710
FXUS63 KIWX 151627
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
1227 PM EDT Sat Jun 15 2024

.KEY MESSAGES...

- Warm and dry this weekend with partly to mostly sunny skies.
  Highs will be in the upper 70s and low to mid 80s today, then
  climb into the upper 80s and low 90s Sunday.

- Hot and humid conditions prevail Monday into next weekend,
  with highs in the 90s. Monday will be exceptionally hot, with
  widespread highs in the mid to upper 90s. Heat indices will
  range from 95 to 105 through the week.

- Isolated showers and thunderstorms are possible daily next
  week, mainly in the afternoon and evening hours.

&&

.DISCUSSION...
Issued at 430 AM EDT Sat Jun 15 2024

All aboard the heat train from now until next weekend! High
temperatures today will be in the upper 70s and low to mid 80s, then
climb into the upper 80s and low 90s for Sunday. By Monday,
temperatures will climb into the mid to upper 90s, with heat indices
of 99 to 105. From Tuesday into next Monday, highs will be in the
90s, with locations generally along and south of US 24 seeing the
majority of the mid-upper 90s. Heat indices in these areas will be
around 100 degrees. While most of the event will reach heat advisory
levels, the prolonged nature of the event (through at least
Saturday) with heat indices around 100 degrees all week suggest a
possible need for an excessive heat watch. Held off on issuing any
headlines this shift per collaboration with the neighbors, as there
are still questions with respect to how much moisture, cloud cover,
and precipitation we can get. At the moment, think that NW OH and IN
counties south of US 24 (especially further east) have the best
chance for reaching excessive heat warning criteria. Outside of
that, temperatures will still be in the low 90s with heat indices
around 95 degrees--so those areas will still experience impacts-but
just may be more likely to stay in advisory criteria.

It should also be noted that we are in a moderate risk for the CPC 8-
14 day US Hazards outlook for excessive heat from June 22nd-24th
(Saturday into next Monday). The slight risk goes until Wednesday
the 26th. So we`re looking at a prolonged event in which impacts
will become cumulative. Even with the concerns of clouds/precip
outlined below, suspect we may need a heat watch for the entire area
just due to the advisory criteria lasting longer than 4 consecutive
days. Overnight lows will only drop into the upper 60s and 70s,
which limits recovery time.

Expect mostly dry conditions with variable cloud cover through the
week, though there are nearly daily LOW chances for afternoon
showers/storms. The tricky aspect of the forecast is that starting
Monday we`ll be on the periphery of a large upper level ridge, with
various shortwaves impinging on the north and west portions. With
abundant moisture/heat in place, we`ll be susceptible to any of
these more subtle waves, which are impossible to really pin down
specifically at this point. For now, carried 20-30 percent chances,
mainly in the afternoon/early evening hours of showers and storms.
Expect the coverage to be quite isolated for most cases-but if the
ridge does stay further east as the GFS depicts, coverage could be
more scattered to numerous at times.

&&

.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...MCD
AVIATION...Johnson