584
FXUS63 KIND 240938
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
538 AM EDT Tue Jun 24 2025

.KEY MESSAGES...

- *HEAT ADVISORY* continues through late day Friday

- Heat indices of 100-109 degrees and low temperatures near or above
  75 degrees each day through Friday

- Scattered daily afternoon showers/t-storms, isolated strong to
  severe wind gusts are possible

&&

.SHORT TERM (Today and tonight)...
Issued at 243 AM EDT Tue Jun 24 2025

Latest radar and surface observations depict quiet weather
conditions across central Indiana. A few locations in the area are
reporting minimal visibility reductions as light winds have allowed
for patchy ground fog to develop. This fog will quickly mix out
after daybreak. Expect hot and muggy conditions once again today
with upper ridging centered over the eastern CONUS.

A heat advisory remains in effect through the period as heat indices
reach 100-105F by this afternoon. Little to no relief from
humidity the past few nights should also enhance the heat threat.
Make sure to take extra precautions if you are planning to spend
time outdoors. Drink plenty of water to stay hydrated and take
frequent breaks in AC or shaded areas. It is especially important
for heat vulnerable populations to limit time outside.

Widely scattered showers and storms are expected to develop this
afternoon within an uncapped unstable airmass. Very hot/humid
conditions will promote strong instability which may support a few
strong storms. Forecast soundings depict high DCAPE values supported
by steep low-level lapse rates and mid-level dry air. This suggest a
favorable environment for downbursts. Strong wind gusts from
thunderstorms later today should mostly remain sub-severe, but
isolated severe gusts cannot be ruled out. Any thunderstorms that
develop are likely going to be short-lived due to weak deep-layer
shear. This further enhances the downburst threat as collapsing
cores result in stronger negative buoyancy. Locally heavy rainfall
and lightning are also threats.

Latest CAMs suggest a remnant outflow boundary from ongoing upstream
convection will also help to fire up storms later today. This
boundary could continue to initiate convection through tonight as
warm-unstable air remains in place. Expect highs to reach the low-
mid 90s today with lows in the 70s again tonight. Isolated diurnal
convection may provide some slight relief from the heat, but
precipitation will increase humidity. There is a chance for patchy
fog to develop tonight once winds become very light, especially in
any areas that see locally heavy rain.

&&

.LONG TERM (Wednesday through Monday)...
Issued at 243 AM EDT Tue Jun 24 2025

HEAT ADVISORY continues on Wednesday through Friday

Wednesday and Thursday -

Models show upper level high pressure and associated ridging
remaining in place across the southeastern states with a ridge axis
extending into Ontario through Thursday. Again, this will result in
the continued weather pattern that we have experienced over the past
several days. Strong high pressure southeast of Indiana will
continue keep Central Indiana within a hot and humid air mass.
Forecast soundings on these days both show afternoon instability and
CAPE available, but 700mb temps remain around 10C. This continues to
suggest the development of isolated diurnally driven late afternoon
and evening showers and storms. HRRR suggests isolated convection
across Central Indiana on Wednesday, and given the little overall
change in airmass and pattern, small chances for afternoon showers
and storms appear prudent at this juncture in time.

Highs in the low to mid 90s will once again be expected with some
relief to anyone who does get a short lived shower or storm.

Friday through Sunday -

Models are still consistent here, showing the upper ridging to the
north pushing east, and a nearly zonal flow develops across the
northern plains and Great Lakes. Again, this will keep the majority
of forcing features well north of Central Indiana. Meanwhile within
the lower levels, high pressure in place over the southeastern
states will continue to keep a hot and humid flow into Central
Indiana. This lack of a change in air mass will result in continued
daily chances for showers and storms and low to mid pops will
continue to be needed. Some additional cloud cover is expected
through the weekend as subsidence will not be as strong as previous
days. This should result in slightly cooler high temperatures,
albeit conditions will still be hot...with highs near 90.

Monday -

Models show on Monday a short wave trough moving through the flow to
the north. This will allow of first taste of upper forcing
pushing toward Central Indiana, interacting with our hot and humid
air mass. Within the lower levels a poorly defined cold front will
be approaching Central Indiana by late afternoon. Thus once again,
chances for showers are storms will be needed, particularly during
the afternoon hours. Highs should once again be in the upper 80s to
near 90.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 536 AM EDT Tue Jun 24 2025

Impacts:

- Isolated showers and storms possible after 19Z today, best chance
  near LAF

- Patchy fog possible late tonight, mainly near LAF

Discussion:

VFR conditions are expected through much of the TAF period. SCT
diurnally driven cu should develop around 040-060 later today with
the potential for isolated showers/storms. The best chance for
convection to develop is near LAF where there is a PROB30 -TSRA.
Confidence is too low at the other sites for an explicit mention
in the TAFs.

Southwesterly winds are generally less than 5kts at this time, but
winds will increase slightly to 5-10kts during the day. Expect winds
to become light and variable again tonight. There is a chance for
patchy fog late tonight, mainly near LAF, but this was not
explicitly mentioned in the TAF due to low confidence.

&&

.IND WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT Friday for INZ021-028>031-035>049-
051>057-060>065-067>072.

&&

$$

SHORT TERM...Melo
LONG TERM...Puma
AVIATION...Melo