637
FXUS63 KIND 060426
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1226 AM EDT Mon Oct 6 2025

.KEY MESSAGES...

- Widespread rain and thunderstorms Monday night into Tuesday

- Dry and seasonable weather Wednesday through Friday, warmer into
  early next week

&&

.FORECAST UPDATE...
Issued at 929 PM EDT Sun Oct 5 2025

A warm evening with clear skies and a steady S/SE wind ongoing. 01Z
temperatures ranged from the mid 60s to the lower 70s.

Forecast is in excellent shape for the overnight as the strong
surface high centered over the western Atlantic Ocean remains the
primary influence. Lingering subsidence and dry air over the region
however will give way to increasing moisture advecting from the
south on the back side of the surface ridge. This will manifest
initially as an expansion of mid level clouds into the forecast area
from the south during the predawn hours with drier air remaining
within the boundary layer. Any scattered showers will hold off until
later on Monday morning as isentropic lift arrives into the
southeast half of the forecast area.

Lows tonight will range from the upper 50s to mid 60s. Zone and grid
updates out.

&&

.SHORT TERM (This evening through Monday)...
Issued at 227 PM EDT Sun Oct 5 2025

Rest of Today and Tonight.

The main focus for today continues to be the elevated fire risk,
mainly across the northwestern portions of central Indiana. RH
values are expected to drop to near 30 percent before moisture
advection ahead of the expected rain Monday night into Tuesday
brings higher dew points to central Indiana. Winds at the top of the
boundary layer will be 20-25 mph which will bring occasional gusts
as high as that across the area with greatest confidence towards
Lafayette. A few localized hot spots have already shown up on GOES16
with additional hot spots likely to pop up through the day.

Diurnal cu will dissipate after sunset with only passing cirrus
aloft tonight. Some mid level clouds will gradually work into the
area towards tomorrow morning, but much of the higher cloud coverage
should hold off until after daybreak. Temperatures tonight will stay
mild with the higher surface dew points with most areas remaining in
the low 60s.

Monday.

By Monday morning the front that will be bringing the stretch of wet
weather will be moving into northwestern Illinois but a weak area of
mid level isentropic lift may bring a few showers to portions of
southern Indiana during the morning and early afternoon hours ahead
of the better forcing. The thermodynamics will be pretty marginal
with little to no instability, so only expect isolated to
potentially scattered showers with little to no chance for thunder.
Highs tomorrow will be dependent on the coverage of rain, but expect
most if not all of the forecast area to reach into the low 80s with
the potential for mid 80s in the north where the rain chances are
minimal.

&&

.LONG TERM (Monday night through Sunday)...
Issued at 227 PM EDT Sun Oct 5 2025

Monday Night Through Thursday.

The front will move into northwestern Indiana late Monday night into
early Tuesday with heavier rain expected across southern Indiana
during the overnight as a surge of Gulf air moves northward with a
strengthening LLJ to the south. Forcing from the surface front will
lag behind the stronger lift from the south which will keep
precipitation chances well into the daytime hours on Tuesday when
the front will pass through the state. Confidence is fairly high
that the front will reach the Ohio River towards the evening with
rain chances rapidly falling after 00Z. The heaviest rain will be
confined to the southern portions of the state, but expect much of
the area to see amounts of 0.5 to 1.0 inches with some locally
higher amounts of around 1.5 inches.

Much cooler weather will move in behind the frontal passage with the
potential for lows in the low 40s Wednesday night and highs in the
upper 60s to low 70s through Friday. Surface high pressure will
dominate the weather pattern through the second half of the week
with dry weather expected.

Friday Through Sunday.

A similar pattern will persist Friday into the weekend with a broad
and weak upper low across the Eastern US with weak flow near the
surface and aloft across the Ohio Valley. Temperatures look to
remain above normal going into the following week, but not quite as
anomalously warm as things have been to start the month. The pattern
continues to favor drier than normal conditions with little to no
signs for additional appreciable rainfall.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1225 AM EDT Mon Oct 6 2025

Impacts:

- Deterioration to MVFR conditions late this afternoon and tonight.
- Scattered showers developing this afternoon, continuing Tonight

Discussion:

Clear skies were found across Central Indiana as High pressure was
departing to the east. Mid and upper level moisture over the deep
south was surging northward, on the backside of the high and ahead of
an approaching frontal boundary to the northwest. This will lead to
increasing clouds through the morning hours, but VFR conditions will
continue through that time.

HRRR suggests as the clouds and moisture arrive on Monday
afternoon and scattered showers will begin to push in to the area
from the south. Confidence in areal coverage and and precise
timing is too low at this point, but a VCSH mention was used for
late this afternoon as some sct/isolated showers will be present.

Forecast soundings tonight show a saturated column across the
area as the moisture surge to the south arrives across Central
Indiana. This will lead to more prevailing rain and MVFR
conditions through the evening hours.

&&

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

$$

UPDATE...Ryan
SHORT TERM...White
LONG TERM...White
AVIATION...Puma