277
FXUS63 KIWX 120936
AFDIWX

Area Forecast Discussion
National Weather Service Northern Indiana
536 AM EDT Mon May 12 2025

.KEY MESSAGES...

- Very warm with increasing humidity in the days ahead with
  highs in the 80s through midweek.

- Several dry hours today but there is a 20% to 40% chance of
  scattered showers and thunderstorms this afternoon.

- Periodic showers and storms expected much of the week, mainly
  during the afternoons. Later Thursday into Thursday night has
  a chance for severe weather.

&&

.DISCUSSION...
Issued at 315 AM EDT Mon May 12 2025

A cut-off low is swirling slowly northward, currently centered over
western Tennessee. High clouds are already streaming in across far
southern counties. Dew points are slowly rising but are in the 40s
or upper-30s. This will limit the chance for showers in the morning
and have thus been removed. Instead, the best moisture advection
occurs this afternoon as the low nears and the 850-mb jet
strengthens slightly over western Ohio. Showers this afternoon
appear widely scattered, primarily along and east of I-69 but some
showers could sneak as far west as US-31. Plenty of dry time today
however. Showers overnight lift north, primarily along a weak
deformation zone on the northern edge of the low, thus allowing
southern areas to dry out overnight.

Diurnally-enhanced showers and thunderstorms are then expected both
Tuesday and Wednesday afternoon. Tuesday afternoon is when showers
and thunderstorms may be most widespread as the center of the low
moves through central/southern Indiana. By this time, dry air will
have certainly been overcome and moisture transport will be free-
flowing from the Atlantic. It is quite plausible that Tuesday night
and is dry, but with the low still in proximity and given at least
low POPs inherited, can`t completely rule out the slight chance
overnight. The low tracks east Wednesday but lingering vort lobes
could be enough to spark a few showers and storms.

No significant change in thinking with respect to Thursday`s severe
weather risk. A deepening low across Minnesota will spread a cold
front eastward late in the day Thursday. Initial indications are
that our environment is on track for ample instability and shear for
storms, through the nocturnal arrival of storms from Illinois will
limit the eastward extent of the severe weather risk. Upper-level
support could be better as well, with guidance generally confining
the 70-knot 500mb jet to northern IL and southern WI.  As mentioned
in the previous discussion, the cold front may linger into Friday,
becoming the focus for additional storms.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 534 AM EDT Mon May 12 2025

Cutoff low over cntrl LA will slowly wobble newd into the lower OH
valley by late Tue. Backing downstream low level flow will aide
in a concerted push of mid lvl moisture across the terminals
toward early aftn of which may be enough to support a few high
based, light showers. Better moisture flux expected after dark
yet will hold with just a vcsh mention given little model
consensus yet. Nevertheless good boundary layer moistening in
time later this evening will support MVFR based cig
restrictions.

&&

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

&&

$$

DISCUSSION...Brown
AVIATION...T