Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 152011

Area Forecast Discussion
National Weather Service Lincoln IL
311 PM CDT Sat Jun 15 2019

.SHORT TERM...(This evening through Sunday)
ISSUED AT 310 PM CDT Sat Jun 15 2019

An active short term forecast period is in store for much of
central and southeast IL for the next 24-36 hours. First of all, a
Tornado Watch is in effect along and east of I-57 - but south of
Champaign/Vermilion counties - into mid-evening. An MCV, from
early morning convection across MO, has shifted into central IL in
Christian/Shelby counties. This feature is expected to enhance
severe thunderstorm potential in eastern IL into early evening. A
convergent low level wind flow and increasing instability near a
boundary just south of I-70 will provide the focus for convection
as it slowly lifts northward. Effective shear parameters in this
same area will provide the potential for a few supercells into
early evening.

In addition, convective clusters from southern MN into central IA
are expected to form into an MCS this evening, and move toward the
IL River Valley from late evening through midnight. The heaviest
rainfall this evening into early Sunday morning is expected to be
south of a Beardstown-Lincoln-Danville line, where another inch or
so of rain is anticipated. Much of this area has already had 1 to
3 inches of rain since last night, so the Flash Flood Watch will
continue through 7 am Sunday.

Most of the shorter range models indicate that we may see a brief
break in the rain Sunday morning as a front/outflow from the MCS
pushes down toward I-70. However, various waves moving along this
boundary in a moderate westerly upper level flow will cause the
front to waver across central IL Sunday afternoon-evening,
resulting in yet another round of showers and t-storms.


.LONG TERM...(Sunday night through Saturday)
ISSUED AT 310 PM CDT Sat Jun 15 2019

The story of the wavering frontal boundary looks like it will
continue through much of the upcoming week. The medium range
models may have their differences in exact timing of various
systems during the upcoming week, but one of the things they have
in common is the continuation of a nearly zonal flow. This will
keep a frontal boundary either in or very close to central/se IL,
which will provide the focus for daily chances of showers and
thunderstorms in most areas.

The exceptions will be along the IL River valley and toward the
I-55 corridor Tuesday/Tuesday night, and then again later on
Thursday when we may see a brief respite from the rainfall.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1258 PM CDT Sat Jun 15 2019

A variety of conditions are present across central and eastern IL
from residual affects of morning convection. IFR ceilings have
settled into areas along the IL River Valley and north of I-74.
This should decrease in coverage across the area as a small scale
circulation NW of St. Louis moves eastward and a few breaks in the
clouds develop.

Spotty showers will continue into late afternoon, before a bit
more widespread showers develop in response to the circulation/MCV
moving across central IL between I-72 and I-70. Generally, will
have VFR conditions during this time, dipping into MVFR levels
during the heavier showers/t-storms.

Thunderstorms have been developing across southern MN into central
IA late this morning into early afternoon. This is expected to
merge into another overnight MCS and drop SE toward central IL
tonight, around or shortly after midnight. Other areas of
convection will also be found along an outflow/weak warm front
close to the I-70 corridor late this evening through early
morning. Should see a bit of a break in the rain after daybreak
Sunday. However the residual low level moisture and relatively
lighter winds will result in IFR ceilings from PIA-BMI, with MVFR
ceilings to the south.


Flash Flood Watch through Sunday morning for ILZ041>057-061>063-



LONG TERM...Miller
AVIATION...Miller is the U.S. government's official web portal to all federal, state and local government web resources and services.