485
FXUS63 KILX 082028
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
328 PM CDT Mon Jul 8 2024

.KEY MESSAGES...

- The remnants of Hurricane Beryl will bring much-needed rain to
  parts of central Illinois on Tuesday. At this time, it appears
  the heaviest rainfall in excess of 2 inches will focus east of
  the I-55 corridor.

- Heat and humidity will return by the weekend...with heat index
  readings topping 100 degrees next Sunday/Monday.

&&

.SHORT TERM...(Tonight through Tuesday)
Issued at 328 PM CDT Mon Jul 8 2024

1930z/230pm regional radar mosaic shows widely scattered
convection developing from just west of Galesburg to near Fort
Madison, Iowa...as well as across the far NE KILX CWA in northern
Vermilion County. These two locations will be the primary focus
for precip over the next few hours before additional activity well
to the south across the Ozarks lifts northeastward toward the
I-70 corridor by early this evening. Elsewhere around central
Illinois, it appears warm/dry weather will prevail through the
afternoon and evening.

As moisture from the remnants of Hurricane Beryl begins to lift
northward, showers will develop across Missouri overnight...then
track into central Illinois toward dawn Tuesday. The precip will
become heavier/more widespread as the day progresses as the center
of Beryl quickly tracks northeastward into the Ohio River Valley.
Based on latest NHC forecasts and 12z CAM consensus, it appears
the remnant low will reach the Missouri bootheel by Tuesday
evening then central Indiana by Wednesday morning. This particular
path is favorable for widespread rainfall across much of central
Illinois...with the heaviest amounts likely setting up in a band
50-150 miles to the left (N/NW) of the track. It appears this
band will primarily focus east of the I-55 corridor where amounts
of 1.50 to 2.50 will be common. Isolated totals over 3 inches will
be possible in a few spots impacted by stronger convection. Meanwhile
rainfall totals will decrease rapidly further NW...with areas
west of the Illinois River seeing 0.25 or less.

There will be a risk for severe weather with Beryl as well:
however, the greatest probabilities for damaging wind gusts and
isolated tornadoes will remain to the right (S/SE) of the low
track across the Ohio River Valley Tuesday afternoon/evening. Will
need to keep an eye on storms as far N/NW as I-70 for the
potential for gusty winds though.

Gradient winds will increase across all of central and southeast
Illinois as the low passes to the S/SE. While some CAMs such as
the HRRR are suggesting gusts potentially exceeding 40mph
along/east of I-57 by Tuesday night, think this is overdone due to
the time of day and lack of deep-layer mixing needed for such
gusts. Have however increased the wind forecast to feature
25-30mph gusts along/east of I-57 as Beryl tracks into central
Indiana.

Barnes

.LONG TERM...(Wednesday through Next Monday)
Issued at 328 PM CDT Mon Jul 8 2024

A few showers will linger across the E/SE CWA into Wednesday
morning before the low departs. After that, rain chances will be
minimal through the extended as upper heights gradually rise.
Models have been consistently showing an upper ridge trying to
build eastward into the Midwest by this weekend. While we will
need to watch for potential nocturnal MCS activity riding along
the N/NE periphery of the ridge, the main story later in the
forecast period will be the building heat and humidity. Air
temperatures will climb toward the 90 degree mark by Saturday,
then into the lower 90s by Sunday/Monday. Given the rainfall
expected from Beryl and the actively growing crops, rich boundary
layer moisture with surface dewpoints above 70 degrees will
likely push heat index readings well above 100 degrees by early
next week.

Barnes

&&

.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 1254 PM CDT Mon Jul 8 2024

SCT-BKN diurnal clouds at 2500-3500ft will continue to develop
across central Illinois this afternoon. Based on satellite imagery
showing a pronounced band of these lower clouds shifting eastward
across eastern Iowa/western Illinois, will need to keep an eye on
KPIA for the potential of a couple hours of MVFR ceilings before
diurnally raising to VFR later this afternoon. Given low confidence,
have maintained VFR at KPIA and will continue to monitor satellite
trends. Any lower clouds will dissipate toward sunset, with just
patches of mid/high clouds expected through the night. As remnants
of Hurricane Beryl begin to approach from the southwest, ceilings
will lower and showers will spread into the area Tuesday morning.
While a good degree of model variability still exists, consensus
suggests MVFR ceilings and showers arriving at KSPI by 13z...then
further northeast to KBMI/KCMI by around 15z. With trajectory of
showers expected to focus from I-55 eastward, have maintained VFR
and only mentioned VCSH further northwest at KPIA. Winds will be
S/SW at 5-10kt this afternoon, then will become light/variable
tonight into Tuesday morning.

Barnes

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Flood Watch from Tuesday morning through Wednesday afternoon for
ILZ066>068-071>073.

&&

$$