597
FXUS63 KIND 120154
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
954 PM EDT Fri Jul 11 2025

.KEY MESSAGES...

- A few showers or an isolated storm possible through this evening
  with a greater chance for storms over the weekend

- Localized flooding and isolated strong to severe wind gusts
  possible this weekend

- Hot and humid conditions persist into next week, slight relief
  possible early next week for portions of central IN

- Daily storm chances next week

&&

.FORECAST UPDATE...
Issued at 954 PM EDT Fri Jul 11 2025

A narrow corridor of subsidence has curtailed any convective towers
over central Indiana, leaving the entire area dry this evening. A
MCS upstream will be the main focus for this update, specifically how
far east it is able to reach before undergoing rapid decay. The
current expectation is for this MCS to decay prior to reaching
central Indiana, due to the lack of strong steering flow and
upstream MUCAPE. That said, there is a strong cold pool developing
that could allow for a remnants of the MCS to breach NW portions of
the area. For that reason a 20% PoP has been kept through the early
overnight period

&&

.SHORT TERM (This evening through Saturday night)...
Issued at 304 PM EDT Fri Jul 11 2025

Rest of this afternoon...

Latest satelitte imagery depicts increasing coverage of diurnal cu
across central Indiana. This is due to strong daytime heating which
is promoting PBL destabilization. Further destabilization over the
next few hours may support a few showers or storms through sunset.
The best chance for isolated convection will be across the south
where slightly greater destabilization is occurring. Otherwise,
expect subtle upper ridging to keep weather conditions mostly quiet
through tonight.

Saturday...

An upper wave and surface boundary moving in Saturday will provide a
better opportunity for convection. Model guidance initially shows an
MCS developing along the boundary this evening near eastern Iowa.
The MCS should weaken as it propagates eastward overnight towards a
more stable environment across central Indiana. However, isolated
showers or storms cannot be ruled out from the weakening MCS
approaching so low POPs are in the forecast late tonight through
Saturday morning.

Strong daytime heating and increasing dynamics above a moist PBL
will promote scattered convection late in the day. Forecast
soundings depict strong instability, weak deep-layer shear, and
steep low-level lapse rates suggesting short lived strong-severe
storms are possible. The primary threats would be isolated damaging
wind gusts from downbursts with the potential for localized flooding
as well. Storms will likely be moving around 20-25 kts which limits
the flooding threat, but efficient rainfall rates or repeated rounds
of storms could still lead to flooding. Hot and humid conditions
will persist with heat indices peaking near 98-102F across south-
central IN.

Saturday night...

Scattered showers and storms may still be ongoing early Saturday
night. Precipitation chances will quickly drop off though during the
overnight period as the disturbance shifts east. There could be
patchy fog development late due to weak subsidence behind the
departing system. The best chance for fog would be near any
locations that receive precipitation earlier in the day.

&&

.LONG TERM (Sunday through Friday)...
Issued at 304 PM EDT Fri Jul 11 2025

Sunday and Sunday night...

The unsettled weather pattern over the weekend is likely to continue
through Sunday. Guidance suggest another upper wave and surface
boundary will push through the region. Increasing dynamics from the
approaching system combined with a moist-unstable airmass supports
the potential for numerous showers and thunderstorms.

A few models are depicting stronger mid-level flow promoting
slightly more favorable deep-layer wind shear for organized
thunderstorm development compared to Saturday. Considering moderate-
strong destabilization is likely for at least southern portions of
central Indiana, there is concern for additional strong to severe
storms. Models are still not in great agreement, but this trend is
worth monitoring. Strong destabilization and steepening low-level
lapse rates could support an isolated damaging wind gust threat even
if mid-level flow remains weak.

Localized flooding will also be a threat as deep moisture remains
over the region. In fact, most guidance shows potentially higher
PWAT values over 2.0 inches on Sunday. These higher values combined
with warm rain processes suggest high rainfall rates are likely in
convection. Training storms is a concern too as the aforementioned
surface boundary may not make much progress. The best chance for
precipitation on Sunday appears to be during the afternoon/evening,
but would not ruled out storms lingering into the overnight hours.

Monday through next Saturday...

Guidance shows the surface boundary shifting slightly southward into
Monday with drier air filtering in. However, some models suggest the
boundary lingers near the area keeping a moist-unstable airmass in
place for south-central IN. Low chance POPs will persist early next
week to account for the front potentially lingering. Organized
thunderstorm development is unlikely and any convection that
develops should be focused during the afternoon or evening.

Better storm chances are expected towards mid-late next week once
deeper moisture returns ahead of an approaching system. Exact
details remain uncertain this far out, but given the time of year
convective coverage would likely be greatest during peak heating.
Models are still showing slightly cooler-drier air by the end of
next week and into the weekend after the disturbance exits the
region. This should provide some relief from the hot and humid
conditions.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 728 PM EDT Fri Jul 11 2025

Impacts:

- Scattered to numerous storms are expected towards the very end of
  the period Saturday afternoon/evening

Discussion:

VFR conditions are expected through much of the period. An
approaching system should support more widespread convection
Saturday afternoon and evening. A PROB30 was added from 18-24Z
Saturday due to the increasing thunderstorm potential. Will refine
this and increase probability as confidence increases.

Look for winds to remain out of the S/SW through the period.
Sporadic gusts to 20kts could occur through sunset today. More
frequent wind gusts around 19-22kts are expected on Saturday.


&&

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

$$

UPDATE...Updike
SHORT TERM...Melo
LONG TERM...Melo
AVIATION...Updike