Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 222358
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
758 PM EDT Thu Jun 22 2017

.UPDATE...
Issued at 747 PM EDT THU JUN 22 2017

Continuing to monitor the rain as it moves across eastern
Kentucky, with what looks to be a pretty good back edge now moving
into our SW CWA. That being said, there is still another round of
precipitation located to our south that will likely make it into
our SE counties over the next few hours. Generally favoring the
HRRR solution which is initializing well with the ongoing
conditions, and has this secondary area of rain moving across the
eastern half of the CWA overnight. Will continue to monitor and
adjust pops and needed. Otherwise, main updates at this time were
just to make sure the temps, dew points, and winds were on track
with current conditions. All changes have been published and sent
to NDFD/web.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 504 PM EDT THU JUN 22 2017

The leading edge of deeper moisture associated with Cindy has
brought widespread showers to eastern Kentucky through the day.
Lightning has been scarce so far today, with most locations
receiving between a few hundredths of an inch and a half inch of
rainfall, as some downsloping flow has cut into totals.

The main band of showers will lift off to our northeast through
this evening, with generally lesser chances expected through the
overnight hours. A low level jet does pick up towards dawn, and
this may initiate some better areal coverage.

The remnants of Cindy will track up the Mississippi Valley on
Friday, before turning more northeast across the northern half of
Kentucky Friday night. An approaching cold front will interact
with this system, allowing for a period of heavy rainfall that
will move in to eastern Kentucky later Friday afternoon into
Friday night. The models have generally shifted the higher QPF
amounts more to the north with time, although given the high
moisture content of the air mass, any location would have the
potential for heavy rainfall and flash flooding.

As such, a flash flood watch is in effect from Friday afternoon
through early Saturday morning. Locations generally near and north
of a line from Mckee to Jackson to Inez will have the higher
flash flood threat, where the higher 6 hour QPF totals will
reside. Depending on the exact amounts, some significant river
rises will also be possible.

In addition to the heavy rainfall, there may also be a severe
threat window Friday afternoon into Friday evening, given the
stronger low level wind profiles in place and the proximity of the
low center. As is typical, instability will be in question as
mid-level lapse rates will be lacking. Have continued to
mention this potential in the HWO.

.LONG TERM...(Saturday through Thursday)
Issued at 244 PM EDT THU JUN 22 2017

The extended portion of the forecast begins on Saturday with the
upper level pattern featuring a stout ridge over the western CONUS
transitioning into a trough over the Great Lakes. The first wave
associated with the combination of tropical moisture and a cold
front will finally exit the area at the start of the forecast
period. So will see a chance of showers over eastern Kentucky
through the day on Saturday as the last of the showers exit the
area by the evening. This will usher in a dry period as models
have trended drier and drier. The mentioned stout ridge in the
west will build as it shifts east nudging the axis over the
Midwest by Wednesday. In addition, a bubble of surface high
pressure will carve out an area of subsidence over eastern
Kentucky and much of the central Appalachians. In fact, the
airmass intrusion behind Cindy will bring some welcomed cooler
temps to start next week with highs in the 70s expected through
Wednesday.

One difference in the forecast might be on Monday afternoon as the
most recent 12Z Euro and GFS has brought a weak wave dropping far
enough south to bring a small chance of showers and a
thunderstorm. This is a change to the model trends so am more
inclined to keep the dry forecast inherited from the super blend.
Otherwise, the extended features dry weather and slightly cooler
high temperatures.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 756 PM EDT THU JUN 22 2017

Showers continue to impact much of eastern Kentucky this evening
as a result of moisture advection associated with Tropical Storm
Cindy. There is a defined back edge to this round of showers,
with drying now occurring at the southern most TAF sites.
However, another round of showers is set to begin moving in over
the next hour or two. CIGS are varying across much of eastern
Kentucky, though predominately VFR, with VIS generally P6SM
except where the heaviest rain showers are currently occurring
(KSYM and KJKL). Expect the VIS to improve as these heaviest bands
move out. As for the rest of the night and into the day tomorrow,
there is still quite a bit of uncertainty. Latest trends in the
Hi-Res models are showing a bit of clearing late tonight and
through the morning at most of the TAF sites before round 2 (the
heaviest rainfall) moves into the region from the west ahead of an
approaching frontal boundary. If this dry period pans out we
could see some transitions between MVFR and VFR conditions through
tomorrow morning, but also cannot rule out some potential fog
development. Low level wind shear will threaten later tonight as
well, as 850 mb winds remain around 40 to 50 kts, while south to
southeast winds at the surface remain at around 5 kts or less. By
tomorrow afternoon expect winds to begin picking up from the SW at
the surface, and showers and thunderstorms moving back into the
region, with a general trend towards MVFR CIGS.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch from Friday afternoon through Saturday morning
for KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120.

&&

$$

UPDATE...JMW
SHORT TERM...GEOGERIAN
LONG TERM...SHALLENBERGER
AVIATION...JMW



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