FXUS63 KIWX 191829
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
229 PM EDT Tue May 19 2026

.KEY MESSAGES...

- Strong to severe storms are possible today through 9 PM EDT.
 
- Damaging wind gusts to 60 mph and heavy rain are the 
  main threats. Low but non-zero risk for hail and an isolated 
  tornado.

- Warm and humid again today with highs in the mid to upper 80s.

- Cooler and dry midweek with highs only in the 60s Wednesday
  and Thursday.
 
- Next chance for rain and a few storms arrive Friday.

&&

.DISCUSSION...
Issued at 225 PM EDT Tue May 19 2026

A cold front currently positioned over Wisconsin and Illinois 
will swing eastward and through the local forecast area this 
evening. Ahead of this front, strong to severe storms will become 
possible this afternoon and evening. The region is well into the 
warm sector with temperatures in the upper 70s to mid 80s and 
dewpoints in the upper 60s to low 70s. The moisture combined 
with daytime heating supports SBCAPE of 2000-2500 J/kg, 
especially east of the I-69 corridor where cloud cover has been 
minimal today. Destabilization is beginning to occur with 
cumulus development evident on satellite. The best chances for 
strong to severe storms will be 3-9 PM EDT today. The greatest 
risk area will be along and south of US-24, where a Slight Risk 
(level 2 of 5) for severe weather is in place. Shear is still 
expected to be weak given a fairly unidirectional vertical wind 
profile, but it will be better than the past few days at 20 to 
30 kts. With weaker shear, the favored storm mode will be 
multicell clusters or line segments. Given DCAPE over 1000 J/kg 
this afternoon and evening and steep low level lapse rates of 
7-8 C/km, damaging winds will be the main threat today. 
Confidence in isolated tornado chances is decreasing due to 
current low level SRH less than 150 m2/s2, and forecast to 
decrease today. If one were to develop, the potential is still 
greatest in NW Ohio, which will have the longest time to heat up
and destabilize today as the cold front takes its time moving 
in from west to east. With PWATs now around 1.5-1.6", even if 
storm clusters are not severe, they will likely be efficient 
with rainfall rates in excess of 1"/hr.

After the passage of the cold front, the second half of the workweek 
will be much cooler with highs only in the 60s through Friday. Rain 
showers will likely be continuing southeast of US-24 on Wednesday 
morning before drier air moves in. The next chance for rain will 
then be on Friday afternoon in association with a shortwave coming 
up from the southwest. We could get a bit of a break on Saturday 
before a stronger upper trough moves across the region on Sunday. 
Unsettled weather will also be possible on Memorial Day, especially 
south of US-30, but model agreement is poor so there is low 
confidence in forecast specifics.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1255 PM EDT Tue May 19 2026

Afternoon destabilization ahead of a cold front is expected to
allow storms to develop rapidly. The satellite picture indicated
a line of convection was developing near the southeast shore of
Lake Michigan. There was a very tight CAPE gradient over Indiana
with values between 2500 to 3000 J/Kg to the east (and values
much lower to the west). All indications are storms will develop
rapidly near and and northwest of SBN, so have included SBN in 
thunderstorms at the start of the TAF period. Winds will shift 
to the northwest behind the front with the activity moving 
southeast of SBN. As for FWA, convection should fill in with the
front, so went for a higher confidence (22-02Z) with chances 
for storms after 02Z. Winds should shift to the northwest at 
both sites with lingering ceilings VFR or close to 030.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LMZ043-
     046.

&&

$$

DISCUSSION...Cobb
AVIATION...Skipper