-- Discussion containing changed information from previous version are highlighted. --
638
FXUS63 KIND 010504
AFDIND

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

.KEY MESSAGES...

-- Changed Discussion --
- 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
-- End Changed Discussion --

&&

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

**Flash Flooding occuring 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.
-- End Changed Discussion --

&&

.SHORT TERM (Today and tonight)...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.LONG TERM (Tuesday night through Monday)...
Issued at 324 PM EDT Mon Jun 30 2025

Generally dry and quiet weather is expected through the remainder of
the week, with some precipitation chances over the weekend.
Northwesterly flow aloft gradually transitioning to broad ridging
will allow for a slow warm-up as well.

A weak cold front pushing through on Tuesday will allow a
continental polar air mass to flow southward. Back trajectories
point towards northwestern Canada as the source region for this air,
and so dew points will finally drop to reasonable levels (upper 50s
and 60s) for the first time in over a week. Despite the air
originating in NW Canada, wildfire smoke shouldn`t be too much of a
concern this time around. Visible satellite does not show much in
the way of smoke upstream, since the atmosphere has been fairly
active up there which hasn`t allowed smoke to build up sufficiently.
However, there is still some smoke...so a period of slightly hazy
skies cannot be ruled out at times.

By Thursday we`ll be entering an upper-level pattern characterized
by broad ridging aloft. This should allow dew points to gradually
rise along with increasing ambient air temps. Precipitation looks
unlikely, though some members of guidance are showing isolated
showers/storms Thursday along a weak warm front developing as
ridging builds.

July 4th: Guidance is in good agreement showing high pressure at the
surface. Combined with our location downstream of the primary ridge
axis, a subsident atmosphere is likely and so precipitation is not
expected. Temperatures may reach 90 degrees by Friday with dew
points once again reaching 70.

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 both Saturday 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, as the
cold front presses southward on Sunday, forcing should increase
enough to increase the coverage and likelihood of precipitation.

Guidance still differs regarding the timing of the front, which may
have implications on which day has the best chance of rain. A faster
front would shift things more into Saturday, and a slower front
would lead to Sunday or perhaps into Monday seeing better rain
chances. We will keep broad but low precip chances Saturday, Sunday,
and Monday for now until model consensus improves.

&&

.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...Eckhoff
AVIATION...White