Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 182336

National Weather Service Jackson KY
736 PM EDT Fri Aug 18 2017

Issued at 735 PM EDT FRI AUG 18 2017

The forecast is looking good so far this evening. The latest obs
were ingested into the forecast grids to establish new trends. No
other changes to the forecast were necessary at this time.


.SHORT TERM...(This evening through Saturday night)
Issued at 430 PM EDT FRI AUG 18 2017

Drier air is on the way in from the west and northwest late this
afternoon. There were some very isolated showers yet over the
eastern tip of the state, but coverage will probably end up being
10% or less, and it`s not worthy of including a 20% POP in the
forecast. Otherwise, there`s nothing more than fair wx cu present,
and these will dry up this evening to leave main clear skies

A shortwave trough will pass through on Saturday. Forecast
soundings show enough instability along with the dynamic support
to warrant a low POP for thunderstorms in our far northern
counties. Anything that occurs should end in the afternoon as the
wave passes to the east. That will leave us with mainly clear
skies again for Saturday night.

Will look for our typical late summer fog each night-- developing
first in the deeper valleys and then spreading. It will dissipate
after sunrise.

.LONG TERM...(Sunday through Friday)
Issued at 343 PM EDT FRI AUG 18 2017

The upper level pattern shows good agreement from the model suites
indicating rising heights to begin the forecast period. This will
provide a platform for a break in the weather through Monday
night. However, both Sunday and Monday we will likely see some
afternoon CU, but this will not kill seeing the eclipse on Monday.
Also did opt to paint a unorthodox diurnal curve to the hourly
temperature grids given the eclipse and time of day. There remains
some uncertainty to the amount of drop in temperature, given this
will be dependent on other elements such as cloud cover and
dewpoint. This will be better picked up by the HRRRX by Monday, as
they have added the eclipse effects in the background of the
model. Another upper level trough will be reloading in the Upper
Midwest and will begin dig and suppress the upper level high by
Tuesday. This along with the approaching cold front will lead to
showers and thunderstorms by Late Tuesday into early Wednesday.
Right now timing wise the better chances of seeing rainfall will
be Tuesday night into early Wednesday. Then the big question will
be does the front make it across the region Wednesday, but right
now the models are in decent agreement with this front moving
east. This would lead to a overall better end to the week next
week, with temperatures in the mid to upper 70 and PWAT values
dropping below 1 inch.


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

Fog will develop in valleys late tonight and spread in breadth
and depth, probably affecting most TAF sites with MVFR conditions
(or perhaps worse) at times toward dawn. JKL may or not see fog
early tomorrow morning, depending on how suppressed the fog is in
the surrounding valleys. Fog and low clouds will dissipate after
sunrise, leaving VFR conditions everywhere by late morning. Clear
to mostly clear conditions and light and variable winds are
expected to prevail through out the period.




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