618
FXUS63 KIND 041337
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
937 AM EDT Sat Apr 4 2026

.KEY MESSAGES...

- Rain and thunderstorms to move through today, which may produce
  occasionally heavy rainfall and renewed flooding along area
  waterways

- Strong to severe storms possible this afternoon and evening;
  damaging winds will be the primary concern. Non-thunderstorm
  gusts up to 40 mph are also possible today

- Drier and cooler weather Sunday through early next week.
  Potential for lows in the low to mid 30 Monday through Wednesday
  mornings. Below 30 is possible Tuesday morning. Frost or freeze
  conditions possible.

&&

.FORECAST UPDATE...
Issued at 937 AM EDT Sat Apr 4 2026

Showers have moved into the western part of the forecast area so far
this morning with convection and lightning strikes into the lower
Wabash Valley. There has been some sunshine further east which has
led to quick mixing of the boundary layer and a subtle increase in
instability from earlier this morning. 13Z temperatures were largely
in the upper 60s and lower 70s.

The focus for the morning update is to tighten up the detail for
convective impacts this afternoon as the cold front sweeps east
across the region. There has been a gradual slowing of the arrival
and passage of the cold front later today from earlier guidance
which supports an uptick in the potential for pockets of stronger
winds associated with the development of a low topped convective
line along the front this afternoon...especially across the eastern
half of the forecast area where instability should be a bit more
pronounced. While CAPE values should remain around 1000j/kg...there
will be an increase in low level SRH which will support an increase
in organization to convection as it shifts east this afternoon. The
risk for severe winds remains low but it is present and will be the
primary threat with the linear convection crossing the forecast area
between 17 and 21Z. Additionally...a subtle increase in directional
shear suggests a non-zero tornado risk as well along the convective
line. Convection will move out of central Indiana prior to the
evening with any lingering showers over the eastern half
of the area diminishing prior to sunset.

One change made to the forecast is to bump up gradient wind gusts
over the next few hours ahead of the rain and storms. Already seeing
peak gusts approach 30mph in some locations this morning and with
good mixing already within the boundary layer...expect that to
increase over the next few hours with stronger flow in the 850 to
925mb layer. Could see gusts peak at near 40mph for a few hours
early this afternoon over the eastern half of the forecast area.

High temperatures primarily in the low and mid 70s still look
reasonable. Temperatures will fall later this afternoon once the
cold front passes with most of the region back into the 50s by early
evening. Zone and grid updates out.

&&

.SHORT TERM (Today through Tuesday)...
Issued at 310 AM EDT Sat Apr 4 2026

A low pressure system is passing to the north of the area while the
associated cold front will push from west to east today. Early this
morning the cold front is draped through western Illinois into
Missouri with a line of thunderstorms along it. Ahead of the front
isolated to scattered showers exist, some of which have made their
way into western Indiana.

The front and more widespread showers and storms should reach the
forecast area around or shortly after daybreak and continuing
eastward today before exiting to the east likely by midnight. There
will be stronger winds aloft with this front, so wind gusts of up to
35 mph are possible this afternoon. Within stronger storms, severe
winds could mix down the surface. Otherwise, no other severe threat
is expected for central Indiana.

Temperatures will remain warm for much of the day before dropping
behind the cold front this afternoon to evening. From tonight
through Tuesday, temperatures instead be near to below normal with
highs generally in the 50s and lows in the 30s. High pressure will
start to influence central Indiana Sunday helping to diminish cloud
coverage, bring calmer winds to the area, and drier conditions. The
surface high will pass through the area Monday night into Tuesday
allowing for the coldest temps then. Monday night is currently
forecasted to be near to below freezing for most of central Indiana
and will likely need frost or freeze headlines. Still monitoring
trends for just how low temps will get that night.

&&

.LONG TERM (Tuesday night through Friday)...
Issued at 310 AM EDT Sat Apr 4 2026

The mid to late week period will be characterized by a return to
above normal temperatures as Canadian high pressure exits to the
east and the pattern shifts back toward a somewhat complex
arrangement of large scale troughing, particularly over the western
CONUS, and broad warm advection in the low levels as a frontal zone
fluctuates from near the area to the north central Plains/upper
Midwest in response to the influence of multiple disturbances.

One additional morning of frost/freeze concerns appears likely
Wednesday morning, with lows largely in the 50s thereafter, and
highs largely in the 70s, with the exception of Wednesday when highs
may only reach the mid to upper 60s.

Low chances for precipitation will be necessary, mainly over
northwestern portions at times from Thursday onward, though
significant uncertainty exists here with respect to frontal
positioning and the potential for convection triggered by the front
to organize and perhaps move further into the region via
thermodynamic influences.

Nonetheless, our cooldown will be mercifully brief with warmer
temperatures returning for the latter portion of the week, with
indications of an active pattern returning and above normal
temperatures and precip continuing into mid April.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 631 AM EDT Sat Apr 4 2026

Impacts:

- Wind shear threat early this morning
- Gusts around 25+KT much of the period
- Widespread showers and embedded thunderstorms much of the morning
  into the afternoon hours
- Widespread MVFR conditions with the rain

Discussion:

Rain is headed towards central Indiana early this morning, coming in
from the west. This line of storms is associated with a cold front
that will push through the region Saturday. Ahead of the line will
bring a wind shear threat that should diminish by midmorning.
Afterwards, wind gusts up to 25KT or slightly higher will take over
and last through this evening. Winds will start off out of the south
and turn westerly behind the front.

Lighter scattered rain ahead of the line could arrive early this
morning then more widespread rain and thunderstorms are expected by
midday. MVFR ceilings, as well as visibilities at times, will
accompany the line of storms. Best chance of lightning will be
midday into the afternoon. Rain is expected to move off to the east
of all TAF sites prior to 00z.

&&

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

&&

$$

UPDATE...Ryan
SHORT TERM...KF
LONG TERM...Nield
AVIATION...Nield/KF