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Area Forecast Discussion (AFD)

Issued by Jackson, KY (JKL)

FXUS63 KJKL 230647 AAC

National Weather Service Jackson KY
247 AM EDT Mon Apr 23 2018

Issued at 240 AM EDT MON APR 23 2018

Despite east to southeast flow with a downslope component a band
of showers continues to progress north across the area. Dewpoints
across southern sections of the area have climbed into the 40s 
with light measurable rain having fallen in many locations out of 
a mid level deck from around SME to Bell and Knox counties per KY 
Mesonet observations and regional RAWS, HADS, and IFLOWS. This 
band will continue to move to the northeast with additional 
showers upstream. Pops will be updated to account for timing of 
this with hourly temperatures and dewpoints also freshened up 
based on recent observations. 

UPDATE Issued at 1120 PM EDT SUN APR 22 2018

Updated the forecast to remove outdated wording from the text
forecast product and to speed up precipitation onset in our
southwest and southern counties by a couple of hours per current
trends in model data and obs. 

UPDATE Issued at 740 PM EDT SUN APR 22 2018

The forecast remains on track so far this evening. Mostly to
cloudy skies will persist overnight, with rain showers expected to
move into the area from the southwest late tonight into early
tomorrow morning. Will leave the forecast as is for now, but will
need to update later in the shift to make other small adjustments
and to remove outdated wording form the zone forecast text
product. Ingested the latest obs into the hourly forecast to
establish new trends.


.SHORT TERM...(This evening through Monday night)
Issued at 351 PM EDT SUN APR 22 2018

The latest surface analysis shows an area of surface high pressure
continue to retreat northward. The east to southeast winds
continue to lead to downslope flow and drier conditions across the
region this afternoon. The latest scans of the regional WSR-88D
radars suggest some of the rain shower activity is just now
creeping into Wayne County. Given the continued slower trend, did
opt to lower POPs for the afternoon. This upper level low to our
south will continue to rotate east and eventually divergence aloft
will lead to best chances of rain showers early Monday. Then a 
lull in activity is expected later in the day mainly in the far
east, as 1000 to 850 mb winds increase leading to increased 
downsloping. The 00Z NAEFS standard anomaly tables show the 850mb
winds are going to be oriented southeast and running greater than
3 standard deviations above normal. There is some weak 
instability in the Lake Cumberland region Monday afternoon and did
lean toward slight chance thunder. The upper level divergence 
becomes broad Monday night, but the surface low and trough will 
come east. This will lead to increasing chances of POPs once again
Monday night.

.LONG TERM...(Tuesday through Sunday)
Issued at 340 PM EDT SUN APR 22 2018

Upper level low will continue to cross the area Tuesday into
Tuesday night with the unsettled weather continuing. Some rumbles
of thunder will be possible with a little elevated instability
present on Tuesday. Best rain chances will reside on Tuesday, 
before the forcing exits east and north. However, with weak 
upslope flow continuing into Wednesday, a few isolated showers or 
pockets of drizzle may be possible. Drier weather returns for 
Wednesday night and Thursday with a surface high crossing the 

Still looks like another shortwave trough will cross the area
Friday into early Saturday with still some timing and strength
differences in the models. Thus, will maintain small rain chances
Friday and Friday night. If the trough is stronger as a few models
indicate, we could see a modest cool down for Saturday. However,
models continue to flip flop on the strength. Any cool down will
be short lived as heights will start to build again by Sunday with
a pleasant end to the weekend expected. There is a chance most of
the weekend could be nice if the trough for Friday night is


.AVIATION...(For the 06Z TAFS through 06Z Monday night)

An upper level low will meander into western TN through the
period. For much of the period the region will maintain a
downslope component of the flow with lower levels slow to
saturate. Thus mainly mid level clouds are expected through about
12Z with some low clouds thereafter but still in the VFR range.
Some brief MVFR is possible in showers or any thunderstorms across
western and northwestern sections of the area after 12Z, but vis
should remain 6SM or higher through the period. Winds should
increase to near or in excess of 10KT at the TAF sites during the
first 6 hours of the period out of the east southeast to