Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 281821 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
221 PM EDT Sun May 28 2017

.UPDATE...
Issued at 221 PM EDT SUN MAY 28 2017

Have adjusted the highs a bit lower still, as mostly cloudy skies
continue to hold readings down this afternoon. A few places may be
able to reach the upper 70s, otherwise mid 70s will be more
common. This will result in less shower coverage for this
afternoon, and have reduced POPs a bit. Also adjusted the timing
of the POPs into tonight, as there will likely be a lull in
activity this evening, until the influence of the front moves in
later tonight.

UPDATE Issued at 1130 AM EDT SUN MAY 28 2017

A few showers are currently popping up near the I-64 corridor,
associated with some passing outflow. Some weaker radar echoes are
showing up a bit further southwest, but probably not producing
more than just a few sprinkles. Extensive cloud cover looks to
remain in place through the rest of the day. This will limit the
heating more and have lowered highs a bit. The latest higher
resolution guidance continues to show some scattered convection
popping up this afternoon; however, it will not be nearly as
robust as what we experienced yesterday afternoon and evening.
Will keep the mention of locally heavy rainfall and some strong
wind gusts in the HWO for now.

UPDATE Issued at 658 AM EDT SUN MAY 28 2017

Shower activity remains off to our south this morning with
subsidence over the area providing a nice break to the recent
rains. This break may carry well into the daylight hours today as
the airmass struggles to recover from yesterday. Latest HRRR
does not seem to have a handle on the radar trends, but based on
those trends, we should stay rain free well into the afternoon.

&&

.SHORT TERM...(Today through Monday)
Issued at 254 PM EDT SUN MAY 28 2017

Deep convection has shifted off to our south with much more
limited instability across eastern Kentucky. A few showers have
managed to pop up over Pike county in the last few hours, but
these should be short lived as subsidence takes over and spread in
on the north side of the convection to the south. CAMs support
very little convective activity through the upcoming day. In fact,
there is very little forcing or triggers to be had. A vort max
sliding northeast across the area could spark some convection, but
instability is limited, so the better threat may be to our north
or northeast. In the wake of the vort max, not much expected
through the afternoon and early evening hours. A cold front
advancing across the Ohio river valley this evening and overnight
will bring the best shot at a few showers or storms, but
instability never fully recovers and models have very limited
activity over eastern Kentucky with most of the instability and
moisture being taken up by the storms to our south near the Gulf
coast. With this said, conditions for flash flooding look very
weak today/tonight and thus, we have decided to cancel the flash
flood watch. The storm prediction center has also downgraded the
area to a marginal mainly due to the lack of airmass recovery
today. If instability can build enough, we could still see a few
severe storms, but overall, the risk appears to be diminished
today. This is good news for those areas recovering from
yesterdays heavy rain and storms.

As the front shifts south early Monday morning, so will the rain
chances, leaving behind a dry Monday. We should also see slightly
less humid conditions as well.

.LONG TERM...(Monday night through Saturday)
Issued at 420 AM EDT SUN MAY 28 2017

The period will begin with an upper level ridge centered north of
the Bahamas and another ridge extending north from Mexico into
the Western Conus while a trough should be approaching the
Pacific Coast at that point. In between, a closed low is
anticipated over the Northern Great Lakes region with an
associated trough south into the Lower OH Valley and parts of the
MS Valley. At the surface, high pressure is expected to be
centered over the Southern Appalachians to begin the period while
an area of low pressure is expected to be across northern Ontario.
A trailing cold front should moving across the Great Lakes and
approaching the Lower OH Valley to begin the period.

The upper level low should meander into the Hudson and James Bay
regions through midweek. Model agreement is best through Wednesday
before timing and strength differences appear with the trough
moving into the West Coast and the ridging downstream moving from
the Intermountain west into the High Plains. The general consensus
is for a disturbance rotating south from Northern Canada and
merging with the Hudson/James Bay upper low with the system
dropping south toward the northern Great Lakes and then into
Eastern Canada from Wednesday night through the end of the period.
Also a southern stream system could reach the MS Valley region by
the end of the period, but uncertainty in interaction between
this system and the upper low moving through the Lakes and
southern Canada leads to below average confidence in timing and
details later in the period.

Under the influence of the trough, the pattern will be at least
somewhat unsettled with some showers possible with the cold front
and associated mid level wave on Tuesday into Tuesday evening.
Another mid level shortwave on Wednesday could lead to generally
diurnally driven convection on Wednesday and moisture might be
sufficient for some thunder too. However, the near term system
and front will have scoured out much of the deeper moisture from
the Ohio Valley. More substantial moisture and dewpoints in the
low to mid 60s may return north and northeast by late Thursday
night and Friday and continuing into next weekend for better
chances for at least diurnally driven convection and more
substantial chances for thunder.

Temperatures should average near normal through the period for
high temperatures while low temperatures should tend to climb to
above normal levels late in the period with more in the way of
cloud cover and higher dewpoints expected.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 221 PM EDT SUN MAY 28 2017

MVFR stratocumulus will raise to above 3k feet agl over the next
few hours. Isolated to scattered showers will develop across the
area, but these will be light, and likely not result in any
significant ceiling or visibility restrictions. A cold front will
approach and move through the area between 06 and 12z, with
scattered showers and possibly a few thunderstorms accompanying
this boundary. Ceilings will likely drop off to IFR or lower in
places towards dawn. Southwest winds of 5 to 10 kts, with some
gusts of around 15 kts, will become more westerly behind the
frontal passage. Lower ceilings will scatter out by the mid-
morning hours on Monday, with a return to VFR conditions.

&&

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

$$

UPDATE...GEOGERIAN
SHORT TERM...KAS
LONG TERM...JP
AVIATION...GEOGERIAN


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