579 
FXUS63 KILX 091743
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1243 PM CDT Sun Apr 9 2017

.UPDATE...
Issued at 1032 AM CDT Sun Apr 9 2017

Windy and warm conditions prevail across central Illinois this
morning...as the region remains sandwiched between sprawling high
pressure along the East Coast and a slowly approaching cold front
in the Central Plains. Considerable high cloudiness currently
covers much of the sky: however, based on satellite imagery, there
will be ample thin spots to allow partial sunshine throughout the
day. Have therefore updated the forecast to go with partly sunny
skies today. Thanks to the sunshine and southerly winds gusting to
between 30 and 40mph at times, afternoon high temperatures will
soar into the 70s. 

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 337 AM CDT Sun Apr 9 2017

Another breezy day ahead for central IL along with even warmer 
high temperatures of 75-80F, despite more cloud cover today. 1020 
mb high pressure over the mid Atlantic states early this morning 
will push off the East coast during the day, while 996 mb surface 
low pressure over sw Nebraska moves into west central Iowa by 
sunset. South winds to gust from 30-40 mph today and be strongest 
in late morning and afternoon hours. Partly to mostly cloudy skies
expected today with more sunshine possible in southeast IL while 
cloudier skies over the IL river valley. Mild lows in the upper 
50s and lower 60s tonight which is actually close to normal highs 
for early April. Low pressure to weaken to 1001 mb by sunrise Mon 
as it tracks ne into central WI. Have 20-30% chance of showers and
thunderstorms moving into far NW CWA late this evening and across
the IL river valley overnight. SPC day1 outlook keeps slight to 
marginal risk of severe storms west/nw of IL through sunrise 
Monday.

.LONG TERM...(Monday through Saturday)
ISSUED AT 337 AM CDT Sun Apr 9 2017

An upper level trof over the central/northern Rockies to move 
east into the Midwest on Monday and have an associated cold front 
move into nw IL late Monday afternoon. SPC day2 outlook continues a 
marginal risk of severe thunderstorms Monday afternoon into mid 
Monday evening east of the IL river, with a slight risk of severe 
storms over Champaign, Vermilion, eastern McLean, eastern DeWitt and 
northern Piatt counties. Primarily for damaging wind gust with 
MLCAPES peaking around 1000 j/kg and unidirectional wind fields. 
Weakening surface low pressure tracks into northern lower MI by 
midday Monday and then pulls a cold front se into the IL river 
valley later Monday afternoon and thru rest of central/southeast IL 
during Mon evening. Highest chances of convection continue east of 
the IL river on Monday afternoon/evening, then just isolated showers 
possible in southeast IL overnight Monday night. Breezy sw winds on 
Monday ahead of cold front bring another mild spring day in the low 
to mid 70s. Lows Mon night range from around 40F nw of the IL river, 
to the lower 50s se of I-70. 

Dry weather returns to the area Tuesday through Wednesday as Pacific 
high pressure moves east into IL Tue evening and over the ohio river 
valley and eastern great lakes by sunset Wed. Temps cool closer to 
normal on Tue and Tue night, with highs Tue around 60F northern CWA 
and mid 60s along and south of I-70 with partly to mostly sunny 
skies. Lows Tue night around 40F northern CWA and near 45F by 
Lawrenceville. Winds become se on Wed but fairly light on back side 
of high pressure, with a fair amount of sunshine, though more clouds 
moving into the IL river valley Wed afternoon. Milder highs Wed in 
the mid to upper 60s with Lawrenceville near 70F. 

Medium range models continue to show a weak frontal boundary pushing 
se into IL around Thu, though timing and associated qpf along front 
differ between models. The front does appear to be stalling out near 
southern IL Thu night/Fri as upper level ridge builds into IL and 
have surface high pressure north over Great Lakes region and also 
south over the southeast states. Have increasing chances of showers 
and thunderstorms nw of I-70 overnight Wed night and then carried 30-
50% chance of showers and possible thunderstorms on Thu with frontal 
boundary nearby. Highs Thu in the upper 60s/lower 70s, mildest in 
southeast IL with Lawrenceville nearing mid 70s. Have isolated 
convection in southeast IL on Thu evening, then dry rest of Thu 
night. But chances of showers and isolated thunderstorms appears to 
return over west central/sw CWA by Fri afternoon and over most of 
area Fri night and Sat as front lifts back ne as a warm front. Highs 
Fri in the mid to upper 60s in central IL and lower 70s in southeast 
IL, warm into the 70s on Saturday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1243 PM CDT Sun Apr 9 2017

Main aviation forecast concern will be potential low clouds and
convection late tonight into Monday morning as a cold front slowly
approaches from the west. Several high-res models are showing
scattered thunderstorms developing well in advance of the front
across Iowa/Missouri late this evening...then pushing into the
Illinois River Valley well after midnight in a weakening state.
Based on HRRR/WRF-ARW timing, have included VCTS at KPIA after
09z...then further east to KBMI/KSPI after 11z. Think the initial
convection will completely dissipate before it reaches KDEC/KCMI,
so have only gone with VCSH at those sites Monday morning. Better
storm chances will materialize along/east of I-55 after 18z as the
atmosphere destabilizes and the front approaches. Strong
southwesterly winds will continue through the entire period, with
gusts in the 20-30kt range. 

&&

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

$$

UPDATE...Barnes
SHORT TERM...07
LONG TERM...07
AVIATION...Barnes