Severe Thunderstorm Warning 101, NWS Paducah, KY

Area Forecast Discussion
National Weather Service Paducah KY
517 PM CDT Tue Apr 28 2020

.UPDATE...
Issued at 515 PM CDT Tue Apr 28 2020

Updated for 00Z TAF Issuance.

&&

.SHORT TERM...(Tonight through Thursday)
Issued at 255 PM CDT Tue Apr 28 2020

Our main challenge in the near term will be with the potential for
severe thunderstorms later this evening and overnight. There is also
some concern for localized flash flooding.

CAMs remain in fairly good agreement with the development of a
squall line or broken line of storms off to our west/northwest late
this afternoon and early evening. This line looks like it will enter
our western counties around 9-10 PM and progress eastward across the
rest of the region into the overnight hours.

Instability will be greatest this evening over southeast Missouri
and southwest Illinois, and will quickly wane by around midnight.
Most models depict essentially no sfc CAPE left after midnight so
the severe threat for the eastern half of the region looks quite
low. Damaging winds look to be the greatest threat with the line,
but some large hail will also be possible given the decent mid level
lapse rates. Can't completely rule out a brief tornado, but that
potential looks rather low.

There is also a risk for some localized flash flooding to develop,
especially in areas that see training of convection. Most areas will
likely receive 1-1.75" for the event, but given the setup the
potential for a few 2"+ amounts is possible.

Precipitation will gradually end from west to east overnight into
the morning hours on Wednesday. However, with the upper level low
parked to our north, wrap around showers and isolated thunderstorms
will spread back into the region by the afternoon tomorrow. Given
the cold air aloft, and mid level lapse rates of 7.5-8C, some small
hail will be possible with a few of the stronger cells.

Pesky shower activity looks to continue into Wednesday night and
Thursday, mainly in our northeastern counties. Clouds may linger
much of the day on Thursday in our east.

Temperatures will be cooler the next couple of days, with highs
generally in the 60s and lows falling from the 50s tonight into the
40s on Wednesday night. Breezy conditions will continue with wind
gusts of 20 to 30 mph on Wednesday and up around 20 mph on
Thursday.

.LONG TERM...(Thursday night through Tuesday)
Issued at 255 PM CDT Tue Apr 28 2020

Thursday night, we'll see our trof of cool/wet weather moving east,
effectively ending our pops and setting us up for the coming thermal
recovery. Driven by record breaking heat across the Southwest U.S.,
we'll see this air spill across the Plains and toward/into our neck
of the woods heading into the weekend. Friday is the transition day
with temps moving closer to seasonal norms, then Saturday and Sunday
we start to see the warmer airmass (albeit modified), with 80s
making an appearance. It's dry to start the weekend, then the
transitory flow pattern setup leads to increasing activity by
Sunday, as pops return to the forecast. Dew points and columnar
moisture on the rise, we could see potential for locally heavy rains
setting up Sunday. While deterministic models suggest a quick system
passage with diminishing pops/ending pcpn Monday, the blend/ensemble
approach lingers some pops. We'll split the diff with our collab
neighbors, which makes for a lingering (smaller) chance pop Monday-
Monday night and then another wave of energy/return chance pop
Tuesday.

&&

.AVIATION...
Issued at 515 PM CDT Tue Apr 28 2020

Restrictions will be fast incoming tonight as a line of
thunderstorms approaches from the west. The 00Z TAF set was fine
tuned for latest CAM/model approach of this line calibrated with
real time, which made for minor 1-2 hour adjustments mostly.
Anticipated a few hours possibility of IFR cigs/vsbys with the
actual line during the 05Z (West) thru 09Z (East) arrival. Wind
shift fropa/lingering restricted cigs/vsbys will ensue for 3-6
hours afterward, with relative mid to late morning improvements
short-lived. Another deterioriation of cigs/vsbys in heavier/more
shower activity during the pm planning phase hours is expected.

&&

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

&&

Hazardous Weather Outlook
National Weather Service Paducah KY
323 PM CDT Tue Apr 28 2020

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-292030-
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-
323 PM CDT Tue Apr 28 2020

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

.DAY ONE...Tonight

There is a chance for thunderstorms this evening and overnight.
Severe thunderstorms are possible with damaging winds and large
hail. Torrential rainfall may also lead to some localized flash
flooding risk with any training of convection.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

There is a threat for isolated thunderstorms on Wednesday,
primarily during the afternoon hours. The main hazards would be
heavy rainfall, lightning, and small hail.

Non-thunderstorms wind gusts up around 30 mph are possible on
Wednesday afternoon, especially across the western half of the
region.

Thunderstorms return to the forecast late this weekend into early
next week. Lightning and locally heavy rain will be the primary
storm hazards.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required late this evening and overnight,
especially over southeast Missouri and southwest Illinois.