366
FXUS63 KIWX 031826
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
226 PM EDT Mon Jun 3 2024

.KEY MESSAGES...

- Warm and humid conditions will bring increasing chances for
  showers and thunderstorms Tuesday afternoon into Wednesday. Severe
  weather is not expected, but locally heavy rain is possible.

- Becoming cooler (closer to normal) for the second half of the
  week with drier conditions (low chances for showers/storms
  around 20%).


&&

.DISCUSSION...
Issued at 225 PM EDT Mon Jun 3 2024

A southerly flow, courtesy of slowly departing high pressure to the
east, will bring a summer-like feel to the area with highs well into
the 80s (warmest Tuesday) and dewpoints in the low to mid 60s (heat
indices mid to upper 80s). Scattered showes and storms are expected
to develop further west across eastern Iowa/NW IL and S WI ahead of
a MCV that will track NE. While a stray model run still attempts to
bring this activity into far NW areas this evening, impacts of the
ridge, loss of daytime heating and departure from the best moisture
and dynamics should result in a weakening trend that warrants no
more than slgt chcs for a few hours this evening.

While instability will increase Tuesday afternoon as highs in the
mid 80s and dewpoints in the low to mid 60s bring roughly 1000 J/KG
of SBCAPE which would normally lead to "pop-up" showers and storms,
several factors lean against development until the glancing blow of
the trough from the cut off upper low in Canada. Low and mid level
lapse rates will be below 6 C/KM and shear will be almost non-
existent and no real boundaries/triggers are anticipated in the
area. The only potential for a trigger could be with any MCV from
today`s convection that maybe drifts into the area. Have went silent
14% or less pops Tuesday morning and trimmed back/lowered pops
Tuesday afternoon.

Main trough arrives Tuesday night into Wednesday with some concering
signals that could indicate less in the way of coverage and impacts
for the area. The trough is moving through a bit quicker, resulting
in a less than favorable timing for fropa Tuedsay night into early
Wed. Models are picking up on this with any development in the west
Tuesday night likely weakening or dissipating overnight with re-
development moreso Wednesday afternoon when the trough will be
exiting the area as will the cold front. Overall model blends are
still bringing likely to cat pops, but may very well need some
serious adjustments over the next 24 hours or so.

GFS/EC/GEM are in somewhat better agreement on deep upper low diving
SE from northern Michigan Thursday morning to somewhere in the PA/NY
area by 12Z Sat. This will lead to cooler temperatures (near or
somewhat below normal) and scattered showers (isolated storm?) with
each disturbance rotating through the flow. Forecast will remain
muddled with slgt chc or chc pops mainly in the afternoon and
evening hours through the rest of the period as overall NW flow
remains in place. We will remain on the edge of it, which may result
in some larger temp gradients SW to NE. Highs may be too warm as
noted by the last shift, but given the strong June sun, doesn`t take
much to warm up.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 103 PM EDT Mon Jun 3 2024

Limited moisture at and under the base of a strong subsidence
inversion has allowed a scattered to occasional low cloud/MVFR
ceiling at FWA near 030. The clouds will mix out later today
with VFR conditions prevailing. A weak pressure gradient is
expected to support south winds under 10 knots through the
period.

&&

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

&&

$$

DISCUSSION...Fisher/Johnson
AVIATION...Skipper