393
FXUS63 KIWX 241855
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
255 PM EDT Mon Jun 24 2024

.KEY MESSAGES...

- A line of thunderstorms is expected to move through late
  overnight through early Tuesday morning bringing a chance for
  locally strong/damaging winds.

- Confidence remains low on details regarding Tuesday
  afternoon/evening showers and thunderstorms. If these develop,
  large hail, damaging winds, and locally heavy rain will be
  main threats.

- Seasonable temperatures and dry conditions expected Thursday
  and Friday before additional rain chances return Saturday.

&&

.DISCUSSION...
Issued at 250 PM EDT Mon Jun 24 2024

After our extended heat wave last week, we return to a more
active, complex weather pattern over the next 24-36 hours.
Convection currently in the Dakotas and MN will grow upscale and
evolve into a MCS as we head through the evening and overnight
hours. Overall agreement is for this complex to maintain
intensity through Wisconsin where the greatest instability will
reside, along with the stronger shear. A gradual weakening
should take place as it works its way southeastward across SE
Lake Michigan and Indiana where a rapid dropoff in overnight
instability will be located. Nevertheless, mesoscale maintenance
of the stronger cells may allow them to produce instances of
strong/damaging wind gusts as they push into our forecast area
and the updated Day 1 Outlook from SPC now drags a Slight Risk
(2 of 5) into North Central Indiana and Southwest Michigan. CAMs
have begun to latch onto this better as well, and given the 4mb
pressure rises on the HRRR as the MCV moves across the lake,
there is some concern for seiche activity along with an increase
in wave action and rip current risk leading into Tuesday. Some
closer evaluation of this will be needed as we head into the
overnight hours...

In the wake of the late overnight into early tomorrow morning
convective complex, steep low/mid level lapse rates and hot
daytime temperatures will contribute to rapid and intense
instability across the forecast area. Bulk shear will be
limited, ranging from 20-30kt, which will likely prevent a more
significant severe episode if anything develops (more below). A
corridor of low LCL heights will be favorable for a tornado
environment, however, we will need existing surface boundaries
to enhance low level helicity as this parameter looks meager.
It`s worth noting that confidence in triggers due to the
aforementioned earlier convection, and a lack of strong forcing
during the day, may keep a lid on afternoon thunderstorms
altogether. Therefore, at this time, confidence is very low in
Tuesday afternoon/evening severe potential. If anything does
develop, the thermodynamic profile will help to create robust
updrafts with a hail and damaging wind threat; we`ll just have
to see how the AM convection shakes out first.

Fortunately, the hottest day of the week will be tomorrow
before a frontal passage returns us back into more seasonable
temperatures. We will have dry days on Thursday and Friday
before another shortwave and surface front brings additional
chances for rain and storms.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 218 PM EDT Mon Jun 24 2024

A lot of uncertainty on how upstream convection will develop,
evolve and move southeast into northern Indiana and impact the
terminals. For now, kept the PROB30 at SBN with VCTS at FWA.
Winds should increase from the south and then become southwest
late.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory from 2 AM to 2 PM EDT Tuesday for LMZ043-
     046.

&&

$$

DISCUSSION...Norman
AVIATION...Skipper