Indiana’s Weather For Friday

HEADLINES
– Morning showers, mainly in the southeastern half of the state.
– Evening showers and storms, ahead of a cold front. Nice weekend!
– 80s return Monday. Humidity and storm chances return Wednesday.

TODAY’S MAP

NWS TECHNICAL DISCUSSION

A strong supergeostrophic jet streak has been able to push overtop
of the Omega Block inducing height falls south of the upper level
trough. This has then led to a low pressure system over the Ohio
Valley. This has led to a conducive corridor for precipitation
development over the southern Ohio Valley, of which has begun pushing
into central Indiana over the last few hours. A dry 900-700mb layer
has kept most of this precipitation light thus far, but continued
moisture advection and deep saturation above 700mb will help moisten
the entire column shortly leading to moderate rainfall rates between
08-13Z.

The lift associated with this passing low is rather
confined, leading to a sharp QPF gradient on the northern edge
(currently expected to be from I-70 to the HWY-26 corridors. South
of I-70 though, 4-6 hours of moderate rainfall should lead to a
broad 0.5-1.0" of rainfall. Given slightly potential for banded
precipitation over far southern central Indiana, there could be
isolated pockets of greater than 1" in these areas. Isolated thunder
within some weak elevated instability is possible, but the primary
mode of precipitation will be non-thunderous showers.

This low should quickly race off to the east late this morning, as
strong dry air advection pushes low surface dew points into the
northern portions of the forecast area. This will lead to mostly dry
weather this afternoon. As the dry air mixes into the norther, it
should assist in scattering cloud cover some NW of I-69, of which
will push NW locations into the low to mid 70s, whereas SE of I-69
temperatures are likely to stay in the 60s.

A quickly advancing shortwave within the strong 700-500mb flow will
arrive from the north tonight. Pressure falls out in front of this
feature will likely induce some convection over northern IL/IN
despite a very dry surface layer. There is still some uncertainty on
the ability for this wave to initiate new convection over central
Indiana without strong surface level outflow, but that shouldn`t be a
large issue in front of any developed MCS that arrives from northern
IN. While the aforementioned dry surface layer will inhibit new
convective growth, it will also aid in mixing strong winds to the
surface ahead of any organized/linear convection. This will lead to
a non-zero severe wind gust risk, primarily over far northern
central Indiana; that said the majority of any wind gusts should
remain sub-severe.

The aforementioned strong 500-700mb northerly jet this evening
through tonight will also allow for a greater volume of Canadian
wildfire smoke to reach the Ohio Valley tonight into Saturday.
Currently the belief is this will remain above the boundary layer
posing a minimal threat to surface based conditions; however, there
are some hints at a narrow window of 50-100 p2.5 in the surface
layer at times tonight within any well mixed environments. We will
continue to monitor smoke related trends and update as needed
throughout the day.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 258 AM EDT Fri May 30 2025

An amplifying upper level trough over the northeast U S will persist
through the weekend before lifting out by early next week. This will
keep the Ohio Valley within a drier northwest flow pattern for
Saturday and Sunday with seasonably cool temperatures. Ridging will
build in with the departure of the East Coast trough with warm and
dry conditions for the first part of the week. The upper level
pattern will gradually transition to a more quasi-zonal flow with
increasing opportunities for convection through the latter part of
next week.

Saturday through Sunday Night

Much drier air will surge south Saturday in the wake of the frontal
passage tonight but the tail end of the boundary will linger back
across Illinois and southwest Indiana...and may offer a small chance
for an isolated shower or storm across the lower Wabash Valley in
the afternoon. A greater impact of the dry air advection through the
course of the day will be to gradually shift the primary plume of
smoke from the Canadian wildfires further southwest before
completely moving out of the forecast area by Saturday night. The
smoke will be kept well aloft in the mid and upper levels with a
hazy sky serving as the primary feature.

Deeper subsidence will be drawn south Saturday night and Sunday with
any convective potential being focused more across the Tennessee and
lower Ohio Valleys. Highs will remain just below normal but pleasant
for Saturday and Sunday ranging from the lower 70s northeast to near
80 in the lower Wabash Valley.

Monday Through Thursday

A ridge aloft will expand into the Ohio Valley for the first part of
next week and is set to bring the warmest air since the middle of
the month. Highs in the mid to upper 80s are expected by Tuesday but
modest dewpoints will limit the overall heat risk. Wednesday may end
up being the day when the heat risk is slightly elevated as
dewpoints will rise into the 60s despite temps a few degrees
cooler than Tuesday highs.

Model guidance has come into better alignment on a cold front
sweeping into the region from the west Tuesday night and Wednesday
with showers and storms. Stronger storms will certainly be possible
with an unstable atmosphere...especially on Wednesday as deeper
moisture advects into the region. As the upper level pattern
transitions to a quasi-zonal flow with multiple embedded
waves...additional chances for storms are possible late week but
models and ensembles do not have a consensus at this early stage.
Temps will drop back slightly in response to the increased chances
for rain and storms late week but remain seasonable for early June
in the upper 70s and lower 80s.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 622 AM EDT Fri May 30 2025

Impacts:

- Rain ending from west to east over the next few hours
- Scattered convection possible this evening at KIND and KLAF
- Northwest wind gusts peaking at 20 to 25kts this afternoon

Discussion:

Rain continues to move across southern Indiana early this morning
but the back edge is already moving through the Wabash Valley.
Expect rain to be largely done at KIND prior to 12Z and should clear
KBMG by 13Z. There is the possibility of some redevelopment on the
back side of the rain area but that is likely to be southeast of all
of the terminals. Clouds will scatter by midday into the afternoon
with northwest winds becoming breezy. Gusts will diminish towards
sunset.

Scattered convection is likely to accompany a frontal boundary as it
drops southeast this evening into the early overnight. While
convection will be in a weakening state...brief impacts are possible
at KIND and possibly KLAF with higher wind gusts. Winds after
briefly backing to westerly ahead of the boundary will veer to
northwest late tonight with mid level clouds lingering.

INDY SEVEN DAY FORECAST
Today: Mostly cloudy morning, with scattered showers. Partly sunny afternoon. High 74.

Tonight: Scattered showers and storms. Low 56.

Saturday: Sunny. High 73.

Saturday Night: Partly cloudy. Low 48.

Sunday: Mostly sunny. High 76.

Sunday Night: Mostly clear. Low 54.

Monday: Mostly sunny. High 85.

Monday Night: Clear. Low 63.

Tuesday: Sunny. High 88.

Tuesday Night: Mostly clear. Low 70.

Wednesday: Partly sunny, hot and humid. Scattered showers and storms by afternoon. High 85.

Wednesday Night: Scattered showers and storms. Low 65.

Thursday: Mostly cloudy. Scattered showers. High 80

NWS CHARTS FOR TODAY/TONIGHT