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000
FXUS63 KILX 210447
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1147 PM CDT Sat Apr 20 2024

.KEY MESSAGES...

- Freeze warning in effect from Schuyler to McLean county north
  from 3-8 am Sunday, with a Frost Advisory south to Shelby, Coles
  and Edgar counties. Low temperatures by dawn Sunday in the low
  to mid 30s with widespread frost expected north of I-70. There
  is a 50-80% chance of below freezing temperatures at dawn Monday
  north of I-72.

- Our next chance for showers and isolated thunderstorms arrives
  later Monday night into Tuesday.

- A more active and warmer period with showers and thunderstorms
  is shaping up for Friday into next weekend. SPC has a 15% risk
  of severe storms west of I-55 on Friday afternoon/evening.

&&

.UPDATE...
Issued at 831 PM CDT Sat Apr 20 2024

A modest northwest breeze persists across central Illinois ahead
of an expansive ridge over the Great Plains. Winds should
continue to gradually taper off, especially as low clouds thin
from the south. Low clouds have already diminished south of I-72
but will be replaced by cirrus at times. Temps are on track to
fall into the lower to mid 30s north of I-70, while thicker cirrus
may prop temps up slightly further south. Assuming clouds clear
out late tonight as currently expected, frost/freeze headlines
should be on track.

Deubelbeiss

&&

.DISCUSSION...
Issued at 330 PM CDT Sat Apr 20 2024

Broken stratocumulus clouds with bases around 5k ft were along and
north of I-72 with mostly sunny skies south of I-72. Thicker
cirrus clouds were streaming eastward over southern IL, with just
thin cirrus into southeast CWA. Cool temperatures were in the mid
40s from Macomb to Bloomington northward with mid 50s along
highway 50 in far southeast IL. Breezy WNW to NW winds 10-18 mph
with gusts 22-32 mph prevailed over central/se IL.

Stratocumulus clouds to pivot into southeast IL late today and
these clouds are forecast to decrease from the nw during overnight
as NW winds diminish after sunset. NW winds have brought in drier
air today with dewpoints in the mid to upper 20s. Guidance pretty
close with lows in the low to mid 30s overnight, coolest in
northern CWA where 30-33F and have issued a freeze warning from
3-8 am Sunday from Schuyler, Mason, Tazewell and McLean counties
northward. Have a frost advisory south of the freeze warning, as
far south as Shelby, Coles and Edgar counties. Patchy frost
possible in southeast IL late tonight/early Sunday morning where
lows in the mid 30s.

Canadian high pressure to drift into the Ozarks Sunday afternoon
and mid MS river valley Sunday night. Still a bit breezy nw winds
on Sunday, though not as breezy as yesterday and today as pressure
gradient starts to weaken. Ample sunshine expected Sunday with
few afternoon cumulus clouds and thin cirrus. Highs Sunday in the
upper 50s to near 60F. Frost likely again overnight Sunday night
into early Monday morning with lows in the mid to upper 30s and
may need a frost advisory. Breezy sw winds develop by Monday
afternoon over central IL and to see some increasing clouds as
well especially IL river valley by Monday afternoon. More
seasonable highs in the mid to upper 60s on Monday. Not as cold
Mon night with lows in the upper 40s eastern IL and lower 50s over
the IL river valley. Northern stream system moving into the upper
Midwest Monday night and over the northern Great Lakes Tue to
bring a cold front se through central IL Tue afternoon/evening.
Have chances of showers and isolated thunderstorms over IL river
valley/nw CWA overnight Monday night, and spreading se over
rest of CWA during Tue. CAPES/Instability is low on Tue so risk
of severe storm is low as deeper gulf moisture stays south of IL.
Have chance of showers and isolated thunderstorms Tue evening
mainly over eastern half of CWA, then dry overnight Tue night and
Wed as 1030 mb high pressure ridge builds into western Ontario
and ridging into IL by Wed afternoon. Cool lows Wed night in the
upper 30s to around 40F, with mid 30s possible from Champaign ne
where patchy frost possibly by dawn Thu.

Some upper level ridging into the MS river valley Thu and should
mostly stay dry over much of central and eastern IL on Thu.
Stronger low pressure moving into the central plains on Thu night
to have a cold front moving east toward IL Fri evening with
increasing chances of showers and thunderstorms late Thu night and
Friday. More instability expected with this storm system
especially western CWA where SPC has 15% risk of severe storms
late Fri afternoon and Fri evening. Models have trended slower
with this storm system so could see lingering convection chances
into Saturday with warmer highs in the 70s.

07

&&

.AVIATION...  (For the 06z TAFs through 06z Sunday Night)
Issued at 1146 PM CDT Sat Apr 20 2024

High pressure will remain over the Great Plains Sunday resulting
in a light NW breeze and VFR conditions across central Illinois.
Winds will pick up diurnally into the 10-13kt range during the
day Sunday, then settle back down to around 5kt as they back to
the W/WSW Sunday evening.

Deubelbeiss

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Freeze Warning from 3 AM to 8 AM CDT Sunday for ILZ027>031-
036>038-040-041.

Frost Advisory from 3 AM to 8 AM CDT Sunday for ILZ042>057-061.

&&

$$