Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 272357

Area Forecast Discussion
National Weather Service Jackson KY
757 PM EDT WED JUL 27 2016

Issued at 630 PM EDT WED JUL 27 2016

Have updated to blend obs into the evening forecast. Clusters of
thunderstorms are ongoing, but coverage has likely peaked for the
time being.


.SHORT TERM...(This evening through Thursday night)
Issued at 305 PM EDT WED JUL 27 2016

...Torrential rainfall on Thursday may lead to Localized Flash

Expect scattered showers and thunderstorms to continue into the
evening with the primary focus turning to the heavy rain potential

A stalled frontal boundary has lifted north of the area and is
expected to stay just north of the state through the day tomorrow.
This has allowed winds to turn more southerly this afternoon. As a
southern stream wave strengthens and lifts out of the Mississippi
Valley overnight tonight, winds will turn a bit more southwesterly
and increase in strength, allowing for an even deeper pull of
moist air. This upper wave will interact with the stationary
frontal boundary, as well as the potential phasing of the
northern and southern stream jets, to create a large surge of warm
deep moisture and lift for which storms to develop across our
area. PWAT values for tonight will be well over 2 inches and will
continue to increase up to 2.4 inches in some places by tomorrow

While CAPE and LI values remain decent per model soundings, the
profiles are long, skinny, and moist with little wind shear. This
type of profile indicates heavy rain and flash flooding concerns,
moreso than severe weather. Mostly unidirectional flow in the mid
and upper levels may lead to training of storms, which would
likely lead to localized flash flooding. Depending on the model,
anywhere from 1.5 to 3 inches of total rainfall is possible
Thursday through Friday morning. Considering the extreme PWATS,
any storm that does form would be a very proficient rain producer.
All this considered, have decided to issue a flash flood watch
for the entire area from late tonight through Friday morning.

The bulk of the rain is expected to exit the area by dawn on
Friday but we can expect unsettled weather to continue into the

Temperatures will take a downward turn tomorrow with the onset of
thick cloud cover and heavy rains, with highs in the low 80s.

.LONG TERM...(Friday through Wednesday)
Issued at 300 PM EDT WED JUL 27 2016

No real break in sight from the unsettled weather as models
project our area remaining in northwest flow aloft with a quasi-
stationary frontal boundary positioned over us over very close by
throughout the period. This will bring us daily chances for
showers and thunderstorms, especially during the afternoon and
evening hours. These should be scattered in nature most days,
although a decent shortwave shown passing through the Ohio Valley
may spawn a little more widespread coverage of showers/storms on
Saturday and indicated higher PoPs there. The ground should be
fairly wet after the short term rainfall so at least isolated
flash flooding will remain a concern, at least through the
weekend. Otherwise, it will remain warm and humid throughout the
period with daytime highs well into the 80s and dewpoints in the
upper 60s to lower 70s.


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

Thunderstorms were ongoing at TAF issuance in some locations,
being driven at this point by outflow boundaries sent out by
earlier thunderstorms. As the lower atmosphere sloshes like a bowl
of jello, the boundaries should eventually overtake each other and
leave all areas in a modified/more stable surface air mass. Along
with loss of heating, this should bring about an end to most
showers and thunderstorms by later this evening, with fairly
uneventful weather then lasting into the overnight hours.

Extent of fog development remains uncertain tonight. A mid level
cloud deck is expected, and may inhibit radiating and fog
development. At this point have used predominant low end mvfr
conditions overnight, but confidence is not high.

A weak upper low currently over AR is expected to move northeast
and bring precip back to our area on Thursday morning, and lasting
through the day. Have kept MVFR going through the day in the
TAFS, but the reality of it will be varying conditions. Showers
and thunderstorms with potentially heavy rainfall are forecast,
but with uncertainty in timing, SHRA VCTS was used in TAFS.


.JKL Watches/Warnings/Advisories...
Flash Flood Watch from 2 AM EDT Thursday through Friday morning
for KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120.



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