Special Weather Statement, NWS Lincoln, IL

Area Forecast Discussion
National Weather Service Lincoln IL
200 PM CDT Sun May 6 2018

.SHORT TERM...(This evening through Monday)
ISSUED AT 200 PM CDT Sun May 6 2018

Boundary moving across Illinois this afternoon will push south of
the state overnight taking any remnant clouds and isolated pcpn
with it. High pressure will build into the state for Monday
enabling dry and sunny weather. Temperatures should drop off a bit
from today as cool northeast flow persists, but still should be
close to normal for early May.

&&

.LONG TERM...(Monday night through Sunday)
ISSUED AT 200 PM CDT Sun May 6 2018

High pressure will dominate Illinois through Tuesday evening ahead
of the next short-wave scheduled to impact the area midweek. 12z
models in good agreement in strength and timing the diving energy
coming around the western ridge and into the Midwest. Strength of
this wave should dig enough to weaken the ridge along the Gulf
coast enough to allow advection of Gulf moisture into the system.

This added moisture should trigger enhanced instability and
sufficient shear is progged to enable convective development.
Strength will be throttled by timing and whether their will be
sufficient heating with abundant cloud cover. 12z GFS and ECMWF
both bring the system in during the first half of the day which
would limit the strength of any convection.

12z GFS continues the run-to-run trend of morphing toward the
established EMCWF solution for a cutoff system to develop over
the intermountian west with waves of energy ejecting northeast
into the upper Midwest. Still lots of uncertainty regarding where
associated frontal system will set up and whether it will be near
enough to give central and southeast Illinois occasional
convection. Will keep best chances for precipitation over the
northern portion of the forecast area for the most part from
Thursday into Saturday.

Although timing is slightly different, operational models bring a
strong northern stream wave into the Midwest over the weekend
pushing the front south and through the area Saturday Day and
Sunday. Depending on the evolution, instability may interact with
enhanced shear associated with the wave to bring a round of strong
convection to the forecast area Late Saturday or Sunday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1201 PM CDT Sun May 6 2018

Cool front and associated showers are currently moving mostly out
of the central Illinois terminals as short-wave moves southeast of
the area. A decrease in cloud cover will follow. However, a
secondary boundary will shift winds from northwest to northeast
during the late afternoon and evening. Models remain divergent in
forecasting the evolution of potential convection this afternoon
and evening with this boundary. CAMs continue to indicate some
development this afternoon while synoptic models are downplaying
the potential. The CAMs should do a better job resolving the
storm-scale processes that would lead to initiation, but given the
dry airmass in place there remains significant uncertainty. Will
use vicinity to indicate potential. Any convection that does
develop will have a potential of wind gusts up to 35-40 kts given
the dry boundary layer.

Clouds and any possible convection should dissapate fairly early
this evening. Mostly clear skies and northeast winds around 10kts
should persist through much of Monday.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM...Barker
LONG TERM...Barker
AVIATION...Barker

Hazardous Weather Outlook
National Weather Service Lincoln IL
314 PM CDT Sun May 6 2018

ILZ027>031-036>038-040>057-061>063-066>068-071>073-071100-
Cass-Champaign-Christian-Clark-Clay-Coles-Crawford-Cumberland-
De Witt-Douglas-Edgar-Effingham-Fulton-Jasper-Knox-Lawrence-Logan-
Macon-Marshall-Mason-McLean-Menard-Morgan-Moultrie-Peoria-Piatt-
Richland-Sangamon-Schuyler-Scott-Shelby-Stark-Tazewell-Vermilion-
Woodford-
314 PM CDT Sun May 6 2018

This Hazardous Weather Outlook is for portions of central
Illinois, east central Illinois, southeast Illinois and west
central Illinois.

.DAY ONE...TONIGHT...

Widely scattered thunderstorms will be possible for the remainder
of this afternoon into early this evening. Although the
thunderstorms are not expected to be severe, a few of the stronger
storms will be capable of producing wind gusts around 40 mph and
small hail.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY...

Thunderstorm chances return by Wednesday, and some of these storms
have the potential to be strong to severe.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated through tonight.

Smith

Special Weather Statement
National Weather Service Lincoln IL
346 PM CDT SUN MAY 6 2018

ILZ041-042-048-051-062130-
Logan-Sangamon-Mason-Menard-
346 PM CDT SUN MAY 6 2018

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN MENARD...
SOUTHWESTERN LOGAN AND NORTHEASTERN SANGAMON COUNTIES UNTIL 430 PM
CDT...

At 345 PM CDT, Doppler radar was tracking a strong thunderstorm over
Middletown, or 9 miles southeast of Mason City, moving southeast at
20 mph.

Dime size hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Sherman, Riverton, Williamsville, Elkhart, Middletown, Cornland,
Spaulding, Dawson, Broadwell, Fancy Prairie and Sweetwater.

This includes the following highways...
 Interstate 55 between mile markers 104 and 119.
 Interstate 72 between mile markers 107 and 109.

LAT...LON 4011 8974 4020 8953 3991 8931 3982 8955
TIME...MOT...LOC 2045Z 332DEG 19KT 4009 8959

Smith