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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KIWX 160443
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
1243 AM EDT Tue Apr 16 2024

.KEY MESSAGES...

- Low confidence on coverage and intensity of showers/storms
  late Tuesday afternoon into Tuesday evening.

- Somewhat higher confidence on strong to severe storms
  Wednesday afternoon into early evening.

- Much cooler this weekend into early next week with some frost
  potential.

&&

.DISCUSSION...
Issued at 246 PM EDT Mon Apr 15 2024

Low confidence forecast for the next 24 to 36 hours as elevated warm
front edges north tonight across the area and sfc warm front arrives
late Tue afternoon into Tuesday night.  A few CAMs suggest some
widely scattered, elevated showers and storms developing on the nose
of increasing 850 mb theta-e, spreading into SW parts of the area
towards 12Z Tue and then working NE before weakening. Will maintain
some low pops for consistency and blending with other offices, but
think activity likely very limited with no severe threat. Additional
showers and storms may develop on the sfc warm front and somewhat
better influx of moisture Tuesday afternoon and evening, with most
likely scenario being convection advecting in from the west
(initiation over E IA into W IL) vs developing overhead or just to
the SW. Have kept pops somewhat limited at this point with likely
pops far SW late Tuesday afternoon and ramping up Tuesday night.
Confidence in coverage, intensity and longevity of upstream
convection into the area remains low as it outruns the more
favorable environment, despite strong shear over the area in the
vicinity of the northward advancing front. Do expected elevated
showers and isolated storms to advance through the area through 6Z
with trends continuing to suggest a faster progress east or
weakening trend after 6Z. Have maintained categorical pops Tuesday
night, but tried to add some resolution (3 hour blocks) and trend
slowly downward with eastward extent. Do suspect pops could be very
overdone (warranting no more than likely west to chc east), but
again for sake of consistency and blending will let later shifts see
what, if any changes are needed as many mesoscale details remain
troublesome. New SPCDY2 marginal risk area has been trimmed
somewhat, limiting to far SW counties mainly during the evening
hours. Any threat would involve isolated hail to 1" in diameter
given the elevated nature.

Confidence does continue to increase somewhat as the area resides in
the warm sector of the approaching system (sfc low likely somewhere
over SE Minnesota around 12Z Wed). Effective shear on the order of
40 kts or more near/along the cold front will help with potential
organization of convection that should develop in the 15-18Z window
to the west of the area and then move quickly east. Main challenges
on coverage and intensity of the storms will lean on if the
advertised low to maybe mid 60 dewpoints advect in along and ahead
of the front and if we can see sufficient clearing (even
partial) to allow for greater MLCAPE to take shape. SWODY3
outlook of slight risk in the SE appears reasonable as this is
the most likely area that can recover and have sufficient time
to see the arrival of the moisture. Damaging winds and large
hail would be the main threats, but an isolated tornado is
possible. While heavy rain will accompany the storms, think
everything will move along fast enough to limit residence time
over any given area. Will need to monitor trends but no flood
watches should be needed.

Compared to the next couple of days, remainder of the forecast
period will be much quieter as the region will be dominated by a
northwestern flow associated with a deep upper low that will remain
in Canada and eventually move to Hudson Bay. This will bring some
light shower chances Thursday into Friday along with falling
temperatures (eventually below normal). With the growing season now
officially underway, we will need to monitor for frost potential
late in the forecast period, but plenty of time to sort this
out.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
-- Changed Discussion --
Issued at 1243 AM EDT Tue Apr 16 2024

VFR this period within wrn flank of retreating sfc ridge although
some showers possible late period as decaying remnants of upstream
convection this aftn trickle ewd this evening. Otherwise gusty serly
winds by late morning.
-- End Changed Discussion --

&&

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

&&

$$

DISCUSSION...Fisher
AVIATION...T