Indiana’s Weather For Thursday

HEADLINES
.KEY MESSAGES…
– Isolated/scattered showers and breezy conditions yet again today.
– Below normal temperatures through Memorial Day. Highs in 60s.
– Early Sunday morning shower chances should stay south/southwest of Indy.
– A few showers later Monday and Tuesday.

TODAY’S MAP

NWS TECHNICAL DISCUSSION

Another cloudy, and at times wet, day for Central Indiana as the
region remains under the influence of an upper trough and quasi-
stationary area of low pressure in the Eastern Great Lakes. Cyclonic
flow around the low and weak waves rotating into the state have kept
lower stratus clouds and drizzle and light showers around early this
morning. ACARs and forecast soundings indicate deep enough low level
moisture to support drizzle outside of any shower activity today.
Greatest coverage for showers looks to be in the mid afternoon
through evening hours. Still not expecting a complete washout of a
day as any precipitation should be fairly light and scattered in
nature.

Temperatures remain well below average for late May as a very cool
airmass is entrenched over the entire Great Lakes region with cloud
cover limiting significant boundary layer heating. Today will likely
be the coldest day for the foreseeable future as highs struggle to
get out of the upper 50s, especially along and north of the I-70
corridor. Breezy conditions at times will make it feel even colder
today with feels-like temperatures remaining in the 50s. While not
as windy as yesterday, the pressure gradient around the surface low
is still strong enough to support winds of 10-15 mph with gusts
upwards of 20 mph at times during the day. Any peaks of sun this
afternoon will work to briefly steepen low level lapse rates and
increasing mixing to bring down a few higher gusts to the surface.

.Tonight...

The weather pattern stuck over the region over the past several days
finally is kicked out to the east by Canadian high pressure dropping
southeast out of Central Canada. Influence from the low gradually
wanes tonight as even cooler, drier air is advected into the region
from the incoming high. Expect a drying and clearing trend toward
and after sunset tonight from west to east with winds significantly
dropping off overnight. Western portions of Indiana will feel the
affects of the high first overnight, with better conditions for
radiational cooling setting up over the Wabash River Valley. Added
fog in the 2AM-8AM timeframe for the entire Wabash River Valley,
east of the Indy Metro, as conditions look conducive for fog
development with such a saturated boundary layer and light winds.

Lows temperatures fall into the low to mid 40s for all of Central
Indiana by the early morning hours Friday. The development of fog in
the west and winds remaining slightly elevated in the east should
prevent any frost development and temperatures from falling into
the 30s.

&&

.LONG TERM (Friday through Wednesday)...
Issued at 258 AM EDT Thu May 22 2025

Friday and Saturday...

Mainly dry and cool weather will be expected on Friday and Saturday.
Models suggest deep upper level low pressure settled over New
England. This will result in cool, northwest flow continuing to flow
across Indiana, while also placing Central Indiana in a favorable
area for subsidence. This is expected to result in cool high
pressure in place at the surface, bringing partly cloudy skies and
cool temperatures as high only reach the mid 60s.

Small chances for rain showers may come in to play on Saturday
afternoon across southwest Central Indiana as a warm front is
suggested to approach. Confidence remains low for this at this time.

Sunday through Thursday...

The upper pattern this time will be dominated by low pressure over
Ontario and Quebec. Initially on Sunday and Monday, this will result
in zonal flow across Central Indiana, allowing a path for upper
level forcing to stream across the state. A pair of these waves are
suggested to pass on Sunday afternoon and again on Monday. Within
the lower levels a warm front will be setting up near the Ohio
River. For now, forecast soundings show deep saturation arriving
after 18Z on Sunday and again on Monday afternoon. Thus clouds and
rain chances will continue to be needed on both of these days.

Rain chances will continue to be needed on Tuesday through Thursday
as the previously mentioned Canadian upper low retrogrades and
wobbles southwest, bringing cyclonic flow aloft all of these days.
Strong and cool high pressure will set up over the high plains
during this time while surface low pressure remains over NY State.
This will continue to bring cool, northerly flow to central Indiana,
resulting in below normal temperatures. Given the cyclonic flow
aloft chances for rain showers, albeit probably light rain showers,
will need to be included. Continued below normal temperatures will
be expected.

INDY SEVEN DAY FORECAST
Today: Mostly cloudy, with spotty showers, mainly in the afternoon. Wind gusting to 25 mph. High 60.

Tonight: Clouds decrease. Low 42.

Carb Day: Mostly sunny morning. Partly sunny afternoon. High 65.

Friday Night: Partly cloudy. Low 46.

Parade Day: Mostly sunny morning. Partly sunny afternoon. High 68.

Saturday Night: Partly cloudy. Low 49.

Race Day: Partly to mostly cloudy. High 68.

Sunday Night: Partly to mostly cloudy. Low 52.

Memorial Day: Partly to mostly cloudy. High 66.

Monday Night: Mostly cloudy. Spotty showers. Low 53.

Tuesday: Mostly cloudy. Spotty showers. High 68.

Tuesday Night; Mostly cloudy. Low 52.

Wednesday: Mostly cloudy. High 71.

NWS CHARTS FOR TODAY/TONIGHT