406
FXUS63 KIWX 190004
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
804 PM EDT Thu Jul 18 2024

.KEY MESSAGES...

- Seasonably cool and dry through the weekend

- Increasing humidity and rain chances early next week

&&

.DISCUSSION...
Issued at 209 PM EDT Thu Jul 18 2024

A large upper level trough is currently draped across the
eastern United States and will move through the CWA Thursday and
Friday. As the trough moves eastward, light northerly flow
should continue for the rest of thursday, which will continue to
usher in dry and seasonably cool temperatures through today and
tonight. Highs should remain in the 70s with lows in the 50s.
High pressure begins building in over the CWA on Friday. This
building high pressure will keep the area dry through the
weekend with mostly sunny skies and limited cloud coverage.
Cloud coverage will likely increase into Sunday and early next
week as high pressure exits the area.

With the building high pressure, winds will become lighter and
more variable, and winds over Lake Michigan will shift from
northerly flow to more southerly flow starting Friday night.
With the changing wind flow over the lake, wave heights of 3 to
5 feet will begin to decrease tonight and wave heights and rip
current risk should remain low through most of the weekend. The
lack of northerly flow will also allow high temperatures to
creep back up into the 80s into the weekend.

Models seem confident in a weak mid to upper level trough dipping
into the upper midwest early next week around a large ridge out west
This upper level trough appears to linger and cutoff to the west of
our region. This will increase southerly and southwesterly flow over
the area. This upper level feature will help to increase humidity
and dewpoints across the great lakes region, which will likely
increase the chances for showers and thunderstorms going later into
Monday, as well as increased cloud coverage.

The chance for showers and storms increases through midweek as this
trough interacts with a Southeast US ridge. Moisture advection is
strong, as is arm air advection, thus humid conditions will
continue through midweek as well. Inherited POPs were broad, on
either side of 40% chance Monday afternoon through Friday which
is warranted given the aformentioned trough. It won`t be until
perhaps Thursday night that the trough axis clears. However,
active flow around the Southeast US ridge threatens to keep some
storms around. A return to summer-like heat is plausible late
next weekended with a 588+dm ridge advertised to our west.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 729 PM EDT Thu Jul 18 2024

Surface high pressure is nudging into the area this evening and will
stay stalled out across the Lower Great Lakes into early next week.
This will continue to bring prevailing VFR conditions to a large
portion of the TAF period. One question does arise at FWA where some
patchy ground fog may be able to form and could obstruct the
observation site a hours Friday morning, but don`t have enough
confidence to lower VISBY too much with this issuance. With the
arrival of the high pressure center, north winds veer more westerly
Friday morning at FWA, but are more variable at SBN where the high
pressure center is overhead.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...Roller