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248
FXUS63 KIWX 242157
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
557 PM EDT Fri May 24 2024

.KEY MESSAGES...

- Shower and thunderstorms return this afternoon, moreso this
  evening, with severe storms possible, mainly west of Indiana
  15/US 131.

- Greater chances for showers and thunderstorms Sunday
  afternoon and night with both severe storms and possibly heavy
  rain/hydro issues existing.

- Lingering showers may impact activities on Memorial Day and
  Tuesday.

&&

.UPDATE...
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Issued at 554 PM EDT Fri May 24 2024

The strong to severe threat looks isolated/limited locally into this
evening, though will have to monitor a multicell cluster and
associated outflow wind segment(s) that could bring isolated wind
damage to areas east into our northeast/central IN zones through 8-9
pm. The main cold front, upstream near the IA/IL border, is
currently active and will shift slowly east through the area later
tonight with additional chances for storms. Not expecting much in
the way of a severe threat though given poor timing and worked over
air mass (small hail possible given lingering steep mid level lapse
rates).
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&&

.DISCUSSION...
Issued at 210 PM EDT Fri May 24 2024

A low pressure system moving through the Midwest today is expected
to bring thunderstorms to the area this afternoon and evening. A
line of storms currently moving through northern Illinois could
reach the western extent of our forecast area as early as 3 pm.
However, isolated storms are beginning to pop up ahead of this line,
in the vicinity of a warm front draped from Berrien County southeast
through Allen County and into Ohio. This will lift slowly northward
this afternoon, and sfc CAPE will increase to over 2000 J/kg with
dewpoints rising into the 60s. Yet bulk shear is marginal at only
around 25-30 kts, so main threat will be strong outflow winds. High-
res models have not done a very good job capturing the ongoing
convection, so confidence is low in the exact timing and location of
storms, but still think the best chances for rain will be between 8
pm and 4 am when the cold front pushes in. The front will still be
over the area Saturday morning with lingering showers, but as it
makes its way east, drier air under northwesterly flow will dominate
through Saturday night.

Another low pressure system will arrive on Sunday afternoon with
more showers and thunderstorms. This has a better chance of severe
weather with NAM sfc CAPE up to 4000 J/kg and bulk shear 50+ kts.
There is also a greater threat for heavy rain on Sunday evening with
precipitable water increasing to around 2 inches. Rain may be slow
to move east Monday morning, but by Memorial Day evening, most
locations should be dry. It will also be much cooler behind this
system with highs only in the low 70s and breezy winds.

Large scale troughing over the eastern half of the US means that
unsettled weather will continue on Tuesday. On Wednesday, high
pressure will build over the plains, and drier conditions will
return, though it will remain cool. It will stay dry on Thursday,
but warm a bit as the ridge shifts east.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
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Issued at 554 PM EDT Fri May 24 2024

Outflow boundary and thunder chances have pushed east of KSBN with
dry conditions expected to start. Upstream cold front near the IA/IL
border does push east through KSBN late this evening into the early
overnight thunderstorms possible, though confidence on this activity
hanging together remains low.

Will continue to monitor multicell cluster now west-southwest of the
KFWA that will have the potential to bring a round of convection and
possibly some brief gusty winds this evening. Mainly VFR and
trending dry otherwise through the day tomorrow.
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&&

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

&&

$$

UPDATE...Steinwedel
DISCUSSION...Cobb
AVIATION...Steinwedel