue through the weekend with a deep
upper level low located near James Bay.

Expect a slow increase in mid and high clouds from the west into the
evening but have largely removed any mention of rain prior to closer
to sunset and beyond with drier air through the boundary layer
quickly advecting south across the forecast area in the postfrontal
airmass. The best chance to see any raindrops will come from mid
evening into the overnight and focus across the southeast half of
central Indiana as deeper moisture noted at the 300K level spreads
into the region. Isentropic lift however is muted with a largely
parallel flow to the moisture axis. This lack of substantial lift
and the drier air remaining below about 8kft noted nicely on model
soundings argues for light showers or sprinkles in an isolated to
scattered fashion that will be hard pressed to generate anything
more than a few hundredths focused mainly along the far southern
border of the forecast area. Any chance to see raindrops will drop
off rapidly to the northwest with a deeper column of drier air and
increasing subsidence spreading southeast.

A few sprinkles or light showers may linger over southeast Indiana
Saturday morning but the trend will be towards clearing skies as
drier air advects into the region. A trailing subtle wave aloft may
be enough to generate scattered diurnal cu for the afternoon
otherwise expect plenty of sunshine.

Temps...lows will hold in the low and mid 50s across the southeast
half of the forecast area with mostly cloudy skies for much of the
night. Across the northern Wabash Valley and north central Indiana
where skies will clear late tonight...lows will drop into the upper
40s. Low level thermals support highs generally in the upper 60s and
lower 70s for Saturday.

&&

.LONG TERM (Saturday Night through Friday)...
Issued at 223 PM EDT Fri Sep 5 2025

A deep upper level trough centered near James Bay will bring an
early taste of Fall to the region for the weekend with unseasonably
cool air and the coolest mornings for central Indiana since May. The
trough will move away to the east being replaced by more zonal flow
aloft by Monday and Tuesday...transitioning further to upper ridging
by late next week with growing confidence in a return to summer like
weather in the 7 to 14 day period.

As mentioned above...the upper trough to our northeast will govern
the weather across the Midwest and Ohio Valley through the weekend.
High pressure over the Canadian Prairies will stretch southeast into
the Midwest keeping northwesterly flow through Indiana. Troughing
overhead results in a much cooler Canadian airmass aloft with well
below normal heights and temperature anomalies. Despite sunny skies
this weekend...below average temperatures through the column will
only support highs in the upper 60s across the north to low to mid
70s further south. The main focus for this weekend will be chilly
overnight lows once again Sunday and Monday morning as good
conditions for radiational cooling and a cold airmass aloft support
low to mid 40s. The coolest locations will be across the Wabash
River Valley and in North Central Indiana where a few of our normal
cool spots may slip as low as the upper 30s...especially on Monday
morning.

The overall pattern begins to shift as next week progresses...
leading to a slow warming trend back to the 80s but with dry weather
persisting. The aforementioned upper trough moves away to the
northeast with increasing heights toward seasonal norms by Monday.
Surface high pressure briefly moves overhead early next week then
moves off to the east enabling a return flow to develop across the
Ohio Valley and advecting warmer air northward. Upper level height
increases and slowly warming 850mb temps indicate a pattern
favorable for a warming trend through the week with highs reaching
the upper 70s to mid 80s Tuesday through Friday. Dry conditions will
still lead to larger diurnal ranges as temperatures quickly fall
after sunset...with lows in the upper 40s to low 50s Tuesday then
increasing to the mid to upper 50s by late in the week.

Forecast confidence somewhat decreases toward the end of the period
as longer range guidance and ensembles struggle to resolve how this
pattern evolves as weak storm systems approach from the west. For
now higher confidence exists in a warm and dry forecast continuing
into next weekend into the following week with daytime highs
consistently in the mid and upper 80s.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 635 PM EDT Fri Sep 5 2025

Impacts:

- Wind gusts of 15-20kt possible Saturday afternoon

Discussion:

VFR conditions are expected through the period.

Mid-level clouds will move in to most sites this evening and persist
overnight before clearing from the northwest. Scattered VFR cumulus
will pop up Saturday, especially for KLAF/KIND.

Some sprinkles/light rain showers with no impacts are possible at
all but KLAF tonight, with KBMG having the highest chance for a
shower.

&&

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

$$

SHORT TERM...Ryan
LONG TERM...Ryan
AVIATION...50