River Flood Warning 37, NWS Paducah, KY

Area Forecast Discussion
National Weather Service Paducah KY
238 AM CDT Wed Mar 28 2018

.SHORT TERM...(Today through Friday night)
Issued at 225 AM CDT Wed Mar 28 2018

With the surface frontal boundary currently positioned over our
southeast, postfrontal rains overruning it continue streaming
across the boundary/overtop the bulk of the FA. This is falling
over grounds that already received 1/2-3/4" QPF amounts from the
rains Tuesday.

The models are doing good on the boundary and the rain/Pop, but
there is a problem between the GFS and NAM on this afternoon.
Overall the GFS has done well, but it totally moves pcpn out this
pm, while the NAM develops another banded zone of QPF over
southwest Ky. The blend of models/collab consensus was to keep a
high pop thru the pm hours, so we couldn't budge off that too
much, esp with the 00z deterministic GFS outlying on that
strategy. As a result, we did like our neighbors and skewed toward
the NAM on Pops/Qpf for late in the day into tonight. This yields
two main bands of pcpn, for the first half of today, then again
late today-tonight-early tmrw. The net total of 2-3 inches
matches nicely with neighbors, and the WPC 2+" line, where the
SLGT risk of exceeding FFG guidance exists. As a result, we've
issued a FFA for our southwest Ky counties in collaboration with
our neighbors. PW's that approach the 99th percentile thru the
life of the watch makes locally heavier amounts possible, with
flooding an ever heightening risk.

While the thunder risk appears minimal with instability a lacking
ingredient, there could be a clap here or there at times. Either
way, locally heavier rains are possible in the banded zones which
may occur at times thru the life of the event.

.LONG TERM...(Saturday through Tuesday)
Issued at 225 AM CDT Wed Mar 28 2018

As with the previous forecast packages the last two days, there is
low to medium forecast confidence in the placement of PoPs/QPF/cloud
cover in the extended portion of the forecast for the WFO PAH area.

The lowest forecast confidence occurs with the approach of the next
closed low moving toward the southern California/Baja region Sunday
into Monday. Each of the medium range guidance solutions
(ECMWF/GFS/Canadian) have different timing and intensity (closed low
vs. open wave) between Sunday afternoon through Tuesday afternoon.
This variability, in turn, impacts the general frontal position and
overrunning expected along and north of that boundary.

For now, with no clear signal for precipitation vs. no
precipitation, a combination of the Canadian (CMCnh) and the
regionally blended model initialization was used for the extended
forecast package.

The takeaway is that the best QPF (precipitation amounts) from
Saturday through the middle of next week will lie along and south of
the southern border counties of southeast Missouri and west
Kentucky. With the exception of any drying on Friday, soil moistures
will remain higher in the aforementioned area and may lead to a much
lower threshold for areal flooding, especially in southern sections
of west Kentucky.

&&

.AVIATION...
Issued at 225 AM CDT Wed Mar 28 2018

Post frontal MVFR ceilings and visibilities will intersperse with
IFR ceilings associated with a band of generally light to moderate
rainfall through the morning hours. A brief break into MVFR/VFR
category ceilings will be possible from late morning into the
early afternoon, before returning to IFR/MVFR ceilings later in
the afternoon and into the evening/overnight as the next banded
rains develop.

&&

.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...Flood Watch through Thursday evening for KYZ001-002-006-008-009-
     011>013-016-017-020>022.

&&

Hazardous Weather Outlook
National Weather Service Paducah KY
305 AM CDT Wed Mar 28 2018

ILZ075>078-080>094-INZ081-082-085>088-KYZ001>022-MOZ076-086-087-
100-107>112-114-291000-
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-
305 AM CDT Wed Mar 28 2018

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

.DAY ONE...Today and Tonight

Locally heavy rainfall is forecast. A Flood Watch is in effect.
Refer to the Watch for details.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

A Flood Watch remains in effect through the day Thursday for storm
total forecast rainfall of 2 to 3 inches. Locally higher amounts
are possible. Refer to the Watch for additional details.

A small chance of thunderstorms is forecast mainly over southeast
Missouri Saturday evening and Monday night, then across the
entire area Tuesday afternoon and evening. At this time, any
severe weather potential is minimal.

A light wintry mix is possible late Sunday night. Little or no
accumulation is expected.

.SPOTTER INFORMATION STATEMENT...

Spotter reports of rainfall and flooding are appreciated.