321
FXUS63 KILX 121603
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
1003 AM CST Wed Feb 12 2025

.KEY MESSAGES...

- Snow amounts continue to trend downward with the system slated
  to impact central Illinois today...with the latest guidance
  suggesting 2-3 inches along/northwest of a Taylorville to
  Danville line.

- A zone of mixed precipitation is still expected just north of
  the I-70 corridor today...with ice amounts of one tenth of an
  inch or less.

- After another storm system brings a mix of rain and snow to the
  region Friday night into Saturday, much colder conditions will
  arrive and linger through next week.


&&

.UPDATE...
Issued at 1002 AM CST Wed Feb 12 2025

A narrow, rogue band of snow lifted north-northwest this morning
and produced a quick dusting, but has moved out of the forecast
area. In the meantime, the main band of snow moving northeast has
reached the Illinois River valley, with visibility down to around
3/4 mile at Galesburg and Peoria. Precipitation band is progged
to reach I-57 around midday. Transition area of rain/ice/snow is
still projected to be in the I-70 vicinity, per latest high-res
models.

Several of the CAM`s are showing a dry slot moving across areas
north of I-70 early to mid afternoon. While current radar mosaics
may be overdoing this due to the low cloud heights in relation to
the radar beam, surface obs are showing this dry slot moving into
north central Missouri. Morning HREF guidance is somewhat narrower
with the dry slot, mainly moving up the Illinois River valley.
It has the heaviest snow rates actually through early afternoon
more between the Illinois River and I-55. Some solutions suggest
the precip west of I-55 may be done as early as sunset. Have not
gone quite that aggressive yet, but some PoP adjustments were made
to ease back in that area late afternoon and early evening.

Geelhart

&&

.SHORT TERM...(Today through Thursday)
Issued at 327 AM CST Wed Feb 12 2025

09z/3am water vapor imagery shows a short-wave trough over
Colorado/New Mexico...with an area of snow spreading northeastward
across Kansas into western Missouri. While the timing of precip
arrival remains unchanged from previous forecasts, the latest CAMs
have been consistently showing a shorter period of snowfall and
thus overall lesser accumulations. The 06z HRRR for example
brings the snow into western Illinois between 12z/6am and 15z/9am,
then quickly pushes it east of the I-55 corridor by mid-afternoon,
followed by just scattered snow-showers for the remainder of the
afternoon into the early evening. Given the shorter duration of
significant snow, storm totals have decreased...with amounts
generally ranging from 2-3 inches along/northwest of a Taylorville
to Danville line. There is still some potential for brief mesoscale
banding, so a few 4-inch totals are not out of the question across
the Illinois River Valley. Since snow amounts will be lower and
the snow will be falling during the daylight hours when temperatures
are warmest, the overall impacts from the system will not be as
significant as once thought. Am still expecting snow-covered and
slick roads for the evening commute...especially untreated secondary
roads, bridges, and overpasses. Further east/southeast, the
elevated warm layer will be significant enough to allow partial to
full melting of ice crystals within the profile and thus lead to
liquid precip. Based on expected surface temps at or slightly
below freezing, the primary zone for icing will set up along a
Shelbyville to Paris line where ice amounts of one tenth of an
inch or less are anticipated. As temps rise above freezing, mostly
rain will occur south of I-70.

The precip will quickly wind down this evening, followed by breezy
and colder conditions overnight into Thursday. Lows tonight will
range from the single digits northwest of the Illinois River to
the lower 20s east of the I-57 corridor. Highs on Thursday will
mostly be in the lower to middle 20s.

Barnes

.LONG TERM...(Friday through Tuesday)
Issued at 327 AM CST Wed Feb 12 2025

After chilly early morning lows in the single digits, southerly
return flow on the back side of departing high pressure will
signal the beginning of a brief warming trend on Friday that will
push afternoon highs into the 30s. As a weak system approaches
from the northwest and boundary layer moisture increases within
the WAA regime, light precip will develop Friday night. The
atmosphere will initially be cold enough to support snow, but as
temps slowly climb...the snow will mix with and change to mostly
rain overnight into Saturday. Once the system passes and NW winds
bring colder air back into the region, the precip will mix with
and change back to snow Saturday afternoon into Saturday night. A
light accumulation will be possible at that time. After that, a
significantly colder airmass will settle into the Midwest on
Sunday...then will linger for much of next week. Highs will drop
into the 20s on Sunday, then will only reach the teens for both
Monday and Tuesday.

Barnes

&&

.AVIATION...  (For the 12z TAFs through 12z Thursday Morning)
Issued at 545 AM CST Wed Feb 12 2025

11z/5am obs show ceilings have lowered to MVFR along/south of a
KPPQ...to KDEC...to KPRG line, as well as west of the Illinois
River. Based on latest satellite trends, have started the 12z TAFs
MVFR at the I-72 terminals, then have spread MVFR into KPIA by
14z and to KBMI by 16z. A large area of snow west of the
Mississippi River will spread eastward this morning...reaching
KPIA by 14z, then further east to KCMI by 17z. Visibilities will
be reduced to around 1 mile for a 2-3 hour window before the
heaviest snow shifts east of the terminals and is replaced by
lighter snow with visbys of 2-4 miles for the remainder of the
afternoon into the early evening. The light snow will then end
from southwest to northeast across the area between 01z and 03z.
Winds will initially be NE with gusts of 20-25kt early this
morning, then will gradually back to N and decrease to around 10kt
late this afternoon. Once the system responsible for the snow
passes, winds will become NW and increase to 10-15kt late tonight.

Barnes

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 3 AM CST Thursday for ILZ027>031-036-
037-040-041.

Winter Weather Advisory until 3 AM CST Thursday for ILZ038-
042>057-061>063-066.

&&

$$