493
FXUS63 KILX 170430
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1130 PM CDT Sun Jun 16 2024

.KEY MESSAGES...

- Seasonably hot and humid weather is on tap this week. Heat index
  values will peak at or above 100 degrees both this afternoon and
  Monday afternoon before readings settle back into the middle to
  upper 90s for the remainder of the week.

&&

.UPDATE...
Issued at 731 PM CDT Sun Jun 16 2024

Well-defined MCV remains clearly visible on radar this evening,
currently spinning across the northern portion of the Chicago
metro. The trailing outflow from the earlier convection lingers
from about Galesburg to Pontiac, with just some thicker clouds and
somewhat cooler temperatures along it. Remaining clouds are
expected to thin out over the course of the evening, with mostly
clear skies by midnight. A warm night is on tap, with low
temperatures generally in the mid 70s across the forecast area.

Geelhart

&&

.SHORT TERM...(Tonight through Monday Night)
Issued at 248 PM CDT Sun Jun 16 2024

19z/2pm analysis shows a Mesoscale Convective Vortex (MCV)
tracking northeastward across eastern Iowa. The airmass
along/south of this feature is moderately unstable and weakly
sheared...with MLCAPEs of 2000-2500J/kg but 0-6km bulk shear of
only around 20kt. Given the instability/forcing present, a cluster
of thunderstorms has accompanied the vortex across southeast Iowa
into northwest Illinois. The primary severe weather risk with the
storms will be damaging wind gusts...and these will mostly remain
N/NW of the KILX CWA over the next few hours. Will need to keep an
eye on the S/SW flank of the MCV to monitor for additional
development. Regional satellite/radar mosaic has thus far shown
little to no development, but the potential exists for storms
along the outflow boundary on the southern edge of the strongest
forcing. Severe Thunderstorm Watch has been issued until 8pm for
Knox, Stark, and Marshall counties to address this risk. Any
storms that skirt the N/NW CWA will exit into northern Illinois
after 01z/8pm...with warm/dry conditions anticipated everywhere
through the night.

As deep-layer moist advection from the western Gulf of Mexico
becomes better established, moisture profiles will become more
favorable for rainfall on Monday. However, no synoptic or
mesoscale boundaries will be present in order to serve as a focus
for development. As a result, am expecting another hot and humid
day with low chance PoPs (20-30%) for afternoon thunderstorms.
High temperatures will be a degree or two warmer than today in the
middle 90s, which will create heat index values in the 100-105
degree range. As was the case today, the heat will once again be
somewhat mitigated by a southwest breeze gusting over 20mph.

Barnes

.LONG TERM...(Tuesday through Next Sunday)
Issued at 248 PM CDT Sun Jun 16 2024

Much of the extended will feature hot and humid conditions with
highs in the lower to middle 90s and heat index readings in the
upper 90s to around 100 degrees. No appreciable frontal boundaries
will come into the region until next weekend when synoptic models
show a cold front settling southward into Illinois. As a result,
PoPs will remain at a minimum until next Saturday night into
Sunday.

Barnes

&&

.AVIATION...  (For the 06z TAFs through 06z Monday Night)
Issued at 1130 PM CDT Sun Jun 16 2024

VFR conditions expected the next 24 hours. Some potential for
brief ceilings near 5,000 feet as the cumulus field develops
around midday Monday. Pop-up thunderstorms from around 20Z through
sunset, though with only 20% chances, spatial coverage precludes a
mention at this point.

Southerly winds will begin to pick up again early Monday morning,
and gusts 20-25 knots are likely from late morning through about
00Z.

Geelhart

&&

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

$$