485
FXUS63 KIND 050238
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1038 PM EDT Mon May 4 2026

.KEY MESSAGES...

- Scattered showers and thunderstorms pushing northward,
  through the afternoon. Potential for severe winds and hail this
  evening into tonight.

- Cooler and rainy on Tuesday. Heavier rain late Tuesday could lead
  to localized flooding.

- Largely below normal this upcoming week, with multiple chances for
  additional rain.

&&

.MESOSCALE UPDATE...
Issued at 1038 PM EDT Mon May 4 2026

Main focus for this evening`s update/mesoscale discussion will be on
the severe threat during the overnight hours across Central Indiana.

Strong upper level divergence over the region in this split flow
pattern in addition to an approaching surface cold front from the
north create more than enough lift for precipitation development
tonight. A strengthening 45-50 kt LLJ ahead of the front will work
to sustain upstream convection and help induce convective
development across Illinois early this evening. Despite a good set
up aloft, poor moisture return northward has resulted in 20-25+
degree dew point depressions across Indiana today. ACARs soundings
look more like an inverted Vs with high LCLs nearing 700mb and steep
mid to upper lapse rates above it around 8-8.5C/Km. While not the
best environment for severe weather, this unique set up for Indiana
in May can support multi and discrete cells capable of producing
some strong winds and hail.

Radar over Illinois has shown a lot of convective development over
the past hour in response to mass upper level divergence on top of a
strong low level jet. The environment west of Indiana is a bit more
conducive for these storms with better lapse rates, slightly higher
dew points, and CAPE of 500-1000+ J/kg. Observations and soundings
show little to no CAPE over Indiana this evening and it will be a
struggle for the atmosphere to destabilize through the overnight
hours. While there are a many convective parameters favoring a
threat for damaging winds and hail from these high based storms, the
lack of CAPE over Indiana may significantly decrease the overall
severe threat as storms approach the IL/IN border.

Currently watching a cluster of storms in Central Illinois producing
quarter size hail at times. Expect these storms to weaken over the
next few hours as they make their way along the I-74 and I-70
corridors. Best chance for any hail will be in Western Indiana in
the 11pm to 1am timeframe. The strong wind threat (gusts up to
50mph) may persist throughout the night as steeper low level lapse
rates within a fairly dry boundary layer will be conducive for
stronger winds to mix to the surface under any shower or storm.
Still, confidence remains low in severe gusts at or above 60 mph as
the storms weaken.

The first round of storms will make its way into Central Indiana
from the west in the 11PM to 1AM timeframe. At the same time,
watching a cluster of thunderstorms and bowing segments along the
cold front in Northern Illinois sagging southeastward. CAMs shows
both of these areas of storms combining during the overnight hours
as they weaken. Northwestern portions of Central Indiana including
Lafayette may have a better strong wind threat as a bowing segment
near Bloomington, IL heads in that direction over the next couple
hours. OVerall, not too concerned with the severe threat for Central
Indiana tonight. Would not be surprised to see an isolated damaging
wind gust or large hail report, but for the most part everything
should remain below severe limits. With that said, gusty winds,
small hail, and lightning can be threats with any of these storms.

&&

.DISCUSSION (This evening through Monday)...
Issued at 325 PM EDT Mon May 4 2026

This afternoon, scattered showers with isolated lightning are
slowly pushing northward. Winds aloft are sitting around 50-55 mph,
with gusts up to 50 mph periodically mixing down to the ground
within stronger showers. Outside of the rain, gusts of 20-35 mph are
also mixing down and these winds are expected to continue into the
early overnight hours.

More showers and storms are expected to arrive this evening, ahead
of a cold front that will be pushing from NW to SE through from
tonight through early Wednesday morning. There is the potential for
severe storms this evening to tonight ahead of the front as winds
aloft and instability increase, potentially enough to overcome
the limited moisture at that time. Main threats will be damaging
winds as well as hail. The tor threat doesn`t look great, but it
is non- zero. The severe threat is expected to come to an end
within a few hours after midnight, but scattered showers and
storms will continue. Models show an additional surge of moisture
from the S/SW to arrive Tuesday afternoon into the overnight hours
then prompting localized flooding concerns, particularly across
our south. In total with this system, 1-2 inches are forecasted
through Wednesday morning, but locally higher amounts, again
mainly in the south, can`t be ruled out.

Also with the front, cooler temperatures arrive tomorrow and last
through much of the rest of the work week. Rain should come to an
end by Wednesday morning or midday, exiting to the SE.

Overall upper pattern remains unchanged for Thursday and on. Models
suggest the upper low that provided the cold front remaining over
eastern Canada, keeping the continued cyclonic flow in place aloft
over much of the eastern 1/2 of the country including Indiana. This
will keep a steady stream of below normal temperatures in place
across Indiana from Thursday through the weekend. Meanwhile at the
surface, a series of weak highs and lows will look to pass. High
pressure is expected to push across the area on THursday, before a
weak trough passes on Friday. Another high arrives for Saturday
followed by a slightly more organized low on Sunday. Given the
cyclonic flow in place aloft, and forecast soundings suggest cold
air aloft with steep lapse rates available each day, daily
convection cannot be ruled out and for the moment, additional
support appears available on Friday and Sunday. Thus daily chances
for rain will be expected in the forecast, however, this will be
mainly due to daily diurnal chances and the passing of the trough
and low on Friday and Sunday respectively. Overall, high confidence
of periodic showers during this period, but low confidence on
specific timing.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 757 PM EDT Mon May 4 2026

Impacts:

- Widely scattered strong storms possible near KHUF and KBMG 02-05z
timeframe
- Main line of storms from the NW moves through Central IN 04z-09z
- Gusty SW winds of 20-25 kt into the overnight hours, higher winds
likely in thunderstorms
- Another round of widespread rain after 12z persisting most of
Tuesday. TSRA may be along leading edge during late morning hours.
- Low MVFR to IFR ceilings starting early to mid morning and
persisting through the day

Discussion:

An active night for aviation weather expected over Central Indiana.
Satellite and radar show a cluster of storms developing in west
central Illinois and also a line of storms along a cold front in
Northern Illinois and Iowa. The cluster of strong to severe storms
may near KHUF and KBMG in the 02-04z timeframe if they can hold
together after sunset with hail, winds, and lightning all being
threats. Higher confidence exists in the line associated with the
cold front which will push southeast through Central Indiana around
the 04z-09z timeframe. Cloud bases should be fairly high, so there
is a good chance that cigs remain VFR with brief periods of MVFR or
worse vis in heavier rain. Erratic wind speeds and directions likely.

Expect wind gusts to remain elevated at 20-25 kts even after sunset
and ahead of the approaching front. Gusts may become more sporadic
after sunset however confidence remains high enough to keep them in
the TAF. Expect a wind shift to the north behind the front.

Widespread rain develops over Central Indiana, impacting all TAF
sites during the mid to late morning hours and persists through much
of the day. There may be a brief period of lightning on the leading
edge of this rainfall before the environment stabilizes and the
lightning threat diminishes during the afternoon. Ceilings are
expected to drop to MVFR around and after 12z and eventually to IFR
as a cold front moves through from NW to SE. Visibilities should
also drop to MVFR within the rain as well.


&&

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

$$

MESOSCALE...CM
AVIATION...CM
DISCUSSION...KF/ Puma