350
FXUS63 KILX 140045
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
745 PM CDT Mon May 13 2024

.KEY MESSAGES...

- Showers and storms are expected (70-90% chance) through Tuesday
  afternoon. Expect generally 0.50 to 1 inch with 10-30% chance
  of over 1.5 inches.

- Another system will bring rain to the area Thursday into Friday,
  with generally another 0.25 to 0.75 inches of rain.

&&

.UPDATE...
Issued at 745 PM CDT Mon May 13 2024

Majority of the showers/storms are currently northeast of a
Galesburg-Olney line. There was a noticeable uptick in lightning
activity in the 5-6 pm time frame, though this has been waning
some over the last half hour as we get closer to sunset. The focus
the remainder of the evening will continue to shift northward,
north of a weak boundary that is currently extending from near
Rushville to Danville. High-res models show some decrease in
showers over most areas after midnight, before the next surge
begins to lift in toward sunrise.

Evening forecast updates mainly concentrated on rain chances into
Tuesday.

Geelhart

&&

.DISCUSSION...
Issued at 324 PM CDT Mon May 13 2024

The expected upper level low is currently in eastern KS according
the latest analysis...but continues to push eastward towards IL.
We`ve seen some showers and weak thunderstorms across central IL
this afternoon and expect coverage to increase through late
afternoon and into the early evening hours. Deep shear remains
weak at <20 kts with MLCAPE of 500-1000 J/kg. The latest RAP model
has a pocket or two of MLCAPE around 1000 J/kg this afternoon from
4-7 PM when storms will likely be the strongest. A few near-severe
storms will be possible with hail close to 1" and/or wind gusts
nearing 60 mph, but generally, severe storms are unlikely this
afternoon/evening.

Showers and perhaps some thunderstorms will be possible through
the night as a mid level vort lobe rotates northward around the
approaching system. Another lobe rotates north- northwestward
tomorrow morning with the low moving from eastern MO into southern
IL during the day Tuesday. Expect showers and embedded
thunderstorms to continue Tuesday, with the strongest storms south
of I-72. With MUCAPE generally around 500 J/kg up to 1000 J/kg
and deep share around 20-30 kts, severe potential is limited once
again tomorrow. Rainfall will likely be in the 0.5 to 1" range
across much of the area, with a 10-30% chance of over 1.5" for the
Mon-Tue total.

The area sees weak ridging on Wednesday, providing a break from
precipitation. However, rain chances return on Thursday and into
Friday as the next upper wave moves through the region. Not too
excited about severe weather chances with this second system at
this time since the NBM has CAPEs at 500 J/kg or less along with
25 kts of deep shear. However, the latest ECMWF is showing some
higher CAPEs for Friday, so will need to watch how this one
evolves. Generally expecting around 0.5" of rain with this system.

Weak ridging in NW flow aloft is expected for Saturday with an
upper wave passing to the north on Sunday. We`ll see a surge of
warm air ahead of the associated surface low pressure system,
bringing highs into the 80s for the weekend. More shower and
thunderstorm activity is possible by Sunday with the frontal
system and upper support. We`re still too far out to speculate on
severe potential with this one.

Knutsvig

&&

.AVIATION...  (For the 00z TAFs through 00z Tuesday Evening)
Issued at 620 PM CDT Mon May 13 2024

Scattered thunderstorms continue across a large part of central
Illinois early this evening, and are expected to continue through
about 02-03Z. Some brief MVFR/IFR visibility drops will accompany
the heavier showers, but a more widespread ceiling lowering is
expected late evening. By 08-09Z, probabilities of ceilings below
1,000 feet are around 60-80%, with any significant improvements
holding off until after midday.

With the storm system slowly advancing across the area Tuesday,
widespread showers will return before midday. Isolated lightning
cannot be ruled out throughout the afternoon, but chances are too
low to include a mention at this point.

Geelhart

&&

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

$$