560
FXUS63 KIND 240712
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
312 AM EDT Tue Sep 24 2024

.KEY MESSAGES...

- Showers and a few thunderstorms continue at times through today,
  with a low chance for an isolated strong to severe storm

- Seasonable temperatures for much of this week with highs in the
  70s and lower 80s and lows in the 50s and 60s

- Potential for more rain late week into the weekend from tropical
  remnants

&&

.SHORT TERM (Today and tonight)...
Issued at 311 AM EDT Tue Sep 24 2024

Bit of a messy situation today as weak low pressure over the lower
Ohio Valley is expected to lift north/northeastward through the
region today into tonight, aided by a lead shortwave/MCV and a
developing cutoff upper low moving into the area.

Disorganized convective complex is moving through southern Indiana
at this hour, with little activity upstream, though high resolution
models suggest some additional development later in the night and
into the morning hours as a broad southwesterly 20-25KT low level
jet interacts with the surface low and attendant boundaries, which
seems reasonable - but broadly speaking, late tonight into the
morning looks to be a relative lull in activity, with significant
uncertainty as to coverage and intensity of showers and
thunderstorms later in the day given limited insolation and
destabilization potential. Some modest deep layer shear is present,
and MCVs are well known to locally enhance low level shear, though
the bulk of the impact from this feature may be more to our south.
Given these factors, the marginal risk for severe over the east is
not unreasonable, but may be limited by weak instability unless
greater cloud breaks develop this afternoon than currently
anticipated.

Profiles will begin to dry rapidly from aloft as the system exits
the area to the east tonight, with perhaps some lingering showers in
the far east just after sunset. Low level moisture could potentially
produce a few spits of drizzle, but will more likely just keep cloud
cover in place across the area throughout the night.

Ensemble spread is relatively low on temps, though NBM appears too
warm today, particularly in the northwest where the cold front will
pass through earlier than elsewhere and cloud cover is likely to be
quite persistent. Have made adjustments in this regard. Lingering
cloud cover, low level moisture, and advection quickly becoming
neutral as the upper low stalls will prevent temperatures from
dropping too dramatically overnight, with mid 50s to low 60s
appearing likely.

&&

.LONG TERM (Wednesday through Monday)...
Issued at 311 AM EDT Tue Sep 24 2024

More rain is in store for the long term although confidence in
precise timing and coverage is low based on the still to be
determined evolution of Potential Tropical Storm Nine, seen on GOES-
16 IR satellite, well to the south of Cuba. There is growing
confidence that trough, currently over the eastern Dakotas, will
plunge southeast across the Ozarks on Wednesday before cutting off .
The strength and circulation of this is expected to hasten the
northward and northeastern progress of what will eventually, likely
become a Hurricane according to NHC. The official NHC track as the
remnants of this tropical cyclone reaching eastern Kentucky by 00z
Saturday and then wrapping around the Ozarks upper low in Fujiwhara
effect fashion. As it does so plenty of tropical moisture will
spread across the Ohio Valley. There is differences on how fast the
moisture and associated rain will get to central Indiana based
partially on the strength of a shaping Great Lakes ridge. That said,
most signs point to Friday as being the timing with the greatest
potential for rainfall. The upper low is expected to absorb the
tropical cyclone remnants this weekend, and then models and
ensembles suggest it will lift northeast across the Ohio Valley late
this weekend and early next week by getting kicked out by a strong
northern Plains and south central Canadian trough. All in all, this
supports PoPs lingering into the weekend and beyond.

There is some concern early this weekend for a few tropical storm
brief spin ups to the right of the storm path, which would favor more
eastern parts of central Indiana. Meanwhile, Friday looks like it
could get windy with the low pressure gradient tightening ahead of
the remnants.

The extensive cloud cover will limit temperatures with afternoon
highs mostly in the 70s and overnight lows in the 60s. These
high temperatures are near normal and lows above normal.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 124 AM EDT Tue Sep 24 2024

Impacts:

- MVFR or worse conditions through the night into early afternoon
  Tuesday, with periods of IFR

- Periods of showers and perhaps a few thunderstorms the night into
  Tuesday

Discussion:

Ceilings vary from high end MVFR to IFR at this time, and expect
conditions to deteriorate through the night with a period of IFR
likely at all sites late tonight into Tuesday morning, before
gradual improvement through the day. VFR conditions will likely
return by late afternoon or evening at all sites.

Showers can be expected at times, with some thunderstorms possible,
though odds are far too low for anything beyond a vicinity mention
at HUF/BMG early in the period as a cluster of storms moves nearby
in the first few hours.

Visibilities will be restricted at times both in showers and fog,
primarily through the night.

VFR conditions should return to all sites during the late afternoon
or evening hours at the latest tonight.

Winds will be around 10KT or less throughout the period, variable at
times overnight but generally veering from easterly to westerly as
low pressure passes through the area.

&&

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

&&

$$

SHORT TERM...Nield
LONG TERM...MK
AVIATION...Nield