220
FXUS63 KIND 020136
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
936 PM EDT Mon Jul 1 2024

.KEY MESSAGES...

- Mostly Clear and pleasant tonight.
- Partly Cloudy and warmer on Tuesday.
- Heat and humidity continues through Friday.
- Rain and thunderstorm chances Wednesday through Friday, A few
  strong to severe storms are possible on Wednesday and Thursday.

&&

.FORECAST UPDATE...

No changes needed to the ongoing forecast with conditions evolving
as expected.  Efficient radiational cooling is expected again for
tonight with dewpoints in the upper 40s to low 50s across the area
and mostly clear skies. Winds are expected to gradually become more
southerly towards daybreak into the mid morning hours tomorrow.

&&

.SHORT TERM (This evening through Tuesday)...
Issued at 243 PM EDT Mon Jul 1 2024

Surface analysis early this afternoon shows strong high pressure in
place over MI. Cool and dry easterly flow was in place over Central
Indiana. GOES16 shows only a few high clouds across Central Indiana,
and dew points were mainly in the 50s. Aloft, water vapor imagery
showed strong ridging in place over the plains states.  This was
resulting in NW flow aloft and subsidence over Indiana. Upper level
moisture was spilling over the ridge into Illinois, but subsiding
over Indiana.

Tonight...

Models suggest the large area of high pressure over the Great Lakes
will drift to the eastern Great Lakes and New England. Ridging and
high pressure aloft will continue to protect Indiana from any upper
support to the west and subsidence remains in play. Thus mostly
clear skies will be expected. Warm air advection is expected to
begin late tonight as the ridge axis aloft reaches the east coast.
This will start the beginning of warm air advection into Wednesday.
Lows overnight should be warmer than previous night as the pool of
cooler air drifts east. Thus expect lows in the middle to upper 50s.

Tuesday...

Increasing clouds and and heat are expected on Tuesday. The upper
ridge axis is expected to drift to the east of coast, allowing
warmer southerly and southwesterly flow to push into Indiana. 850MB
levels show a surge of warm air advection and the development of a
thermal ridge across Indiana as temps there approach 20C. Forecast
soundings remain dry and show a mid level inversion that should
prevent much CU development. However with the southwest flow in
place aloft and a lack of wide subsidence, some passing high clouds
seems reasonable. Given the expected warm air advection, highs in
the upper 80s seem on the mark.

&&

.LONG TERM (Tuesday night through Monday)...
Issued at 243 PM EDT Mon Jul 1 2024

Tuesday night through Friday night...

The latter half of this week looks rather active with showers and
thunderstorms likely Wednesday through Friday. A decaying complex of
storms ahead of an approaching front could move into the area around
daybreak Wednesday. Deep-layer shear quickly weakening with eastward
extent and a narrow corridor of deep moisture are limiting factors
for the aforementioned storms to survive as they move into central
Indiana. Model guidance is in good agreement that convection will
quickly weaken with little to no impacts during the morning hours
due to this.

By Wednesday afternoon, moisture advection and daytime heating
should promote moderate-strong destabilization ahead of the
aforementioned frontal boundary. This along with low-level
convergence will likely lead to the development of thunderstorms.
Lingering cloud cover from convective debris in the morning may
limit destabilization some, but latest model runs continue to show
strong destabilization occurring. Modest effective bulk shear around
25-30 knots supports the potential for organized convection. The
primary threat is damaging wind gusts, but large hail and locally
heavy rainfall cannot be ruled out. Heat/humidity will also be
concerning as heat index values could reach or exceed 100F.

Forcing primarily confined along the front should allow for upscale
growth to occur with time. If an organized cold pool can form, then
expect the frontal boundary to briefly be shunted southward towards
the Ohio River. Precipitation chances remain high Wednesday night,
but POPs may need to be lowered depending on where the front ends up.

The front looks to return north Thursday as a low amplitude
shortwave moves into the region. Increasing dynamics and moderate
to strong destabilization once again will likely promote
thunderstorm development during the afternoon. Slightly stronger
deep-layer shear suggest another round of strong to severe storms
is possible. However, there are some caveats to the forecast.
There are signs that clouds could stick around for much of the day
with convection possible in the morning. This may augment the
thermodynamic environment potentially limiting the severe weather
threat. Damaging wind gusts and locally heavy rainfall are the
primary threats.

A third day of storms is expected on Friday with another deeper
trough moving in which will finally kick the annoying frontal
boundary out of the area. Favorable dynamics combined with
destabilization during the day could promote organized convection
once again. There is even greater uncertainty in this setup for
multiple reasons. Thursday night/early Friday morning potential
convection, location of the frontal boundary, and larger model
spread limit confidence for the threat of strong storms on Friday.

Mostly dry conditions are expected over the weekend as weak surface
high pressure settles in. Rain chances then begin to increase late
Sunday into next week with another system potentially approaching.
Outside of hot conditions on Wednesday, temperatures generally look
near seasonal through the extended. Daily chances for showers/storms
mid-late week could limit diurnal heating to some degree.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 656 PM EDT Mon Jul 1 2024

Impacts:

-None.

Discussion:

VFR conditions expected through the TAF period with mostly clear
skies.  Near surface subsidence should limit the diurnal cu during
the afternoon hours tomorrow. Winds tonight will generally remain
easterly at 7-10kts before gradually becoming more southerly towards
mid morning tomorrow.


&&

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

$$

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