Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 250341

National Weather Service Jackson KY
1141 PM EDT Sat Mar 24 2018

Issued at 1141 PM EDT SAT MAR 24 2018

All headlines were dropped late this evening. Remaining precip had
changed to rain, or a mix of rain and snow, and temperatures were
generally above freezing. Back edge of significant precip is
progressing south across the area. Temperatures in northern
locations may drop back down below freezing overnight, with some
slick spots possible where roads don`t dry, and an expanded SPS
will be used.

UPDATE Issued at 720 PM EDT SAT MAR 24 2018

Updated the forecast to drop the Advisory counties as temperatures
have climbed above freezing there and they are no longer under a
threat of accumulating snow or sleet. Did issue an SPS covering
the slush and slick spot potential for the roads tonight in those
locations. Additionally, fine tuned the convection and thunder
threat for the area through the evening with this update. A
freshened set of zones and new HWO was issued along with the WSW
cancellation statement. The WSWs continue with accumulating snow
and related problems likely to continue. The updated grids have
been sent to the NDFD and web servers.


.SHORT TERM...(This evening through Sunday night)
Issued at 455 PM EDT SAT MAR 24 2018

20z sfc analysis shows a dynamic and complex spring storm system
moving through southern Kentucky. This has pumped copious amounts
of moisture into the area with its warmer air overrunning a cold
dome to the northeast that has been slow to retreat. As a result
heavy snow fell through the northeast third of the state
overcoming initially warm roads to accumulate and create
treacherous driving conditions generally from the Mountain
Parkway northeast as well as on the ridges to the southeast. The
snow became more convective with time and several good squalls
moved through northeast of the snow line dumping inch plus per
hour amounts for much of that area. This necessitated pushing the
warnings further east just as the advisory had to be extended a
tier of counties to the south due to the cold air holding in
longer than modeled. As it stands, now the convective element has
taken over much of the state with rain and snow showers scattered
through the north and showers/thunderstorms found in the south.
Cannot rule out thunderstorms developing north of the snow line
potentially giving a complete mixed bag of pcpn, including hail,
out of any such cell that develops there. Readings currently vary
northeast to southwest across the JKL CWA from the low 30s in the
cold air to the lower 40s nearer the Tennessee border while
dewpoints are not far from temperatures everywhere contributing to
patchy fog. East to northeasterly wind flow continues across the
area at 10 to 15 kts with occasional higher gusts.

The models are similar aloft through the short term portion of
the forecast. They all depict a strong, but dampening wave
cutting through Kentucky in a larger regime of rising heights
that will leave heights similar through the next 12 to 18 hours.
This wave turned out to be more dynamic than modeled so far so
will continue to favor the stronger NAM12 solution. Northwest flow
follows on Sunday as the ridge pushes further east and over
Kentucky through Monday morning - where the NAM solution was also

Sensible weather will feature a changeable situation with warmer
air finally overwhelming the cold through the evening. Convection
will accompany this change with elevated instability in place
resulting in a concern for storms this evening and early overnight
for much of the CWA. Hail will be the main problem from these,
but gusty winds and heavy rains will also threaten. This mixed bag
of weather will finally settle down after midnight with the snow
threat ending as well as the convection. The amount of rainfall
from this system will likely lead to rises on the Cumberland and
Kentucky River basins, but probably not enough to get to flood at
any location as the better rains fell to the north of those
headwaters. Cooling temperatures late tonight will also lead to a
potential for black ice where roads are wet or slush covered. The
sfc low responsible for this storm will not completely clear the
area, though, so that a few rain or snow showers may linger into
Sunday. Sunday night looks dry, for the most part, with a
potential for frost, though thick cloud cover should keep it at
bay for most places.

Used the CONSShort and ShortBlend grids as a starting point with
extra cooling added overnight and on Sunday for the snow covered
areas. As for PoPs, lingered them longer on Sunday and then
dampened them that night in the southeast.

.LONG TERM...(Monday through Saturday)
Issued at 512 PM EDT SAT MAR 24 2018

An amplified long wave pattern will remain in place across the
CONUS through the middle of next week, before then transitioning
to more zonal flow by the start of the next weekend. A ridge will
start out across the Mississippi Valley, with a trough across the
West. The trough will gradually push east, allowing for a
northeast to southwest baroclinic zone to take shape from the
Great Lakes down to the Arklatex region. This boundary will then
take its time moving across the Mississippi Valley, yielding
another extended period of unsettled weather across the Ohio and
Tennessee valleys.

Dry weather will be short-lived across eastern Kentucky to start
the work week, as a warm front lifts northeast across the area
by Monday night into early Tuesday morning, bringing the threat
of showers to our area. The remnant surface cold front will then
slowly push east across the area Tuesday through Thursday, with
multiple waves of low pressure riding up along the boundary. This
will bring gradually increasing rain chances from northwest to
southeast across eastern Kentucky. By Friday, there has been more
discontinuity as the final trough axis pushes through the area,
so have stayed close to the blended solution, allowing for POPs to
hang on a bit longer. Drier weather then returns to start the
weekend. Temperatures will trend towards slightly above normal
readings through the work week, before cooling down a bit for the


.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)

Low cigs and vis impacts continue for the TAF sites this evening.
Most of them have seen a changeover for good to rain, but we could
still see some switching back at SYM and SJS. Conditions will
remain LIFR/IFR for the bulk of the night before improving toward
dawn from west to east - continuing into Sunday morning.
Additionally, the terminals across southern to southeast Kentucky,
including SME/LOZ may still see a few bolts of lightning until
late evening as some elevated thunderstorms remain possible.
Conditions everywhere improve for Sunday with clearing vis and
cigs coming up to MVFR at the least. Winds will be generally
northeast to east at 5 to 10 kts with occasional gusts up to 15
kts through the remainder of this evening and again during the day




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