Strong Wind in Illinois, December 27, 2020

Area Forecast Discussion
National Weather Service Paducah KY
1141 AM CST Sun Dec 27 2020

.UPDATE...
Issued at 1140 AM CST Sun Dec 27 2020

Updated aviation discussion for the 18Z TAF issuance.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 235 AM CST Sun Dec 27 2020

Broad ridging aloft will give way to a weak frontal system moving
across the PAH forecast area tonight. Ahead of this feature, skies
are forecast to be mostly sunny during the morning hours, then
clouds should increase over much of the area before the sun goes
down, though the Pennyrile region of KY may not cloud over until
after dark. Deep southwesterly flow in the lower levels will
translate to sustained southerly surface winds 15 to 20 mph with
gusts 25 to 35 mph in the afternoon, with highest wind speeds
generally in southwestern IL. Highs should peak in the middle 50s.

As the cold front makes its way eastward overnight, lift of
limited deep moisture will allow scattered rain showers to
develop just ahead of it, possibly as early as mid-afternoon
across the northwestern-most tier of counties in southeastern MO/
southwestern IL. After nightfall, there should be a rapid
expansion eastward of convection, in fact, models indicate most of
the limited QPF will occur before midnight for most of the
region. The National Blend of Models really downplayed the PoP
with this event, so for more realism, more HREF data than usual
was included, which helped the collaboration picture.

Another ridge of high pressure will keep conditions rain-free
Mon and Tue, though from time to time there will some high
cloudiness emanating from the next system brewing out west. Peak
afternoon temps should drop 13-16 degrees by Mon, with a slight
rebound by Tue. After daybreak Tue, clouds are forecast to
increase more substantially from the west as southerly low level
winds just off the surface start up ahead of the approaching
large low pressure system.

.LONG TERM...(Tuesday night through Saturday)
Issued at 235 AM CST Sun Dec 27 2020

The mid week pcpn chance is slowing somewhat, according to the last
24 hours of model runs, and the NBM/mean picks up on this trend. It
reflects in our forecast with holding pcpn off til after 06Z
Wednesday, and only moving into our western third of the area at
that. It's warm enough for all rain even then.

With parent Lows so far north and south of us, not sure about buying
the higher qpf totals (particularly into the Ozarks) Wednesday
evening, but at least the NBM has been consistent suggesting our
highest pops/qpf will be Wednesday night.

Still relatively high pops Thursday translate west to east across
the area, but may wane some as the southern Low takes over with the
northern Low well off into the Northeast U.S. by 00Z Friday. After a
day of temperatures generally in the 40s, cold air will start to be
pulled down into the area, but the models are all over the place on
the amount of cold incoming, and how much interplay there is with
the moisture field and the northward lifting track of the now
predominant southern Low. The NBM just blurs it all into a mean rain
to snow change-over with some accums possible, particularly in our
northwest. We'll stay away from any specifics, given the low
confidence on this primarily late day 5 into early day 6
possibility, but it definitely bears watching closely. Similarly
with overall (liquid) storm total qpf, we're mindful of a good 1 to
2 inches of rain, while the 2 plus inch amounts this NBM run
produces are something to monitor.

&&

.AVIATION...
Issued at 1140 AM CST Sun Dec 27 2020

Breezy southerly winds will continue through the rest of the day
around 12-18 kts gusting up to 30 kts. Scattered showers will be
possible ahead of a late evening cold front which will bring a
wind shift towards northwesterly winds. Wind speeds will fall to
around 10 kts behind the front. Cigs are expected to drop to near
MVFR once showers arrive. Some models show gaps in low level
clouds for PAH/KCGI overnight before returning with a second band
of low clouds in the morning; the forecast leans this way but
this feature has lower confidence. Towards the north/east post-
frontal MVFR clouds are expected to continue for the remainder of
the TAF period, with at least some clouds below 2 kft mid-
morning.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&

UPDATE...ATL
SHORT TERM...DB
LONG TERM...DH
AVIATION...ATL

Hazardous Weather Outlook
National Weather Service Paducah KY
302 AM CST Sun Dec 27 2020

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-281100-
Jefferson-Wayne IL-Edwards-Wabash-Perry IL-Franklin-Hamilton-
White-Jackson-Williamson-Saline-Gallatin-Union-Johnson-Pope-
Hardin-Alexander-Pulaski-Massac-Gibson-Pike-Posey-Vanderburgh-
Warrick-Spencer-Fulton-Hickman-Carlisle-Ballard-McCracken-Graves-
Livingston-Marshall-Calloway-Crittenden-Lyon-Trigg-Caldwell-
Union KY-Webster-Hopkins-Christian-Henderson-Daviess-McLean-
Muhlenberg-Todd-Perry MO-Bollinger-Cape Girardeau-Wayne MO-Carter-
Ripley-Butler-Stoddard-Scott-Mississippi-New Madrid-
302 AM CST Sun Dec 27 2020

This Hazardous Weather Outlook is for portions of southern
Illinois, southwestern Indiana, western Kentucky, and southeastern
Missouri.

.DAY ONE...Today and Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.