Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 240145
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
945 PM EDT Fri Jun 23 2017

.UPDATE...
Issued at 944 PM EDT FRI JUN 23 2017

Continuing to monitor and update pops/weather for latest radar
trends over the last couple of hours. It looks as though there is
a scattering out/back edge starting to move into our SW counties
now, and across portions of central KY. With this last update,
went ahead and knocked pops down across the west a bit faster
based on these latest trends, though will keep isolated to
scattered POPs in through much of the night until we have a better
idea of the latest radar and CAM trends. Also loaded in the latest
observations to make sure the temps, dew points, and winds were on
track with current conditions. All changes have been been
published and sent to NDFD/web. Will issue an update on the zones
as well as the HWO.

UPDATE Issued at 745 PM EDT FRI JUN 23 2017

Made a few more tweeks to pops and weather based on latest radar
trends over the last couple of hours. Also loaded in the most up
to date observations to make sure the near term grids were on
track with current conditions. A band of heavy rain is now
impacting our northern CWA with reports of flash flooding now
coming in. Will continue to monitor this and make adjustments in
the grids as needed. As of now all grids have been published and
sent to NDFD/web with no updates to the forecast package needed.

UPDATE Issued at 502 PM EDT FRI JUN 23 2017

Small update to freshen up the near term grids to make sure they
were on track with current conditions. Also updated pops and
weather based on the latest radar trends and hi-res model data,
with more widespread precipitation now entering into the western
CWA and expected to continue and progress eastward throughout the
afternoon/evening. All changes have been published and sent to
NDFD/web. Since the afternoon package ZFP started with tonight
wording, these updates should not impact the current product.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 359 PM EDT FRI JUN 23 2017

Severe weather and flash flood threat continue this evening.
Center of tropical depression Cindy has moved into western KY
while cold front now stretches from southeast MI through northwest
IN to OK. The low pressure center will continue to move ENE while
the front advances southeast. The interaction of these systems
will bring showers and thunderstorms to our area this evening and
early tonight.

Higher precipitable water is now advancing into eastern KY in
advance of the remnants of Cindy. Precipitable water will
increase to 2 to 2.25 inches so showers and thunderstorms will be
efficient rain producers. Rainfall rates in excess of 2 inches per
hour will be possible with the heaviest thunderstorms. It does
appear the heavy rain threat will mainly be confined to the time
frame before midnight, but will allow the flash flood watch to
continue as is, though it will likely be able to be cancelled
early.

As noted earlier today the surface to 1 KM storm relative helicity
will approach or exceed 400 m2/s2 this afternoon and evening. Some
rotating storms are likely and with rather low lifting
condensation levels a rotating storm could result in a brief
tornado touchdown. While breaks in the clouds this afternoon have
allowed for low level lapse rates to increase, mid level
instability remains rather limited. While a damaging wind and
tornado threat exist, any occurrences of severe weather are
expected to be isolated.

After the frontal passage tonight cooler and drier air will begin
to move into the area for the weekend.

.LONG TERM...(Sunday through Friday)
Issued at 359 PM EDT FRI JUN 23 2017

The long term portion of the forecast will be highlighted by a
stretch of dry weather with well below normal temperatures
resulting from a mean upper level ridge in the western part of the
U.S. and a trough in the eastern part of the country. 850 mb
temperatures will drop to the single digits Celsius early next
week, and we`ll see a multi-day stretch with maximum temperatures
in the 70s and and minimums in the 50s. Dewpoints will be around
50 degrees for the first part of the week. By the end of the week
the trough will be lifting out and flow will become more zonal and
temperatures will warm and dewpoints will increase back into the
60s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 752 PM EDT FRI JUN 23 2017

TAFS are currently being impacted by a combination of moisture
from tropical depression Cindy, combining with an approaching cold
front, producing widespread heavy rain and isolated thunderstorms
to much of eastern Kentucky. The heaviest rain is currently
aligned in a band along the northeast portion of the state,
impacting KSYM. Over the next few hours, expect this rain to
continue to shift eastward as it slowly loses strength through
about 6Z. Winds will generally be from the S to SW and a bit
gusty, especially in any of the heavier rain/storms. After 6Z,
the rain will become less of a factor, and winds will diminish,
however residual moisture will likely lead to fog at the TAF
sites, and continued cloud cover throughout the night. Have
included a slow deterioration to below airport mins (mainly for
VIS) between 9Z and 11Z at all TAF sites, however timing and
exact impacts may need to be tweaked as fog sets up. By tomorrow,
a drier airmass will begin to take hold. Once fog lifts and
dissipates in the morning, expect only a few VFR fair weather CU
throughout the afternoon. Winds will generally be from the west
under 10 knots.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 8 AM EDT Saturday for KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.

&&

$$

UPDATE...JMW
SHORT TERM...SBH
LONG TERM...SBH
AVIATION...JMW



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