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000
FXUS63 KILX 261529
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
1029 AM CDT Fri Apr 26 2024

.KEY MESSAGES...

- There will be multiple rounds of showers and thunderstorms today
  through Monday. Some of the storms could be strong to severe
  through Sunday (5-15%). Much of the area can expect over 1 inch
  of rain (50th percentile) through Monday, but localized amounts
  in the 1.5 to 2 inch amounts are possible particularly west of
  the Illinois River.

- Warmer and more humid conditions and windy conditions are
  expected this weekend. Daily highs will be in the upper 70s and
  lower 80s accompanied by breezy southerly winds gusting 30 to
  40 mph at times.

&&

.UPDATE...
Issued at 1028 AM CDT Fri Apr 26 2024

15z/10am surface analysis shows a 996mb low near the Kansas/Nebraska
border with a warm front arcing southeastward into the Ozarks. An
initial wave of showers/thunderstorms has lifted northward into
west-central Illinois...primarily along/west of the I-55 corridor.
A second wave is noted upstream within the warm sector across
southern Missouri into northern Arkansas and this activity will
track northeastward into central Illinois this afternoon. Based on
radar timing tools and the latest HRRR/RAP, it appears this area
of convection will mostly impact locations along/east of I-55
from early to mid-afternoon. After that, another lull in precip
coverage will occur before the potential for more showers this
evening. All in all, it is shaping up to be a cool/breezy and wet
day across much of the KILX CWA. The warmest/driest area will be
along/south of I-70 where the rain will hold off until afternoon
and highs will reach the upper 60s/lower 70s. Further north, am
expecting highs in the lower to middle 60s.

Barnes

&&

.DISCUSSION...
Issued at 355 AM CDT Fri Apr 26 2024

Predawn surface map shows 993 mb low pressure over nw KS with its
warm front over northeast KS into sw MO and central AR. 1032 mb
Canadian high pressure was near Montreal close to the the southern
Quebec/Ontario province border and ridging westward over the Great
Lakes. An east to ESE flow around this high pressure over CWA was
keeping lower dewpoints in the mid 30s to around 40F, with even
lower 30s over Lacon, Pontiac and LaSalle/Peru. Not as cool as
last night with temps in the mid 40s to upper 40s in central IL
and lower 50s in southeast IL. Radar mosaic shows widespread
showers and scattered thunderstorms over central and western parts
of MO/IA with stronger southerly low level jet west of IL. Also
some scattered showers in southern IL south of I-64 and into sw KY
and mid TN.

A 925-850 mb warm front to lift ne over central IL during this
morning and early afternoon, with a band of showers and isolated
thunderstorms lifting ne over CWA. Showers to reach far sw CWA by
Scott county around or just after sunrise and to the Indiana
border by 17Z/noon. Then another wave of showers and a few
thunderstorms to move eastward into central IL during this
afternoon, especially west of I-57. Low threat of severe
thunderstorms this afternoon as air mass does not get that
unstable yet, with the stronger instability poised west of IL
today and into tonight where slight to enhanced risk over MO and
Iowa. SPC day1 outlook has marginal risk of severe storms over
much of central and western IL with 5% risk of large hail and
damaging winds for mainly this evening. There is a 2% risk of
tornadoes west of a Macomb to Jacksonville line. Highs today range
from lower 60s from I-74 north to lower 70s along and south of
highway 50 in southeast IL. Breezy SE winds develop today with
gusts 25-30 mph likely.

Surface low pressure to track ne toward the northern WI and MN
border by dawn Saturday, with warm front lifting north of central
IL. Low pressure weakens as it moves into eastern Lake Superior
by sunset Saturday, while pushing a cold front through central
parts of WI/Iowa. Looks like a lull in convection over central/se
IL Saturday morning, but a more unstable air mass develops by
Saturday afternoon of 1500-2500 j/kg Saturday afternoon, most
unstable western/nw CWA where wind shear values nearing 30 kts.
SPC day2 outlook continues slight risk of severe storms along and
nw of the IL river Sat afternoon/evening while marginal risk
extends as far se as a Danville to Sullivan to Litchfield line.
Main severe wx threats are damaging winds and large hail while
2-5% risk of tornadoes from the IL river west. Greater threat of
severe storms Sat and Sat night will still west of IL closer to
frontal boundary. Stronger southerly winds develop in warm sector
over CWA on Saturday with gusts 30-40 mph and bringing warmer
highs in the upper 70s and lower 80s. More humid as well with
dewpoints getting into the mid 60s.

Another surface low pressure develops in southeast CO Sat
afternoon and eject ne toward the upper MS river valley late
Sunday night. This to bring another round of showers and
thunderstorms Sunday afternoon and Sunday night. SPC day3 outlook
has marginal to slight risk of severe storms over all but far
eastern IL during this period, with the slight risk west of Peoria
and Springfield. Cold front to push eastward over IL during Monday
and likely continues chances of showers and thunderstorms though
weaker instability on Monday so lower threat of severe storms than
this weekend. Rainfall amounts over 1 inch over much of CWA today
through Monday with locally 1.5-2 inch amounts over areas west of
the IL river as PW values will be around 1.5 inches at times.
Though any training of thunderstorms could bring over 2 inch
amounts of rainfall. Strong southerly winds gusting 30-40 mph on
Sunday and even approaching 45 mph north of I-70, with warm highs
in the lower 80s with Lawrenceville near 85F. Highs Monday in the
mid 70s.

Looks like a brief lull in convection chances overnight Monday
night into Tuesday, though could be a little more convection
developing later Tue with approaching of next wx system into the
upper Midwest. Still mild Tue with sw breezes with highs in the
upper 70s to near 80F. Next chance of showers and thunderstorms to
be later Wed into Thursday and Wed night as yet another wx system
moves over the upper MS river valley and pushing a front into IL.
Highs in the upper 70s to around 80F again on Wed and in the low
to mid 70s Thu.

07

&&

.AVIATION...  (For the 12z TAFs through 12z Saturday Morning)
Issued at 555 AM CDT Fri Apr 26 2024

A band of showers and isolated thunderstorms will lift ne across
the central IL airports during this morning, reaching SPI between
13-14Z, PIA and DEC by 15Z and BMI and CMI between 16-17Z. VFR
conditions early this morning will deteriorate to MVFR conditions
later this morning or midday and continue into tonight. ESE winds
10-15 kts with gusts 18-24 kts early this morning to veer SE and
increase to around 15 kts with gusts 22-28 kts this afternoon and
turn southerly this evening. Added LLWS between 02-03Z with 2k ft
sw winds 45-50 kts.

07

&&

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

$$