373
FXUS63 KIWX 120457
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
1257 AM EDT Thu Jun 12 2025

.KEY MESSAGES...

- Warm with highs in the lower to mid 80s today and Friday.

- There is a slight chance (20%) for isolated storms late this
  afternoon near the Michigan border.

- Chances for showers and embedded storms increase Friday
  afternoon (30-40%) into Saturday (50-80%). Locally heavy
  rainfall possible.

&&

.DISCUSSION...
Issued at 212 PM EDT Wed Jun 11 2025

Warmer low level southwest flow under a quasi-zonal upper-level
pattern will persist through the end of the week with highs well
into the 80s and a gradual increase in humidity levels. At the
surface, a weak west-to-east oriented frontal boundary is expected
to sage southward to near the Michigan border Thursday into early
Thursday evening. The atmosphere destabilizes (~1500 j/kg of SBCAPE)
by mid-late afternoon with a few storms possible (20%) near the
shallow convergent boundary. Brief downpours, lightning and gusts to
30 mph the only threats given the lacking flow and forcing aloft.

Attention later Friday through Saturday evening will turn to a
moisture-laden upper low lifting northeast from southern Plains to
the Mid MS/OH Valleys. The associated moisture advection with
precipitable water values nearing 1.75 inches should lead to more
widespread coverage of showers and embedded storms. However, it
is worth noting that model guidance continues to differ on
timing and track given the interaction with subtle shortwaves
tracking east through the Upper Midwest and Great Lakes in zonal
flow. This leaves some uncertainty on how quickly showers reach
the area Friday into Friday night, with Saturday likely the
best bet locally for numerous showers and possibly some locally
heavy rainfall given the high moisture content. Sunday then a
drier/seasonable day as the bulk of guidance shunts this system
and frontal zone off to the south-southeast.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1228 AM EDT Thu Jun 12 2025

The bottom line as far as storms - it will be very difficult to
overcome the combination of dry air entrainment, stable mid
level lapse rates and a capping inversion at the base of the
subsidence. The dynamics with a very weak front should not be
enough to trigger storms. Have kept storms out of TAFs given
these parameters. Winds should stay south to southwest at 3-8
knots with very weak synoptic flow. Some haze or smoke may be
present, but at this time the concentration appears low and does
not appear to be operationally significant.

&&

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

&&

$$

DISCUSSION...Steinwedel
AVIATION...Skipper