758
FXUS63 KIWX 151831
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
231 PM EDT Sat Jun 15 2024

.KEY MESSAGES...

- Hot and increasingly humid conditions to dominate much of the
  forecast with heat indicies either side of 100 degrees and
  warm overnight lows. Greatest concerns exist Wednesday through
  Saturday.

- Showers/storms are possible Sunday night into Monday as is a
  trend towards somewhat cooler conditions.

- The hot and dry pattern will likely set the stage for a
  return to drought conditions for some areas.

&&

.DISCUSSION...
Issued at 230 PM EDT Sat Jun 15 2024

The big picture forecast is pretty straight forward for much of the
upcoming 7 days with heat and humidity becoming a concern as summer
settles in with a vengeance. Despite this, there are some
details that lead to challenges in terms of handling of the
greatest periods of concern and related headlines.

The center of a stronger upper level ridge will situate over the
Carolinas Sunday, remaining in place and expanding its influence to
locations further and further NW with time through the upcoming
week. Heights of 586 to 590 dm will edge in for Sunday through
Tuesday resulting in highs climbing to near or just above 90. Model
blend is running quite high wrt to highs on Monday with mid 90s
seeming unrealistic given the lack of significantly dry
conditions and noted upper level heights and low temperatures
profiles. Have lowered a few degrees for both Monday and Monday
night to account for this. While still quite warm, this causes
some challenges wrt headlines as heat indices (based on a 65
degree dewpoint) would also be in the low to mid 90s. Further
increasing concerns is the fact that 700 mb temps (area looked
at for capping of the unstable airmass) will generally be 8 to
10 degrees C, which while still strong, can allow some cu
development and even widely scattered showers/storms in what
will be a rather unstable environment. No strong signals as to
triggers this far out that would increase confidence of anything
developing like some models indicate, but a subtle disturbance
passing through at the right time could allow for some
development. Extensive collaboration took place with surrounding
offices and given some of the concerns for Monday and Tuesday,
no heat related headlines will be issued with continued emphasis
on social media posts and the HWO to cover. Those outside
should not focus on the lack of headlines with regards to
ensuring you take plenty of breaks and remain hydrated.

Upper level heights begin to increase starting Wednesday and really
take hold Thursday through at least Saturday ((592-596 dm),
suggesting highs in the low to mid 90s and no chances for
precipitation. This combined with dewpoints in the mid 60s or
higher leads to a greater likihood for heat headlines as heat
indices reach at least 95 to 100 and possibly higher along with
warm overnight lows resulting in a lack of cooling for those
with no or ineffective means to cool.

Med range models do agree on a trough approaching the area Sunday
night into Monday which may bring a chance for some showers and
thunderstorms along with somewhat cooler temperatures. More than
enough to worry about before we get there, but have left the slgt
chc to chc pops in place.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1226 PM EDT Sat Jun 15 2024

No changes needed to the 18Z TAFs. VFR conditions prevail
throughout the period at KSBN and KFWA with light winds out of
the east.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Air Quality Alert from midnight tonight to midnight EDT Sunday
     night for INZ020.
OH...None.
MI...None.
MARINE...None.

&&

$$

DISCUSSION...Fisher
AVIATION...Johnson