316
FXUS63 KIND 262247
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
647 PM EDT Sun Apr 26 2026

.KEY MESSAGES...

- Quiet and pleasant weather tonight

- Severe thunderstorms possible Monday afternoon into Monday night.

- Isolated showers and thunderstorms possible on Tuesday, mainly
  across southern Indiana.

- Cooler temperatures expected Wednesday through Sunday.

&&

.DISCUSSION (This evening through Sunday)...
Issued at 203 PM EDT Sun Apr 26 2026

Surface analysis this afternoon shows high pressure in place over
Ontario and Quebec, spilling southwest across the Great Lakes to
Indiana. This was resulting in a cool, easterly flow. GOES19 shows
earlier stratus clouds had burned off, leading to mostly sunny skies
across central Indiana. Aloft, water vapor shows ridging in place
over Indiana and the Great Lakes extending into eastern Ontario.
Strong subsidence was shown over Indiana. Temperatures across the
the forecast area were rising through the 60s.

Quiet weather is expected this evening. The strong high pressure and
ridging in place aloft will continue to result in a dry column this
evening and into the early overnight hours. Given our dew points in
the lower 50s, lows mainly in the mid 50s will be expected.
Meanwhile, convection over the plains states overnight will begin to
propagate toward Indiana. Convective debris blow-off should begin
arrive late tonight allowing for some increasing high clouds.

AN ACTIVE WEATHER DAY IS EXPECTED ON MONDAY WITH BEST SEVERE WEATHER
POTENTIAL ON MONDAY NIGHT

As we begin Monday, there is uncertainty in regard to progression of
upstream convection that will have developed overnight. Models
disagree on how far and how long the remnants of that system will
linger across Indiana. If the remnants fail to reach Indiana, or
only produce high cloud that dissipates, the severe weather threat
for Monday night will be remain significant as favorable conditions
for heating and destabilization will be in place. Should the
remnants linger and prevent heating through the day, the severe
threat will be somewhat diminished. All of this is occurring because
the surface high will drift well east of Indiana tonight, allowing
the return of warm and more moist southerly flow and placing central
Indiana within the warm sector. Meanwhile aloft, a moderate short
wave pushing out of the plains will push toward Indiana, with
diffluent flow aloft, which will push to Indiana on Monday night.
Other ingredients in play include a moderate LLJ of 50-60 knots
ahead of the associated surface low pushing across Indiana and the
305K GFS isentropic surface shows strong mid level lift pushing into
Indiana during the afternoon and evening with high specific
humidity. Forecast soundings suggest favorable CAPE with values over
2K J/KG. Model CAMS are suggesting on convective developing over
Illinois in the afternoon, possibly supercellular, before pushing
eastward and transitioning to a strong QLCS pushing across Indiana.
Models differ on intensity of the line, but all seem to focus on a
rough time frame of 00Z-04Z. As these storms transition to QLCS, the
main weather hazard will be damaging straight line winds. Although
not the main threat, isolated, brief spin-up tornadoes will also be
possible. These storms should exit Indiana during the overnight
hours, ending the severe weather threat.

Thus summing up Monday, small chances for morning/lunchtime precip
due to leftover thunderstorms upstream, best chances for this are in
NW central Indiana. This will be followed by a mostly sunny and warm
afternoon with highs reaching the upper 70s to around 80, with
strong storms expected on Monday night.

For the moment, Tuesday looks dry as southwest flow will be in place
as an upper low sets up over Canada. Little in the way of upper
support looks to pass and forecast soundings suggest subsidence and
a dry column in the wake of the Monday night wave and cold front.
Look for highs on Tuesday to only reach around 70s.

Wednesday through Sunday...

Continued cooler weather is expected from mid week through the
weekend. This will be primarily due to a strong and broad area of
upper level low pressure over northern Ontario. This large low will
provide cool cyclonic flow across the NE quarter of the United
States, including Indiana. A steady stream of cool, Canadian air
will flow across Indiana during this time. Several short waves
within the cyclonic flow aloft look to pass from time to time. This
in combination with diurnal heating will bring chances for showers
most days. At the moment, a lack of a wave on Thursday along with a
dry column shown within forecast soundings suggest lesser chances on
that day, however confidence in that remains low due to possible
timing differences and changes that could occur in upcoming runs.
Within the lower levels, models suggest surface low passing near
Indiana on Wednesday and Friday, thus for the moment those appear to
the best days for showers and storms for the moment.

Compared to yesterday, models suggest pushing the upper low east on
Sunday now, as they did this on Saturday yesterday. Stronger high
pressure is shown to settle over Indiana and the Ohio Valley as yet
another cold front appear to approach from the northwest for Sunday
night.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 647 PM EDT Sun Apr 26 2026

Impacts:

- S-SE wind gusts 20 to 25 kt Monday
- Scattered to numerous convection, mainly Monday evening

Discussion:

Tonight will be quiet with mainly high clouds moving through.
Outside of convection, VFR conditions are expected through 00Z
Tuesday, with a gradual lowering of ceilings occurring. Winds will
increase Monday, with frequent gusts to around 25kt, with a
potential for a few gusts near 30kt in the afternoon.

Uncertainty ramps up quickly Monday in terms of rain. There could be
some weakening convection in the morning hours, mainly showers. Some
convection may develop after 18Z depending on mesoscale features,
but better odds of thunderstorms will occur after 22Z. Will use
PROB30s, but when details become clearer, TEMPOs will be needed in
later issuances.

&&

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

$$

AVIATION...50
DISCUSSION...Puma