Flash Flood Warning 40, NWS Lincoln, IL

Area Forecast Discussion
National Weather Service Lincoln IL
831 PM CDT Wed Aug 21 2019

.SYNOPSIS...
Issued at 340 PM CDT Wed Aug 21 2019

The threat of showers and some thunderstorms will persist across
central and southeast Illinois through Thursday night. The best
chances will be along and south of I-72, where around 1 to 1.5
inches of rain is possible by dawn Friday. A chance of showers and
thunderstorms will linger in southeast IL on Friday before the
frontal boundary pushes further south of the area. Warm and humid
conditions again this afternoon will transition to cooler and
less humid conditions during the next few days.

&&

.UPDATE...
Issued at 816 PM CDT Wed Aug 21 2019

A few showers and thunderstorms are developing across central
Illinois this evening and expect to see widely scattered coverage
continue over the next few hours. A boundary is draped roughly
along the I-70 corridor this evening where dew points are pooling
into the low to mid 70s contributing to moderately strong
instability on the warm side of the boundary. Moderate and slightly
elevated instability is in place farther north. MUCAPE values of
around 2000 J/kg are indicated up to roughly the I-72 corridor,
and the instability gradient seems to the be the focus so far for
convection. Meanwhile, to the west, an MCV is noted coming across
the Mississippi River near Quincy and seems to be the impetus for
the current convection. A shortwave trough is just behind digging
across the mid Missouri River Valley. These features will
continue to support widely scattered showers and storms into the
overnight hours then should exit east during the predawn hours
Thursday.

&&

.SHORT TERM...(This evening through Thursday)
ISSUED AT 340 PM CDT Wed Aug 21 2019

Remnants of an MCS that moved into central IL this afternoon,
produced an outflow boundary that was pushing se toward I-70
at mid afternoon. A few mainly light rain showers were over the IL
river valley behind this boundary with some thunderstorms over ne
IL tracking ENE toward Chicago metro. A band of thunderstorms
extended from near Evansville IN into southeast MO and nw AR, more
numerous over the Ozarks. LAPS capes were 2000-3200 j/kg over
eastern/se IL, while higher capes over 3500 j/kg were over sw IL
into southern MO with better support of stronger thunderstorms sw
of our CWA. Also have an MCV near the IA/MO border with scattered
convection over parts of IA into nw MO. Mostly cloudy to overcast
skies prevailed over central IL with partly sunny skies in
southeast IL.

Expect convection chances to increase into tonight across the CWA
as outflow boundary moving into southeast IL could develop some
late day convection, and also the MCV moving east from IA and
northern MO to increase coverage of convection over northern CWA
too going into tonight. SPC day1 update continues a marginal risk
of severe storms over southern half of CWA into this evening for
mainly gusty winds. Also have marginal to slight risk of excessive
rainfall thru tonight, highest chances (slight chance) in
southeast IL. Lows overnight mostly in the mid to upper 60s, but
range from lower 60s nw of Peoria to near 70F in southeast IL.

Best chances of convection to shift into southern CWA on Thu as
frontal boundary slowly moves southward into southern/se IL while
marginal risk of severe storms shifts just south of CWA on Thu.
WPC has a marginal risk of excessive rainfall over southeast IL
mainly south of I-70 on Thu. Highs Thu in the upper 70s to near
80F in central IL and lower 80s south of I-70.

.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 340 PM CDT Wed Aug 21 2019

Convection chances linger over southern CWA especially southeast
IL Thu night into Friday as a weak surface low tracks along the
boundary to our south into the mid MS river valley overnight Thu
night. Meanwhile northern CWA starts drying out. Lows Thu night
range from upper 50s to around 60F northern CWA and mid 60s se of
I-70. Highs Friday in the upper 70s in central IL and around 80F
in southeast IL, with less humid conditions especially in central
IL.

Lingering small chances of showers and isolated thunderstorms in
far southeast IL Friday night into Saturday, while brunt of CWA
should be dry with frontal boundary getting further south.
Highs Saturday again in the upper 70s to near 80F and less humid
air pushing into southeast IL too by Saturday. Saturday night into
Sunday appears dry over much of CWA, then slight chance of
convection in southeast IL on Sunday afternoon due to weak
instability toward the Ohio river valley. Lows Sat night in the
upper 50s to near 60F, highs Sunday in the upper 70s to near 80F.
Dry wx expected across area on Sunday night with lows of 60-65F.

