Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 220836 CCA
AFDJKL

Area Forecast Discussion...CORRECTED
National Weather Service Jackson KY
436 AM EDT WED JUN 22 2016

.SHORT TERM...(Today through Thursday)
Issued at 418 AM EDT WED JUN 22 2016

A weak warm front is currently residing across the northern portion
of the CWA, with low level southerly air in place but continued NW
flow in the mid and upper levels. This warm front is expected to
begin slowly moving northward throughout the day today, as a surface
low pressure system moves eastward across the central plains and
into the upper midwest throughout the day, reaching northern IL by
0Z this evening. This low will continue its track eastward and just
north of the Ohio River Valley Wednesday night, before dropping an
associated cold front southeast across the region during the day
Thursday.

An expansive area of convection has emerged near the center of low
pressure over IL and points to the NW. This is expected to continue
a eastward track along with the low, expanding into KY throughout
the day. Furthermore, daytime heating and instability will work with
the warm frontal boundary in place across the state, to create a
secondary epicenter for convective development. Latest hi-res models
continue to support some scattered small cell development in our
south through 12Z, as a result of the outflow boundary from the
storms to our northeast tapping into heating as the sun rises. From
here, the best potential for convection will remain across the
northern half of the CWA, closer to the larger MCS outflow and along
the warm frontal boundary. This also pairs well with the SPC`s
analysis for best Theta-E gradients. Decent low level shear in
place, in addition to CAPE values well above 3k j/kg, and impressive
LI`s dropping below -8 late in the afternoon, are all good
indicators that these storms will pack some punch, with good severe
potential. DCAPE values will also tip 1k j/kg late in the day as
well, between 21z and 0z, so expect some good downdraft potential
with these storms as well.

SPC now has most of the southern CWA in a slight risk area, with the
northern CWA upgraded to an enhanced threat. While large hail and
isolated areas of rotation are possible, the main threats outlined
by SPC will be in the realm of damaging wind concerns. Torrential
rainfall cannot be ruled out in the stronger storms, which will need
to be carefully monitored given the already well worked over ground
from yesterdays storms, and ongoing flooding concerns.

As the surface low passes to our north during the overnight, expect
convection to become much more confined to an area surrounding the
low, with loss of daytime heating preventing more widespread
convection. As such, kept chances pops mainly across the far north
and northeast portion of the CWA throughout much of the night.
During the day Thursday, however, strong SW flow in place ahead of
the approaching cold front will work to pull in a strong flow of
warm moist and unstable air from the Gulf of Mexico. This will spawn
more showers and thunderstorms across the area, with the best
likelihood across our far northern CWA, closer to the incoming
frontal boundary. Temperatures will also rise back to a very humid
upper 80 degree range. SPC has much of the CWA in a slight risk area
once again, with damaging winds being the main concern. CAPE values
Thursday afternoon will top out well above 4k j/kg across the
southern half of the CWA in the afternoon, and near 5k j/kg in the
northern half. Furthermore, LI`s will drop to -10 to -12 and PWATs
will increase to or exceed 2 inches. All things put together, would
not be surprised based on the soundings, to see large hail
development as well as another round of very torrential rainfall and
isolated flooding concerns. We are very lucky that llvl directional
wind shear is not greater, otherwise this has the makings of a
classic rotating super scenario.

.LONG TERM...(Thursday through Tuesday)
Issued at 313 PM EDT TUE JUN 21 2016

The long term period will be dominated by a southern US ridge and
shortwave impulses embedded within the northern stream flow. At the
start of the period, the southern ridge will hold steady just south
of Kentucky as the northern stream begins to amplify. This northern
stream amplification will allow for a northern stream impulse to
skirt by Kentucky on Friday. The ridge extends its influence north
over the region on Saturday and Sunday, though another trough rides
east along the US/Canadian border. Ahead of this feature`s push
toward the Great Lakes, energy will scoot along the northern extent
of the ridge to affect Kentucky mainly Monday and Tuesday, with some
significant height falls expected. The trough axis approaches East
Kentucky Wednesday night into Thursday with additional energy ahead
of the trough.

At the surface, a trailing cold front extending from a low pressure
system over the Great Lakes will pass through the region late
Thursday into Friday. Depending on the timing of the frontal
passage, strong to severe storms may be possible with this frontal
passage. The front is expected to push south of Kentucky by the end
of the work week which should allow for a mostly dry weekend across
the forecast area. Precipitation chances then increase through the
rest of the forecast period as heat and humidity build back in, with
convection possible each day.

Temperatures will remain warm throughout the period with highs
generally in the mid to upper 80s and lows in the upper 60s. The
warmest days of the period will be over the weekend where
temperatures could surpass the 90 degree mark.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 143 AM EDT WED JUN 22 2016

Heavy rains and convection that plagued eastern Ky though the
evening have since exited the region and dissipated. In it`s
wake, lingering moisture and partially clearing skies have led to
fog development across much of the region. This fog will likely
affect the TAF sites in some form throughout the night, but will
may be variable based on continued light SW winds. As such, geared
most of the TAF sites toward MVFR vis after 8Z, with worsening
conditions at KJKL based on already deteriorating conditions at
TAF issuance. Will continue to monitor throughout the night in
case further updates are needed based on impacts of fog at each
site. Fog should clear out between 11 and 13Z tomorrow. However,
convection will begin threatening eastern Ky once more, as early
as 13Z in the northwest. Kept with VCTS mention throughout the
afternoon at TAF sites to account for this potential, though
confidence is still low on when and where these storms will set up
throughout the day in relation to the TAF sites. Winds will remain
south to southwesterly, generally between 5 and 10 knots through
the day Wednesday.

&&

.JKL Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...JMW
LONG TERM...JVM
AVIATION...JMW



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