Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 270551
AFDJKL

Area Forecast Discussion
National Weather Service Jackson KY
151 AM EDT WED JUL 27 2016

.UPDATE...
Issued at 1038 PM EDT TUE JUL 26 2016

Have updated to blend late evening obs into the forecast grids,
with no substantive change to the overall forecast.

UPDATE Issued at 841 PM EDT TUE JUL 26 2016

Convection over the JKL forecast area has mostly died out, and
there are no existing convective systems lined up for us, and no
indications of anything organized during the night. Won`t rule out
some activity popping up, but it would seem the probability is
low, and the POP has been dropped to slight chance category.

UPDATE Issued at 427 PM EDT TUE JUL 26 2016

A small convective system is tailing down into our northern
counties late this afternoon. Extrapolation takes it eastward
largely north of the mountain parkway, and the POP has been
increased to 60 percent there in a pre-first period before 00z.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 328 PM EDT TUE JUL 26 2016

The frontal boundary stalled along the Ohio River will remain the
primary feature of concern through tomorrow. Storms along this
boundary early this afternoon are showing signs of organization as
they track eastward. This cluster of storms is expected to track
across the Gateway Region of northeast Kentucky later this
afternoon with outflows probably generating additional scattered
showers/storms further to the south. PWATs are analyzed above 2
inches across our northern counties, and are near record highs
according to latest Mesoscale Precip Discussion from WPC. Thus
these storms will produce torrential rainfall and any training of
cells will pose a threat for isolated flash flooding. A severe
storm or two is possible, mainly over our northern counties, with
damaging winds the primary severe weather hazard.

Convection should exhibit a strong diurnal trend again and
diminish quickly after sunset before firing up again with daytime
heating tomorrow afternoon. Models want to nudge the front a
little to the south by tomorrow so anticipate scattered storms
developing over our area, instead of to our north as has happened
today. Another warm and muggy day is anticipated tomorrow with
highs in the upper 80s to near 90 and afternoon heat indices 95 to
100.

A shortwave will track northeast out of the western Gulf on
Wednesday forcing a wave of low pressure to develop on the front
to our southwest. This will move into western Tennessee late
Wednesday night and bring a slug of Gulf moisture northeastward
into central and eastern Kentucky forcing an increase in showers
and storms by late Wednesday night.

.LONG TERM...(Thursday through Tuesday)
Issued at 328 PM EDT TUE JUL 26 2016

Unsettled weather will continue through the forecast period as upper
level troughiness remains over Eastern Kentucky. The operational GFS
and ECMWF are in good agreement aloft with this overall pattern. The
main concern during the long term is the potential phasing of
northern and southern stream waves Thursday into Friday. The initial
wave from the Mississippi Valley is progged to lift northeast
through our area Thursday, followed shortly by the northern stream
wave from the Great Lakes. The GFS model is slightly quicker and
stronger with these waves and tries to phase them as they move
through the area. This system looks to exit Kentucky late Friday
but a series of upper level waves passing by will keep
precipitation chances in the forecast through the remainder of the
period.

At the surface, there will be daily chances for showers and
thunderstorms. The best chance for substantial rainfall will be
Thursday into Friday as a surface low, coinciding with the passing
of the previously mentioned upper level waves, moves across our
area. Model soundings on Thursday are skinny and saturated from the
surface up through the upper levels, with PWATS nearing 2.3 inches.
This would be a record value for our area, per ILN climatology.
These types of soundings are indicative of heavy rain producers and
flash flooding. Additionally, winds through the profile are
unidirectional, with training of showers and thunderstorms a decent
possibility. There is also potential for some of the storms to
become strong with CAPE values in excess of 2K. That being said,
rain and thunderstorms will be possible with this system beginning
Thursday morning and continuing into Friday evening. Saturday
through Tuesday, shower and thunderstorm activity should be limited
to the afternoon and evening hours each day.

Afternoon temperatures throughout the long term will generally
remain in the low to mid 80s thanks to afternoon shower chances each
day. Expect morning lows near climatological normals, in the mid and
upper 60s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 151 AM EDT WED JUL 27 2016

Conditions have cleared out across eastern KY tonight. The most
significant rainfall during the late afternoon and evening was
over the northeastern part of the area. This will favor more
extensive fog at sites such as KSYM & KSJS, with visibility
restrictions already been observed as of TAF issuance. However,
any of the TAF sites could drop to IFR overnight. Fog will
dissipate after sunrise and give way to VFR conditions during the
remainder of the morning. But with daytime heating and a stalled
frontal boundary across the northern portion of the state,
scattered showers/thunderstorms should pop up again and reach peak
coverage by late afternoon. An upper level wave will begin to move
into the region Wednesday night, which may keep scattered
convection going through the remainder of the TAF period, so kept
VCTS going. Winds will generally be light and variable, though
any stronger showers or thunderstorms could produce some briefly
gusty conditions.

&&

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

$$

UPDATE...HAL
SHORT TERM...ABE
LONG TERM...JVM
AVIATION...JMW



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