346 
FXUS63 KILX 061736
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
1236 PM CDT Mon Sep 6 2021

.SYNOPSIS...
Issued at 330 AM CDT Mon Sep 6 2021

Dry weather continues across much of the region on this Labor Day
with a fair amount of sunshine again and highs in the low to mid
80s. The next chance of showers and thunderstorms comes Tuesday 
afternoon and evening, as the next frontal system moves through 
the Great Lakes. Warm highs in the upper 80s are expected Tuesday
with breezy southwest winds. Temperatures then fall back into the
upper 70s and low 80s through the end of this week.

&&

.UPDATE...
Issued at 1039 AM CDT Mon Sep 6 2021

Today will almost be a repeat of yesterday, however a little
warmer as westerly to southwesterly winds continue to usher warmer
air from the central Plains. High pressure continues to dominate
the weather, although a weak almost non-existent shortwave slides
through eastern Illinois into Indiana this afternoon. Forecast
remains dry, however would not be surprised to see a sprinkle to
very isolated shower develop in eastern Illinois towards Indiana
this afternoon.

&&

.SHORT TERM...(Today and tonight)
ISSUED AT 345 AM CDT Mon Sep 6 2021

Another nice day expected on this Labor Day over central and SE 
IL, as 2 of the 3 days of this holiday weekend enjoying a fair
amount of sunshine (yesterday and today). Patchy shallow fog in 
southeast IL should lift by mid morning. Otherwise mostly sunny 
skies overall today as few- scattered cumulus clouds develop by 
late morning and afternoon. Also have scattered mid level clouds 
with bases 8-10k ft moving se into central IL near I-55 early this
morning ahead of a weak cold front over northern IL that pushes 
south toward far northern CWA by early afternoon and to near I-74 
late this afternoon. Highs in the low to mid 80s today, and 
dewpoints elevating into the low to mid 60s. IL remained in a nw 
upper level flow aloft with a strong 595 dm 500 mb high over NV 
and central CA and upper level trof over the central Great Lakes 
into the OH/TN river valleys. A few CAMs show some light rain 
showers developing along I-74 by 21Z/4 pm but feel sprinkles at 
best as little lift and have a capping inversion. 

The weak front to start lifting back north as a warm front
tonight, lifting north of CWA by overnight. A bit milder tonight
with SSW winds, with lows in the low to mid 60s, coolest near the
IN border. A narrow band of moderate instability along and ahead
of the cold front with CAPES reaching around 2000 j/kg per GFS
model and much higher per NAM model which has higher
dewpoints. The 0-6 km bulk wind shear values rise to 35-50 kts by
late Tue afternoon. SPC day2 keeps marginal risk of severe storms
ne of CWA for Tue afternoon/evening with damaging winds main
threat. We have some capping to overcome and will need to watch 
closely for northern CWA late Tue afternoon and early Tue evening.
Breezy sw winds on Tue to gust 25-30 mph and warmer highs in the
upper 80s along with dewpoints in the mid to upper 60s. Chances of
showers/thunderstorms to shift se of CWA after 1 am Tue night with
cold frontal passage. Lows Tue night range from mid 50s
northern/nw CWA to lower 60s south of I-70. 

Cold front pushes se of the Ohio river on Wed with upper level
trof digging into the Great Lakes and Oh/TN river valleys. A fair
amount of sunshine Wed over central/se IL with breezy nw winds 
bringing in cooler and less humid air. Highs Wed in the upper 70s 
in central IL and lower 80s in southeast IL. Cool lows Wed night
in the low to mid 50s. 

Weak 1020 mb high pressure to drift east over IL by sunset Thu
with lighter winds Thu and a fair amount of sunshine again. Highs
Thu in the upper 70s over much of the CWA with Lawrenceville near
80F. Lows Thu night mostly in the mid 50s. Slight modification in
temps Fri with highs in the lower 80s and humidity levels staying
fairly comfortable as weak high pressure drifts east of IL. 

The strong 500 mb high pressure over the Desert SW will start to 
build back closer to central IL this weekend (500 mb heights rise 
to 588-591 dm Sat afternoon into Sunday), with storm track being 
north of IL, as another storm system passes north of the Great 
Lakes on Sat. Temperatures to return to more summer like readings
during this weekend, highs in the low to mid 80s Sat and upper 
80s by next Monday.

.LONG TERM...(Tuesday through Sunday)
ISSUED AT 410 AM CDT Mon Sep 6 2021

A northern stream short wave/trof over the southern Canadian
Rockies to develop a fairly strong surface low pressure about 997
mb just north of Lake Superior by 18Z/1 pm Tue and push a cold
front into far nw IL then. Latest forecast models have trended
slower with cold front pushing se to between the IL river and I-55
by sunset Tue, and pushing into southeast IL around 06Z/1 am Tue
night.  

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1222 PM CDT Mon Sep 6 2021

Starting to see a cu field develop from IND to CMI along I-74 
corridor, with clouds already streaming from just north of BMI to 
DVN. Expecting VFR ceilings to prevail as more cu development 
occurs on I-74 corridor. Winds remain westerly to wsw through the 
afternoon, 8-10kts sustained. Southwest winds increase Tuesday, as
the High moves through Tennessee Valley, ahead of the next 
frontal system.

&&

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

$$

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