116
FXUS63 KIWX 272250
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
650 PM EDT Thu Mar 27 2025

.KEY MESSAGES...

- Mild overnight with an increasing chance of showers and
  thunderstorms prior to daybreak.

- Drying out Friday afternoon but becoming breezy with southwest
  gusts up to 40 mph.

- Warm but rainy weekend with a chance of thunderstorms as well.

&&

.DISCUSSION...
Issued at 240 PM EDT Thu Mar 27 2025

Cyclogenesis is underway over the Central Plains this afternoon. In
the warm sector, extending into far western IL, convection is
underway and is anticipated to become reinvigorated overnight. This
boost is courtesy of a blossoming 60-knot 850-mb jet. While the
primary instability pool will reside over Iowa and western Illinois,
a broad corridor of 500 j/kg is noted on the 12z HREF primarily west
of I-69 overnight. Severe weather is not anticipated, though pea
sized hail cannot be ruled out as observed earlier today along the
ILX-LOT forecast border.

As the nose of this jet moves east, coverage of showers and
thunderstorms will diminish through Friday morning. There will be a
brief period of gusty southwest wind (35 to 40 mph) in the afternoon
as cloud cover decreases and we mix-down strong low-level winds. The
HREF indicates only a 10% to 20% chance of wind gusts greater than
45 mph Friday afternoon.

By Saturday morning, a large portion of our area could be split by
1) rain to the north over central Michigan (driven by Friday`s warm
front now relocated) and 2) renewed moisture advection to our south
across central IN. Low pressure emerging from the Rockies opposes an
offshore Southeast US ridge resulting in a steady dose of moisture
transport. There will be some dry hours Saturday, especially along
the north of the US 30 corridor. However, broad chance POPs remain
in the absence of high resolution guidance at this time. Thunder
appears unlikely Saturday owing to a lack of instability. Overnight,
rain lifts into northwest Ohio. Rain is perhaps most widespread
Sunday as the low moves across southern Lake Michigan. Meager
instability returns as well bringing thunder back to the forecast.
Paired with about 30 knots of shear, I imagine at least a sliver of
our forecast area will remain in a convective outlook by the Storm
Prediction Center. However, know that the overall severe weather
risk appears low for our local area.

Sharply colder Sunday night and Monday when highs will only be in
the 40s (compared to 70s Friday through Sunday). Milder by midweek
as zonal flow resumes. After Monday morning, the next chance for
widespread rain is Wednesday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 638 PM EDT Thu Mar 27 2025

VFR and mainly dry conditions outside of a isolated sprinkle
this evening. Overnight and into Friday morning, ahead of a
warm frontal boundary pushing northward into the region,
showers and even an embedded thunderstorm or two will be
possible after 07-08z Friday and lowering of cigs with the
frontal passage by late morning to early afternoon will bring
MVFR categories and in heavier showers slightly lowered cigs
may temporarily drop to IFR levels, especially for KSBN. After
16-17z Friday we begin to see cigs improve and VFR conditions
return. Post frontal we will see gusty southwest winds with
gusts up to 27 knots.

&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...None.
OH...None.
MI...None.
MARINE...Small Craft Advisory from 3 PM Friday to 4 AM EDT Saturday for
     LMZ043-046.

&&

$$

DISCUSSION...Brown
AVIATION...Andersen