Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 220543
AFDJKL

Area Forecast Discussion
National Weather Service Jackson KY
143 AM EDT WED JUN 22 2016

.UPDATE...
Issued at 135 AM EDT WED JUN 22 2016

Just did a small update between 11pm and 12am to better capture
the exiting precipitation in the far southeast portion of the CWA.
Precipitation has now exited the state and dissipated, and should
pose no further threats. However, given the ongoing impacts of
high water from the evening rains, and ongoing water rescues, the
flash flood warning was extended into the late night (now expiring
at 3am). In the wake of the exiting rain, fog has developed across
much of eastern KY. Will keep current fog grids in for now, but
may reassess increasing intensity and coverage for the upcoming
morning package. An SPS was issued to highlight fog concerns
through 6am. Finally, did a quick refresh of the near term temp,
dew point, and wind forecasts to make sure they were in line with
current conditions. All changes were published and sent to
NDFD/web, though no updates to the forecast package are needed at
this time.

UPDATE Issued at 1108 PM EDT TUE JUN 21 2016

The last batch of heavy rainers looks to exit far southeastern
Kentucky through midnight. These have been very persistent over
the past three hours across portions of Knox, Bell, Clay, Leslie,
and Harlan counties producing intermittent rainfall rates of over
4 inches per hour. Once these storms exit, it should be a quiet
rest of the night. Will maintain some slight pops towards dawn,
with the potential influence from upstream convection.

UPDATE Issued at 819 PM EDT TUE JUN 21 2016

Scattered to numerous showers and thunderstorms continue to fire
up along a stalled outflow boundary aligned from Mount Vernon
down through Harlan. Most of the higher resolution guidance and
general radar trends advertise a gradual weakening trend over the
next 1 to 2 hours. Locally heavy rainfall will be the biggest
concern out these storms, although given the long stretch of dry
weather we have seen, most hydro problems should be limited to
flood prone areas. Have freshened up pops over the next few hours
to account for the latest radar trends. Have also allowed for more
of a lull through the night, with higher resolution models
suggesting any further convective activity moving in from the
northwest looks to arrive mainly after 12z Wednesday. Any partial
clearing will allow for areas of fog, and have continued to
advertise this in the forecast.

UPDATE Issued at 608 PM EDT TUE JUN 21 2016

As much of the instability has waned across the area and any upper
level support has shifted to the east, the severe threat has
ended and the watch has been cancelled. In fact, with left over
showers and weaker storms in place, the environment will need till
tomorrow to replenish instability. Hi res models have trended on
this with a later arrival time tomorrow of the next disturbance.
This has also left a stable period overnight with fog development
likely and possibly dense. Will need to reevaluate heading into
the evening hours.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 343 PM EDT TUE JUN 21 2016

Current surface analysis as of 1930z features a line of convection
along and just ahead of a nearly washed out boundary tracking
southeast through eastern Kentucky. Some readily available shear
and ample instability at the start of this event has allowed for
some rotation in the storms as some have even had supercell
characteristics. Otherwise with a good mid level jet in place the
main concern will continue to be for wind through the rest of the
afternoon. As the afternoon wanes into the early evening hours,
surface instability will eventually weaken with the loss of
heating and lack of support. Would expect this to occur by 00z.

Heading into tonight, as the convection from earlier today begins
to dissipate as it slides southeast, a new low pressure system and
associated cluster of storms develops and begins to track
southeast. As this occurs, a developing warm front lifts northeast
as southwesterly warm and moist air increases. This next round
begins to ramp up and track into the area in the mid morning hours
on Wednesday morning. The question here will be how early the
activity arrives and amount of coverage. If convection lingers
through the morning, afternoon heating and increased instability
will be stunted with a lesser severe threat on Wednesday
afternoon.

With a slight risk of severe storms slated for Wednesday, the main
threat will be confined to the north and northeastern portions of
eastern Kentucky. The NAM and GFS hint at early convection will be
concentrated over the south and southwest Wednesday morning before
transitioning to the northeast through the day as the warm front
develops. By Wednesday night as the front lifts through the area,
skies will begin to clear out in the south with fog development
then becoming a concern. The main question over the next couple of
days for this pattern will be despite the ample instability each
day, organization of strong to severe convection can depend on
timing of arrival and max heating and debris from previous dying
MCS cutting off instability from future developing ones

.LONG TERM...(Thursday through Tuesday)
Issued at 313 PM EDT TUE JUN 21 2016

The long term period will be dominated by a southern US ridge and
shortwave impulses embedded within the northern stream flow. At the
start of the period, the southern ridge will hold steady just south
of Kentucky as the northern stream begins to amplify. This northern
stream amplification will allow for a northern stream impulse to
skirt by Kentucky on Friday. The ridge extends its influence north
over the region on Saturday and Sunday, though another trough rides
east along the US/Canadian border. Ahead of this feature`s push
toward the Great Lakes, energy will scoot along the northern extent
of the ridge to affect Kentucky mainly Monday and Tuesday, with some
significant height falls expected. The trough axis approaches East
Kentucky Wednesday night into Thursday with additional energy ahead
of the trough.

At the surface, a trailing cold front extending from a low pressure
system over the Great Lakes will pass through the region late
Thursday into Friday. Depending on the timing of the frontal
passage, strong to severe storms may be possible with this frontal
passage. The front is expected to push south of Kentucky by the end
of the work week which should allow for a mostly dry weekend across
the forecast area. Precipitation chances then increase through the
rest of the forecast period as heat and humidity build back in, with
convection possible each day.

Temperatures will remain warm throughout the period with highs
generally in the mid to upper 80s and lows in the upper 60s. The
warmest days of the period will be over the weekend where
temperatures could surpass the 90 degree mark.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 143 AM EDT WED JUN 22 2016

Heavy rains and convection that plagued eastern Ky though the
evening have since exited the region and dissipated. In it`s
wake, lingering moisture and partially clearing skies have led to
fog development across much of the region. This fog will likely
affect the TAF sites in some form throughout the night, but will
may be variable based on continued light SW winds. As such, geared
most of the TAF sites toward MVFR vis after 8Z, with worsening
conditions at KJKL based on already deteriorating conditions at
TAF issuance. Will continue to monitor throughout the night in
case further updates are needed based on impacts of fog at each
site. Fog should clear out between 11 and 13Z tomorrow. However,
convection will begin threatening eastern Ky once more, as early
as 13Z in the northwest. Kept with VCTS mention throughout the
afternoon at TAF sites to account for this potential, though
confidence is still low on when and where these storms will set up
throughout the day in relation to the TAF sites. Winds will remain
south to southwesterly, generally between 5 and 10 knots through
the day Wednesday.

&&

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

$$

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



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