636
FXUS63 KIND 251043
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
643 AM EDT Sat Apr 25 2026

.KEY MESSAGES...

- Patchy fog, locally dense, this morning

- Warm and dry this weekend

- Severe thunderstorms possible from mid afternoon Monday into
  Monday night

- Cooler temperatures expected late next week

&&

.DISCUSSION (Today through Friday)...
Issued at 304 AM EDT Sat Apr 25 2026

A cold front passed through Indiana yesterday, but the air mass
change has yet to occur. Winds have diminished becoming light and
variable. High boundary layer moisture content remains following
widespread rainfall earlier. Despite thin cirrus, fog has been
gradually developing across much of the area. Fog has become locally
dense, especially in favored areas such as within river valleys.
Thickening cirrus and a gradually increasing northerly wind should
help keep dense fog patchy through morning.

Surface high pressure builds to our north allowing winds to become
northeasterly later today. Mainly clear skies should help
temperatures rebound nicely even with cooler air advecting from the
Great Lakes region. Highs both today and tomorrow are expected to
climb into the mid 70s. Lows dip into the upper 40s/low 50s each
night.

MONDAY`S SEVERE WEATHER POTENTIAL

Guidance is in good agreement showing a potent shortwave trough
ejecting out of the Rockies late Sunday. This feature moves
northeastward fairly quickly, passing to our north Monday evening.
Surface cyclogenesis progresses rapidly on Monday over the Great
Plains, with the resulting low strengthening to between 990-998mb.
Such deepening will help drive a potent mass response, lifting a
broad warm/moist sector rapidly northward. Additionally, a
developing low-level jet (LLJ) is modeled to strengthen through the
day Monday and especially into Monday evening.

Convection fires up over Illinois later Monday afternoon. Most of
the day looks to be dry here in Indiana, with storms arriving as
early as 6-8pm at the Indiana/Illinois state line. The environment
within the warm sector can be characterized by moderate to high
levels of instability and strong effective wind shear. Model
soundings show steep lapse rates with MLCAPE values between 2000-300
J/Kg, though this decreases a bit after sunset to 1000-2000 J/Kg.
Model hodographs are long and curved during the afternoon,
elongating further as the LLJ ramps up after 00z. Corresponding 0-
1km SRH values between 200-300 m2/s2 are shown, peaking after 00z.

Model shear vectors are roughly SW to NE, which aligns with the
system`s surface cold front. Given the shear present and the shape
of the hodograph, convection over Illinois likely becomes
supercellular quickly after initiation. Given the orientation of the
shear vector, however, quick upscale growth also appears likely.
Looking at potential hazards, all hazards appear possible especially
over Illinois. Large hail, tornadoes, severe wind gusts, and
flooding are possible with any supercell that develops and remains
discrete. Upscale growth into a line/MCS is probable by the time
convection reaches Indiana. Severe wind gusts are likely the primary
hazard over Indiana. However, given the very large amounts of 0-1km
SRH, relatively low LCLs, and a strengthening south to north LLJ...a
QLCS tornado threat may develop and mesoscale conditions will need
to be monitored very closely.

Storms likely weaken with eastward extent as they outpace the best
forcing and instability. Therefore, the best chance of severe
weather currently looks to be over the western half of our CWA,
though this could easily change.

TUESDAY ONWARD

A second shortwave ejecting from the Rockies closely behind Monday`s
may provide another chance at showers and storms. However, given the
potency of Monday`s system, much of the moist unstable air will have
been swept away by the time the second system arrives. Sufficient
moisture return may be possible for storms over the southern half of
Indiana late Tuesday. Severe weather may again be possible should
this occur, especially further south, but this depends on how
quickly moisture and instability can advect back northward.

After Tuesday, persistent troughing aloft takes hold and cooler
conditions are favored for the second half of the week. High
temperatures in the 60s (which is right around average) and lows in
the 40s appear likely Wednesday through Saturday.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 638 AM EDT Sat Apr 25 2026

Impacts:

- Fog this morning before 12z at BMG. LIFR conditions possible.

- IFR stratus near LAF this morning.

- Becoming breezy this morning, wind gusts up to 20kt.

Discussion:

Patchy fog has diminished across most of central Indiana, with
only BMG under 1 mile visibility as of 11z. Fog has lifted into a
low stratus deck near LAF, with ceilings around 800 feet. Improvement
is expected after sunrise with a quick return to VFR.

Some diurnal cumulus likely develops this afternoon but will
remain FEW or SCT. Guidance hints at low-level stratus arriving
from the northeast overnight into Sunday morning, potentially
becoming BKN at times.

Winds become east-northeasterly overnight tonight into Sunday
morning, remaining breezy between 5-10kt.

&&

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

$$

AVIATION...Eckhoff
DISCUSSION...Eckhoff