Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 251455 AAA

National Weather Service Jackson KY
1055 AM EDT Tue Oct 25 2016

Issued at 1055 AM EDT TUE OCT 25 2016

14z sfc analysis shows high pressure sliding by to the north of
Kentucky. This high, along with light to calm winds, settling
quicker than anticipated originally, and clear skies through the
night led to another cold morning with frost reported in some of
the valley locations, along with some areas of dense fog along
the rivers. The fog has cleared off now and temperatures are
rebounding with near full sunshine back up through the 40s and
into the lower 50s. Dewpoints, meanwhile, are generally in the
lower 40s and winds still light. Have updated the forecast to fine
tune the T and Td grids through the afternoon - incorporating the
latest ShortBlend guidance along with current obs and trends.
These have been sent out to the NDFD and web servers. A zone
update, mainly to remove the dense valley fog wording was also

UPDATE Issued at 657 AM EDT TUE OCT 25 2016

Drier air is starting down across the higher terrain with the
dewpoint at Black Mountain now down to 28 and falling quickly now.
This should be the start of mixing down the drier air as we go
through the day today. RH`s look to bottom out between 20 and 30
percent under sunny skies. Fortunately, winds will be rather light
today, to limit the fire danger. Based on the fog channel, it
looks like the fog is most prevalent in the eastern valleys, and
forecast has this covered well. No changes warranted this morning
except to freshen up temperature and dewpoint grids.


.SHORT TERM...(Today through Wednesday)
Issued at 300 AM EDT TUE OCT 25 2016

Mid level ridge axis will slowly work eastward over the next 24 to
36 hours, keeping our weather dry through Wednesday. Temperatures
have settled into the 30s in the colder valley locations early
this morning. Despite the chilly start to the day, afternoon highs
should rebound nicely with 850mb temperatures a degree or two
higher than yesterday. This will put highs generally into the mid
60s across northern Kentucky to around 70 in southern Kentucky.
Model soundings show some very dry air just off the surface that
will likely mix down into the afternoon and evening hours with
dewpoints crashing to around 30. While the ridge will start to
move east of the area tonight, we should remain under its
influence and would expect at a minimum for valley locations to
decouple. Given the drier air in place, it seems reasonable that a
few of the eastern valleys could approach the freezing mark.
However, it appears temperatures for most will stay in the mid to
upper 30s with lower 40s on the ridges. While temperatures may
stay above cross over temperatures tonight, limiting fog or frost
formation, we are close enough to freezing in some of our far
eastern valleys to include a mention of some patchy frost late
tonight. By Wednesday, heights continue to build with 850mb
temperatures warming to just over +12C. This would support highs
into the low to mid 70s, making for another beautiful eastern
Kentucky fall day. Went slightly under guidance for dewpoints on
Wednesday as models are bringing moisture back into the area much
too fast, despite the southwest winds.

.LONG TERM...(Wednesday night through Monday)
Issued at 356 AM EDT TUE OCT 25 2016

An upper trough axis will swing through the Great Lakes to
Tennessee Valley Wednesday night, as a surface low tracks across
the upper Ohio Valley and lower Great Lakes. Moisture from the
Gulf of Mexico will advect into eastern Kentucky downstream of
these features as an attendant cold front moves toward the lower
Ohio Valley, bringing a chance for showers to the Bluegrass
region near or shortly after midnight. Have inserted isolated
thunder mention at this juncture as elevated instability continues
to look to be present with MUCAPE values of a few hundred J/kg.
Surface-based instability of 500-1000 J/kg may be realized
Thursday afternoon ahead of the cool front before a secondary
surge of energy across the lower Great Lakes along with a surface
ridge building into the Ohio Valley push the front into eastern
Kentucky. Deep layer shear of 25-35 knots through the afternoon
may be enough to generate a couple of sustained/organized
updrafts, capable of producing gusty downdraft winds underneath
any shower or storm.

High pressure parking overhead will lead to a crisp Friday morning as
valley temperatures bottom out in the mid-upper 30s with ridgetops
remaining in the low-mid 40s. However, a quick return of warm air
advection will take place Friday morning/afternoon as an upper
high builds across Texas with anticyclonic flow stretching through
eastern Kentucky. Following high temperatures in the mid-upper 60s
Thursday, Friday looks to potentially be the beginning of a
prolonged warm period as highs climb into the upper 60s to mid

Upper ridging looks to continue to meander much of the Gulf
of Mexico through the Mississippi Valley and Great Plains through
the weekend as northern stream energy traverses south central
to southeastern Canada into the northern United States. Current
trends have pointed toward warm and dry conditions remaining in
place for the most part across eastern Kentucky into next week,
but will have to monitor southern extent/strength of
aforementioned energy regarding sensible weather locally.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)

Mainly VFR conditions and light winds will be seen through
Tuesday night. Some patchy dense valley fog is expected early this
morning, but should not impact the TAF sites.




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