569
FXUS63 KIND 030146
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
946 PM EDT Thu May 2 2024

.KEY MESSAGES...

- Showers and thunderstorms move in overnight.

- Multiple chances for showers and storms throughout much of the
  forecast period, with continued above normal temperatures.

- Potential for severe weather during the middle of next week,
  highest chances Tuesday evening and Wednesday night.

&&

.FORECAST UPDATE...
Issued at 945 PM EDT Thu May 2 2024

Forecast is in good shape this evening. The warm front remains north
of central Indiana, and the relatively drier air remains in place
across the area with dewpoints in the upper 50s at many locations.

Isolated convection should remain just west and southwest of the
area for a couple of more hours, but as upper energy and a cold
front approach tonight, forcing and moisture will increase. This
will bring increasing coverage of showers and thunderstorms to the
area overnight. Relatively weak instability and low shear should
keep any thunderstorms below severe limits.

Previous forecast reflected this, so just tweaked hourly PoPs as
needed based on latest radar and short term model trends. Similarly,
tweaked temps and sky cover based on latest trends in observations.

&&

.SHORT TERM (This evening through Friday)...
Issued at 249 PM EDT Thu May 2 2024

As of 2pm, temperatures have climbed into the mid 80s across much of
central Indiana. With partly cloudy skies and a couple more hours of
heating...it is not out of the question that a few record high temps
are set before the day is out. A rather large cumulus field
signifies that we have reached our convective temps across most of
the area, however. This could act to limit further warming to only a
degree or two. Though some drier air filtering in from the south may
allow for a better rate of warming, especially south of Indy.

The aforementioned cumulus field has shown some vertical growth as a
low-level capping inversion is slowly eroded. Higher-res guidance
continues to depict a few showers or thunderstorms developing this
afternoon, especially near the warm front where richer moisture can
be found. Coverage will be limited, as large-scale lift is weak and
drier air is flowing from the south as mentioned before.
Nevertheless, ACARS/model soundings show sufficient mid-level dry
air for DCAPE values over 1000 J/Kg, which supports the potential
for gusty winds/downbursts. Additionally, lapse rates and CAPE
profiles support a marginal hail threat. Hail size may be limited by
weak storm top flow and a CAPE profile that tapers towards the top
of the hail growth zone. Overall, any strong wind gusts / hail will
be limited to the strongest updrafts...which will be very isolated
in nature.

Overnight, a cold front to our west begins to work its way into
Indiana. Richer moisture and forcing accompany it, and so our
chances for rain go up quite a bit. Most locations will see showers
at some point through tomorrow morning. A few thunderstorms may be
embedded within the area of showers, but weak lapse rates and low
shear should limit severe potential.

Rain slowly diminishes during the day on Friday as the front slowly
works its way through Indiana. Showers may persist on and off, along
with low cloud coverage, through the afternoon. Once the front
passes, gradual improvement is expected as we head into the weekend.

&&

.LONG TERM (Friday night through Thursday)...
Issued at 249 PM EDT Thu May 2 2024

Friday Night Through Sunday.

Active weather is expected for much of the long term period with
near daily chances for showers and thunderstorms with the potential
for severe weather at times next week. The first round is expected
Friday night into early Saturday with the passage of a cold front.
There will be little instability and only 15-20kts of effective bulk
shear with this frontal passage, so not expecting anything more than
a few rumbles of thunder and up to a half inch of QPF. Model
soundings show much drier air working in the aftermath of the
frontal passage which should help skies to quickly clear out for
much of Saturday.

This break in the rain will be brief with the next cold front
passage expected late Saturday night into early Sunday. There will
be a weak wave associated with the southern jet which may enhance
precipitation across the southern counties along with the potential
for a decaying MCS out of the northwest associated with the main
system. The front should be through by the early afternoon with
drier weather returning into late Sunday.

Monday Through Thursday.

On Monday a rapidly deepening upper level low pressure system will
eject eastwards from the Rockies and begin to travel to the
northeast with broad ascent across the Ohio Valley as a LLJ begins
to advect warm and moist air through the column. This low pressure
system is expected to slowly move through the Dakotas through
Thursday with daily chances for showers and thunderstorms across
central Indiana along with the potential for severe weather.

The timeframe for highest confidence in thunderstorms are Tuesday
evening and again Wednesday night as the cold front associated with
the main system finally pushes through. During both of those
timeframes, damaging winds and large hail are possible with the
highest confidence in severe weather during the overnight hours
Wednesday night into Thursday which is when shear will be
maximized ahead of the frontal passage. The pattern will then
shift late Thursday into the weekend with cooler and drier weather
as the flow aloft becomes more northwesterly.

MMEFS river runs show that the expected rainfall of 1-3 inches
between now and next Thursday shouldn`t cause much more than a
prolonging of action stage to low minor flooding through next week.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 656 PM EDT Thu May 2 2024

Impacts:

- MVFR conditions expected approximately 08-18Z

- Showers and isolated storms mainly overnight into Friday
  morning

Discussion:

First several hours of the TAF period will remain VFR. Isolated
convection will be possible, mainly north, but confidence and
coverage are too low to mention.

Overnight, showers and isolated storms will overspread the area,
reducing conditions to MVFR. There is a low chance of IFR at KBMG
which will have to be monitored. These will move out by early
afternoon Friday, but as a cold front moves through, there is a low
chance for additional convection. Winds will become north behind the
front.


&&

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

$$

UPDATE...50
SHORT TERM...Eckhoff
LONG TERM...White
AVIATION...50