Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 171736
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1236 PM CDT Sun Mar 17 2024

.KEY MESSAGES...

- Hard freeze expected both tonight and Monday night. Precautions
  should be taken to protect any newly emerged sensitive
  vegetation.

- Next chance for precipitation arrives late Thursday into Friday.

&&

.UPDATE...
Issued at 942 AM CDT Sun Mar 17 2024

The forecast remains on track this morning as a cool airmass
continues to filter into the region from the northern Plains.
Current temperatures in the mid to upper 30s north of I-70 are not
anticipated to warm much today with the continued cool advection
by blustery northwest winds, though we currently have a bit of
sunshine which should yield at least a little radiational warming
through late morning/early afternoon for highs in the 40s south of
a Macomb to Champaign line.

Bumgardner

&&

.SHORT TERM...(Today through Monday)
Issued at 323 AM CDT Sun Mar 17 2024

Breezy and cool weather will prevail across central Illinois
today. The pressure gradient will remain tight enough to support
NW winds of 10-15mph with gusts of 20-25mph. Skies will initially
be sunny: however, as a short-wave trough noted on 08z/3am water
vapor imagery over northern Minnesota dives southeastward, enough
synoptic lift will be generated to produce SCT-BKN clouds this
afternoon. Given the increasing cloud cover and brisk
northwesterly winds, high temperatures will remain several degrees
below normal for this time of year...ranging from around 40 far
north near Galesburg and Lacon to the upper 40s south of I-70.
Winds will decrease tonight as a 1030mb high builds southward out
of Canada into the Central Plains. Since the center of the high
will remain well to the west, think winds of 5-10mph will persist.
This will produce enough mixing to keep the atmosphere from
cooling quite as efficiently as it could on a clear/calm night.
Nonetheless overnight lows will drop into the 20s across the
board. 00z Mar 17 HREF shows high probabilities (40-60% chance) of
lows dipping below 25F along/north of the I-72 corridor. Given the
recent stretch of very warm weather from mid-February, early
spring vegetation is running 2-3 weeks ahead of schedule. As a
result, some newly emerged tender vegetation will be susceptible
to damage from the hard freeze and should be protected tonight.
The heart of the coldest airmass will be over central Illinois on
Monday as GFS 1000-500mb thicknesses fall to around 522dm. The
resulting high temperatures will only reach the upper 30s and
lower 40s. Another cold night will be on tap Monday night as lows
once again dip into the 20s. Coldest readings in the middle 20s
will be focused near the Indiana border...with areas further west
likely seeing slowly rising temps overnight as a SW return flow
develops.

Barnes

.LONG TERM...(Tuesday through Saturday)
Issued at 323 AM CDT Sun Mar 17 2024

After a brief warm-up on Tuesday when highs climb back into the
upper 50s/lower 60s, a cold front will sink southward through
central Illinois by the middle of the week. This will send
readings back to near or slightly below normal in the 40s for
Thursday/Friday. All model solutions show a short-wave trough
tracking eastward from the Northern Plains into the Great Lakes by
Friday, which will bring central Illinois its next chance for
precipitation. While the timing of the precip still remains
somewhat in question, it appears the strongest lift and deepest
moisture profiles will coincide Thursday night into Friday
morning. With low temperatures dropping into the 30s, forecast
soundings support a rain/snow mix or perhaps even all snow
along/north of a Macomb to Bloomington line. QPF will be quite
light and with the warm ground conditions, am expecting no snow
accumulation.

Barnes

&&

.AVIATION...  (For the 18z TAFs through 18z Monday Afternoon)
Issued at 1233 PM CDT Sun Mar 17 2024

Northwest winds will continue to gust upwards of 25 kt through the
afternoon as deep mixing taps into strong winds aloft with an
incoming upper trough. Scattered to broken cumulus should
diminish with the loss of surface heating this evening, but
guidance suggests there`s around a 40-70% chance (highest
northeast) that stratus will return for low VFR ceilings again
between 13z and 16z (8-11 am CDT) tomorrow.

Bumgardner

&&

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

$$


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