Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 222322

Area Forecast Discussion
National Weather Service Jackson KY
722 PM EDT FRI JUL 22 2016

Issued at 615 PM EDT FRI JUL 22 2016

WSR-88D radar indicating isolated to scattered showers and storms
are tracking slowly south and east across eastern KY. The best
coverage has resided across the north and east portions of the
CWA. The CAMS have struggled given the more mesoscale driven
nature of the storms. Also not handling the outflow boundary which
is emanating southwest from the storms. While this outflow may
kick off a few more storms as it moves SW, the loss of daytime
heating will lead to a down tick overall in any storms ongoing or
that develop. Those that do see storms will see heavy rain, gusty
winds, and frequent lightning. More minor updates to mainly pop to
better handle ongoing convection.


.SHORT TERM...(This evening through Saturday night)
Issued at 314 PM EDT FRI JUL 22 2016

Two issues to address in the short term part of the forecast.
First is the chance for thunderstorms for the remainder of today
and then on Saturday. A weak mid level short wave is passing
across the area this afternoon. Convection that has been
developing in the northern part of our area has been short lived
with an apparent mid level cap in place which is hinted at by some
of the model data. As this cap continues to weaken should see
isolated to scattered storms mainly in the north and west for the
latter part of the afternoon. With outflow from any convection
late today possibly triggering additional convection, the threat
for a few showers and thunderstorms will linger into the
overnight. With the passage of the short wave tonight it appears
that the better chance for thunderstorms on Saturday will be over
the southern part of the area. However chance will remain low,
about 30 percent chance in the south and 20 percent chance in the
north on Saturday.

The second issue to address is the heat for Saturday. Current
temperature forecast for Saturday is for maximums in the lower
90s, and this will combine with humidity to once again push heat
indices to around 100. With heat advisory criteria of 105 degrees
will still not need to issue a heat advisory for our area.

.LONG TERM...(Sunday through Friday)
Issued at 314 PM EDT FRI JUL 22 2016

Models continue to show good agreement and continuity with mid and
upper level features through the period. Broad, flattened mid and
upper level ridge across the southern CONUS buckles in response to
multiple short wave troughs tracking across the northern tier. The
main center of the high retrogrades to the west coast just as the
all too familiar Bermuda High reforms off the southeastern United
States. In between a mean trough develops over the Upper Mid-West
and Great Lake Region by the end of the forecast window.

With our area lying on the southern periphery of an active northern
stream, sensible weather will manage some isolated to at times
scattered convection at just about any time through the period.
There will be a greater chance of rainfall early next week as a cold
frontal boundary drops southward to the Ohio River by late Monday,
or possibly Tuesday. This boundary stalls out and will tend to keep
any convection focused across the region through mid week. What`s
left of the boundary lifts northward Thursday, just as another
trough begins to drop into the region from the northwest by late
Thursday or Friday. The loss of mid and upper level ridging combined
with daily convection will help keep our high temperatures close to
normal for this time of the year, or possibly slightly cooler. But
overall our weather will remain quite muggy. Overnight lows will be
warm, running a little above normals.


.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)

Most sites are beginning the TAF period VFR with exception of
some sites seeing vis restrictions. This mainly due to rain and
storms moving across those sites. That said the WSR-88D radar
continues to show rain and storms across portion of eastern KY
this hour. Many of these storms have been sparked by a outflow
boundary that continues to progress southwest. This activity will
die off as sunsets and we loose daytime heating. Then the question
is fog overnight, right now the guidance wants to hit this hard.
Leaned toward southern sites of LOZ/SME and also SYM given more
rain. All and all think most of this will be confined to the
typical river valley locales. Winds will remain light, but sites
that see a stronger storm could see 15 to 20 knot gust. Did go
VCTS for the southern sites given overall higher pop, but will
likely have to look at this closer in next TAF issuance area wide.


.JKL Watches/Warnings/Advisories...


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