Extended models show a large mid/upper level northern stream trof
digging into the Midwest by Monday and across the Great Lakes
region by Tue and digging further into the area by next Wed. A
frontal boundary to push se into the area early next work week,
though some timing differences between models with this feature.
Stayed close to consensus from Monday on. This could return a
chance of showers and a few thunderstorms Monday into Wed over the
area.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 630 PM CDT Wed Aug 21 2019

A few widely scattered showers and thunderstorms are possible
across central Illinois this evening and tonight, but expect
coverage to remain fairly low so will only include a VCSH in the
forecast for now. Precip chances will shift east overnight, then
attention will turn to fog and stratus development. For now the
best chances for fog appear along the I-72 corridor terminals
where a surface boundary is lingering and dew point remain in the
low to mid 70s. There is another slight chance for showers and
storms on Thursday, but it appears the focus will shift south of
the terminals towards the I-70 corridor.

&&

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

UPDATE...Deubelbeiss
SYNOPSIS...07
SHORT TERM...07
LONG TERM...07
AVIATION...Deubelbeiss

Hazardous Weather Outlook
National Weather Service Lincoln IL
322 PM CDT Wed Aug 21 2019

ILZ027>031-036>038-041>046-221100-
Champaign-De Witt-Fulton-Knox-Logan-Marshall-Mason-McLean-Peoria-
Piatt-Stark-Tazewell-Vermilion-Woodford-
322 PM CDT Wed Aug 21 2019

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

.DAY ONE...TONIGHT...

Scattered thunderstorms will be possible through tonight:
however, severe weather is not expected.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

Thunderstorm chances will linger across the area Thursday and
Thursday night. The potential for severe weather appears low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed through tonight.

ILZ040-047>057-061>063-066>068-071>073-221100-
Cass-Christian-Clark-Clay-Coles-Crawford-Cumberland-Douglas-Edgar-
Effingham-Jasper-Lawrence-Macon-Menard-Morgan-Moultrie-Richland-
Sangamon-Schuyler-Scott-Shelby-
322 PM CDT Wed Aug 21 2019

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

.DAY ONE...TONIGHT...

Scattered thunderstorms will be possible through tonight. There
is a Marginal Risk that some of the storms may produce damaging
wind gusts to 60 mph.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

Thunderstorm chances will linger across the area Thursday through
Friday. The potential for severe weather appears low both days.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed through 8 pm.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LINCOLN IL
925 PM CDT WED AUG 21 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0854 PM     HEAVY RAIN       DECATUR AIRPORT         39.83N 88.87W
08/21/2019  M1.32 INCH       MACON              IL   ASOS

            MOST OF THE RAIN FELL BETWEEN 8-9 PM

0835 PM     HEAVY RAIN       DECATUR                 39.85N 88.93W
08/21/2019  M1.38 INCH       MACON              IL   MESONET

            RAIN FELL IN 45 MINUTES. WEST SIDE OF TOWN.

&&

25

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LINCOLN IL
929 PM CDT WED AUG 21 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0758 PM     FUNNEL CLOUD     2 SSE HARRISTOWN        39.81N 89.05W
08/21/2019                   MACON              IL   BROADCAST MEDIA

            FROM WAND-TV

&&

25

Special Weather Statement
National Weather Service Lincoln IL
1034 PM CDT Wed Aug 21 2019

ILZ066-067-071-072-220415-
Clay-Richland-Jasper-Effingham-
1034 PM CDT Wed Aug 21 2019

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN JASPER...NORTHERN
RICHLAND...NORTHEASTERN CLAY AND EFFINGHAM COUNTIES UNTIL 1115 PM
CDT...

At 1033 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Shumway to near Ingraham. Movement was
northeast at 5 mph.

Winds in excess of 40 mph and torrential rain will be possible with
these storms.

Locations impacted include...
Effingham, Olney, Altamont, Teutopolis, Watson, Noble, Dieterich,
Beecher City, Bible Grove, Shumway, Wheeler, Sailor Springs,
Ingraham, West Liberty, Bogota, Dundas, Moccasin, Mason, Wakefield
and Heartville.

This includes the following highways...
 Interstate 57 between mile markers 145 and 166.
 Interstate 70 between mile markers 79 and 100.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3904 8881 3917 8880 3919 8876 3920 8852
      3881 8793 3865 8827
TIME...MOT...LOC 0333Z 243DEG 5KT 3913 8866 3880 8823

Deubelbeiss