254
FXUS63 KIWX 160912
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
512 AM EDT Mon Jun 16 2025

.KEY MESSAGES...

- Warming trend continues today and Tuesday. Peak afternoon
  heat indices near 90 degrees on Tuesday and Wednesday.

- There is a 20% to 40% chance showers and storms along and
  southeast of the US 24 corridor this afternoon and tonight.

- Multiple rounds of showers and storms likely late Tuesday
  night through Wednesday night. There is the potential for
  severe storms and heavy rainfall on Wednesday.

- The warmest and most humid air of the season so far arrives
  this coming weekend.

&&

.DISCUSSION...
Issued at 1254 AM EDT Mon Jun 16 2025

With western periphery of a low level ridge in place over the
CWA, dry conditions will continue through at least this morning.
A southern stream weak trough axis will ripple through the
zonal flow through the eastern half of the CONUS. This
disturbance will provide enough instability that will allow for
the development of scattered showers and a few thunderstorms
especially south and southeast of the US-24 corridor this
afternoon and evening.

In the wake of this disturbance a southwesterly push of more
humid and warmer airmass ahead of a ridge axis extending
northwest from an associated broad ridge building over the
southern US. Dew points will surge higher on Tuesday going from
the upper 50s today to values in the lower 70s by Tuesday
afternoon before slightly increasing further by a couple degrees
on Wednesday. These higher dew points coupled with high
temperatures in the upper 80s on Tuesday and in the mid 80s on
Wednesday will make for very uncomfortable conditions. This will
also increase chances for instability showers and thunderstorms
on Tuesday evening into Wednesday. The exact evolution of
convection further west of the area on Tuesday into Wednesday
and how much of that convection continues on Wednesday morning
is still uncertain this far out. However, these details will
dictate where the best potential for severe weather on Wednesday
afternoon will exist due to the forcing provided by a cool
frontal boundary dropping southeastward through the CWA
associated with a shortwave trough originating over the Pacific
Northwest and moving eastward through the flow into the region
on Wednesday. PWATs on Wednesday will be just shy of 2 inches
and this adds the potential for localized flooding with any of
the thunderstorms. SPC does currently have our entire CWA marked
for a slight risk of severe storms on Wednesday.

A brief reprieve from the heat and humidity will take place on
Thursday in the wake of the cool front. But, ridging over the
central CONUS begins to build north and eastward into the region
on Friday and by the weekend dew points will be back into the
lower 70s and daytime highs will be back into the upper 80s and
lower 90s. Sunday morning low temperatures will only drop into
the 70s which will not provide much of a break from the
uncomfortable conditions.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 510 AM EDT Mon Jun 16 2025

The stagnant pattern will continue north of the Ohio River with
weak flow through the mid levels and stable conditions aloft.
Winds should stay under 10 knots but should veer from the
northeast to the southeast.

&&

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

&&

$$

DISCUSSION...Andersen
AVIATION...Skipper