545
FXUS63 KILX 080501
AFDILX

Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1201 AM CDT Sat Jun 8 2024

.KEY MESSAGES...

- A decaying thunderstorm complex will arrive late tonight into
  early Saturday morning...with the highest rain chances (60-90%)
  focused along/south of a Macomb to Mattoon line.

- Near to slightly below normal temperatures will continue for the
  next several days before the return of summertime warmth with
  temperatures in the middle to upper 80s by the end of next
  week.

&&

.UPDATE...
Issued at 926 PM CDT Fri Jun 7 2024

The only change to the forecast this evening was a slight
northward pull of PoPs tomorrow (Saturday) evening, as recent
iterations of various 00z HREF members show thunderstorms
developing along the southward-moving cold front. The HRRR remains
the most bullish of the bunch, having pockets of 60+ dBZ simulated
reflectivities (indicating perhaps some hail) in the feistiest
cells between 7 and 10 pm, so we`ll have to have one eye on
mesoscale trends tomorrow evening. Though the HREF mean would
suggest 35-40+ kt of 0-6km bulk shear near the front, storms to
our southwest will get the first drink from the faucet of warm and
moisture advection from the LLJ, theoretically robbing our area
from the more appreciable instability necessary to sustain strong-
severe storms. The HRRR`s 2000-3000 J/kg of SBCAPE ahead of the
front remains the outlier pulling up the HREF mean (nearer 1000
J/kg), but it still bears consideration; we`ll keep an eye on
things tomorrow evening, but at this time feel severe chances are
quite low (less than 5%) at any given location.


Bumgardner

&&

.SHORT TERM...(Tonight through Saturday)
Issued at 248 PM CDT Fri Jun 7 2024

A short-wave trough dropping southeastward across Saskatchewan and
Montana is providing the necessary synoptic lift for thunderstorm
development across Nebraska this afternoon. 19z/2pm satellite
mosaic shows cells blossoming over far southern South Dakota into
central Nebraska and these are expected to become more numerous
and spread southeastward this evening...eventually aided by a
50-60kt 850mb jet oriented northeastward from the Texas panhandle.
The storms will push into Missouri later this evening, then will
spill into parts of central Illinois overnight. Most CAMs keep the
bulk of the convection just S/SW of the KILX CWA, but bring
showers into parts of the area before dawn Saturday. Based on
current satellite trends and the 18z HRRR, have focused highest
PoPs along/south of a Macomb to Mattoon line from 09z/4am to
15z/10am. Instability will be meager as NAM MUCAPE values remain
below 100J/kg. Nevertheless have included slight chance for
thunder due to strong LLJ curving northeastward toward central
Illinois toward dawn.

Once the early morning showers depart into Indiana, mostly dry
weather is anticipated for the remainder of Saturday. A weak cold
front will push into the area from the northwest, so cannot rule
out widely scattered showers/thunder during the afternoon/evening,
but think most locations will remain dry. Have held on to chance
PoPs south of I-70 into Saturday night as the front settles
southward into the Ohio River Valley, but it appears the bulk of
the convection associated with the nocturnal jet will occur well
S/SW across Missouri into western Kentucky.

Barnes

.LONG TERM...(Sunday through Next Friday)
Issued at 248 PM CDT Fri Jun 7 2024

Cool and predominantly dry weather is expected early next week
with highs in the 70s and lows in the 50s Sunday through Tuesday.
Coolest night will be Monday night when lows perhaps dip into the
upper 40s along/north of the I-74 corridor. After that, upper
heights will rise and temperatures will climb back above normal
into the middle and upper 80s by next Thursday/Friday.

Barnes

&&

.AVIATION...  (For the 06z TAFs through 06z Saturday Night)
Issued at 1159 PM CDT Fri Jun 7 2024

VFR conditions should continue through early this morning, with
MVFR ceilings materializing mid to late morning. These ceilings
should clear behind a cold front crossing the area between 22z
Saturday and 03z Sunday. Behind that front, gusty southwest winds
will veer to northerly and then gradually ease. A couple
thunderstorms could form along and just ahead of that front, but
uncertainty is too high to warrant a mention of lightning in the
TAFs at this juncture.

Bumgardner

&&

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

$$