048
FXUS63 KIWX 120957
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
557 AM EDT Fri Jul 12 2024

.KEY MESSAGES...

* There remains chances (20-30%) for widely scattered showers and
  storms today, best chances during the afternoon.

* Periodic chances (20-40%) for thunderstorms Saturday night through
  Tuesday. There is the potential for severe storms, especially
  later Sunday night through Tuesday.

* Hot and humid conditions are expected Sunday and Monday,
  dependent on storm chances.

&&

.DISCUSSION...
Issued at 251 AM EDT Fri Jul 12 2024

A broad upper trough axis, currently over Lake MI and IL, will
track toward Lake Huron by this evening. Broad ascent on the
southern flank, and building SBCAPE up to 1500 j/kg, will likely
allow for widely scattered showers and storms to once again increase
in coverage today. Focus will be near a subtle quasi-stationary low
level boundary and outflows, best chances (20-30%) over
east/northeast portions as a well-defined vort max pivots east
through the lower Great Lakes. Similar to yesterday, any convection
should remain disorganized and transient given poor mid level lapse
rates and weak flow through the column. Subsidence and drying then
builds in Friday night into most of Saturday behind the departing
upper wave with dry/seasonable wx anticipated. Did continue to carry
a low PoP over western IN Saturday afternoon as weakening elevated
convection over IL could work in advance of an approaching warm
front.

A building instability reservoir does fold in on the northeast
fringe of a building thermal ridge with hot/humid conditions and
periodic storm chances Saturday night through Tuesday. Warm front
and associated impressive MUCAPE gradient does lift through in this
transition Saturday night into Sunday morning with initial chances
for convection, best chances north as a weakening MCS may accompany
a convectively aided disturbance tracking east-southeast through the
Great Lakes. A capped and muggy airmass follows in behind the warm
front into Sunday afternoon with heat indices possibly nearing
advisory levels (100), dependent on potential convective cloud
debris and boundary layer recovery if a more organized MCS tracks
through in the AM. Additional episodes of convection (strong to
severe potential) remains on the table later Sunday night through
Tuesday, though confidence on timing and impacts on temps are always
of lower predictability in these "ring of fire" west-northwest flow
summer regimes (hence the broadbrush chance PoPs through the
period). This pattern breaks down beyond Tuesday as an upper trough
drops into the Great Lakes forcing the active boundary and
instability off to the south.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 555 AM EDT Fri Jul 12 2024

Weak flow will persist over the area with nearly saturated
conditions at ground level at the onset. Light fog was in the
VCNTY of the terminals and may briefly encroach upon the
terminals early this morning. Otherwise, little if any winds
should be the rule. Kept VCTS at FWA given the diurnal
favorability for convection there.

&&

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

&&

$$

DISCUSSION...Steinwedel
AVIATION...Skipper