158
FXUS63 KILX 092344
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
544 PM CST Sat Nov 9 2024

.KEY MESSAGES...

- Low visibility in fog and drizzle is anticipated late tonight
  into early Sunday morning...particularly along/west of the I-57
  corridor. Motorists are advised to drive with caution.

- The next chance for showers will arrive by Wednesday: however,
  significant rainfall is not expected.

&&

.SHORT TERM...(Tonight through Sunday)
Issued at 324 PM CST Sat Nov 9 2024

21z/3pm surface analysis shows a 1006mb low over southern Nebraska
with an occluded frontal boundary arcing southeastward into the
Ozarks. Showers have developed ahead of this feature and have been
spilling into central Illinois since midday. While the airmass was
initially quite dry, ceilings have gradually lowered to 4,000-8,000ft
and measurable precip has been noted in most locations west of the
I-57 corridor. With continued top-down moistening, showers will
become more widespread and heavier across the entire KILX CWA this
evening. Instability will remain meager:however, NAM MUCAPE values
of 200-400J/kg will be enough to support isolated thunder mention.

The showers/thunder will shift eastward overnight and mainly be
confined to the far E/SE CWA by dawn Sunday. As the precip ends,
the CAMs are suggesting lowered visibilities overnight. Thanks to
weak lift in the saturated boundary layer, think patchy fog/drizzle
will develop once the showers depart. The lowered visibilities
will be primarily contained to locations along/west of the I-57
corridor through the overnight hours...followed by rapid visby
improvement from SW to NE across the area by early Sunday morning.
12z HREF shows a 30-40% chance of visibilities dropping below 1
mile.

Once the fog dissipates, skies will become partly to mostly
sunny across a good chunk of central Illinois on Sunday as drier
air advects in from the southwest. HRRR/RAP shows low cloud cover
potentially wrapping back into the N/NW CWA toward midday as the
Nebraska low lifts into the Great Lakes. The other big weather
story for Sunday will be the increasing winds. Given at least
partial clearing and the development of deep-layer mixing, SW
wind gusts will range from 20-30mph at times. The sunshine and SW
breeze will help boost afternoon highs several degrees warmer
than today...ranging from around 60 in the Illinois River Valley
to around 70 south of I-70.

Barnes

.LONG TERM...(Monday through Next Saturday)
Issued at 324 PM CST Sat Nov 9 2024

Quiet weather is anticipated for both Monday and Tuesday before
the next short-wave trough arrives by mid-week. Models have been
trending weaker with the system, with the 12z ECMWF now showing a
1006mb surface low passing well to the north of Illinois across
southern Canada during the day Wednesday. This is in stark
contrast to its previous runs that showed a much more amplified
upper pattern and a deeper/further south surface low. The weaker
solution is in better alignment with the current positive phase of
the North Atlantic Oscillation (NAO). As a result, think only
scattered showers will accompany a progressive cold frontal
passage on Wednesday...followed by a return to dry weather by the
end of next week.

Barnes

&&

.AVIATION...  (For the 00z TAFs through 00z Sunday Evening)
Issued at 544 PM CST Sat Nov 9 2024

VFR conditions will start each TAF site with cigs around 5kft or
higher. Lower, MVFR, clouds will advect over the sites this
evening with cigs dropping to around 2.5kft but then get even
lower around midnight to below 1kft...IFR & LIFR. Drier air is
forecast to move into the area from the southwest and this will
scatter clouds our for the morning hours; however, skies should
become mostly cloudy by around noon with MVFR cigs returning for
the late morning into the afternoon at all sites. Showers will
continue this evening, but lower layers are dry...so vis will not
drop to below 3sm until around midnight when the IFR cigs arrive.
Lowest vis expected with the drizzle is 2sm. Vis improves tomorrow
morning through the afternoon. Winds will be east to southeast
through the evening, but then become southerly as the low pressure
area moves north of the state. Southwest winds are expected
tomorrow morning, but then become more southwest for late morning
into afternoon. Speeds will be 10kts or less through the evening,
overnight and into the morning. Gusty winds are expected for late
morning through afternoon with gust speeds reaching over 25kts.

Auten

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$