Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 170648

National Weather Service Jackson KY
248 AM EDT Thu Aug 17 2017

Issued at 130 AM EDT THU AUG 17 2017

Did a minor update to the grids to add some patchy dense fog in
the river valleys late tonight. Also fine tuned the Sky, T, and Td
grids per the latest obs and trends. These have been sent to the
NDFD and web servers.

UPDATE Issued at 1052 PM EDT WED AUG 16 2017

The forecast remains on track so far tonight. The latest obs were
ingested into the hourly forecast grids to establish new trends,
but no major changes to the forecast were necessary.

UPDATE Issued at 727 PM EDT WED AUG 16 2017

Forecast appears to on track so far this evening. Ingested the
latest observations into the hourly forecast to establish new
trends. Will issue an quick forecast update to remove outdated pre
first period from the zone forecast text product.


.SHORT TERM...(This evening through Thursday night)
Issued at 359 PM EDT WED AUG 16 2017

Showers continue to push east across eastern Kentucky this
afternoon with much of the activity actually showing a slight
weakening trend over the past few hours. While a dry wedge is
working in from central Kentucky, more showers and storms are
starting to move in from the west. However, still quite some
distance for this additional activity to travel and it may not
make it here to capitalize on present instability. Thus, still
expect a gradual decrease in shower coverage heading into the
evening hours as the dry wedge works east across the area. A few
models show some isolated showers redeveloping late tonight, but
not a lot of forcing present except a weak low level jet. Perhaps
this would be enough for a few showers to pop up just prior to

As we head through the day tomorrow, a cold front will push east
into the Ohio river valley and bring a line of showers and storms
across eastern Kentucky through the evening hours. Models are in
pretty good agreement with this activity, so have trended higher
with the pops through the evening period. Activity will exit
southeast overnight with the front hanging up over the area.
However, subsidence behind departing showers/storms will lead very
little potential for additional activity, but a few isolated
showers would remain possible.

.LONG TERM...(Friday night through Wednesday)
Issued at 250 AM EDT THU AUG 17 2017

The extended portion of the forecast begins Friday night with a
continued active pattern in place. To start the period, an upper
level shortwave ridge will be passing over the area as a mainly dry
weekend will be on tap for eastern Kentucky. The one exception
will be over northeastern KY when the eastern CONUS will continue
to be under a lingering longwave trough. Thus another weak wave
will follow in behind Friday`s exiting front providing a small
chance of precip over the northern half of the forecast area for
Saturday afternoon. High pressure will keep the area dry for
Sunday. In fact, models suggest that the bubble will linger into
Monday keeping the area dry another day, at least in far eastern
Kentucky as the return flow will eek a bit of moisture into the
I-75 corridor area. Still only a slight chance of precip is
possible over the northern portion of the forecast area.

By Tuesday morning, combined with return flow advecting ample
moisture into the OH Valley and TN Valley, a strong cold front
will move into the region creating a prolonged period of showers
and thunderstorms Tuesday through Wednesday. The heavier activity
will coincide with the max heat of the day on Tuesday as it seems
PWATS will range between 1.75 and 1.90 during this period. Ample
moisture in place during this prolonged period may be enough for a
few minor flooding problems for early Tuesday through Wednesday


.AVIATION...(For the 06Z TAFS through 06Z Thursday night)

The TAF period starts out with mostly clear to partly cloudy
skies. Expect a period of MVFR vis from fog at most sites in the
predawn hours with a potential for dense fog and VLIFR conditions.
Have included this in the lower elevations TAFs as a tempo. The
cloud cover will then gradually increase throughout the day,
Thursday, as an area of low pressure and its associated surface
cold front approach from the west. By late afternoon SYM and SME
can expected numerous showers and scattered thunderstorms, as the
cold front begins to move across the area. JKL, LOZ, and SJS
should see the best convective threat a bit later. Winds will be
generally out of the southwest at 5 to 8 KTs during the day,
otherwise light.




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