Greenwood, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

152
FXUS63 KLOT 111945
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
245 PM CDT Sat Apr 11 2026

.KEY MESSAGES...

- An unseasonably warm and humid pattern will arrive on Sunday
  and persist through at least the middle of the workweek,
  accompanied by periodic showers and thunderstorms, and a
  threat for severe weather Monday night through Wednesday.

&&

.DISCUSSION...
Issued at 245 PM CDT Sat Apr 11 2026

Our Saturday began with sunny skies, but blowoff cirrostratus
from a decaying MCS along the IA/MO state line is now filtering
our sunshine for the afternoon. Temperatures are a few degrees
warmer than this time yesterday sitting in the 50s across the
area as of 2 PM. That decaying system will survive as a cluster
of showers as it progresses over our area later today and
tonight. Showers look to approach the I-39 corridor toward the
end of this afternoon and work eastward through the evening,
primarily across areas north and west of the I-55 corridor. Deep
layer moisture and marginal instability provide a potential for
a few heavy downpours and possibly a couple of embedded storms.
If any surface-base storms get going, they may attempt to
organize given an impressive 0-1 km shear profile, but parameter
spacing for organized convection looks pretty messy outside of
this, so the potential is low. These showers will move away from
the area late tonight.

A strong warm advective regime will spread into the region on
Sunday sandwiched between a strong high over the Mid-Atlantic
and deepening Plains cyclone. This will bring both unseasonably
mild temperatures and windy conditions to Sunday. A northern
Plains low will lift its warm front north across the area Sunday
night and temperatures should begin warming prior to daybreak.
Middle and upper 70s are expected by the afternoon. Strong SSW
winds will allow for such a warmup and gusts to 35 to 40+ mph
are forecast for the late morning and afternoon.

At least the first half of Sunday looks dry with gusty winds
and maybe a few breaks in the clouds. Suppose an isolated shower
or two can`t be ruled out earlier in the day amid the deep
moist upglide. Precip will blossom out to our west during the
afternoon out ahead of a sharp, moisture-laden shortwave impulse
ejecting out of the southern Plains. Scattered showers could
get going in our western CWA as early as early-mid afternoon
with precip coverage expanding across the CWA into the evening
as the wave lifts through the area. Despite the warm surface
temps on Sunday, relatively warm air aloft will generate very
marginal instability. For this reason, not expecting anything in
the way of severe convection on Sunday. Enough instability
should be around to certainly offer a chance for some embedded
thunderstorms, though thunder coverage may be fairly slim. The
biggest concern with storms later Sunday would be pockets of
very heavy rain given the deep layer saturation. Most of the
rain, including the heavy rain and thunder potential, should
move away from the area prior to the start of Monday, but a few
showers could linger into the morning.

A drier airmass will work into the region behind the wave
clearing out precip by Monday morning. That aforementioned low
pressure center will progress across the upper Midwest Sunday
night, but its cold front will get hung up to our northwest.
This will then serve as the warm front for a deepening low
spinning up over the Plains. This will lock us in an open warm
sector and keep the low level warm advection going into Monday.
However, the middle and upper levels will cool in the wake of
the departing wave leading to steep mid- level lapse rates and
high instability aloft on Monday. Throughout the day, though,
any apparent convective triggers will remain outside of the CWA.
There`s disagreement on how much capping we`ll maintain in the
warm sector during the day, but the boundary layer looks to
remain markedly capped at least into early afternoon and
guidance generally isn`t resolving any free convection going up
in our area. So thunder coverage during most of the day looks
likely scarce, if any, but certainly can`t rule out the
potential for some freely convecting storms in the PM hours
given that instability and a *potentially* uncapped boundary
layer.

The primary window of concern for Monday would be during the
evening and mainly across our north. Guidance likes the idea of
an MCS charging east across the upper Midwest as a strong
shortwave impulse interacts with the surface warm front. There
is uncertainty on how far north into WI the front will set up
and the MCS will track. A majority of medium range camps
including the GFS, NAM, and RDPS track storms Monday evening
across northern or north-central WI which would greatly limit or
altogether prevent thunder coverage down into IL. However, the
Euro has consistently been parking the front just north of the
state line which would give us a better shot at getting in on
some of that evening convection, especially across our northern
CWA. The latest day 3 outlook from the Storm Prediction Center
lines up well with this thinking having a Slight Risk (Level
2/5) along and north of the WI state line with a Marginal Risk
extending south to about I-80. Any storms that do develop in our
area on Monday would have the ingredients necessary to become
severe.

Additional opportunities for severe weather in the region exist
on Tuesday and Wednesday, although uncertainty grows after
Monday. Anomalously warm, moist, and unstable airmass will
remain in place into Tuesday with highs progged in the lower 80s
away from the lake. Convection is anticipated to blossom east
of that aforementioned Plains low during the PM hours. Guidance
is struggling with where to track this low and the
position/orientation of the warm front which will have
implications on convective chances locally. But simply given the
ambient environment at hand being strongly supportive of deep,
robust convection, will want to maintain a close eye on forecast
trends during this period. The center of the low looks to work
across the upper Midwest on Wednesday or Wednesday night driving
a strongly forced cold front through the area, but again with
lots of uncertainty in the timing and path. While not quite as
unstable, a convectively favorable environment will be found
ahead of this front and whatever is lost in instability may be
made up for by a strengthening shear profile and forced ascent
along the front. A lot of details are obviously yet to be ironed
out, so stay up to date on the forecast for Wednesday as well.
Continued warmer-than- normal conditions are favored during the
latter half of the week.

Doom

&&

.AVIATION /18Z TAFS THROUGH 00Z MONDAY/...
Issued at 1216 PM CDT Sat Apr 11 2026

Generally east to southeast winds and gradually thickening mid
to upper-level cloud cover will prevail through the afternoon
as a surface high pressure system centered on the Great Lakes
starts shifting eastward.

This evening and overnight, an MCV currently drifting eastward
along the IA/MO border will shift into the Lower Great Lakes.
With a pocket of dry air in place across the region, the
expectation is that precipitation will begin to wane as the
circulation approaches the area this evening. Nevertheless,
will maintain the inherited PROB30 groups for VFR SHRA focused
on the 00-06Z timeframe. Renewed shower and thunderstorm
development is expected overnight as a low-level jet develops
and intersects the remnant circulation. While CAM guidance
favors renewed convective development across Wisconsin
overnight, do have some concern eventual development could end
up a hair further south (near RFD and possibly even DPA/ORD)
given the center of the MCV is further south than depicted in
guidance. Did consider adding additional PROB30 groups for the
early morning hours for this potential, but felt the probability
is a hair below 30% at this point in time. This will be
something to monitor for later TAF packages. Winds will turn
southeasterly to southerly overnight.

After daybreak, winds will turn southwesterly and increase in
magnitude as mixing builds into the base of the LLJ. Gusts may
quickly ramp up to 30-35kt by the end of the TAF package.

For the last 6 hours of the 30-hour TAF window at ORD/MDW,
increasing low-level moisture and warm-air advection will
support the development of convective instability by
midafternoon. As a convectively-invogorated shortwave approaches
the region by evening, isolated to scattered convection may
develop within the airspace. As a result, opted to introduce
PROB30 groups for TSRA for the last portion of the outgoing TAF.

Borchardt

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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