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000
FXUS63 KIWX 171352
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
952 AM EDT Wed Apr 17 2024

.KEY MESSAGES...

- Isolated storms may redevelop this afternoon with large hail and
  damaging winds possible east of I-69.

- Showers and thunderstorms Thursday night.

- Cool and dry this weekend with highs mostly in the 50s and lows in
  the 30s. Frost possible.

&&

.UPDATE...
Issued at 951 AM EDT Wed Apr 17 2024

Some destablization continues across western Indiana in advance
of the approaching front. SBCAPE of around 1000 J/KG is in place
already in an uncapped environment. Showers and storms have been
slowly expanding in northwestern Indiana and should continue to
do so over the next several hours. While higher confidence in
severe weather still remains along and east of I-69 we will
need to watch storms west of I-69 given a lack of mixing out of
the 60 dewpoints that was suggested.

&&

.DISCUSSION...
Issued at 333 AM EDT Wed Apr 17 2024

A pair of upper level systems will bring 2 rounds of showers and
scattered storms to the area today. The initial round was ongoing in
an zone of isentropic lift per 305K GFS surface moving across
northern Indiana and far southern Lower Michigan at this time. SPC
mesoanalysis indicated virtually no instability. South Bend picked
up a quick >0.10" in less then 1 hour. Given the lack of shear and
no instability, do not expect any severe weather from these showers
and storms. However, the 2nd upper level system approaching from the
west will be accompanied by an occluding front. Several parameters
support the chance for severe weather, especially large hail and
damaging winds east of I-69. Bulk shear (0-6km) was already >
70kts from St Louis to Chicago per SPC mesoanalysis. Made some
major updates to lower shower/storm coverage per HRRR. The
latest HRRR favors VERY limited storm coverage today.

Otherwise, one last system will move across the area Thursday
night before cooler air and drier weather arrives for the
weekend. Severe storms should stay southwest and south of the
area given the surface low track. Rainfall amounts should be up
to half an inch and should not have major impacts on renewal of
recent flooding. At this time, frost is likely Saturday night
and Sunday night. The best chances for freezing temperatures are
near and north of the Michigan border.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 605 AM EDT Wed Apr 17 2024

Cutoff occlusion over sw MN will wobble east through the nrn lakes
today as downstream warm sector pinches off in time.
Decaying/residual low level moisture plume spreading into wrn zones
attm and supporting brief MVFR cigs near term. Any renewed
shower/storm development ahead of weakening sfc cold front will be
isolated/brief at best from late morning (west) into mid aftn (east)
as successive guidance continues to down trend. Primary aviation
issue remains with strong gradient srly gusts this morning veering
to wrly this aftn with gusts to 35kts likely.

&&

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

&&

$$

UPDATE...Fisher
DISCUSSION...Skipper
AVIATION...T