Indiana’s Weather For Saturday

HEADLINES
– May goes out like a lamb.
– Breezy this afternoon then cool tonight.
– Warmer temperatures return for the first half of next week
– Daily storm chances increase for the second half of next week

TODAY’S MAP

NWS TECHNICAL DISCUSSION

Increasingly amplified flow aloft will develop across the country
today with an unseasonably strong upper low dropping south through
Quebec helping to carve out a deep trough across the eastern U S.
Central Indiana will reside on the back side of the trough today and
throughout the weekend maintaining cooler than temperatures and
largely dry conditions. The aforementioned boundary across northern
Indiana will slide southwest through the day and may have just
enough forcing to generate isolated convection focused across the
lower Wabash Valley before washing out tonight as high pressure
takes over.

Quiet weather is anticipated for the rest of the predawn and through
the morning with just scattered mid level clouds. Expect a hazy sky
courtesy of the smoke aloft from the Canadian wildfires. Model
guidance shows smoke levels will be highest during the first half of
the day and will gradually be forced to the southwest as much drier
air advects into the region behind the boundary. Observational
analysis across the lower Great Lakes this morning is not indicating
any near surface layer issues from the smoke with minimal if any
restrictions to visibility. Expect that to continue into the
daylight hours as smoke remains confined to the mid and upper levels.

A deeper area of subsidence will move into the region from the north
this afternoon into the evening and in the process will help to
augment an already sharp dewpoint axis from southwest to northeast.
This may contribute along with limited forcing aloft and subtle
elevated instability in the vicinity of the remnant boundary to
generate isolated showers or perhaps a thunderstorm or two from mid
afternoon into the early evening over far southwest portions of the
forecast area. Further to the northeast skies will become mostly
clear with breezy N/NW winds and dewpoints dropping potentially as
low as the low 30s by late day as the stronger subsidence advects
in.

The boundary will wash out this evening as it runs into high
pressure over the lower Mississippi Valley and the expanding high
dropping out of the Great Lakes. Expect generally clear skies as
subsidence remains strong across the northeast half of the forecast
area into the early overnight before weakening late.

Temps...low level thermals suggest a modest temperature gradient
from northeast to southeast today with highs from 70 to 80., With
the very dry air and deep subsidence into tonight...much of the
northeast half of the forecast area will open up June in the mid and
upper 40s with lower 50s further southwest.

&&

.LONG TERM (Sunday through Friday)...
Issued at 221 AM EDT Sat May 31 2025

Strong AVA on the backside of the current amplified trough will
lead to subsidence and height rises over the Ohio Valley late
Saturday through Sunday. In return, surface high pressure will
build, peaking between 1018-1021mb Sunday night. This combination of
subsidence aloft and high pressure near the surface will provide
quiet weather for Sunday. With a continental polar airmass still
over central Indiana, temperatures will likely remain near to below
normal despite efficient daytime heating. Current expectation is for
afternoon highs in the mid 70s.

This surface high will slowly meander eastward but largely remain
close enough to the Ohio Valley to keep broad subsidence over the
region. This will be further supported by a very elongated but
strong ridge pushing in from the west early next week. Starting
Monday, moderate 850-700mb WAA within westerlies will alter the
airmass, leading to the of above normal temperatures for central
Indiana. This stretch of above normal temperatures will largely
continue through most of week, albeit less amplified late week due
to greater cloud cover. The warmest day of the week is likely to be
Tuesday as the upper ridge axis nears and the surface high keeps
skies clear; Tuesday`s afternoon high forecast is currently 88 for
Indianapolis.

As midweek arrives, ensemble guidance starts to vary considerably,
mostly focused on the variance of a strong high pressure system over
the SE CONUS. If the high is able to maintain itself upstream of a
few passing shortwaves, central Indiana will likely remain mostly
dry outside of some light showers until late Thursday into Friday.
On the other hand, if the surface high depletes and allows greater
moisture advection and lift eastward, central Indiana will likely
see multiple periods of rainfall Wednesday and Thursday. We will
continue to monitor trends and update the forecast as needed; in the
mean time, probability guidance is mostly split with a 50% chance of
rainy stretches Wednesday afternoon through Thursday night.

Despite the low confidence over the middle of next week, there is
some semblance of similarities in long range guidance with mostly
weak teleconnection patterns, but a strong AO. This should lead to
mostly strong zonal upper level flow for the second week of June.
These summer patterns typically lead to mostly seasonal
temperatures, with periodic rain chances along shortwaves within the
zonal flow. Generally, these patterns tend to be more active than
typical, but will likely not have a large QPF footprint within each
wave.

INDY SEVEN DAY FORECAST

NWS CHARTS FOR TODAY/TONIGHT