902
FXUS63 KIND 010552
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
152 AM EDT Tue Jul 1 2025

.KEY MESSAGES...

- Flash flooding ongoing for portions of southwest and south central
Indiana early this morning

- A much drier week ahead with a warming trend back to the low 90s
  by late week

- Scattered showers and thunderstorms return to the forecast by
Saturday night and Sunday

&&

.MESOSCALE UPDATE...
Issued at 103 AM EDT Tue Jul 1 2025

**Flash Flooding occurring across portions of South Central
 Indiana during the overnight hours**

Satellite and radar imagery show a cluster of thunderstorms slowly
moving into portions of Southwest and South Central Indiana
Indiana...the same areas which received 3-8 inches of rainfall over
the past 24-36 hours. Flash flooding is likely with this activity
through the overnight hours. The environment across the region
this evening is conducive for continued convective development and
maintenance of the cluster as ACARs soundings indicate a very
moist, unstable environment with sufficient upper level support.
Flash Flood warnings have already been issued for Knox and
Sullivan Counties and more headlines may be needed further
downstream over the next several hours.

From WPC:

Deep convection has persisted across much of southern/southeastern
Illinois over the past couple hours despite nocturnal boundary layer
cooling.  Abundant low- and mid-level moisture across the area ahead
of the convection was helping to maintain an axis of 1000-1500 J/kg
MLCAPE ahead of the storms while also supporting efficient rain
rates within the convection. Areas of 1-3 inch/hr rain rates have
been estimated per MRMS, which has occasionally exceeded local FFG
thresholds and prompted spots of low to moderate MRMS Flash
responses.

Unfortunately, this cluster of heavy-rain-producing convection was
moving toward portions of southern/central Indiana (near
Bloomington) that have received between 3-8 inches of rainfall over
the past 24-36 hours.  Ground conditions are saturated as a result,
and it is likely that as the cluster of storms moves eastward, Flash
Flood Guidance thresholds will be exceeded and excessive runoff will
occur. Locally significant flash flood impacts cannot be ruled out.

&&

.SHORT TERM (Today and tonight)...
Issued at 103 AM EDT Tue Jul 1 2025

Ongoing flash flooding is occurring in portions of South Central
Indiana as a a cluster of thunderstorms produces very heavy rainfall
over the same areas which picked up 3 to 8 inches of rainfall since
yesterday. Please refer to the update and mesoscale discussions for
more information on the storm and flood threat.

Rest of today...

The short term discussion will focus for the most
part on the upcoming weather pattern once the morning round of
storms exists the region.

Another stretch of summertime heat and humidity is expected through
the rest of the week, but fortunately the level of heat is not
expected to as oppressive as last week`s heat wave. Surface high
pressure quickly builds in from the north and west through the day,
advecting in a slightly drier airmass while working to push morning
storms off to the east. Ample sunshine and low level mixing will
still result in a warm day for Central Indiana with highs pushing
the mid to upper 80s. Dry air advection from the north and mixing
lead to dew points dropping through the day into the 60s for most
areas, which will be quite noticeable compared to recent humidity.
Areas which saw overnight rain may take longer to dry out than areas
along and north of the I-70 corridor.

Tonight...

Good conditions for radiational cooling set up tonight as the
pressure gradient weakens with high pressure centered over
Missouri. Tonight may be the first night that many areas drop below
the 70 degree mark in almost 10-14 days! A drier airmass in place
plus radiational cooling will result in dropping temperatures into
the low to mid 60s for much of Central Indiana.

&&

.LONG TERM (Wednesday through Monday)...
Issued at 151 AM EDT Tue Jul 1 2025

Another stretch of summertime heat expected again for the rest of
the week and into the week for all of Central Indiana. While
conditions are not expected to be as oppressive as they were last
week, both humidity and temperatures will be on the rise into the
weekend.

Strong ridging develops across the Central and Northern Plains this
week and slowly slides eastward into the weekend. The low and upper
ridge axis remain well to the west midweek, keeping the core of the
heat and humidity further west as well, but still maintaining
relatively warm and dry conditions locally. The ridge axis moves
overhead Friday then  slides east of the region, resulting in a
warming trend back to the 90s as the core of the heat and humidity
advect into the Ohio Valley and Great Lakes.

Midweek features highs in the mid to upper 80s with relatively lower
humidity values than seen over the past several weeks.
Northwesterly flow on the east side of the surface high and
associated ridging will largely prevent Gulf moisture from surging
northward, keeping oppressive dew points in the 70s well south of
the region. Low level mixing Wednesday and Thursday afternoon may
even bring enough dry air to the surface for dew points to fall into
the upper 50s briefly...relatively dry and comfortable for this time
of year.

A gradual warming and moistening trend occurs during the week, with
each day being a few degrees warmer and more humid than the previous
day as ridging slowly progresses eastward.

July 4th: Mid to long range guidance continues to be in agreement
with ridging moving overhead by Friday and low level flow becoming
southerly. Confidence is increasing in highs reaching the lower 90s
for much of Central Indiana with dew points making a run for 70
degrees again. While hazardous heat conditions are not expected at
this time, increasing heat and humidity result in afternoon heat
indices approaching 100 degrees. NWS Heat Risk already shows a
moderate risk for heat for the 4th of July, as sensitive populations
may need to take precautions if out in the heat all day.

Large-scale ridging looks to break down over the weekend with
guidance showing a weak trough and cold front approaching from the
northwest. With increasing dew points and instability, some showers
and thunderstorms are possible Saturday night and Sunday. Flow aloft
is very weak on Saturday, so any activity should be pulse-like pop-
up in nature, and coverage is likely to remain low. However, higher
confidence exists in a more widespread threat for storms Saturday
night into Sunday as a front pushes into the region. As of now,
timing of the front looks to be overnight Saturday night into
Sunday; however with this being more than 5 days out, there will
likely be small shifts regarding timing of the convection. Higher
confidence exists in Saturday being the drier day next weekend, with
a great coverage for storms on Sunday.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1249 AM EDT Tue Jul 1 2025

Impacts:

- MVFR to briefly IFR vsbys at HUF/IND/BMG through 12Z, worst at BMG

- TSRA at times at BMG through 12Z

- Winds shifting through period from WSW to NW

Discussion:

Frequent showers to continue at HUF and BMG through daybreak with
potential for additional development near IND. Greatest impacts will
be at BMG where frequent MVFR and occasional IFR vsbys are expected
along with the best chance for MVFR cigs. Rain will come to an end
after daybreak with clearing skies. Winds will continue to become
more northwesterly with a low chance for gusts to 18kts this
afternoon.


&&

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

$$

MESOSCALE...CM/WPC
SHORT TERM...CM
LONG TERM...CM
AVIATION...White