000
FXUS63 KILX 211450
AFDILX

Area Forecast Discussion...Updated
National Weather Service Lincoln IL
950 AM CDT Sun Apr 21 2024

.KEY MESSAGES...

- Overnight lows tonight will dip down into the middle 30s. A
  Frost Advisory is in effect for all of central and southeast
  IL Monday morning.

- Shower and isolated storm chances return Monday night into Tuesday.

- A warmer and more active weather pattern arrives late in the
  week into next weekend. Several chances for showers and storms
  exist Thursday night through the weekend, including the
  potential for severe weather.

&&

.UPDATE...
Issued at 950 AM CDT Sun Apr 21 2024

We`ll be seeing a quiet weather day today with sunny skies and
light winds across central IL. Winds will be on the lighter side,
from the northwest, with highs in the upper 50s to near 60 (around
5-10 degrees below average for this time of year). The forecast
looks on track.

Knutsvig

&&

.DISCUSSION...
Issued at 406 AM CDT Sun Apr 21 2024

Surface high pressure is centered over the central Plains with
ridging extending eastward through the Midwest states. Water vapor
imagery denotes an upper shortwave trough axis stretched from the
eastern Great Lakes region southwestward through Illinois, Missouri,
and points west. Scattered to broken mid-level clouds associated
with this feature are noted across parts of the state. Cloud cover
will continue to shift southeast with the upper trough through this
morning, parting way to mostly clear skies. Temperatures as of 3
am range from freezing underneath clear skies to the low 40s in
our southeast where cloud cover is most evident. Aside from the
cloud cover, gentle westerly winds and near freezing temperatures
could still lead to frost formation over the next few hours mainly
north of I-70.

Surface ridging sinks further into the southern Plains today, but
will still largely influence a majority of the central US. Highs
today will be unseasonably cool, but closer to 60 for most. Another
cool night is in store tonight with gentle winds and clear skies
resulting in a good radiational cooling setup. Lows should fall into
the low to middle 30s, posing a threat for frost formation once
again. A Frost Advisory has been issued for the entire area from
late tonight into Monday morning.

Southerly return flow ramps up Monday as the surface high migrates
into the southeast US and a surface low works across southern
Canada. Temperatures will return to near normal values both Monday
and Tuesday, but will be accompanied by breezy southwest winds. A
cold front associated with the aforementioned low will approach from
the northwest, spreading showers into the area late Monday night
into Tuesday. A few storms will be seen with FROPA on Tuesday,
though an overall lack of moisture will prevent widespread coverage.

A brief midweek cool down commences as northwest flow sets up behind
the cold front. Upper ridging will get pushed into the Midwest
states Thursday as a series of upper troughs move onshore the
western US. Temperatures will rebound back above normal by the end
of the week, but will be accompanied by a more active weather
pattern through the weekend. The previously mentioned upper troughs
will eject northward late in the week and weekend, bringing a series
of showers and storms. The first wave will arrive late Thursday
night into Friday as a warm front lifts north through the area.
Better moisture looks to stay south of Illinois on Friday, but
supportive wind shear and steep lapse rates may allow a few stronger
storms to develop. SPC continues to highlight a 15% risk for severe
weather on Friday.

Another chance for showers and storms looks likely later this
weekend or early next week as another trough ejects northward into
the Plains states and spins up a surface low in the lee of the
Rockies. The overall progression of this system has slowed the last
several model cycles, showing the cold front pushing through late
Monday night or Tuesday. Better moisture and stronger shear from
what appears to be a coupled upper jet coul(d lead to another
period to watch for severe storms.

NMA

&&

.AVIATION...  (For the 12z TAFs through 12z Monday Morning)
Issued at 559 AM CDT Sun Apr 21 2024

VFR flight rules will prevail through the TAF period. West winds
will turn to the northwest later this morning with speeds increasing
to 10-15 mph. Mid-level clouds will exit the area this morning, with
SKC behind.

NMA

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Frost Advisory from 2 AM to 8 AM CDT Monday for ILZ027>031-
036>038-040>057-061>063-066>068-071>073.

&&

$$