Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 250800
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
300 AM EST Sat Nov 25 2017

.UPDATE...
Issued at 1055 PM EST FRI NOV 24 2017

Hourly temperatures have been updated to account for the latest
trends in valley temperatures. A few of the normally cold spots in
the Big Sandy Region likely will drop to the freezing mark or just
below before leveling off or even rising late when the clouds
increase and the pressure gradient increases. The increasing
pressure gradient ahead of the approaching cold front is already
evident on top of Black Mountain at the KY mesonet site, where
winds are gusting into the 20 to 25 mph range with sustained winds
near 15 mph there and at the Pike Co KY Mesonet site at 2770 ft
msl. Winds in these locations should increase further overnight,
into the 15 to 20 mph range, with gusts up around 30 mph per
model trends. Winds and gusts about 2500 feet have been increased
for the duration of the night.

UPDATE Issued at 735 PM EST FRI NOV 24 2017

Temperatures were cooling off faster than the previous forecast
in eastern valley locations. Hourly temperatures were adjusted for
these trends with min T lowered a few degrees for some of the
normally colder locations. Otherwise, no other changes were needed
at this time.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 309 PM EST FRI NOV 24 2017

It was a cold start to the day with morning temperatures in the
valleys in the lower to middle 20s. Under abundant sunshine temperatures
have warmed into the lower 60s in much of the area this afternoon.

With dewpoints in the 20s in the north and east, temperatures
will fall quickly in the valleys this evening. A ridge valley
temperature difference will develop especially in the east, and
this is depicted in the forecast grids with lows in the middle 30s
in the eastern valleys and in the middle 40s on the ridges. It is
possible this may not be enough of a ridge valley difference and
temperatures may need to be further adjusted this evening.

Clouds will increase late tonight in advance of a cold
front. The front will make its way across the area on Saturday.
We will continue with the previous forecast thinking and keep the
sprinkle threat in the forecast late tonight and Saturday. After
the frontal passage on Saturday colder air will work its way back
into the area, though we`ll only receive a glancing blow with the
main cold air staying off to our north and northeast.

.LONG TERM...(Sunday night through Friday)
Issued at 300 AM EST SAT NOV 25 2017

The extended portion of the forecast begins on Sunday night with an
amplified but still rather progressive upper level pattern in
place. Current trends place the upper level in a split flow with
a northern stream flowing over the Rockies and a southern jet
stream coming out of the four corners region. With the northern
stream starved for moisture and lacking any significant flux, the
eastern Kentucky area has and will remain dry for the first half
of the extended forecast. This is in good agreement between the
GFS and Euro with the area remaining dry at least through
Wednesday. As such, with this scenario, no real change in air mass
is expected through the first half of the extended as well. In
fact, temperatures will remain near normal, if not a bit above.

By Wednesday night, a shortwave tracking over the Plains along
with a separate piece of energy along the southern stream by
Thursday morning will form a front tracking into the OH Valley.
This will provide the first strong surge of a change in air mass
as warmer air is drawn north into the area with high temps
reaching near 60. This will also provide a good chance of showers
lasting into Friday. With a lack of good instability as well, will
keep thunder out of the forecast. Models seem to be coming in
better agreement but still lack strong consistency. Thus, will
continue to stick with the super blend solution.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 1255 AM EST SAT NOV 25 2017

VFR conditions currently expected to prevail through the period.
Cloud decks will lower overnight into this morning as ceilings
develop. Still anticipating these to remain in the 5-10k foot
range or above, but could see some brief periods of ceilings
nearing MVFR criteria at around 3k feet from mid morning into the
afternoon as a cold front moves through eastern Kentucky.
Regarding precipitation, a few sprinkles will be possible into
mid-late afternoon. Increasing southwest winds of 5-10 knots
tonight will further increase and veer northwesterly through the
day Saturday while remaining near 10 knots with periodic gusts.
May have to monitor lingering low clouds for ceiling potential
this evening into tonight depending on how quickly high pressure
builds in and low level moisture scours out.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JP
SHORT TERM...SBH
LONG TERM...SHALLENBERGER
AVIATION...GUSEMAN


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