179
FXUS63 KILX 081551
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
1051 AM CDT Wed May 8 2024

.KEY MESSAGES...

- Areas of dense fog along and south of I-70 early this morning.

- Severe weather is possible along and south of a Quincy to
  Danville line this afternoon and evening: however, the highest
  probabilities for damaging winds, very large hail, and
  tornadoes will be focused further south from the Ozarks into the
  lower Ohio River Valley.

- Cooler weather is on tap for the end of the week with overnight
  lows dipping into the 40s Thursday night through Saturday night.

&&

.UPDATE...
Issued at 1050 AM CDT Wed May 8 2024

Current forecast is on track, but needed to make some adjustments
with the pops/wx grids to account for current thinking. Update
will be forthcoming.

Auten

&&

.SHORT TERM...(Today through Thursday)
Issued at 329 AM CDT Wed May 8 2024

Drier air advected into central Illinois from the W/SW last
evening...resulting in 08z/3am surface dewpoints dropping into the
lower to middle 50s everywhere north of I-70. Further south where
dewpoints remain in the lower 60s, fog has formed thanks to
clearing skies and calm winds. Given lowering visby trends and IR
satellite signals suggesting expanding fog, have issued a Dense
Fog Advisory for all counties along/south of I-70 through 8am.

After the early morning fog dissipates, quiet weather will prevail
through midday as attention focuses on an area of low pressure
tracking slowly eastward through Missouri. CAMs have consistently
shown convection developing near the low across west-central
Missouri by mid-morning...with the storms then tracking E/SE
along the prevailing baroclinic zone into southern Illinois/western
Kentucky. Think this will be the primary severe weather threat
this afternoon/evening...and several CAMs suggest it will remain
south of the KILX CWA. Given enhanced low-level shear near and
north of the stationary frontal boundary, NAM 0-3km VGP values
increase to 0.3-0.4 as far north as I-70. As a result, think
scattered cells with a risk of damaging wind gusts, large hail,
and tornadoes will be possible mainly across the SE CWA between
3pm and 9pm. Further north toward I-72, decreasing instability in
the drier airmass will lead to a much lower risk for an isolated
strong/severe cell.

Widely scattered showers and thunderstorms will remain in the
forecast tonight as the low pivots through the region...while the
primary severe threat drops further southeastward into the
Tennessee River Valley. The low will exit into Indiana on
Thursday: however, an upper trough over the Upper Midwest will
drop southward toward Illinois by late in the day. Given
increasing synoptic lift and ample lingering moisture, showers and
a few thunderstorms will be possible as high temperatures drop
into the 60s everywhere north of I-70.

Barnes

.LONG TERM...(Friday through Tuesday)
Issued at 329 AM CDT Wed May 8 2024

A series of short-wave troughs dropping southward out of Canada
will ensure below normal temperatures and periodic shower chances
across central Illinois through Saturday. Highs both Friday and
Saturday will remain in the 60s while overnight lows dip into the
40s.

As the prevailing upper trough lifts northeastward and heights
begin to rise, temperatures will warm back to normal for this time
of year in the middle 70s by Sunday...then above normal to around
80 degrees by next Tuesday. Rain chances will increase as
well...particularly by the middle of next week as a southwesterly
flow pattern tries to establish itself.

Barnes

&&

.AVIATION...  (For the 12z TAFs through 12z Thursday Morning)
Issued at 547 AM CDT Wed May 8 2024

Main aviation forecast challenge will be timing potential
convection later today. Latest CAMs continue to focus most of the
thunder further south across southern Illinois into the Ohio River
Valley, with very little activity into central Illinois. Based on
the 06z HRRR/RAP, have opted to include showers with VCTS at
KSPI/KDEC between 21z and 02z. Further north, have only mentioned
showers at the I-74 terminals after 23z. Low pressure will track
through the region this evening and once it passes into Indiana,
forecast soundings suggest MVFR to perhaps IFR ceilings developing
overnight. Have brought ceilings down to MVFR at KPIA by 03z...then
further south to KSPI/KDEC by 08z.

Barnes

&&

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

$$