Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 181401
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
901 AM CDT Mon Mar 18 2024

.KEY MESSAGES...

- Hard freeze expected again tonight. Precautions should be taken
  to protect any sensitive vegetation.

- High probability (80-100% chance) of winds gusting over 30mph on
  Tuesday.

- Next precipitation chance arrives Thursday night into Friday
  morning. Light rain across much of the area...with a rain/snow
  mix north of the I-74 corridor.

&&

.UPDATE...
Issued at 901 AM CDT Mon Mar 18 2024

With several folks observing flurries, a couple ASOS obs of light
snow, and radar returns on the 0.5 degree tilt, flurries were
added to the forecast. I was less confident about extending it
through this afternoon, however the HRRR was showing an increase
in flurry activity across mainly our northeast CWA during that
time frame and forecast soundings suggested at least a very small
portion of the DGZ saturated with sfc based instability...so that
will remain in the forecast through around 23z/6pm, unless
observations suggest it`s no longer coming down sooner. Temps,
currently in the upper 20s across most of the region, remain on
track, and are likely to stay in the 30s for many locations
particularly north of I-72.

Bumgardner

&&

.SHORT TERM...(Today through Tuesday)
Issued at 324 AM CDT Mon Mar 18 2024

08z/3am satellite imagery shows a persistent area of low clouds
along/northeast of a Peoria to Robinson line in association with a
sharp upper trough axis diving through the region early this
morning. While this initial batch of clouds will tend to
dissipate/scatter toward sunrise, continued cyclonic flow aloft
and steep lapse rates will lead to additional diurnal cloud
development...particularly east of the Illinois River where NAM
Cu-rule shows values of -2 to -5. End result will be a partly to
mostly cloudy day across the KILX CWA...with clearing skies
along/west of I-55 by late afternoon. Thank to at least partial
cloud cover as well as brisk northwesterly winds, high temperatures
will remain below normal for this time of year in the upper
30s/lower 40s. Skies will clear and winds will temporarily
diminish this evening, allowing temperatures to bottom out in the
middle to upper 20s. Coldest readings at or below 25 degrees will
be focused in the Wabash River Valley. Lows will likely be
achieved by midnight, followed by slowly rising temps overnight as
W/SW return flow increases markedly ahead of the next approaching
frontal boundary.

As the pressure gradient tightens ahead of a cold front dropping
out of the Northern Plains, strong W/SW winds will develop on
Tuesday. 00z Mar 18 HREF shows high probabilities (80-100% chance)
of wind gusts over 30mph...with lower probabilities (40-60% chance)
of gusts exceeding 40mph everywhere north of the I-70 corridor
during the morning. Partial sunshine and the strong SW winds will
push high temperatures into the upper 50s and lower 60s.

Barnes

.LONG TERM... (Wednesday through Sunday)
Issued at 324 AM CDT Mon Mar 18 2024

Cold front will pass through the region late Tuesday, dropping
temps back below normal into the 40s for Wednesday and Thursday.
Canadian high pressure will ensure cool/dry weather both days
before a pair of short-wave troughs approach Thursday night into
Friday. A southern stream wave ejecting eastward out of
Texas/Oklahoma will remain south of Illinois, while a northern
stream wave skirts by just to the north. The strongest forcing
and best moisture will be focused across the northern half of the
CWA late Thursday night into Friday morning when a period of light
rain showers is anticipated. With surface temperatures dropping
into the middle to upper 30s, a rain/snow mix will be possible
north of the I-74 corridor: however, no snow accumulation is
expected.

Once the wave exits into the eastern Great Lakes, cool/dry weather
will return Friday afternoon through Saturday before a more
significant system takes shape across the Plains and begins to
approach by late next weekend. Ample model spread leads to low
forecast confidence at this time: however, it appears precip
chances will ramp up considerably by next Sunday/Monday.

Barnes

&&

.AVIATION...  (For the 12z TAFs through 12z Tuesday Morning)
Issued at 535 AM CDT Mon Mar 18 2024

VFR conditions will prevail through the entire 12z TAF period.
Patches of clouds at around 5000ft will persist through the
afternoon...especially east of the Illinois River where ceilings
will be most prevalent. The clouds will dissipate/scatter from
west to east across the area late this afternoon, followed by
clear skies this evening. NW winds will initially gust to around
20kt through the afternoon, then will temporarily drop to less
than 10kt after sunset. As a cold front approaches from the
northwest, winds will back to SW and increase after midnight.
Forecast soundings suggest gusts will reach 20-25kt at KPIA/KBMI
after 10z Tue...with even higher gusts across the board after
sunrise.

Barnes

&&

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

$$


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