716
FXUS63 KIND 060140
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
940 PM EDT Tue Aug 5 2025

.KEY MESSAGES...

- Scattered showers and storms producing locally heavy rainfall
  possible into this evening, focused especially across the southern
  half of central Indiana

- Isolated storms possible over eastern portions of the area
  Wednesday then decrease late week into the weekend

- Progressively warmer and more humid conditions over the next
  several days

&&

.FORECAST UPDATE...
Issued at 939 PM EDT Tue Aug 5 2025

The forecast remains in good shape with only minor adjustments
needed. Current KIND radar imagery still shows a few lingering
showers across southeast portions of central Indiana, but they are
quickly weakening due to the loss of daytime heating. Surface high
pressure centered near the region will provide mostly quiet weather
conditions overnight. A weak pressure gradient should also allow for
winds to remain light and variable. Temperatures will cool down towards
dewpoints in the 60s overnight.

The combination of light winds with low-level moisture and recent
rainfall is expected to promote fog development late tonight. The
greatest coverage will likely be across south-central Indiana
where the most precipitation has fallen over the past day and a
half. Look for any fog to quickly mix out Wednesday morning.

&&

.SHORT TERM (This evening through Wednesday)...
Issued at 304 PM EDT Tue Aug 5 2025

Convection has been slow to redevelop so far this afternoon with
just isolated showers over southern counties where low level
moisture was more prevalent. 18Z temperatures were largely in the
upper 70s and lower 80s.

Scattered convection is still anticipated for the second half of the
afternoon and into the early evening focused especially across the
southern half of the forecast area as a broad upper level trough
drifts across the Ohio Valley. With the remnant MCV responsible for
the persistent showers and storms Monday night and early this
morning well off to the east...should see a much quieter night
tonight with fog becoming a primary concern due to the abundance of
shallow moisture lingering. The potential for isolated convection
will shift into the eastern part of the forecast area as the
troughiness aloft shifts into the upper Ohio Valley.

Suspect subtle subsidence and the presence of slightly drier air in
the wake of the MCV is at least partly responsible for the lack of
more substantial convective development to this point this
afternoon. The KIND ACARS sounding confirms this with poor lapse
rates aloft and drying above the boundary layer leading to less
instability that was expected by this time. There remains a diffuse
boundary just north of the I-70 corridor that could still serve as a
focal point for some development this afternoon as it is acting as
the dividing line between deeper moisture to the south and drier air
further north. But as of mid afternoon...cumulus is more agitated
across southern portions of the forecast area south to the Ohio
River...likely signaling that this will be the location for initial
development through 20-21Z before coverage expands north.

Will maintain scattered pops for the southern 2/3 of the forecast
area with lower chances further north where a more stable air is
present. PWATs have fallen back to closer to 1.50 inches which is
still more than sufficient for heavy rainfall rates. Freezing levels
remain high at near the 500mb layer and supports a continued
potential for warm rain processes within convection through the
evening. With convection moving slowly in the lack of substantial
shear...localized flooding will remain the greatest threat from
storms over the next several hours with an emphasis on the lower
Wabash Valley and south central Indiana where heavy rainfall Monday
and Monday night have lowered thresholds. While showers and storms
will diminish towards sunset...may take into the late evening before
fully dissipating.

Expecting largely dry conditions overnight tonight although a stray
shower cannot be entirely ruled out with the upper trough in the
area. The bigger concern as the night progresses though will be the
development of fog with deep moisture persisting within the near
surface layer and the possibility for clearing skies and light
winds. Primary concern will be in areas that received rainfall over
the last 24 hours or so with a focus across the southwest half of
the forecast area. Fog will burn off quickly Wednesday morning.

Deeper moisture shifts east into Ohio on Wednesday in tandem with
the upper trough axis as drier air advects into the region from the
west. The trough will remain close enough for isolated afternoon
convection across eastern counties. Expect diurnal cu for the
afternoon elsewhere across central Indiana but overall there will be
increased sunshine.

Temps...lows tonight will hold mainly in the mid 60s. Low level
thermals support highs in the mid 80s for Wednesday right near the
early August normals.

&&

.LONG TERM (Wednesday night through Tuesday)...
Issued at 304 PM EDT Tue Aug 5 2025

Strong ridging aloft will remain anchored over the southern Rockies
and High Plains, stretching into the eastern Midwest from midweek
into the weekend. At the surface, flow, although weak, will be
largely southerly and thus advecting in both warmer temperatures and
additional Gulf moisture. This will help to bring high temps into
the upper 80s to near 90 with lows in the upper 60s to low 70s.
Despite the expected increased moisture, the ridging will act to
suppress much in the way of showers and convection through
Saturday.

Meanwhile, a large upper low over Canada will slowly be progressing
eastward through the week. By late weekend, the low will break up
the ridging and an approaching associated cold front will drop into
the region by late weekend or early next week and could become
nearly stationary over the region next week. This would keep a warm,
humid, and unsettled pattern across the Ohio Valley with any
substantial cooldown coming from a frontal passage being delayed
until late next week at the earliest.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 715 PM EDT Tue Aug 5 2025

Impacts:

- Isolated convection diminishing this evening

- Fog possible at terminals late tonight and Wednesday morning

Discussion:

Isolated showers are possible through about 00Z this evening, but
confidence is too low for any explicit mention in the TAFs. Winds
will remain light E/SE through the period. Wind direction will
likely be variable at times or possibly even throughout the period
for some sites.

Cloud coverage decreases this evening along with any lingering
showers diminishing. Low-level moisture and recent rainfall will
likely lead to fog formation late tonight into Wednesday morning
with the possibility for IFR or lower conditions at the outlying
sites. Fog will burn off quickly Wednesday after sunrise with
diurnal cu developing again by midday. Isolated showers could also
develop in the afternoon, but expected coverage and confidence is
far too low for a mention in the TAFs.


&&

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

$$

UPDATE...Melo
SHORT TERM...Ryan
LONG TERM...KF
AVIATION...Melo