Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 140900
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
400 AM CDT Thu Mar 14 2024

.KEY MESSAGES...

- Another unseasonably warm day today with high temperatures in
  the upper 60s to mid 70s, more typical of early to mid May.

- Slight risk of severe storms over central and southeast IL today
  and into this evening, with a couple rounds of storms expected.
  All severe weather modes at play including large hail, damaging
  winds, and a few tornadoes. Severe thunderstorm watch in effect
  until 10 am for counties along I-72 and north.

- Much cooler weather after a cold frontal passage late Saturday
  afternoon and Saturday evening. Hard freeze likely Sunday night
  and Monday night may harm any tender emerging vegetation.

&&

.DISCUSSION...
Issued at 400 AM CDT Thu Mar 14 2024

Storm Prediction Center issued a severe thunderstorm watch until
10 am for counties along I-72 and northward. Primary threats
include scattered large hail and isolated very large hail events
to 2 inches in diameter likely, scattered damaging wind gusts to
65 mph possible and a tornado or two possible into mid morning
Increasing SSW low level jet is aiding this convection/MCS over
northern and west central IL into northern MO and southeast Iowa
early this morning. The warm front had lifted just north of CWA
by 330 am with its convection affecting northern Knox, Stark and
Marshall counties. A line of strong to potentially severe
thunderstorms was racing eastward around 50 mph toward Macomb and
Quincy and just west of Schuyler county. This convection should
track eastward over central and northern CWA through mid morning
and is running a few hours ahead of the HRRR model. Maybe a lull
in convection later this morning into mid afternoon before a new
line of convection fires up ahead of cold front se of the IL river
late this afternoon/early evening and presses through southeast
IL during mid evening into early overnight. This convection could
be severe as well and SPC has entire area in a slight risk of
severe storms today and evening. SPC day1 outlook has 10% or
greater probability of 2 inch or larger hail se of the IL river
and nw of I-70 for today. Areas south of a Quincy to Bloomington
line have greater than 5% risk of tornadoes today, mainly with the
2nd round of storms late afternoon and evening. Heavy rain threat
today as well as WPC has marginal risk of excessive rainfall
today over much of CWA. Another unseasonably mild day in the upper
60s to around 70F from I-74 north and 70-75 south of I-74. Much
of central/se IL will see their 7th day in the 70s past two weeks
since Feb 26th. Convection chances to diminish from nw to se
during tonight with passage of cold front and much of area should
be dry by dawn Friday, perhaps a few isolated showers in southeast
IL Fri morning. Lows overnight range from around 40F from IL
river nw to the lower 50s se of I-70.

Weak high pressure ridge nosing eastward over KS/MO and into IL on
Friday with active frontal boundary moving into the southern
states where stormy/heavy rain threat will be. Northern stream
short wave trof starts dropping into the upper MS river valley
late Friday but its weather to stay north of IL. Clouds to
decrease from nw to se during the day Friday, with southeast IL
likely staying mostly cloudy to overcast much of the day while IL
river valley enjoys more sunshine by Fri afternoon. Cooler highs
Friday in the mid to upper 50s with north breezes gusting 20-25
mph. Lows Friday night in the mid to upper 30s.

Stronger WSW winds develop on Saturday ahead of approaching cold
front dropping southward into northern IL Sat afternoon. Wind
gusts of 30-40 mph likely north of I-70 by late Sat morning and
Sat afternoon. A bit milder highs Saturday in the lower 60s with
mid 60s from Springfield sw. Though temps will be falling by late
afternoon in northern CWA with passage of cold front.

Much colder temperatures expected early next week behind passage
of cold front late Sat afternoon/Sat evening. Highs Sunday in the
mid to upper 40s in central IL and lower 50s in southeast IL.
Monday to be the coldest day with highs in the upper 30s/lower
40s. Hard freeze over much of central IL Sunday night and into
southeast IL too on Monday night with lows getting into the mid to
upper 20s Sunday night and low to mid 20s Mon night. Consensus of
models keep most of light qpf ne of central IL early next week but
could be close to ne CWA where a few light snow showers possible
if precipitation does occur to to much colder air mass. Highs Tue
of 45-50F and modify into the mid to upper 50s on Wed as strong
upper level trof pulls away from IL.

07

&&

.AVIATION...  (For the 06z TAFs through 06z Thursday Night)
Issued at 1240 AM CDT Thu Mar 14 2024

A line of showers and thunderstorms associated with a warm front
and on nose of SSW 25-35 kt low level jet to affect I-74 airports
next few hours with MVFR conditions and possible IFR vsbys with
heavier rain showers. Some of the stronger cells have pea to 1
inch hail in McLean and Peoria counties and will need to monitor
BMI and PIA for this possibility. Convection along warm front
projected to lift north of I-74 airports late tonight, but then
more widespread convection from MCS over northern MO/southern IA
to track se toward IL river/PIA by 11-12Z, to I-55 by 12-13Z and
to CMI and DEC by mid morning (14-15Z). Could see IFR to MVFR
conditions return for a few hours in the morning hours. Outside of
thunderstorms expected VFR conditions with SE winds becoming SSW
winds 10-15 kts during the morning and gusting to 18-23 kts. Cold
front then pressing se through central IL late in the afternoon
and evening to bring another chance of showers and thunderstorms
with SW winds shifting north to NE at 10-15 kts during Thu evening
and few higher gusts.

07

&&

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

&&

$$


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