130
FXUS63 KIWX 231035
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
635 AM EDT Mon Sep 23 2024

.KEY MESSAGES...

- Dry today and not as warm with highs in the 70s.

- Scattered showers and thunderstorms arrive Tuesday and linger
  through much of the day.

- Dry midweek before a low chance (20-30%) of showers late this
  week into the weekend.

&&

.DISCUSSION...
Issued at 250 AM EDT Mon Sep 23 2024

The surface low that brought welcome rain to the area is now over
the eastern Great Lakes. Plenty of clouds upstream, however,
associated with a Pacific moisture plume arriving atop a Southeast
US Ridge. While dry weather is anticipated today, a surface low
lifts in from the southern Mississippi River Valley tonight. This
brings showers and thunderstorms by daybreak Tuesday that
lingers most of the day. I fear there is some bust potential
with how widespread this rainfall is. Guidance varies notably
with where the axis of heavy rainfall occurs. This primarily
hinges on how quickly showers and thunderstorms develop in the
vicinity of a strengthening 500-mb jet, improving moisture
transport, and potential deepening of the surface low. Generally
speaking, rain totals will be notably less Lakeside, while
those in northeast Indiana northwest Ohio could be in line for
0.75"-1" especially if thunderstorms develop in the afternoon.

Some CAMs indicate a high likelihood of thunderstorms Tuesday
afternoon in the vicinity of the low`s triple point and
baroclinic zone aloft. Forecast soundings are characterized by
tall, skinny CAPE profiles and increasing shear (30 knots
0-6km). Low- level lapse rates pale in comparison to Friday when
two microbursts occurred. Nonetheless, 7 C/km represents an
adequate value for an isolated damaging wind threat. Hodographs
present some concern for rotating mesocyclones as well. This all
will be worth monitoring over the next 24 hours and will hinge
on how well we can destabilize Tuesday afternoon.

Drying out Wednesday with highs in the low-to-mid 70s. A subtle
warming trend follows as heights rise aloft in response to a
ridge just east of the Four Corners. Trouble is brewing in the
Gulf of Mexico and the tropical system that follows could bring
rain to at least a portion of our area over the weekend. First,
said moisture would need to overcome a Great Lakes ridge (sound
familiar?). At this distance, hard to deviate much from the in-
house blend which calls for 20-30% chance of showers late this
week and into the weekend.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 635 AM EDT Mon Sep 23 2024

Postfrontal CAA and residual boundary layer moisture will
continue to support low stratus through the morning. KSBN
currently at 300ft but will slowly improve over the next few
hours with MVFR expected by 14Z. Low MVFR likely to hold at KFWA
though some brief IFR ceilings not impossible around sunrise.
Both sites will return to VFR by 18Z as mixing and dry air
advection increase. Return to MVFR late tonight though as next
low pressure system approaches.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...Beach Hazards Statement until 4 PM CDT this afternoon for
     INZ103.
OH...None.
MI...Beach Hazards Statement until 5 PM EDT this afternoon for
     MIZ177-277.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LMZ043-
     046.

&&

$$

DISCUSSION...Brown
AVIATION...AGD