Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 220906
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
506 AM EDT Thu Jun 22 2017

.SHORT TERM...(Today through Friday)
Issued at 445 AM EDT THU JUN 22 2017

Early this morning, a rather zonal pattern in nature is in place
across the northern Conus with a ridge centered over the Desert
Southwest and another ridge centered between the Bahamas and
Bermuda. Surface high pressure in place from the Appalachians to
the Carolinas. Meanwhile, Tropical Storm Cindy is gradually
nearing the Gulf Coast near the TX and LA border. Tropical
moisture is already moving north across the Southeast and string
to surge north toward the TN and OH Valley regions. Despite an
increase in mainly cirrus with a few mid clouds, a moderate
nocturnal inversion has developed with ridgetops around 70 or the
lower 70s and valleys in the 60s. Valley fog was present in a few
valley locations.

At the same time that Tropical Storm Cindy and eventually its
remnants track toward the Arklatex region through this evening,
return flow between it and departing high pressure will bring a
plume of Gulf moisture north into the East KY. In addition, a
shortwave trough will move into the Northern Plains and approach
the Great Lakes tonight. A preceding cold front should move into
the Central Great Lakes by dawn on Friday and approach the Lower
OH Valley. Meanwhile the center of the remnants of Cindy should
reach southeastern AR by dawn on Friday. The shortwave trough
should move into the Great Lakes on Friday with the trough axis
nearing the Lower OH Valley. Also, the cold front should approach
the area from the north at that point.

A round of showers and a few thunderstorms is expected across the
region, arriving around midday into the afternoon in the south
and then spreading northeast through evening. The deeper moisture
should arrive first in the southwest and this combined with less
influence of a downslope southerly flow in the low levels will
lead to heavier rainfall there today. The chances for locally
heavier rain from thunderstorms will also be greatest across the
southwest or west this afternoon and evening. This rain will
occur with some isentropic lift on the leading edge of moisture
gradient as PW climbs rather dramatically to the 1.95 to about
2.1 inch range by sunset. Some solar insolation may also aid in
some shower and thunderstorm development.

Scatter to possibly numerous shower chances will continue into the
overnight tonight and into Friday morning as the front and
shortwave trough approaches and interacts with moisture from the
remnants of Tropical Storm Cindy. The threat of heavy rain should
return again on Friday afternoon as the center of the remnants of
Cindy nears and interacts with some daytime heating. A period of
some dry slotting or drier air moving at mid and upper level
should work across the area in between the rounds of rain and
allow for heating on Friday to warm temperatures to around 80 or
the lower 80s. At the same time, moisture will again increase
from the south and west and band of showers and some thunderstorms
are possible as the approaching front, trough, and circulation
form the remnants of Cindy near. This circulation should locally
enhance low level shear and this combined with daytime heating in
potential bands of convection will bring a chance for a few
strong to possibly severe thunderstorms along with heavy rain.
Damaging winds would be the main threat although with the
increased shear in the afternoon to early evening, a stray weak
tornado cannot be ruled out.

The heavy rain threat will continue to be highlighted in the HWO
as well as an ESF. The threat for a couple of strong to severe
storms is also highlighted in the HWO. If current trends continue,
a Flood Watch will likely be needed for Friday into Friday night.
Uncertainty remains in exact placement of the axis of axises of
heaviest rainfall, but one could develop by the long term period
over east KY with another closer to the approaching front.

.LONG TERM...(Friday night through Wednesday)
Issued at 309 AM EDT THU JUN 22 2017

The primary concern in the extended will be the potential for heavy
rainfall and flooding Friday night. The remnants of Tropical Storm
Cindy will likely be moving across the Tennessee valley region to
begin the weekend. The moisture associated with this feature will
also likely be interacting with a frontal boundary that may already
be in place across the region. The enhanced lift associated with
these two features, along with large amounts of tropical moisture,
could lead to widespread moderate to heavy rainfall across eastern
Kentucky. At this time, it appears that areas south of the Mountain
Parkway would be receiving the highest rainfall amounts Friday
night. The rain will gradually move across the area Saturday
morning, and should be out of eastern Kentucky by late Saturday
afternoon. Rainfall amounts will vary across the area depending on
the exact track of whats left of Cindy and the orientation and
timing of the preceding cold front. However, in general it appears
that 1 to 2 inches of rain will be possible Friday night. After
that, it looks like the next chance of rain will not arrive until
Monday, and based on the latest data it would be only isolated to
scattered light rain showers and a few storms east of the I-75
corridor. Any rain we see on Monday should be out of the area by
early Monday evening. The rest of the period should be dry after
that.

Temperatures should be close to normal on Saturday, with highs
around 80 expected, below normal Sunday through Tuesday, with highs
in the mid to upper 70s forecast on each of those days, and back to
near normal values again on Wednesday, with highs expected to top
out in the lower 80s. Nightly lows should be in the 60s Friday night
and Wednesday night, and in the 50s from Saturday night through
Wednesday night.


&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 215 AM EDT THU JUN 22 2017

High pressure remains in control early this morning, with high
clouds moving into the area as moisture begins to surge in from
the SW ahead of Tropical Storm Cindy. A low level jet is expected
to increase from the south and southwest generally after 12Z and
in particular 18Z and after bringing an increase in moisture, some
showers and storms and lowering ceilings. CIGs should lower to the
MVFR at SME, LOZ, and JKL between 18Z and 23Z and closer to 0Z at
SJS and SYM where moisture arrives later and there will be an
initial downslope component to the flow. A direct hit from a
stronger shower or a storm may reduce conditions briefly to IFR at
a locations. Winds will be light and variable through 12Z, then
become south southeast to south at 5 to 10KT.

&&

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

$$

SHORT TERM...JP
LONG TERM...AR
AVIATION...JP



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