Flooding in Illinois, May 21 to 31, 2020

Area Forecast Discussion
National Weather Service Paducah KY
235 PM CDT Thu May 21 2020

.SHORT TERM...(Tonight through Friday night)
Issued at 235 PM CDT Thu May 21 2020

The upper-level low remains in central Kentucky this afternoon,
slowly drifting northward, bringing a few light showers to the
Pennyrile. Some thunder is possible in the far southeastern corner
of the CWA near Hopkinsville as a couple storms have developed
farther to the east the past two hours. The low will finally work
its way into Ohio tonight, drying things out overnight.

While slight ridging and a shift towards southerly wind will lead
to highs in the upper 70s to near 80 tomorrow, a shortwave will
bring a chance of showers and storms to the entire area, with the
highest chances in Southern Missouri and Western Kentucky. Some
thunderstorms are possible, primarily south of a Perryville, MO to
Owensboro, KY line.

A warm front will cross the area Friday night, leaving overnight
lows elevated in the mid 60s. The associated low pressure system
positioned to the northwest will bring a line of showers and
storms to the area late Friday night towards Saturday morning.

.LONG TERM...(Saturday through Thursday)
Issued at 235 PM CDT Thu May 21 2020

The weekend and much of next week will have a markedly different
feel to it than this week; that is, a more summer like feel. Each
day will be repetitious in several mean weather parameters...surface
dew points will be in the upper 60s/around 70, highs and lows will
range mid 80s/upper 60s, and the available columnar moisture/Pwats
will run in the 90s percentile. There will be no discernibly
significant shear or energy parameters in the flow pattern over this
period of time, so diurnal evolution of storm chances coincident
with realization of convective temps (lower 80s each day) will be
the primary driver in peak pcpn chances (afternoon) and minimum pcpn
chances (night)...which means what looks like a very wet forecast
with daily rains will actually be dry for large/bulk periods of that
same forecast. It also means that repeat or sustained locally
heavy/efficient downpours may still lead to minor flooding issues
with time, despite the overall time limited pcpn duration.

Also over time, the pattern does evolve to where high pressure aloft
strengthens its grip upon the Commonwealth. If this pans out, we'll
see pops wane some off their early week peaks, during the middle
(and latter) portion of the week.

&&

.AVIATION...
Issued at 1219 PM CDT Thu May 21 2020

Terminals across the Quad State region have seen either steady or
off-and-on MVFR conditions through the morning. Through the
afternoon, cigs are expected to rise to a more consistent VFR
though scattered lower clouds are expected during the forecast
period. Winds will be light and variable, tending to have an
easterly component today and a southerly component tomorrow. Cloud
cover will be generally broken which will limit visibility
reductions overnight. Vsbys are held in VFR at this time though
could conceivably drop to MVFR briefly at a site or two if clouds
cover becomes patchier overnight.

&&

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

SHORT TERM...ATL
LONG TERM...DH
AVIATION...ATL

Hazardous Weather Outlook
National Weather Service Paducah KY
240 PM CDT Thu May 21 2020

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-221945-
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-
240 PM CDT Thu May 21 2020

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

.DAY ONE...This Afternoon and Tonight

There is a slight chance of thunderstorms this afternoon in the
southern Kentucky Pennyrile. Lightning is the primary hazard.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

Isolated thunderstorms are possible late Friday morning to Friday
afternoon, primarily in Western Kentucky, and Southeast Missouri,
and far Southern Illinois. Lightning will be the primary hazard.

Scattered to numerous thunderstorms will be most active
during the peak heating hours of the afternoon and early evening
Saturday through Thursday. Lightning and brief heavy rainfall will
be the primary storm associated hazards, but an isolated wind
gust is also possible in a stronger storm.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.