892
FXUS63 KIWX 041707
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
107 PM EDT Tue Jun 4 2024

.KEY MESSAGES...

- Hot today followed by scattered showers and thunderstorms
  tonight.

- Showers and thunderstorms linger through Wednesday.

- Turning cooler starting Thursday with passing showers at
  times.

&&

.DISCUSSION...
Issued at 335 AM EDT Tue Jun 4 2024

Ridging over the Ohio Valley has steered showers and thunderstorms
over Wisconsin and into central Michigan early this morning.
Meanwhile, two additional features of note on water vapor: 1) a low
spinning over far western Arkansas and 2) a trough digging in over
Montana. The Arkansas low is forecast to slowly drift northeast in
response to a buckling upper-air pattern. Scattered thunderstorms
are forecast to develop over southern Illinois and Indiana in the
vicinity of this feature. Locally, forecast soundings are very dry
paired with shear of only 20 knots making pop-up convection unlikely
today. However, tonight scattered storms drift into the area with
now acceptable upper-level support while kinematics remain poor.
Overall coverage is uncertain with a variety of solutions among
guidance. Therefore, I generally offer "chance" POPs early tonight,
increasing prior to dawn Wednesday.

These rain chances increase as, what was the Montana trough is now
becoming cut off over the Canadian Prairies, and a cold front from
the surface low is spreading into the Great Lakes. A marginal risk
of severe thunderstorms was introduced by SPC primarily along and
east of I-69 Wednesday afternoon and evening ahead of the cold
front. Shear is lacking, but instability and lapse rates could prove
sufficient for a damaging wind gusts from discrete thunderstorms.

Cooler with sporadic showers in the days that follow as the upper-
level low swirls over the Great Lakes perhaps through the
weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 104 PM EDT Tue Jun 4 2024

VFR ceilings will persist for the next few hours, but mid level cumulus
clouds should start to build this afternoon in advance of
scattered showers/storms moving in this evening. Scattered
showers/storms will be hit or miss overnight, but have added
thunder at both terminals from 00-09Z Wednesday to account for
this. Ceilings will be MVFR to potentially IFR overnight and
Wednesday morning, with NBM probabilities of MVFR ceilings at
about 50-60%.Another round of rain/storms is likely Wednesday
afternoon as a cold front pushes through the forecast area.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...Johnson