Area Forecast Discussion
Issued by NWS Jackson, KY-- Highlight Changed Discussion --
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FXUS63 KJKL 300007 AAA
Area Forecast Discussion...UPDATED
National Weather Service Jackson KY
807 PM EDT SUN MAY 29 2016
Issued at 807 PM EDT SUN MAY 29 2016
Convection has diminished across the area with the loss of heating
and weakening outflow boundary migration. A weak cold front
remains off to our west and this will move in later this evening
and into the overnight. Scattered convection has fired up along
and ahead of the boundary; however, by the time the forcing moves
in, instability will be on the demise. As such, have maintained
only isolated pops. Mainly adjusted the pop timing based on the
latest short term model and radar trends. Otherwise the forecast
remains on track.
.SHORT TERM...(This evening through Monday night)
Issued at 355 PM EDT SUN MAY 29 2016
As of mid afternoon, a mid level ridge extended from the Atlantic
northwest toward the Northeastern Conus with the upper level
system associated with TD Bonnie now over SC. A shortwave trough
was approaching the area from the west with another weak shortwave
nearing the Lower Oh valley from the west. At the sfc, an area of
low pressure associated with the trough was centered over NW
Ontario with a cold front trailing south into the Lower OH Valley.
Convection near the VA border has diminished over the past hour,
though locally heavy rain has occurred with some of this activity.
Meanwhile, a broken line of convection has developed along the
boundary from Ohio Southwest into parts of Western KY.
The first shortwave trough will move across the region this
evening, while the second shortwave approaches the area late this
evening and moves across the area tonight. The cold front will
also approach the area, but become more diffuse as it moves into
Eastern KY by late tonight. The upper level system and area of
low pressure associated with TD Bonnie will meander over the
There is low confidence in the convection near the cold front that
is expected to move into Central KY over the next couple of hours.
Much of the guidance shows the convection diminishing as it moves
into the area late this evening. Isolated to scattered convection
over the southeast part of the area should continue to diminish
over the next couple of hours although the airmass remains rather
warm and moist and marginally to moderately unstable as SBCAPE is
generally in the 750 J/KG range to about 2000 J/KG range with
slightly lower MLCAPE. Shear remains weak however and more typical
of mid summer and makes the diminishing convection possibility
seem more likely. An outflow boundary from the earlier convection
over the southeast is working west and north and could lead to
additional convection developing. Isolated to scattered pops were
used through the evening to account for the convective possibilities.
Several locations received at least light rain today and with
light winds and partial clearing or periods of clearing anticipated
fog will become a concern in locations that received rain earlier
today and the typically favored valley locations.
The rather diffuse cold front will continue to work across the
area and become ill defined by tomorrow afternoon. Additional weak
impulses in the flow could lead to isolated convection near the VA
border on Monday afternoon, but most locations should remain dry.
Sfc high pressure will build into the area late Monday into Monday
night valley fog may again become a concern.
.LONG TERM...(Tuesday through Sunday)
Issued at 253 PM EDT SUN MAY 29 2016
Forecast confidence is high on dry weather persisting through
Wednesday morning. High pressure will provide this period with
tranquil weather and low humidity. Should be a fairly decent
stretch of weather. High will shift east on Wednesday with return
flow strengthening. This will bring slightly better moisture into
eastern Kentucky. Models are persistent on a small chance of a
shower popping up on the high terrain in far southeast Kentucky.
Will go with a shower, but lack of forcing or trigger, will keep
activity very isolated and instability may not be enough quite yet
to warrant any thunder. Thus, will just go with a slight chance of a
shower in southeast Kentucky. Otherwise, most areas should stay dry
through Wednesday night.
Models remain persistent on a mid level trough working east across
the great lakes and Ohio river valley on Thursday bringing a surface
cold front into the region. While the greatest forcing will remain
north...there will be a glancing shot of PVA into eastern
Kentucky...setting up the best rain chance for the upcoming week by
Thursday afternoon. While instability likely won`t be in question,
shear may be lacking to provide much of a severe threat. What shear
there is is all unidirectional, and at best might lead to a small
threat for a damaging wind gust. Overall, not looking great, but
models might be undercutting the shear given the presence of an
approaching cold front. Regardless, still something to watch for as
Models are much more progressive with the front today, dragging it
south of the area by late Friday. Will maintain a chance for
showers into Friday as the boundary slips south and perhaps a stray
thunderstorm in the south with some lingering instability. By the
weekend, weather looks to turn much drier and pleasant with highs
back into the 70s behind the exiting cold front. Overall, models in
decent agreement through the weekend, so confidence is slightly
higher than normal in the extended part of this forecast.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 807 PM EDT SUN MAY 29 2016
Isolated convection will continue to threaten through 06z as a
weak cold front approaches and eventually passes through the area.
Following the front, fog will form, likely becoming dense in the
deeper river valleys as well as across locations that saw more
significant rainfall recently. Have included IFR or worse for most
TAF locations, with the worst conditions generally seen between 09
and 13z. Once the fog dissipates, VFR conditions will return.
Light and variable winds will become northerly at 5 to 10 kts on