958
FXUS63 KIWX 121035
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
635 AM EDT Wed Mar 12 2025

.KEY MESSAGES...

- Large temperature differences can be expected today from
  southwest to northeast. Much warmer temperatures arrive Thursday
  into Saturday with highs in the 70s Friday.

- A period of showers and storms is expected Friday night into
  early Saturday. While confidence is low, the potential exists
  for locally damaging wind gusts. Outside of any convection, it
  will be breezy.

- Even stronger winds are possible Saturday prior to the passage
  of a cold front. A period of gusts to 45 mph or possibly
  higher exists.

&&

.DISCUSSION...
Issued at 502 AM EDT Wed Mar 12 2025

A plethora of forecast challenges remains through Saturday
involving temperatures, periods of strong winds and even a
narrow window for strong to potentially severe thunderstorms.

Sfc front was located across southern IL/ON/OH with 850 mb
baroclinic zone sitting across the southern part of the forecast
area. Models continue to waver on how far north the low level
thermal gradient mixes north, resulting in highs in the low to
mid 60s vs the 50s north of the boundary. Minor adjustments were
made to the forecast, mainly far NE to add a few degrees, but
otherwise held with persistence, One other element adjusted was
to add some slightly higher wind gusts into the morning with sfc
obs depicts some occasional gusts of 20 to 25 kts as somewhat
higher wind fields above the sfc attempt to mix down. By the
time we reach Thursday, 850 mb front will make a more pronounced
surge north through the day. While some gradient will remain,
more of the area will enjoy temperatures into the 60s and even a
few 70s across the far south.

The much discussed, rapidly deepening trough and associated sfc
features will become the main focus starting Friday as an
increasing SW flow ushers in the warmest temperatures of the
year so far, as well as 2 windows of gusty winds and throw in a
small window for an area of convection in a low CAPE/high Shear
environment Friday night. Mixing of stronger wind fields will
start Friday into Friday night with gusts of 35 to 40 mph
expected prior to and even outside of any showers/storms that
may impact the area. Don`t think advisories will be needed for
this period, but something to watch. With regards to the
convective potential, the magnitude of the system taking shape
to our west and associated dry line sweeping in Friday night
will set the stage for severe storms moreso west and south of
the area Friday evening where an Enhanced risk was introduced in
the new DY3. As this convection moves E and N, it will likely
have some organization to it and could very well be a mature
QLCS as it approaches the Indiana state line. Models remain
consistent on quality of the low level moisture being less than
desired, but other elements such as strong shear, 60 to 70 kt
LLJ and steep mid level lapse rates all likely to make up for
the moisture. Unfortunately, as is often the case in this very
dynamic systems that have the sfc low well NW of the area, there
is a huge bust potential on either side. Some hints of
convection popping ahead of the main QLCS could disrupt the
overall organization, 6Z NAM pushes main surge of convection
into NW IL and then the eastward extent of the line becomes more
disjointed. Suffice to say, something to be monitored in the
next couple of days. If the severe threat can materialize,
damaging winds and maybe some spin up tornadoes would be the
main threat. The overall speed of the convection will likely
limit any QPF. Based on all of this, the new DY3 introduced a
slgt risk into our SW counties with a tight gradient for a
marginal risk NE from there.

And we aren`t done yet...as behind the dryline strong mixing of
dry air/subsidence and clearing skies will likely bring down
some potentially stout wind gusts mid morning Sat into Saturday
afternoon. Wind advisory level gusts seem fairly plausible
with lesser confidence on higher end gusts that could approach
warning criteria.

Limited attention was given to the periods beyond Saturday
night, with main items to note being a "cool down" Sunday into
Monday back to more normal levels followed by some moderation
thereafter and additional chances for some precip.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 635 AM EDT Wed Mar 12 2025

A stalled boundary resides just south of FWA tonight, but will
slowly meander northward as warm advection ensues and is also helped
along by diurnal heating. This allows for mainly east winds in the
first 12 hours of the TAF period and that`s also when the strongest
sustained winds are expected to be with some potentially reaching 10
kts at times. This boundary is dry and is expected to keep
conditions in VFR through the period.

&&

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

&&

$$

DISCUSSION...Fisher
AVIATION...Roller