Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 270805
AFDJKL

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

.SHORT TERM...(Today through Thursday)
Issued at 405 AM EDT WED JUL 27 2016

Clouds were starting to increase in coverage at 7z, with a few
showers starting to pop up across the central TN and moving into
south central KY. Kept low end isolated pops in across the southern
extent of the CWA to cover these isolated showers through daybreak.
Otherwise, today should be much in the same as yesterday, with the
stalled frontal boundary still in place across then northern half of
the state, and a warm, very moist airmass in place. As we head into
the daylight areas, expect convection to begin popping here, across
our northern CWA, then quickly spreading across the remainder of the
CWA throughout the afternoon. Kept with scattered pops across the
CWA through the afternoon given the uncertainty of where and when
storms will actually form. This may need to be fined tuned a bit as
convection starts developing today. PWATs continue to hover around
the 2 inch mark today, so any storms that do develop will continue to
be heavy rain producers. This, combined with very little directional
shear, could lead to some training of storms as well, so will
continue to monitor for any flooding concerns.

Focus then shifts to the overnight hours tonight and heading into
the day Thursday. The stationary front across the state will push
slightly north of the Ohio River late tonight, and remain just north
of the state through the day Thursday. Winds will take on a slightly
more SW heading, and increase intensity, allowing for a deeper pull
of moist southerly air. This increase will be due to a deepening
shortwave, which is expected to move across the mid Mississippi
River Valley tonight, and then across Kentucky Thursday and Thursday
night. This wave will interact with the stationary boundary as well
as the phasing of the southern and northern jet streams, to create a
large surge of warm deep moisture, and lift for which storms to
develop. PWAT values for tonight will be well over 2 inches, and
will continue to increase to up to 2.25 inches or just above in some
places during the day Thursday. CAPE values and LIs remain decent
from tonight through Thursday, but overall the more long/skinny
nature of the CAPE continues to lend itself to heavy rain being the
primary concern. Somewhat unidirectional flow in the mid and upper
levels Thursday may also lend itself to some training of storms,
which would be worst case scenario for any peoples under these
storm`s path. Flooding will likely be imminent, the question is how
isolated will it be, and where will it occur. No flood watch has
been posted at this time.

Temperatures today will continue to be warm and muggy, topping out
in the upper 80s to near 90, with heat indices int eh mid and upper
90s. With the introduction of thick cloud cover and heavy rains
Thursday, temperatures will take a downward turn, with highs only in
the low 80s. It will be wet, but a welcome relief from the heat.

.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.
&&

$$

SHORT TERM...JMW
LONG TERM...JVM
AVIATION...JMW



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