969
FXUS63 KILX 202022
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
322 PM CDT Sat Jul 20 2024

.KEY MESSAGES...

- Cooler than normal temperatures continue through the new week.

- Low-end precipitation chances (20-30%) return Monday and Tuesday
  with somewhat better chances (30-50%) by midweek.

&&

.DISCUSSION...
Issued at 322 PM CDT Sat Jul 20 2024

500 mb analysis shows a deep upper low slowly working across
northern Quebec with a cut off low/split flow regime over the
Midwest states. At the surface, broad high pressure is in place
keeping conditions dry and cool. A few subtle bits of energy
rotating through the Midwest has sparked the development of showers
mainly west of the Mississippi River this afternoon, with scattered
to broken cirrus further east in Illinois atop fair weather cumulus.
The upper trough will begin to pivot eastward on Sunday, increasing
our mid-level moisture and thickening cloud cover. Scattered
afternoon shower activity will near closer to central Illinois, but
dry air in the low-levels should prevent much of this from reaching
the ground.

Dewpoints will continue to climb into the middle to upper 60s by the
start of the new week as the upper trough axis sets up overhead/just
east of here. A few weak shortwaves moving through Monday and
Tuesday may generate isolated showers/storms especially in the
afternoon, but better chances hold off until midweek when a slightly
stronger shortwave drops through the Great Lakes Region, sending a
cold front into the area. Overall weak flow and jet dynamics will
keep the severe threat at bay as this system/front move through.

Canadian surface ridging slides southeast behind the front for
the end of the week, leading to another period of cooler and dry
weather going into next weekend. Flow aloft looks to turn
southwesterly by late next weekend into the following week, which
would support the return of more seasonable temperatures and
perhaps occasional precipitation chances.

NMA

&&

.AVIATION...  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1255 PM CDT Sat Jul 20 2024

VFR conditions are forecast to continue across the central IL
airports through 18Z/1 pm Sunday. Scattered to broken cumulus
clouds with bases of 4-6k ft along with some passing cirrus
clouds around 20-25k ft will occur into early evening. Mid clouds
will increase across the area during tonight and continue into
Sunday, as more cumulus clouds with bases of 3.5-5k ft develop
after 15Z/10 am Sunday. Nearby weak 1020 mb high pressure near the
IA/IL border to keep winds light next 24 hours, primarily out of
the NE direction.

&&

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

$$