165
FXUS63 KIWX 120113
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
913 PM EDT Thu Jul 11 2024

.KEY MESSAGES...

- Some patchy fog possible again late tonight into early Friday
  morning, especially west of Interstate 69.

- Periodic chances for showers and thunderstorms between Friday
  and the middle of next week. There is a potential of some
  strong to severe thunderstorms at times during the Sunday
  through Tuesday period.

- 90 degree high temperatures are most possible Sunday through
  Tuesday of next week, dependent on thunderstorm chances.

&&

.UPDATE...
Issued at 904 PM EDT Thu Jul 11 2024

Scattered showers and thunderstorms have diminished across most
of the area this evening with development of weak surface based
CIN. The exception is across far southwest portions of the area
where some isolated stronger showers continue in a pocket of
locally stronger low level convergence and best lingering
SBCAPEs on order of 500-1000 J/kg. While lower coverage trend
should continue through remainder of the evening, upstream flow
is highly perturbed with several short waves progressing across
the Ohio Valley and Great Lakes region into Friday. Will
maintain these low PoPs through the night with some slight
increase in coverage possible again overnight as a vort max
across the Corn Belt gets sheared into the Ohio River Valley.
With some possibility of lower cloud cover across the west, a
better source of near sfc moisture from recent rainfall, and
light winds...will add some patchy fog mention for areas west of
Interstate 69 late tonight into early Friday.

&&

.DISCUSSION...
Issued at 122 PM EDT Thu Jul 11 2024

Orphaned disturbance over nw IL caught within elongated
leftover upper troughing through the wrn lakes will slowly
liftout into ern ON by late Fri. A ribbon of sfc confluence and
weak moisture return out ahead of this sys stretches from ern IA
into cntrl IN and the focus for aftn tstorm development.

Cam solutions are fairly robust and initiate convection after
21Z far south/sw in proximity to this zone of weak convergence
which will move little if any through this aftn. Certainly
favorable destabilization underway here and will retain low chc
pops to account. Otherwise general liftout of this sys will
afford some nwd spread in weak return flow overnight of which
may prompt some shower development late toward ne IN/nw OH
similar to what was observed across nrn IL this morning.
Tomorrow sfc confluence zone expected to mix further north into
the US6 corridor and again support at least isolated storms in
the aftn timed with favorable destabilization. No severe wx is
expected either today or tomorrow in light of poor mid lvl lapse
rates, weak forcing and weak flow.

However that will all change significantly in coming days as
the plains centered thermal ridge amplifies and heats, leading
to a potentially stormy period Sun-Tue. Otherwise in tandem with
upper ridge building, a return of very warm and humid wx is on
tap.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 740 PM EDT Thu Jul 11 2024

Scattered showers and isolated thunderstorms continue early this
evening, primarily along and east of the Interstate 69 corridor.
Several outflows from these showers have triggered additional
showers and a few thunderstorms. Waning diurnal instability
should limit additional thunderstorms with probability of
thunder affecting KFWA too low for an inclusion at this time.
Coverage of showers should diminish through 03Z, but isolated to
scattered showers should persist into late evening/early
overnight as a pair of upper level upstream short waves track
across the southern Great Lakes. The last of these short waves
should be slow to track across northern Indiana on Friday with
weak low level convergence reflection of this wave. This should
yield some additional isolated-scattered convection but
confidence in coverage and location is too low to include. VFR
conditions are expected through most of the period, with
possible exception of late tonight/early Friday with some patchy
fog potential. Currently expecting best chances of this fog west
of Interstate 69 where some reduced cloud cover is possible
overnight and where remnant low level moisture from recent rain
is more plentiful.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.

&&

$$

UPDATE...Marsili
DISCUSSION...T
AVIATION...Marsili