Indiana’s Weather For Friday

HEADLINES
– Hot again, with highs into the mid and upper 80s.
– Storms this evening will be strong to severe.
– Large hail, damaging wind gusts, and tornadoes possible.
– Cooler breezes behind cold front tomorrow. Nice weekend at the Track.

TODAY’S MAP

NWS TECHNICAL DISCUSSION

Synopsis: Strong low pressure was found over the eastern Dakotas
with a frontal boundary stretching east across northern MN, then
southeast to lower Michigan and western Ohio. This was resulting in
a warm and humid southwest flow over Indiana. GOES16 shows mainly a
few high clouds in the wake of the convection that has pushed east
to Ohio. Water vapor imagery shows a tropical plume of moisture
streaming from the Pacific, across TX to KY and TN, while dry air
and subsidence from MO/IL/WI was swirling into the upper low over
the northern plains.

An active weather pattern is set up for today. Broad cyclonic flow
around the deep upper low over the northern plains is expected to
continue drive the weather across Central Indiana. We will remain
within the warm sector, with moderate southwest winds in place
across our area through the day, due to the moderate pressure
gradient in place. Furthermore plentiful lower level moisture
appears in place as dew points across area were in the middle and
upper 60s. Looking aloft, models suggest a short wave pivoting
around the upper low pushing across IL and nosing toward Indiana by
late afternoon. A tight gradient in place aloft suggests strong
dynamics with this feature. By late afternoon and into the evening
models suggest a LLJ of 40-50 knts across the area.

Further support for convection is found within the forecast
soundings where steep lapse rates are displayed with convective
temperatures in the middle 80s and afternoon CAPE values over 2400
J/KG. Helicity values also appear favorable for rotating updrafts,
particularly across the southern half of Indiana late this afternoon
and evening. HRRR continues to suggest thunderstorm development with
this wave and instability initializing over IL late this afternoon,
before pushing across Indiana during the 22Z to 02Z time frame.

Although an isolated tornado cannot be ruled out anywhere in Central
Indiana this afternoon and tonight, the best chances for tornadoes
will be along and south of a Sullivan-Bloomington-Greensburg line,
while straight line winds and hail appear to be the larger threat
across points to the north. This situation will evolve as the day
progresses and these areas could change in later analysis. Thus
today is a day in Central Indiana where people will need to stay
weather aware, listen for watches and warnings, have multiple ways
to get weather information and ensure your are familiar with your
safety plan.

Overall, low pops to no pops will be used this morning, with near
categorical pops late this afternoon and early evening when storms
are expected. Highs again should be at or above persistence, in the
mid to upper 80s.

Tonight -

In the wake of the storms by mid evening, cyclonic flow will remain
in place, however the flow aloft will shift to westerly and mid
level subsidence is seen flowing into the system. The arrival of
westerly winds will allow dew points to fall to the 50s, resulting
in a cooler and less humid air building across Indiana overnight.
Models show ridging building across the northern plains states late
tonight, leading to lee side subsidence over IA to build across IN
as the night progresses. Thus skies should become partly cloudy in
the wake of the storms overnight. Given the start of the change in
air mass, lows in the the middle 50s will be expected.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 307 AM EDT Fri May 16 2025

An exiting low will move off to the NE at the start of the period.
Behind the low, broad riding across the central plains will
initially dominate this weekend. Pressure gradients between the
system will keep wind gusts to around 25-30 mph during the afternoon
on Saturday but will be much calmer for Sunday.

A more active pattern is then expected for much of the work week as
an upper low, with a couple of short wave, moves through the region.
Models are struggling to determine the details at this time as
different solutions show varying tracks and strengths to the system.
Confidence on temperatures is also low as it will depend on what
side of the low central Indiana ends up with. Despite the
uncertainties, it does look like there will be a good amount of
moisture to work with, so could see a threat for multiple days of
heavy rain, and temperatures probably below normal for much of the
week.

Towards the end of the long term and into the holiday weekend, a
ridging pattern may set up to bring from the rain expected next
week, but it is still too soon to have much confidence in this yet.

&&

INDY SEVEN DAY FORECAST
Today: Mostly sunny, and hot again. High 86.

Tonight: Showers and storms after 6pm. Some strong to severe. Low 59.

Saturday: Mostly sunny morning. Partly sunny afternoon. Less humid. Wind gusting to 30 mph. High 71.

Saturday Night: Partly cloudy. Low 54.

Sunday: Mostly sunny. High 75.

Sunday Night: Partly cloudy. Low 53.

Monday: Mostly cloudy, with scattered showers. High 71.

Monday Night: Scattered showers and storms. Low 54.

Tuesday: Partly to mostly cloudy. Scattered showers and storms. High 68.

Tuesday Night: Scattered showers and storms. Low 56.

Wednesday: Partly to mostly cloudy, with scattered showers and storms. High 63.

Wednesday Night: Scattered showers. Low 48.

Thursday: Mostly cloudy. High 61.

NWS CHARTS FOR TODAY/TONIGHT