Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 280600 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
200 AM EDT Tue Mar 28 2017

.UPDATE...
Issued at 145 AM EDT TUE MAR 28 2017

Updated the near term grids to reflect the departure of the bulk
of the rain earlier in the night - though still allowing for a
passing shower or two through dawn as the actual cold front
moves across the area. Otherwise, have tweaked the T and Td grids
per the latest obs and trends. These have been sent to the NDFD
and web servers.

UPDATE Issued at 1159 PM EDT MON MAR 27 2017

Have eliminated the thunder in the far east as the leading edge
has moved into West Virginia and Virginia. Also freshened up the
POP trends as the southern cold pool showers gradually move east
and dissipate. Updates have been sent.

UPDATE Issued at 1112 PM EDT MON MAR 27 2017

The severe threat is over, as the last of the storms will exit
far eastern Kentucky before midnight, with just some cold pool
showers following on its heels, as well as another area of showers
affecting locations along and south of the Hal Rogers Parkway and
Highway 80 corridors. These showers will exit southeastern
Kentucky in the next few hours. There will be lull in the activity
following this, until the surface cold front and short wave
trough axis nears before dawn. Have allowed for an uptick in
showers once again that will carry into Tuesday, before finally
diminishing by Tuesday night. Patchy fog will also be seen
overnight, especially in areas that saw locally heavy rainfall.
Temperatures will not move much from current readings in the mid
to upper 50s.

UPDATE Issued at 843 PM EDT MON MAR 27 2017

Ongoing complex of strong to severe thunderstorms is gradually
winding down as it heads east well ahead of the parent forcing.
There are still pockets of severe wind gusts following a
persistent lead supercell in the central portion of the forecast
area. Expect a continuing gradual decline of this activity through
10 pm, with a lull in the action until a short wave trough axis
approaches from the west overnight. This will likely bring an
uptick in convection once again, but mainly just showers.
Freshened up the POP timing based on the radar trends.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 440 PM EDT MON MAR 27 2017

A shortwave trough is expected to dampen as it moves into the OH
and TN Valley regions through tonight and then across the
Appalachians on Tuesday morning and then the Eastern Seaboard by
the end of the period. At the same time, a surface low will track
near or north of the OH River through this evening and tonight
and then into the mid Atlantic states through the end of the
period. Height rises and mid and upper level ridging area expected
behind the shortwave with surface high pressure nosing into the OH
Valley on Tuesday night.

Isolated to at times scattered convection continues to move
across parts of central and eastern KY in advance of more
organized convection over western and west central Ky and western
and middle TN. This earlier convection has produced some hail
across the region and marginally severe hail and some wind would
appear to be a threat over the next couple of hours. MLCAPE of 500
to 1000 J/KG over the far south and MUCAPE of 500 to 1000 J/KG
across the area combined with 35 to 40KT of 0-6km shear would
support this although much of the area has been worked over and
the southwest part of the area should be the first to destabilize
again per RAP and model forecasts though much of the western part
of the CWA is expected to reach ML or MUCAPE near 1000 J/KG for a
time in the west. Satellite trends would also support another
window for heating in the south. The far southwest counties remain
in a Severe Thunderstorm Watch through 3Z. Trends will continue to
be monitored for Severe thunderstorm chances further east, but
much of this area has received convection this evening or in the
case of the VA border counties has lower sfc dewpoints due to
downsloping effects.

Some of the convective allowing models bring the convection into
east KY around 23Z to 01Z but weaken the eastern line segment as
this will near sunset and boundary layer should begin to
stabilize. The models generally take the westernmost line east or
southeast with the recent HRRR runs favoring southeast while some
previous runs brought some of that convection more toward Lake
Cumberland. However, pending strength of cold pool, the first more
northern line segment of convection may not weaken as quickly as
models project as it moves in. Wind appears to be the primary
threat with any of this convection with bowing line segments and
possibly marginal hail from the strongest updrafts. Locally heavy
rain will also be possible if storms could train in an area.

Chances for thunderstorms will begin to diminish overnight with
shower chances also decreasing late as well as the surface low
tracks into the mid OH Valley and the cold front works into the
area and the axis of the 500 mb trough approaches. Chances for
convection will decrease through the day on Tuesday as the trough
and low pressure system exit to the east and northeast and mid and
upper level as well as sfc high pressure begin to build in. Low
level moisture is expected to linger well into Tuesday night, but
if the low clouds thin, radiational fog will be possible and
subsidence could bring some stratus build down late Tuesday night.

.LONG TERM...(Wednesday through Monday)
Issued at 310 PM EDT MON MAR 27 2017

The extended period should once again feature good chances for
showers and thunderstorms from late Thursday morning through early
Friday evening. The trigger for this activity will likely be a
slow moving area of low pressure that is progged to move across
the Tennessee and lower Ohio Valley regions. The slow forward
motion of the system should keep rain in eastern Kentucky through
Saturday morning. Thunderstorm chances should come to an end
around 0Z Saturday, as the best upper level support and overall
lift should be east of the area as the low pressure system moves
off to our east. The rain should begin quickly tapering off
around dawn Saturday morning, with the rain being completely out
of the area before noon on Saturday. The weather should remain dry
from Saturday afternoon through late Sunday night, as an area of
high pressure settles over the region. Our next round of rain
could move into eastern Kentucky very early Monday morning, but
due a lot of uncertainty still exists that far out in the period.

Temperatures will continue to run well above normal, with daily
highs ranging from the mid to around 70 on most days. Thursday
looks to be by far the warmest day, with forecast highs on that
day in the 70s. Nightly lows should generally be in the 40s and
50s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 200 AM EDT TUE MAR 28 2017

Although a passing shower will still be possible through dawn,
ceilings will gradually lower through the night - likely down to
IFR levels, as winds shift from the southwest to west northwest
behind a cold front moving through. Look for ceilings to
marginally improve later today.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...GREIF
SHORT TERM...JP
LONG TERM...AR
AVIATION...GREIF



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