Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 060206

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
906 PM CDT Mon Jun 5 2023

Issued at 906 PM CDT Mon Jun 5 2023

Hazy skies, caused by wildfire smoke from Canada, will persist
across eastern Illinois into Tuesday, but the smoke should
eventually exit the area to the south. There is a 20-30% chance of
scattered showers beginning north of I-74 Tuesday afternoon, then
progressing south across the area through Wednesday morning. Any
rainfall amounts should be light, generally less than a quarter
inch. After the cold front passes, high temperatures will be in
the low 80s for Wednesday and Thursday, with low humidity values.


Issued at 906 PM CDT Mon Jun 5 2023

High pressure remains west and northwest of the CWA this evening,
producing light winds and mostly clear skies. Though most of the
smoke has moved off to the south and west, additional smoke could
return during the overnight hours from the northeast. Eastern
areas of the CWA could still see some hazy conditions due to the
smoke, while the remainder does not. Current forecast has a good
handle on the haze and expected temps overnight, as well has the
sky and winds. No update planned at this time.



Issued at 305 PM CDT Mon Jun 5 2023

---------- Key Messages ------------

1. Hazy skies and occasional air quality impacts are possible
into Tuesday, especially in southeast Illinois.

2. Multiple rain chances are present in the forecast! The first
being Tuesday afternoon into Wednesday, then another this weekend.

3. Temperatures cool by mid-week, returning to near-normal, with
highs in the low 80s instead of 90s.


The current upper air pattern remains characterized by an Omega
block, and while that pattern will remain dominant through the
work week, the upper low over New England does retrograde to the
west, resulting in height falls across central IL through Wed

Skies remain hazy due to smoke, with a few sites across eastern IL
dropping down to five mile visibility at times earlier today.
Champaign has been reporting air quality that is unhealthy for
sensitive groups for several hours now, but otherwise PM2.5 levels
have only been in the moderate category across central IL today.
RAP/HRRR near-surface smoke fields suggest any potential
visibility/air quality impacts this evening will be east of I-55.
Smoke will generally be headed out of the area into Tues, although
a hazy sunrise and degraded air quality still appear possible
near and south of I-70.

A backdoor cold front will track from north to south across the
area on Tues/Wed, producing scattered showers and a few storms as
it does. There are still some wide differences in onset timing
among CAMs, with some models showing showers as early as midday
along the I-74 corridor/northward, but others keeping the area
precip free through Tues evening. The precip chances will linger
until the front departs the area Wed afternoon, with the best
chance for precip on Wed being south of I-72. Given the scattered
nature of the precip, not everyone will see rain. For those that
do, QPF amounts are likely (70-80% chance) to be on the light side
(less than 0.25"), but with how dry it`s been, we`ll take any
rain we can get.

Once the cold front passes, several days of cooler, near-normal
temperatures are expected, with highs in the low 80s Wed-Fri.
Continued northeasterly flow will keep the area dry with
unseasonably low dewpoints during that stretch, with afternoon
readings only in the 30s and 40s, which should make it feel quite
nice by June standards. Additionally, the most recent HRRR-smoke
forecast shows minimal smoke concentrations, either at the surface
or aloft, following the frontal passage.

Into the weekend, a shortwave digs out of the Canadian Prairie and
closes off. As the associated cold front sweeps through the
Midwest Sat evening into Sunday, it should provide another chance
of rainfall. While there is some moisture recovery ahead of this
front, current forecast guidance doesn`t suggest much in the way
of robust instability for this front to work with. Nevertheless,
it does appear to be one of the better precip chances we`ve had in
some time. The GEFS has a roughly 40% chance of exceeding 0.50",
and the latest deterministic QPF from the NBM is generally between
0.30- 0.60". Following this cold front, temps again turn a bit
cooler for Sun/Mon before a gradual warming trend into the middle
of next week.



.AVIATION...  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 618 PM CDT Mon Jun 5 2023

VFR conditions will prevail at all TAF sites next 24hrs. Cirrus is
moving away from the sites, so expecting clear skies overnight and
through tomorrow morning. Smoke is currently moving south, but vis
satellite loop shows more out there to the north. We could still
see some smoke this evening/overnight, but not going to put it in
the TAFs right now. Will wait and see what happens later. Mid
clouds begin to move into the area tomorrow afternoon as a front
moves into the area. Slight chance of precip, but does not appear
to be wide spread enough to warrant VCSH at this point. AC will be
scattered at all sites except SPI. Winds will be light and
variable through the night with northwest winds less than 10kts
tomorrow afternoon ahead of the front.




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