Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 232000
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
400 PM EDT Thu May 23 2019

.SHORT TERM...(This evening through Friday night)
Issued at 400 PM EDT THU MAY 23 2019

The afternoon surface analysis shows a cold front is stretched
out across the Ohio Valley from a surface low north of the Great
Lakes. This feature along with a weak 500mb wave have begin to
generate thunderstorms in north central Kentucky this afternoon,
with some being strong to severe this afternoon. The environment
is characterized by MLCAPE around 1000 to 1500 J/kg and effective
shear 30 to 40 knot range which is not a awful balance. SPC has
opted to go with a MCD given the increasing instability and shear
through the afternoon, but right now watch issuance probability is
at 40 percent. This will be monitored closely through the
afternoon and early evening, as this convection advects eastward.

Tonight the boundary will move closer, as it progresses into the
lower Ohio Valley. Did keep the fog mention in the valleys, but
this will more more dependent on where rain falls and if skies
clear in some locations. Did keep some mention of showers and
thunderstorms in a good portion of the night given the nearing
boundary.

Friday the boundary will be stretched from NW to SE across far
eastern and northeastern Kentucky. Kept the better PoPs residing
in this area given the better forcing from low level convergence
would reside. However, there will be less influence from aloft and
heights will be reinforcing. By Friday night the convection will
lessen given the better forcing progresses east and the heights
continue to play a role. Given the lessening convection and sky
cover did keep temperatures splits and added some fog for the
valleys.

.LONG TERM...(Saturday through Thursday)
Issued at 346 PM EDT THU MAY 23 2019

Still forecasting a strong upper level ridge to be in place
throughout much of the extended. Systems will approach the region on
NW flow, but will pass north of the state or fall apart as they
reach Kentucky. Models have varying degrees of agreement with any
rainfall that makes it into the CWA, but generally expect anything
to be light in amounts and isolated to scattered in coverage.
Furthermore, with surface high pressure located off the coast in the
Atlantic, Kentucky will find itself in return flow. This will aid in
both moisture and warm air advection. This will do two things.
First, it will keep well above normal temperatures in place each
day. And second, it will produce enough instability that any precip
that does affect the state will most likely be in the form of a
thunderstorm. Wouldn`t be surprised that some of these storms,
especially in the afternoon under peak heating and best instability,
could become strong at times.

The upper level ridge will finally begin to shift eastward away from
the Deep South on Tuesday. Meanwhile a deepening trough across the
central U.S. will begin progressing eastward. Surface low pressure
and an associated cold front will shift eastward with this
progression, bringing fairly large swath of precip towards the
Mississippi River Valley by Tuesday night. This precip will then move
through the sate of Kentucky Wednesday into Wednesday night. With
still fairly stable and dry air in place, and an area of low
pressure that is shifting NE and away from the region, precip
coverage will lesson as it moves over the state. But being so far
out in the forecast, there is surprisingly good agreement between the
models as this precip swath moves in.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 145 PM EDT THU MAY 23 2019

The period is starting off VFR across eastern Kentucky. This as
much of the morning convection has decreased this afternoon, with
outflow boundary moving south into southeast Kentucky. Additional
convection may form along and near this boundary, but given the
uncertainty of how this will or will not evolve will leave thunder
mention out at this time. However, will keep VCSH in many of the
TAF sites through the afternoon. More fog is possible tonight, but
will mainly be concentrated across the valleys. The winds are
increasing this afternoon, with gust around 20 knots out of the
southwest. These winds will remain elevated through the afternoon
before decreasing through the evening.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...DJ
LONG TERM...JMW
AVIATION...DJ


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