464
FXUS63 KIND 220201
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1001 PM EDT Tue Jul 21 2026

.KEY MESSAGES...

- Thunderstorms exiting by mid to late afternoon.

- Dry and cooler weather through at least Thursday, with warmer
temperatures returning this weekend.

&&

.FORECAST UPDATE...
Issued at 1001 PM EDT Tue Jul 21 2026

The main focus with the evening update is on the advancement of a
secondary boundary currently on a line from Lafayette to Newcastle.
The primary impact will be a wind shift from W/NW to N/NW, but there
is enough confluence along this boundary for isolated showers.

The remainder of the forecast is on track with a strong cold front
arriving late tonight into tomorrow morning. This will drop highs
down in the 70s for tomorrow, a nice reprieve from the hot and humid
conditions.

&&

.DISCUSSION (This evening through Tuesday)...
Issued at 155 PM EDT Tue Jul 21 2026

Surface analysis early this afternoon shows low pressure over
northern Ontario with a cold front that extended SW to Indiana and
southern IL. Radar shows convection developing ahead of the front
over southern Central Indiana, quickly moving SE. Southwest flow was
in place ahead of the front across southern Indiana, while flow
shifted to the west or NW across the northern half of the state.

Late this afternoon, convection ahead of the front is expected to
continue across the southern parts of the forecast area and exit by
20Z or earlier. Storms may produce heavy rain and gusty winds within
this moisture rich air mass and marginal dynamics in place.

Tonight through Thursday...

Quiet and cooler weather will settle across Central Indiana starting
tonight and continue through at least Thursday. This will be due to
strong upper ridging building across the western CONUS and the
resultant NW flow and lee-side subsidence across the upper midwest
spilling across Indiana. Models suggest a strong and large area of
high pressure building across Indiana through Thursday, along with
cooler north or northeast flow. This Canadian high will provide
mostly sunny days and mostly clear nights through Thursday. Below
normal temperatures will be expected with highs in the middle 70s on
Wednesday before rising to around 80 on Thursday.

Friday through Tuesday...

Dry weather with a warming trend looks in store for Friday through
Sunday, while minimal, uncertain rain chances return on Monday and
Tuesday.

During this period, models continue to suggest strong ridging aloft
building over the western CONUS. This will result in continued
northwest flow and lee side subsidence forming over the Upper
midwest, spilling southeast to Indiana and the Ohio Valley. This
will result in a large area of high pressure settling and lingering
across Indiana and the Ohio Valley through Sunday. Northeasterly
winds on Friday and Saturday will allow cooler temperatures to spill
into Central Indiana, resulting in below normal temperatures through
the first part of the weekend.

By Sunday, reorganization of the high pressure systems east of
Indiana will allow for warmer, southerly surface flow to return to
Central Indiana. This will allow highs to return to the middle and
upper 80s for Sunday.

Yesterday/s runs suggested weak waves moving across Indiana within
the flow aloft on Sunday and Monday, which could provide forcing for
rain. However today, models have shifted these features farther east
and slower. Models now suggest Indiana will continue to be protected
by ridging aloft on Monday and NW flow on Tuesday. Confidence for
rain during those times remains low until a stronger and more
significant signal appears.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 706 PM EDT Tue Jul 21 2026

Impacts:

- None.

Discussion:

VFR conditions are expected through the TAF period. An initial
frontal boundary has passed to the south, resulting in gusty
winds out of the W/NW this afternoon. Gusts and winds should wane
over the next few hours, settling around 7kt out of the NW. A
second boundary will pass through tomorrow morning, turning winds
to northerly, but should remain below 10kt. Diurnal cu will be
likely tomorrow afternoon, with a SCT deck around 5000ft.


&&

.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Updike
AVIATION...Updike
DISCUSSION...Puma