361
FXUS63 KIND 031855
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
255 PM EDT Mon Jun 3 2024

.KEY MESSAGES...

- Warmer, periodic thunderstorm chances Tuesday and Wednesday. The
  best chances will be Wednesday late morning through the
  afternoon.

- Below normal temperatures in the 70s late week into the weekend

&&

.SHORT TERM (This evening through Tuesday)...
Issued at 254 PM EDT Mon Jun 3 2024

The main focus for the short term will be on timing and coverage of
convection associated with impulses in southwest flow aloft and
weak to moderate instability.

This afternoon, southerly winds and partly sunny skies have allowed
temperatures to climb a few degrees above average to the lower and
middle 80s. Hi-Res soundings are showing a gradual increase in
moisture through Tuesday. Although confidence in timing of any
convection is low, it appears convection will mostly hold off until
Tuesday afternoon as temperatures warm up and the atmosphere becomes
more unstable.

Winds will stay up enough to prevent any big fog issue and the
Hi-Res models agree.

The combination of southerly winds and increasing cloud cover should
keep temperatures no cooler than the middle 60s overnight.
Meanwhile, temperatures Tuesday afternoon should be on par with
today`s temperatures with above normal readings in the middle 80s.
If convection is more widespread than currently thinking, then
temperatures may not quite make it that high. Will go with 30-50%
PoPs for Tuesday afternoon with best chances southwest, closer to
the broad upper trough.

&&

.LONG TERM (Tuesday night through Monday)...
Issued at 254 PM EDT Mon Jun 3 2024

Tuesday Night and Wednesday:

By Tuesday night, central Indiana will be fully established in a
broad warm sector out in front of an amplifying trough. The primary
lift along an advancing surface trough will lag behind initially,
but diurnal convection and upscale growth upstream could lead to
some mesoscale features of ascent Tuesday night. Any thunderstorms
that do occur will likely be confined to a relatively small area,
but there is enough of a threat for a 20-50% chance of
rain/thunderstorms across the state throughout the night. Greatest
chances for precip will be over S/W portions of the area, strictly
due to their closer proximity to upstream convection. Continued
southerly moisture advection, and pockets of cloud cover will likely
keep overnight temperatures mild on Tuesday with lows in the upper
60s to near 70.

By Wednesday morning, the parent low and resulting surface trough
will be much closer to central Indiana, providing greater lift over
the area. Best lift for the morning will be within the greater mid
to upper level forcing near the pressure center over northern
Indiana. By the mid afternoon, low level destabilization will allow
for convective initiation to become more likely within surfaced
based forcing further south along the pressure trough. At this time
scattered to numerous cellular convection is expected to occur moving
slowly (15-25kts) to the east.

Thermodynamic profiles are still varied amongst CAM guidance, but
generally, 0-6km lapse rates between 7-7.5 C/km along with low LCLs
should lead to 2k+ J/kg of CAPE across most of central Indiana by
the early afternoon. High EL along with low LCLs will allow for
rather deep instability as well with rain rates expected to be high
within organized cells.

Overall shear will be more on the marginal side of the spectrum due
to the lack of upper level support, but there should be enough
concentrated in the 900-700mb layer for some updraft organization.
Given the potential for a handful of prolonged convective cell
growth, an isolated wind and hail threat will be possible. This will
primarily be a concern in the afternoon as 0-3km lapse rates
increase. Low level shear is also present (0-1km SRH around 100),
although low in magnitude, providing a minimal but non-zero tornado
threat.

By the evening, the pressure trough should be east of central
Indiana, with a drying surface layer in its wake. This essentially
ends the precip threat. Temperatures should remain near to above
seasonal behind this departing system, but dew point temperatures
are expected to be lower providing more comfortable conditions.


Thursday through Saturday:

NW flow will arrive for the late week into the early portions of the
weekend. AVA on the backside of the trough within this NW flow will
support low level height rises and eventually surface high pressure
over the Ohio Valley. This should keep conditions dry Thursday and
Friday. This dry pattern could continue through Saturday, but
uncertainty increases as the upper level ridge begins to break down.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1210 PM EDT Mon Jun 3 2024

Impacts:

- Thunderstorms and related MVFR flying conditions possible after
  10z-12z Tuesday

Discussion:

VFR flying conditions are expected the bulk of the TAF period,
however thunderstorms are possible by Tuesday morning. That said,
expected coverage is too low to mention in the TAFs.

Winds will be from the south less than 10 knots.


&&

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

$$

SHORT TERM...MK
LONG TERM...Updike
AVIATION...MK