Indiana’s Weather For Sunday

HEADLINES
– Warm again, with severe storms this afternoon and early to mid evening.
– Much colder Monday.
– Heavy rain and possibly strong to severe storms again Wednesday.

COMPUTER MODELED RADAR AT 4PM, 6PM, AND 8PM

TODAY’S MAP

NWS TECHNICAL DISCUSSION

A strengthening upper trough will move into the western Great Lakes
by early evening. At the surface, a surface low will move into lower
Michigan, with a strong cold front associated with it. Plentiful
moisture will be continue to be pumped into the area, helped along
by near 50kt winds at 850mb.

SEVERE WEATHER POTENTIAL

Strong forcing with the system will tap into available instability
(which will exist despite clouds/scattered rain today) to produce
convection. Given the strong wind fields present with this system,
shear will be sufficient for convection to be organized.

Shear vectors are more parallel to the surface cold front, so would
expect mainly linear convection to prevail. That being said, there
could still be cells ahead of the line, especially across the
western forecast area earlier in the event. These could exhibit
supercell characteristics.

Given the above, feel that the primary threat will be damaging wind
gusts across central Indiana this afternoon into early to mid
evening hours. Large hail is also possible, again especially west
where individual cells are possible.

Tornadoes will be a threat as well, both with the individual cells
and along the linear convection with meso convective vorticies. The
highest threat for tornadoes looks to be in the southern forecast
area where favored parameters are highest.

The flash flooding threat for individual storms is low given the
expected speed of the convection. However, will have to watch for
the potential of training storms.

UNCERTAINTIES/OTHER SCENARIOS

More specific timing of the convection remains uncertain, with CAMs
having different ideas of how early convection gets into the western
forecast area. Some have the main convection arriving as early as 2-
3PM EDT while others are closer to a 4-6PM arrival. For now will
reluctantly continue with a larger window of convection timing until
details become clearer later today.

Another item to consider is the fate of the early morning convection
to the west. If it holds together it could impact the development of
the afternoon convection, including impacts from old outflow
boundaries.

Remainder of the Evening into the Overnight...

Rain chances will diminish during the night as the cold front moves
through, and cooler and drier air arrives behind it. Low
temperatures will be in the lower 40s most areas.

&&

.LONG TERM (Monday through Saturday)...
Issued at 336 AM EDT Sun Mar 30 2025

The long term period will start off dry and cooler with near to
slightly below normal temperatures. These conditions will be short
lived however as an active pattern sets up over the region from
midweek through at least the weekend.

The arrival of this pattern will start off with yet another day of
severe weather potential on Wednesday as surface low tracks from the
central Plains up to the upper Great Lakes. The associated warm
front is expected to move through during the morning, placing
central Indiana within the warm, moist sector for much of the day,
advecting in dew points in the 60s and high temperatures in the 70s.
At some point while in the warm sector through when the cold front
moves through (unclear exactly when the cold front moves through
yet, but potentially Wednesday night before stalling near southern
Indiana the remainder of the week) there is a threat for severe
weather. Details are lacking as convective models don`t go out far
enough yet, but lapse rates, CAPE, and SRH look to be high enough
for all severe hazards to be in play. With ample shear as well, non-
thunderstorm winds, potentially near 35-40 mph, will also be a
factor to contend with Wednesday. Hodographs in recent runs from
global models have some curvature to them, especially in southern
Indiana, thus hinting at the tornado threat.

While much of the details during the day Wednesday are unclear
outside of a severe threat being possible, there is also a higher
confidence in a flooding threat for the Ohio Valley for Wednesday
and beyond. Model soundings show a saturated column so a good amount
of moisture to work with, but the front setting up somewhere in the
region will continue the flooding threat into the weekend. For now,
it looks as if the boundary will set up just south of our forecast
area but could creep into south-central Indiana. As of now, it looks
like that boundary won`t push eastward until this weekend or early
next week when another progressive short wave arrives.

NWS CHARTS FOR TODAY/TONIGHT