129
FXUS63 KIND 091257
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
857 AM EDT Tue Jun 9 2026

.KEY MESSAGES...

- Scattered showers/t-storms today and again tonight. Isolated
  flooding possible

- Humid and very warm this week...rain chances continue through
  Thursday night...readings near 90F on Wednesday and Thursday

- Slightly cooler weather for the weekend with lower rain chances

&&

.FORECAST UPDATE...
Issued at 857 AM EDT Tue Jun 9 2026

Surface analysis this morning shows warm and humid SW flow in place
across Central Indiana. This was mainly due to low pressure in place
over the high plains and high pressure east of the middle Atlantic
States. Water Vapor shows an upper trough in place over the Great
Lakes and Indiana. The warm and humid air mass in combination with
the upper forcing has resulting in a few scattered showers and
storms across Indiana.

Ongoing chances for afternoon showers and storms appear on track.
The upper trough over the area is expected to continue to exit to
the east, however the warm and humid air mass across the region will
continue to allow for shower and storm chances through the
afternoon. Forecast soundings suggest ample CAPE over 2000 J/KG, and
again, pwats remain high, over 1.7 inches. HRRR also suggests spotty
shower and storm development this afternoon. Thus ongoing forecast
with afternoon shower and storm chances along with highs in the
middle 80s appears on track.

&&

.DISCUSSION (Today through Monday)...
Issued at 304 AM EDT Tue Jun 9 2026

Anomalous upper-level ridging persists over the northeastern US and
eastern Canada. Troughing dominates over the northern Rockies. The
jet stream wraps around the base of the trough and into the northern
Plains, extending northward into Canada north of the Great Lakes. As
such, an active storm track has been observed over the northern
Plains with multiple days of severe weather. Here in Indiana, a
subtle vort max displaced from the progressive jet has been
meandering nearby for a few days now. Combined with rich moisture
moving northward from the Gulf, this feature has allowed for
scattered showers and thunderstorms. The lack of strong flow aloft
has limited severe potential, but heavy rainfall and occasional
flooding have been a persistent threat. With the vort max expected
to remain in the vicinity for another day, additional showers and
thunderstorms are expected today. Coverage will again be isolated to
scattered, with locally heavy rainfall rates.

Guidance is in good agreement showing the vort max exiting the
region tonight. Southwesterly flow develops as the western troughing
edges eastward a bit. Subtle height falls associated with nearby
troughing should lead to steepening lapse rates tonight. Though
forcing from the vort max is gone, there may be enough isentropic
upglide to promote thunderstorm development overnight into early
Wednesday. Convection may be deeper given steeper mid-level lapse
rates. Some uncertainty remains regarding the development of a low-
level jet tonight. Some CAM guidance shows a slight increase in the
925 to 850 mb mean flow but overall the signal is weak. Should a low-
level jet develop, convection that initiates via warm advective
processes may begin back-building on the ensuing cold pool. Corfidi
upshear vectors are under 10kt, which may lead to flooding potential.

A Flood Watch was considered but we will hold off for now, since
much of the convective activity over the next 24 to 48 hours looks
to be widely scattered. Additionally, the probability of a back-
building MCS tonight into early Wednesday is low, owing to the
relatively subtle forcing. Trends will need to be closely monitored,
however.

The renewed warm advection is expected to bring hot weather over the
next few days, with highs near 90 possible Wednesday and Thursday.
Dew points in the 70s could lead to heat indices near 100 at times.
Heat stress risk (HeatRisk) climbs into moderate to major territory
both days, since overnight lows in the 70s will offer little day to
day relief.

Thunderstorm potential returns Thursday into Thursday night, due to
a cold front arriving from the northwest. Timing of the front may
work in our favor, since most guidance show a 03z-09z arrival. By
that point, much of the daytime instability will be lost.
Additionally, the parent trough is low amplitude and the best
forcing may pass well to our north. Wind shear decreases quickly
with southward extent as well. The most likely scenario, as of right
now, would be any upstream convection that consolidates into an MCS
would likely become outflow dominant as it moves southeastward.
Guidance is a bit mixed on whether convective activity reaches
central Indiana at all...but regardless, any activity that makes it
will probably be in a weakening state as it moves through.

Once the cold front moves through early Friday a cooler air mass
will settle in. Upper-level troughing, slowly moving east through
the week, reaches the Great Lakes region simultaneously. Ensemble
guidance is in decent agreement showing persistent troughing through
the weekend and into early next week. A cooling trend appears likely
with temperatures trending back towards normal (highs near 80, lows
near 60).

&&

.AVIATION (12Z TAF Issuance)...
Issued at 646 AM EDT Tue Jun 9 2026

Impacts:

- MVFR conditions today, IFR briefly possible this morning.
- Occasional -SHRA and isolated TSRA
- -SHRA/TSRA possible again this evening near BMG

Discussion:

Isolated showers and thunderstorms are possible this morning as low
pressure passes to the north of Indiana. Coverage and timing will be
tricky to narrow down, as shower/storm activity is widely scattered
and should remain so through the morning hours. The most probable
time frame is through 14z. After that, there may be a bit of a break
in activity but a stray shower/storm cannot be ruled out at any
point today. Shower/storm chances increase again this afternoon
and evening.

Ceilings have gradually deteriorated overnight as rain showers
have become more widespread. Some pockets of VFR remain, but
overall MVFR or lower conditions now prevail. A period of IFR
cannot be ruled out, and HUF is BKN006 as of this writing. MVFR
ceilings should be present through the morning hours and into the
afternoon.

Winds should remain out of the south/southwest, peaking during the
afternoon hours and diminishing after 00z this evening. Gusts up to
20kt possible on Wednesday.


&&

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

$$

UPDATE...Puma
AVIATION...Eckhoff
DISCUSSION...Eckhoff