Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 260618
AFDJKL

Area Forecast Discussion
National Weather Service Jackson KY
218 AM EDT FRI AUG 26 2016

.UPDATE...
Issued at 218 AM EDT FRI AUG 26 2016

A few minor changes to the forecast package, mainly to beef up the
valley fog wording to patchy dense based off of reports. Also had
some slight adjustments to overnight lows, again mainly in our
typically cooler valley locations but probably not significant
enough to alter the zones.

UPDATE Issued at 1030 PM EDT THU AUG 25 2016

IR Sat showing a few high clouds moving across the Lake Cumberland
region, but otherwise clear skies for most. Just minor tweaks to
the grids with latest obs and trends in mind.

UPDATE Issued at 706 PM EDT THU AUG 25 2016

WSR-88D radar showing the afternoon convection has diminished and
this is in line with the forecast grids. Otherwise we are looking
at a warm and humid evening under the upper level ridging and
return flow at the surface. Grids are on track and only overnight
issue will be valley fog potential. Therefore only minor tweaks
needed for current conditions tonight in the grids and taking the
thunder out of the HWO.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 348 PM EDT THU AUG 25 2016

Upper ridging across the Tennessee Valley will edge northeast
into the Appalachians and Mid-Atlantic Friday into the weekend,
keeping a hot and humid airmass in place across eastern Kentucky.
This airmass has led to isolated shower and embedded thunderstorm
activity this afternoon along a weak moisture gradient. Will see
these diminish into late afternoon as this gradient and subsequent
low level forcing decrease. Decay of diurnal cumulus field and
increasing subsidence will allow for patchy fog development
tonight and Friday morning, especially in sheltered valleys. An
influx of relatively drier air coupled with another generally
precipitation free day should limit more widespread development.

Deep layer subsidence, stemming from the above mentioned upper
ridge moving overhead, and a lack of forcing for ascent should
lead to a dry Friday. An upper shortwave trough and weak cool
front look to remain confined to the Ohio Valley and north as
ridging holds strong locally. Best chance of any development would
be off the Cumberland Plateau and higher terrain along the
Virginia border, but a theta-e minimum in place along with
subsidence aloft should preclude mentionable chances. This will
allow for a hot afternoon as temperatures soar into the upper 80s
to lower 90s.

.LONG TERM...(Saturday through Thursday)
Issued at 348 PM EDT THU AUG 25 2016

Not the best agreement amongst the extended this time around. The
ECMWF was consistently drier through out the period than the GFS.
The blended model data settled around a solution that features
showers and storms moving into the area Saturday afternoon, and
persisting Monday afternoon, with the most active periods being the
afternoon and evening hours. It then appears that a ridge of high
pressure will settle over the area from Monday evening through
Tuesday morning, bringing a brief respite from shower and storm
activity. A sluggish cold front will attempt to push into the area
from early Tuesday afternoon onward. This boundary may spark a few
showers and storms in our far western counties on Tuesday. After
that, another ridge of high pressure is progged to spread over the
area Tuesday evening and early Tuesday night. More showers and
storms are then expected to plague the area from late Tuesday night
through the end of the week. With the amount of uncertainty in the
model data, decided to keep only very low rain chances in the
forecast, at least until the models have a better handle on things.

Hot and muggy conditions are expected to persist through out the
period, with highs around 90 expected from Saturday through
Wednesday. The expected clouds and precipitation should allow
temperatures on Thursday to not be quite as warm, with highs in the
mid to upper 80s on that day.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 218 AM EDT FRI AUG 26 2016

VFR conditions expected for most terminals. Both KLOZ and KSME
could see some MVFR VSBYS due to fog late tonight into the early
Saturday morning. Fog should lift and dissipate totally across
the area by 10 a.m. Winds will be light and variable through the
period.

&&

.JKL Watches/Warnings/Advisories...None.

&&

$$

UPDATE...RAY
SHORT TERM...GUSEMAN
LONG TERM...AR
AVIATION...RAY


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