River Flood Warning 16, NWS Lincoln, IL

Area Forecast Discussion
National Weather Service Lincoln IL
859 PM CDT FRI JUL 15 2016

.UPDATE...
Issued at 859 PM CDT Fri Jul 15 2016

High pressure over northern IL tonight will keep weather fair
overnight with light winds shifting from N to NE. A weak upper
level shortwave approaching from the west this evening will bring
a period of mid-level cloud cover starting in the late evening and
continuing into early morning. A few echoes noted on radar under
this cloud cover but no observations of anything making it to the
ground. A sprinkle is perhaps not out of the question but not
significant enough chance to include in evening update. Main
update this evening is for cloud cover. Lows expected from the
upper 50s to low 60s tonight.

&&

.SHORT TERM...(This evening through Saturday)
ISSUED AT 311 PM CDT Fri Jul 15 2016

1021 mb high pressure was over the eastern Dakotas into western
MN/IA, while a frontal boundary had sagged south of CWA by mid
afternoon. A broken line of showers and thunderstorms was developing
ahead of this front along a Cincinnati to Evansville, IN line and
into southeast MO. This line of convection will stay south of
Clay, Richland and Lawrence counties rest of today so went with a
dry forecast through Saturday across CWA. Scattered showers were
over northern IL along and north of I-88 associated with a weak
short wave/trof moving into the upper Midwest and these showers
should stay north of CWA rest of today. We are seeing some broken
cumulus clouds as far south as I-74 and also have more cumulus and
cirrus clouds south of I-72. Diurnally enhanced cumulus clouds
should decrease around sunset with skies becoming mostly clear
tonight. Few cumulus clouds to appear by late Saturday morning but
overall a mostly sunny day over CWA Sat per layered rh model field
as high pressure drifts east over the Great Lakes region. Cooler
lows overnight in the upper 50s/lower 60s with mildest readings in
southeast IL. Highs Saturday mostly in the lower 80s with coolest
readings around 80F from I-74 north.

.LONG TERM...(Saturday night through Friday)
ISSUED AT 311 PM CDT Fri Jul 15 2016

Saturday night will see high pressure departing to the east, as an
MCS develops in the northern Plains and progresses toward N IL/S
Wisconsin. The track and timing of that system remains in question,
with the NAM and GFS about 6 hours faster and farther north than the
ECMWF and Canadian-NH. Even the more southern models indicate the
system will trigger showers/storms only in our northern counties.
Therefore, we kept a narrow corridor of slight chance PoPs late
Sat night NW of the IL river, then gradually expanded chance PoPs
from NW to SE on Sunday, down to a line from Rushville to Lincoln
to Farmer City Sunday afternoon. The better instability params
point toward northern IL for higher severe potential, with our
northern counties in a Marginal Risk for Day 3 at this point. The
low level jet will remain focused north and west of our counties
through the event supporting a farther north severe threat.

Sunday night, the shortwave will help trigger the advance of a cold
front into Illinois, expanding storm chances farther south to
include all of our forecast area during the day on Monday. Once
again, severe potential appears low during that FROPA, with
limited low level convergence and a dissipating frontal
circulation. Storm chances should begin to shift southward out of
our northern counties Monday night, with only slight chance PoPs
needed south of I-70 on Tuesday as dry high pressure air builds
southward into Illinois.

On Wednesday, a strong upper level ridge will begin to build east
from the Plains into Illinois, bringing some very warm and moist
air. A few showers/storms may develop in western and northern IL
near an advancing warm front Tuesday night through Wednesday
night. But only slight chance PoPs were utilized to outline that
threat.

By Thursday afternoon, heat and humidity will combine to push heat
indices over 100, especially west of I-57. A warm layer near 10K
ft should help to preclude storm development, despite 0-6km
MUCAPES in the 4000-5500 J/kg range. Bulk shear will be marginal
in the 20-25kt range. Friday looks to see heat index readings a
few degrees warmer across the entire forecast area, with higher
MUCAPE but less shear than Thursday. Have opted to keep Thur and
Fri dry, due to the likely presence of a capping inversion.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 654 PM CDT Fri Jul 15 2016

High pressure will settle over the region through the next 24
hours for predominantly fair weather at central IL terminals. With
light winds overnight could see some MVFR vsby fog and haze in
the early morning however mid level cloud cover heading for the
area will tend to limit fog formation. Mostly clear skies for
Saturday except for some shallow widely scattered cumulus around
4000 ft AGL. Winds generally under 10 kts through the period
gradually turning from NNW to NE to SE.

&&

.ILX Watches/Warnings/Advisories...
NONE.
&&

UPDATE...Onton
SHORT TERM...07
LONG TERM...Shimon
AVIATION...Onton

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE LINCOLN IL
229 PM CDT FRI JUL 15 2016

ILZ027>031-036>038-040>051-053-161100-
CASS-CHAMPAIGN-DE WITT-FULTON-KNOX-LOGAN-MACON-MARSHALL-MASON-
MCLEAN-MENARD-MORGAN-PEORIA-PIATT-SANGAMON-SCHUYLER-SCOTT-STARK-
TAZEWELL-VERMILION-WOODFORD-
229 PM CDT FRI JUL 15 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
ILLINOIS...EAST CENTRAL ILLINOIS...NORTH CENTRAL ILLINOIS AND
WEST CENTRAL ILLINOIS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A CHANCE OF THUNDERSTORMS FROM SUNDAY THROUGH MONDAY
NIGHT. THERE IS A MARGINAL RISK OF SOME OF THESE STORMS BECOMING
SEVERE ON SUNDAY.

HOT AND HUMID WEATHER IS EXPECTED BY THURSDAY WITH AFTERNOON HEAT
INDICES OF 100 TO 105.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT.

ILZ052-054>057-061>063-066>068-071>073-161100-
CHRISTIAN-CLARK-CLAY-COLES-CRAWFORD-CUMBERLAND-DOUGLAS-EDGAR-
EFFINGHAM-JASPER-LAWRENCE-MOULTRIE-RICHLAND-SHELBY-
229 PM CDT FRI JUL 15 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
ILLINOIS...EAST CENTRAL ILLINOIS...SOUTH CENTRAL ILLINOIS AND
SOUTHEAST ILLINOIS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THERE IS A CHANCE OF THUNDERSTORMS FROM SUNDAY NIGHT THROUGH
MONDAY NIGHT.

HOT AND HUMID WEATHER IS EXPECTED ON THURSDAY WITH AFTERNOON HEAT
INDICES OF 100 TO 105 DEGREES.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED THROUGH TONIGHT.

07