Indiana’s Weather For Wednesday

HEADLINES
– Rain this afternoon, with light amounts under a quarter-inch.
– Showers and storms Thursday afternoon and evening, mainly south of I-74.
– Warmer weekend ahead!

TODAY’S MAP

NWS TECHNICAL DISCUSSION

Winds will quickly increase in intensity throughout the morning into
the afternoon ahead of a weak shortwave. This will usher in warmer
conditions with afternoon highs in the low the mid 50s for most of
central Indiana. Surface moisture will lag behind mid level moisture
leading to mid level clouds and virga prior to precipitation onset
late in the morning into the early afternoon. Over NW portions of
central Indiana, precip may initially begin as a light rain/snow
mix, but should quickly transition into all rain as the
temperature column warms ahead of the wave. Showers should remain
scattered to isolated for most of the day until confluence
increases leading to greater moisture convergence in the
evening/early overnight. Total rainfall amounts for Wed/Wed Night
are currently between 0.1-0.3".

Cloud cover, greater surface moisture and maintained S/SW wind will
greatly inhibit diurnal cooling tonight and end the string of below
freezing mornings.

&&

.LONG TERM (Thursday through Tuesday)...
Issued at 256 AM EDT Wed Apr 9 2025

An amplifying jet pattern will develop during the long range.
Precipitation chances will be mainly early in the period as today`s
system departs and troughing develops overhead. Another chance of
precipitation arrives near the end of the forecast period.

On Thursday, unstable air associated with the trough should allow
for a diurnal convective precipitation mode. Guidance is showing
greater instability with southward extent, with values as high as
1000-2000 J/Kg in far southern Indiana. Additionally, with the jet
stream displaced to our south there may be enough shear for storm-
scale organization and thus a non-zero severe weather threat. RAP
soundings show thick CAPE profiles within a rather shallow
atmosphere (Equilibrium Level as low as 9km), very steep lapse rates
(over 8C/Km), and moderate shear (30-50 kt through 8Km). Hodographs
are essentially straight as west to slightly northwesterly flow
dominates the column. Fast winds near the Equilibrium Level may
allow for some good storm top ventilation. Those factors point in
the direction of a hail threat, especially over southern Indiana
southward. Steep lapse rates and some dry low-level air may allow
for a downburst/wind threat as well but this seems minor. This may
end up staying just south of our CWA, though we will need to monitor
model trends in case it creeps northward a bit.

Forcing for convection appears to be a secondary cold front in
conjunction with a vort max embedded within the broader
northwesterly flow. Both of these features seem subtle to some
extent, and rather noisy in the model data...so some uncertainty
exists regarding convective coverage and timing. Given the diurnal
nature of the instability, best timing is during the afternoon and
evening hours. Storm motion will be to the east-southeast.

As the trough digs southward, Indiana will be firmly within the
colder upper-level air mass by Friday. Chilly conditions are likely
into the weekend with lows near to below freezing Friday morning and
Saturday morning. Lingering clouds and wind Thursday night may keep
temperatures higher than they otherwise would be on Friday morning.
Saturday morning looks to be the coldest of the two as ideal
radiative cooling conditions should be in place. Warm air advection
begins on Sunday as surface high pressure slides eastward allowing
winds to turn southerly. Warm air advection continues into next week
as cyclogenesis begins over the northern Plains.

Ensembles show the resulting system passing over the Great Lakes,
with its attendant cold front passing through Indiana during the day
Monday. Various models do show some moisture return ahead of this
front which leads to some instability. As such, thunderstorms are
possible with this boundary and thunder will be added to the
forecast Monday afternoon. As for severe weather, deterministic
models show shear and instability aligning which may promote a
strong thunderstorm threat. However, it`s hard to say more than that
as model differences are still quite large at this range.

INDY SEVEN DAY FORECAST
Today: Clouds increase. Showers in the afternoon. High 51.

Tonight: Evening rain, then mostly cloudy. Low 42.

Thursday: Partly to mostly cloudy. Scattered afternoon showers and storms. High 60.

Thursday Night: Scattered evening showers and storms, then mostly cloudy. Low 38.

Friday: Morning clouds, and afternoon sun. High 52.

Friday Night: Mostly clear. Low 33.

Saturday: Sunny. High 58.

Saturday Night: Mostly clear. Low 37.

Sunday: Partly sunny. High 65.

Sunday Night: Partly cloudy. Low 52.

Monday: Partly sunny. Spotty afternoon showers. High 75.

Monday Night: Spotty showers possible. Low 50.

Tuesday: Partly sunny. Shower chances. High 66.

NWS CHARTS FOR TODAY/TONIGHT