736
FXUS63 KIND 181036
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
636 AM EDT Mon Aug 18 2025

.KEY MESSAGES...

- Isolated to scattered showers and storms today and tonight

- Very warm to hot and humid conditions will be around into
  Tuesday

- Showers and storms are expected to surround the frontal passage
  Tuesday into Wednesday

- Dry and cooler late this week through early next week; Highs
  falling into the upper 70s and low 80s by Sunday

&&

.SHORT TERM (Today and tonight)...
Issued at 233 AM EDT Mon Aug 18 2025

Early This Morning...

A surface boundary is across northeastern Illinois into northwest
Indiana. Weak isentropic lift along this boundary is creating some
light showers near the IL/IN border near the northwest forecast
area. Satellite shows some continued development of clouds in the
northwest forecast area as well.

This lift will continue through the early morning hours, so may have
to add some slight chance PoPs for parts of the western forecast
area.

Stronger lift farther northwest was producing convection across
areas closer to Chicago, but convection from this has weakened as it
moved closer to the local areas or has moved away from the area.
Feel this will continue and keep storms out of the area given little
change early this morning. Will monitor closely though.

Today...

The surface boundary will remain across the northwest forecast area
today. Weak isentropic lift will persist as well. Isolated showers
may linger this morning, so will have some slight chance PoPs.

Even though upper ridging remains this afternoon, the isentropic
lift may interact with increasing instability to bring isolated to
scattered convection to the northwest forecast area this afternoon.

Will add some low PoPs there this afternoon. Cannot rule out that
these will spread farther east, but confidence isn`t high enough to
include. Severe storms are not expected given weak shear.

High temperatures will be middle 80s northeast to lower 90s
southwest. Dewpoints will be in the 70s most areas, making it feel
more like the middle and upper 90s over much of the area.

Tonight...

Any initial convection from this afternoon will diminish by early
evening. During the night. forcing from an upper wave north of the
area will generate more convection. This convection has the
potential to move into portions of the northwest half of the area.

Will go with some slight chance to chance category PoPs across the
northwest half, with the highest PoPs in the far northwest. Shear
increases some, but instability will be diurnally weakening. Thus
feel that severe storms are not likely.

Lows will be in the middle 60s to lower 70s.

&&

.LONG TERM (Tuesday through Sunday)...
Issued at 233 AM EDT Mon Aug 18 2025

Tuesday and Wednesday...

The greatest and only expected rain chances are early in the period
when an upper wave and cold front move through the region.
Southwesterly surface flow ahead of the system will help to pull
gulf moisture northward. This combined with increasing dynamics
favors scattered to numerous thunderstorms on Tuesday. The greatest
coverage is expected during peak heating when instability is
strongest. Weak deep-layer shear should mostly limit the threat for
severe, but an isolated strong to severe wind gust cannot be ruled
out given strong instability and steep low-level lapse rates.

Deeper moisture and forcing is expected to shift south on Wednesday
resulting in rain chances diminishing. However, daytime heating atop
lingering PBL moisture could promote isolated to widely scattered
convection. Look for hot and humid conditions to persist Tuesday
before temperatures slightly cool off into the 80s Wednesday.

Thursday onward...

Mostly quiet weather conditions are expected late this week through
early next week. Guidance depicts primarily N/NW flow with upper
ridging and surface high pressure providing dry weather through
Friday. An upper wave is then expected to push a dry cold front
through the region late Friday into Saturday. Precipitation is
unlikely due to marginal moisture ahead of the system though it
will bring a noticeable cooldown.

Expect highs generally in the 80s late this week with lower
dewpoints. A more substantial cooldown should occur behind the
aforementioned dry cold front. Most guidance suggest highs will fall
into the upper 70s on Sunday for portions of the area while
widespread highs in the 70s are possible by Monday. Dewpoints are
also likely to drop substantially as drier air advects into the
area, making it feel more like early fall.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 636 AM EDT Mon Aug 18 2025

Impacts:

- MVFR ceilings possible early, mainly at KLAF
- Fog very early at KBMG
- Convection possible at times near KLAF

Discussion:

Lower VFR clouds continue to develop this morning, with some patches
of clouds below 3000FT. Most sites will see SCT-BKN low VFR this
morning before a broken VFR ceiling becomes likely for a time this
afternoon at mainly the northern sites. Cannot rule out brief MVFR
ceilings this morning.

Isolated showers will be around this morning mainly near KLAF, and
isolated storms could be around KLAF this afternoon. Odds are too
low to mention for these. Near the final quarter of the TAF period,
more storms may move into KLAF.

&&

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

$$

SHORT TERM...50
LONG TERM...Melo
AVIATION...50