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574
FXUS63 KIWX 240743
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
343 AM EDT Fri May 24 2024

.KEY MESSAGES...

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- Driest periods of the holiday weekend look to be through this
  afternoon and again Saturday through early Sunday.

- Shower and thunderstorm chances return this afternoon and
  evening with strong to possibly severe storms 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.
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&&

.DISCUSSION...
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Issued at 253 AM EDT Fri May 24 2024

Unfortunately, this holiday weekend period there will be
several active weather periods into next week beginning later
today. A low pressure system currently over the Dakotas will
move northeastward into Minnesota and an associated warm front
draped southeastward will move northward into the CWA today.
This will allow for a moistening of the air with dew points
getting back into the 60s once again. Highs today will be in the
low to mid 80s. Surface based CAPE values this afternoon will
approach 1500-2000 J/kg along with bulk shear values around
25-35 knots. This will set- up the atmosphere for some
convection that will be focused around a cold front further west
which will already have thunderstorms going earlier this
afternoon.

Expectation is around 18-19z the cold front and the accompanying
thunderstorms will be at the Mississippi river and should start
to enter our western parts of the CWA around 22z. A more
isolated coverage of thunderstorms will occur and then should
increase in coverage as the front gets closer. There is still
some questions on how strong the storms will be once they arrive
with the later timing and also with a more organized area of
convection that may push further north over Lake Michigan.
Latest HRRR guidance suggests an MCV develops over northern IL
and heads northeastward with scattered thunderstorms building
southward over our CWA. However, with the aforementioned
instability and sufficient shear over the area would not be
surprised for some of the thunderstorms to become strong to
severe. The main threats as of now looks to be wind and somewhat
less so being hail. Further west into northern IL the SPC does
have a 5% tornado probability and around a 2% area for the far
western parts of northern IN. SPC also still has mainly the
western portions of our area under a slight risk and further
eastern sections as marginal for severe storms. The cold front
should push through most of the area after 12z on Saturday
however a few remaining showers and thunderstorms will be
possible into Saturday afternoon for mainly east of I-69.

Once the cold front moves through on Saturday clearing skies
will be left in it`s wake and slightly cooler and more
comfortable airmass. Highs will be in the lower 70s closer to
the lake and upper 70s to low 80s for areas further south and
east. This will be the better part weather wise of the holiday
weekend and will continue into early Sunday morning. Another
developing low over the Plains will then move northeastward and
pass just northwest of the area but will bring another
rinse/repeat scenario with a warm front on Sunday morning
increasing clouds and chances of showers along with a slug of
moisture with dew points getting into the mid to upper 60s.
Highs will also warm back into the upper 70s and low 80s.
Another cold front will then move through Sunday evening
bringing another chance of strong to severe thunderstorms. SPC
currently has Sunday marked with a 15% chance of severe storms.

Lingering showers and a few thunderstorms will continue for
Memorial Day into Tuesday. Temperatures will be cooler both days
with highs each day in the lower 70s with northern parts of the
CWA struggling to get out of the 60s. The next break in
precipitation chances look to come by Wednesday into Thursday
with broad ridging moving into the center of the CONUS which
will bring a warming trend into the end of next week.
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&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 144 AM EDT Fri May 24 2024

Predominantly VFR conditions at the TAF sites outside of
potential MVFR/IFR with any showers and thunderstorms that move
through after 00z. Most of the model guidance keeps KSBN dry
until 2z, but there are a few stragglers that suggest earlier
timing (more like 22-01z). Added VCTS for 1z onward, with a
prob30 to account for potentially impactful showers/storms that
arrive with a frontal boundary. Similarly, most of guidance
(with the exception of the RAP) keep precipitation out of KFWA
until after 3z, so have added VCSH for now. Held off on thunder
mention given low confidence (may be closer to 6-7z when storms
arrive). Otherwise, light and variable flow will strengthen out
of the ESE and gradually shift southward through the evening.

&&

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

&&

$$

DISCUSSION...Andersen
AVIATION...MCD