Stroh, Indiana Weather Forecast Discussion

801
FXUS63 KIWX 202326
AFDIWX
Area Forecast Discussion
National Weather Service Northern Indiana
726 PM EDT Sat Sep 20 2025
.KEY MESSAGES...
- A wet period is ahead this entire upcoming week with numerous
chances for showers.
- Isolated to scattered thunderstorms are possible most days.
- The best chance for marginally severe storms is Sunday with
  strong to possibly damaging winds the greatest threat.
&&
.DISCUSSION...
Issued at 107 PM EDT Sat Sep 20 2025
Scattered showers and an occasional isolated thunderstorm were
occurring west of Highway 31 and mainly west of a line from Eau
Claire to SBN to Monticello. Locally heavy rainfall of 1-2
inches had fallen earlier with showers and storms. The latest
HRRR indicates more activity should redevelop tonight after 01Z
(9pm EDT) west of Interstate 69. Severe weather is not expected
but locally heavy rainfall is possible.
The SPC has the entire forecast area in a Marginal severe storm
risk Sunday. More energy from the upper level trof should reach
northern Indiana and be accompanied by unidirectional flow at 20
to 30 knots with CAPE values < 800 J/Kg. The best chances for
any strong to severe storms favor 3pm EDT to 11pm EDT. Strong
to possibly damaging winds are the greatest threat.
A very active pattern is setting up that will persist through the
upcoming week. A negatively tilted upper level trof had developed
over the forecast area as energy from the Pacific had topped the
upstream ridge. Numerous impulses of energy throughout this upcoming
week will bring showers and scattered storms as this pattern
persists.  The latest WPC forecast indicates over 3 inches of rain
are expected through Friday night.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 722 PM EDT Sat Sep 20 2025
Showers and thunderstorms will continue to stream S to N within a
moisture axis and colocated LLJ this afternoon and evening. With the
instability dissipating after sunset have allowed for the conversion
of the VCTS/tempo -shra to just -shra the first few hours of the TAF
period. Rain appears heavy enough that it could bring MVFR flight
conditions to SBN, but nailing down if it hits or misses is the main
question. Will use a tempo group between 2 and 6z for the
potential of these conditions within rain during that time
period. Thereafter, the moisture and jet axis shifts eastward
with some potential for the rain to completely miss FWA. As a
result, am inclined to keep FWA dry until after 12z when another
wave moves through the area. There is some potential for things
to dry out during the day Sunday until later that
afternoon/evening. At this point, am inclined to leave SBN and
FWA dry until that evening period and will use prob30 to
indicate the afternoon/evening chance.
Winds become light and variable if not easterly overnight before
taking over out of the south on Sunday. Given mixing potential and
the low level jet setting up overhead, 10 kts sustained is likely
and some gusts around 20 kts will be possible at SBN, which the jet
is closest. Decided to leave the gusts out for now, but the next
shift will want to weigh that possibility in its issuance.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...None.
&&
$$
DISCUSSION...Skipper
AVIATION...Roller

NWS IWX Office Area Forecast Discussion