Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 172347

National Weather Service Jackson KY
747 PM EDT Thu Aug 17 2017

Issued at 747 PM EDT THU AUG 17 2017

The forecast is on track for the most part so far this evening.
The model consensus in general is suggesting that ongoing showers
and storms will continue moving eastward, and will eventually
move across eastern Kentucky. There are some differences amongst
the models as to the exact timing and coverage of convection this
evening and tonight, but the inherited forecast is handling the
current evolution of ongoing showers and storms well enough to
warrant not an update at this time. Will need to issue and update
later in the shift, however, to at least remove any outdated
evening wording.


.SHORT TERM...(This evening through Friday night)
Issued at 438 PM EDT THU AUG 17 2017

A rather strong storm system near the upper Great Lakes was
bringing a flow of warm and humid air to the area ahead of a cold
front today. An upper level wave was also approaching from the
west. This has led to scattered showers and thunderstorms. The
most significant area of showers and thunderstorms was over
southern OH and northern KY late this afternoon. Other storms
tailed southwestward int western KY. The most significant winds
aloft were also located to our north, and that is where the
greatest threat of severe weather is. Models suggest that the
precip developing over northwest and western KY will progress
into our area tonight, but be on the decline as it moves through
late tonight. The actual cold frontal passage and change in air
mass is not expected until Friday, and additional showers and
thunderstorms can not be ruled out ahead of the front on Friday,
especially in southeast KY where the front will arrive the latest.
Friday night the entire area should be dry as surface ridging
builds in from the west. The drier air mass should also allow for
somewhat cooler lows.

.LONG TERM...(Saturday through Thursday)
Issued at 343 PM EDT THU AUG 17 2017

The period will begin with the upper level trough axis swinging
across the Ohio Valley on Saturday. After this heights rise and
pattern flattens through Tuesday before another trough digs into
the eastern US to round out the period. The models are in decent
overall agreement upper level wise through the long term period.
This initial trough will bring a small chance of showers and
thunderstorms to the far north Saturday afternoon. Then a break
will come for late Saturday into early Monday. There remains some
question on what will develop for Monday and right now there is
only a small chance of showers and thunderstorms north of the
Mountain Parkway in the afternoon. However, this is really only
showing in one model solution and therefore confidence remains
low. Then the next trough will approach by Tuesday and bring best
chances of showers and thunderstorms by late Tuesday into
Wednesday. This trough will swing east and push a cold front
through the region, with chances lessening through the day on
Thursday. That said, there is some disagreement on how much the
front pushes through in the guidance and this could lead to
changes in the timing and coverage on Thursday. Temperature
through the period will remain near to above average for this time
of year.


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

The TAF period should start off fairly quiet with only FEW to SCT
clouds moving across the area. The clouds will be on the increase
between 1 and 3Z, however, as lines and clusters of showers and
thunderstorms approach from the west. The various forecast models
are all handling the evolution of the showers and storms
differently, but the general consensus is that SYM and SME will
see showers and storms first between 4 and 5Z, followed by LOZ,
JKL, and SJS between 6 and 7Z. This activity should taper off
steadily overnight due to loss of heating. The most active period
for rain tonight should between 4 and 10Z. After 10Z the showers
and storms will taper off through out the morning on Friday, and
should be out of the by early Friday afternoon. A few of the
storms this evening could produce isolated strong wind gusts,
especially at SYM. MVFR or worse conditions will be possible with
any thunderstorm. Fog is also expected later tonight into early
tomorrow morning, and could produce MVFR to IFR conditions,
especially between 9 and 11Z Friday.




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