Special Weather Statement, NWS Lincoln, IL

Area Forecast Discussion
National Weather Service Lincoln IL
325 PM CDT Sat Jun 16 2018

.SHORT TERM...(This evening through Sunday)
ISSUED AT 325 PM CDT Sat Jun 16 2018

Isolated thunderstorms have developed this afternoon: however, due
to synoptic subsidence and an increasingly strong mid-level cap,
areal coverage has been scant at best. Any cells that manage to
develop over the next couple of hours will be short-lived and will
dissipate by sunset. Mostly clear and warm conditions will be the
rule for tonight with overnight lows remaining in the lower to
middle 70s. Another hot and humid day will be on tap for Sunday as
the upper ridge in place across the Midwest/Ohio River Valley
continues to build. Resulting highs will reach the middle 90s,
with peak afternoon heat index values from 100 to 105 degrees.

&&

.LONG TERM...(Sunday night through Saturday)
ISSUED AT 325 PM CDT Sat Jun 16 2018

The heat will continue into Monday as the ridge holds firm and
temps once again reach the lower to middle 90s. Meanwhile, a
short-wave tracking across southern Canada will carve out a
prevailing trough over eastern Canada/New England by the middle of
next week. As this wave passes to the north, it will push a cold
front southward toward Illinois. Previous runs of the GFS had
suggested the wave would be strong enough to push the front
completely through the KILX CWA by Wednesday: however, the 12z
June 16 run now shows the front stalling across central Illinois
Tuesday through Friday. This more northern trend with the
baroclinic zone was first hinted by the 12z June 15 ECMWF, with
the latest run of that model now even further north with the
front. Based on this clear northward trend and the overall
strength of the upper ridge, it appears the front will get hung up
in the vicinity for much of the coming week. Based on model
consensus, have confined low chance PoPs to the northern CWA
Monday night...then further south across the remainder of the area
Tuesday through Saturday. It will not be a wash-out by any means,
but it appears scattered showers and thunderstorms will develop
each day.

While models now agree with the southward extent of the
initial front, disagreement arises concerning the speed/track of
a significant short-wave tracking through the Plains later in the
period. The latest GFS shows this wave approaching, then lifting
northward into Canada by next weekend...while the ECMWF brings the
wave into the Midwest and essentially cuts it off from the main
flow. Will need to keep an eye on the evolution of this feature,
as it could potentially provide enhanced synoptic lift and a
higher rain chance by Friday/Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1242 PM CDT Sat Jun 16 2018

VFR conditions will prevail through the entire 18z TAF period.
FEW-SCT diurnal Cu at around 4000-5000ft will develop this
afternoon, then dissipate by sunset. Winds will be S/SW at 10kt or
less through Sunday morning.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT Monday for ILZ027>031-036>038-
040>057-061>063-066>068-071>073.

&&

SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Barnes

Hazardous Weather Outlook
National Weather Service Lincoln IL
345 PM CDT Sat Jun 16 2018

ILZ027>031-036>038-040>057-061>063-066>068-071>073-171100-
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-
345 PM CDT Sat Jun 16 2018

...HEAT ADVISORY IN EFFECT UNTIL 7 PM CDT MONDAY...

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

.DAY ONE...TONIGHT...

Heat Index values will range from 98 to 103 degrees late this
afternoon, and lower to around 90 degrees by sunset.

An isolated thunderstorm will be possible late this afternoon. No
severe weather is expected. The threat for a thunderstorm will
end by sunset this evening.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

Summerlike heat and humidity will continue Sunday and Monday.
Afternoon heat indices in a few locations may approach 110 degrees
Sunday afternoon, and around 105 degrees Monday.

A better threat for more widespread thunderstorms will return
Monday night through Tuesday night as a frontal system drops
south into our area, with a daily chance for thunderstorms
continuing for the remainder of the work week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated through tonight.

Smith

Special Weather Statement
National Weather Service Lincoln IL
449 PM CDT SAT JUN 16 2018

ILZ061-162215-
Shelby-
449 PM CDT SAT JUN 16 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN SHELBY COUNTY UNTIL
515 PM CDT...

At 449 PM CDT, Doppler radar was tracking a strong thunderstorm over
Stewardson, or 9 miles northwest of Effingham, moving north at 20
mph.

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

Locations impacted include...
Stewardson.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3922 8861 3922 8871 3934 8869 3931 8852
      3921 8858
TIME...MOT...LOC 2149Z 202DEG 16KT 3924 8864

SB