Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 190200

National Weather Service Jackson KY
1000 PM EDT Wed Jul 18 2018

Issued at 1000 PM EDT WED JUL 18 2018

Valley temperatures have dropped off quickly this evening, and
overnight mins have again been dropped slightly in the deeper
valleys in the eastern portion of the forecast area.

UPDATE Issued at 752 PM EDT WED JUL 18 2018

In light of afternoon highs and min dew points, have forecast a
bit faster temperature drop in valleys this evening, and lowered
morning lows slightly in the coldest valleys.


.SHORT TERM...(This evening through Thursday night)
Issued at 347 PM EDT WED JUL 18 2018

A warm and mostly dry weather pattern is in store in the short
term. A ridge of high pressure will continue to exert its
influence on the region through the end of the on Thursday.
However, the dry pattern will begin to change Thursday evening, as
a trough of low pressure aloft, and its surface cold front, begin
moving across the Great Lakes and Ohio Valley regions. Isolated to
scattered rains showers and a few thunderstorms will be possible
late Thursday, as a weak surge of moisture from the Gulf of Mexico
moves into the area. The better chances for rain will come late
Thursday night into early Friday morning, as the surface front
begins to inch closer to our area. Temperatures should be close
to normal, with lows the next two nights bottoming out in the 60s
and highs on Thursday maxing out in the upper 80s.

.LONG TERM...(Friday through Wednesday)
Issued at 347 PM EDT WED JUL 18 2018

The extended period will generally be dynamic and progressive, with
the main system of focus bringing rain and chances of thunderstorms
through Monday. The upper level pattern will feature an amplified
trough evolving into a cutoff low as it tracks into the Ohio Valley
from just west of the Great Lakes by Saturday evening. The low
remains fairly stationary through Monday until it is absorbed by the
flow of the northern stream. Closer to the surface, a stout surface
low pressure system, coincident with the upper level pattern, will
make its way into the Ohio Valley. By Friday evening, the warm front
associated with this system will move through eastern Kentucky,
bringing showers and the potential for thunderstorms. The system
will shift just north of eastern Kentucky, allowing the cold front
to progress through by Saturday evening. The system will then move
to the northeast of the Commonwealth and, similar to the upper level
pattern, be fairly stagnant through the first part of the work week.
MUCAPE values are modest through the weekend, but are greatest on
Saturday. This will result in the greatest chances of thunderstorms
on Saturday. By Tuesday, warm, moist air from southerly flow will
keep shower and storm chances in the forecast through the rest of
the extended.

The models are in fairly good agreement with the upper level pattern
through the long term, but the GFS does trend a bit higher with
precipitation amounts as opposed to the ECMWF. With decent model
agreement, just made minor adjustments to the PoPs for the weekend
system. However, with the weekend still a few days out, there
remains uncertainty in terms of the rainfall amounts at this time.

High temperatures will begin in the mid to upper 80s Friday, then
decrease with the weekend system to be upper 70s, low 80s. Temps
will then gradually increase to be in the mid 80s again by midweek.
Low temperatures will generally be in the mid to upper 60s.


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

The usual summertime dense radiation fog will affect deep valleys
containing large streams late tonight into early Thursday.
However, TAF sites will likely remain unrestricted. Otherwise, the
forecast calls for VFR conditions with light winds through the




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