283
FXUS63 KILX 050446
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1146 PM CDT Fri Oct 4 2024

.KEY MESSAGES...

- Unseasonably warm conditions return tomorrow ahead of a cold
  front, with most locations warming into the mid 80s for highs.

- There is less than a 20% chance for any measurable
  precipitation during the next 7 days, which will result in
  worsening drought conditions across central and southeast IL.

&&

.UPDATE...
Issued at 907 PM CDT Fri Oct 4 2024

Broken to overcast skies currently over most of the CWA, covering
everywhere except the southeast counties...south of I-70, are
forecast to continue through the night by most of the models. Some
holes will develop in the cloud deck, but believe broken clouds
will be the rule over most of the area and then become scattered
between 7am-noon, and then clearing out tomorrow afternoon. This
could have some affect on overnight lows, but still think temps
falling to round 60 is a good forecast. Winds are east to
northeast around 10kts and current forecast is for winds a little
less. May tweak the winds a bit for this update. With the
increase in cloud cover and the minor adjustment to winds, an
update will be forthcoming.

Auten

&&

.DISCUSSION...
Issued at 208 PM CDT Fri Oct 4 2024

At long last, the morning convection has come to an end, leaving
only scattered clouds around in its wake. Breaks in these clouds
will allow some warming the next couple hours, but high temps will
be confined to roughly the mid 70s near and north of the I-72
corridor as the rain cooled airmass is slow to recover.

Tonight, temps are forecast to drop only into the upper 50s to low
60s as winds slowly veer to the southeast and low level moisture
gradually increases. The surface pressure gradient will tighten a
bit during the afternoon-evening tomorrow, resulting in southerly
wind gusts to around 25-30 mph which will strengthen advection of
moisture from the Gulf into the area, ultimately bringing dewpoints
into the low to mid 60s by the time a cold front sweeps in from the
northwest late tomorrow night into Sunday morning. Ahead of that
front tomorrow, the area is also expected to remain sunny allowing
radiational heating to warm the area well into the 80s; in fact, NBM
suggests a 30-40% or greater probability of max temps over 85 degF
along and west of the I-55 corridor tomorrow. Unfortunately, the
better forcing (and vertical wind shear) associated with the system
approaching tomorrow night will be displaced well to our north and
closer to the parent upper low - leaving our area with less than a
10% chance of precipitation. It will, however, bring an at least
temporary reprieve from the unseasonable warmth (and humidity), with
deterministic guidance suggesting quite the gradient in dewpoints
along the front (04.12z HRRR suggests dewpoints will fall into the
low 30s across our west by 12z/7am CDT Sunday). The drier airmass
behind the front on Sunday will likely be quick to warm during the
afternoon and evening if we end up sunny (for efficient radiational
warming) as NBM suggests, offsetting cool advection and resulting in
highs in the mid 70s to low 80s.

Northwest winds, forecast to gust to 20 to 25 mph Sunday afternoon,
will ease Sunday night into Monday morning, combining with mostly
clear skies to result in seasonably cool lows in the 40s. Starting
the day off cooler should result in cooler highs on Monday as well,
though the forecast highs in the upper 60s to low 70s might be a
little too low if winds indeed remain as light as guidance would
suggest as gradients weaken with the system`s gradual departure.
Same goes for both Tuesday and Wednesday, although by Wednesday and
especially heading into Thursday middle of the road ensemble
guidance (LREF mean) suggests h5 heights will be approaching 580 dam
as a ridge of high pressure expands into the area from the Great
Plains. Highs are thus forecast to warm a couple degrees per day
Wednesday through Friday, by which time NBM deterministic (near the
70th percentile of the ensemble) is sticking some 80+ degF highs in
the forecast for areas near and west of the IL River. Throughout the
entire forecast period, both NBM and the raw ensemble (LREF) suggest
chances are less than 20% for any measurable precipitation.

Bumgardner

&&

.AVIATION...  (For the 06z TAFs through 06z Saturday Night)
Issued at 1146 PM CDT Fri Oct 4 2024

VFR conditions will prevail at all TAF sites next 24hrs. Broken to
overcast mid clouds around 8kft is covering the area and cover all
TAF sites during overnight. Guidance suggests clouds will become
scattered from west to east tomorrow morning and then become clear
from late morning through around 18z...again from west to east.
Clear skies are expected from afternoon into the evening tomorrow.
Winds will be northeast to east this overnight, then become more
east to southeast early tomorrow morning. Wind speeds will be
around 10kts this overnight but increase to around 12-15kts
tomorrow with gusts around 25kts by around noon, which will last
into the evening hours.

Auten

&&

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

$$