Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 210241

National Weather Service Jackson KY
1041 PM EDT Wed Sep 20 2017

Issued at 1041 PM EDT WED SEP 20 2017

Forecast is on track for a quiet but potentially foggy night
ahead. Airport obs have not shown any visibility restrictions
below 7 miles yet. However, many obs are at saturation, and the
first indications of valley fog are starting to show up on the RGB
microphysics satellite channel. The fog will continue to expand
during the night.


.SHORT TERM...(This evening through Thursday night)
Issued at 350 PM EDT WED SEP 20 2017

Current radar mosaic is showing isolated showers and
thunderstorms across the region with slightly better coverage
across central portions of the Commonwealth. Expect this activity
will continue for a few more hours before waning around sunset.

Models are in good agreement through the short term. Additional
short wave energy will drop down into the area tomorrow on the
south side of a developing mid/upper level ridge. This ridge will
nose its way northeastward through the period, expanding from the
southern plains into the mid Mississippi Valley overnight, and
then into the Great Lakes by end of the day Thursday.

Sensible weather will see another night with fog. However, while
the fog will be locally dense in places expectations are that the
overall coverage and intensity should not be quite as bad as last
night. With short wave energy riding along the southeastern edge
of the ridge Thursday, can not rule out another day of isolated
convection across the area tomorrow, similar to the last couple
of afternoons. Temperatures will continue to run about 5 degrees
above normal through the period.

.LONG TERM...(Friday through Wednesday)
Issued at 328 PM EDT WED SEP 20 2017

The period will be controlled by upper level ridging moving across
the Tennessee and Ohio Valleys and surface high nosing south from
time to time. This well established ridge will keep the tropical
systems well away from the Ohio Valley. The only issue will be the
potential for mainly valley fog and slight ridge valley
temperature splits in the morning. However, towards the end of the
long term period we do see signs of the eastern lower 48 ridge
breaking down, and this will allow for slightly cooler afternoon
temperatures (closer to average for this time of year) and
lowering heights.


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

Most showers have died out as of TAF issuance, and the primary
concern for non-VFR weather will be fog late tonight and into
Thursday morning. It will develop in valleys first, but then
spread in breadth and depth. All TAF sites are expected to end up
affected. The fog will be dense in many locations, with VLIFR
conditions. It will dissipate by late Thursday morning, giving
way to mainly VFR conditions for the rest of the period. There is
a slight chance of showers and thunderstorms developing on
Thursday afternoon, mainly south of the Mountain Parkway. They
could bring localized IFR conditions. However, the probability at
any given time/point is too low to warrant inclusion in TAFs.




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