Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 280619
AFDJKL

Area Forecast Discussion
National Weather Service Jackson KY
219 AM EDT SUN AUG 28 2016

.UPDATE...
Issued at 219 AM EDT SUN AUG 28 2016

Precip finally died out. The inherited forecast had this in hand.
Have blended latest obs into the forecast grids, and also updated
sky cover through Monday based on 00z model runs.

UPDATE Issued at 1045 PM EDT SAT AUG 27 2016

Isolated to scattered convection has been persistent into this
evening across the south, but the latest radar trends are
encouraging for a gradual diminishment in the next hour or so. Have
freshened up the POPs accordingly, along with the sky cover, as
plenty of debris clouds will hang in through 06z, before
generally decreasing. Low temperatures around the 70 degree mark
look reasonable and mainly freshened up the hourly temperatures
and dew points to account for the current trends in observations.
Updates have been sent.

UPDATE Issued at 821 PM EDT SAT AUG 27 2016

It is very much a storm-scale driven pattern early this evening,
as multiple outflow boundaries are currently migrating across the
area. Most of the earlier convection has ended; however, there are
a few clusters across the TN/KY border that will skirt along our
southern counties over the next 1 to 2 hours. Will also leave an
isolated storm mention generally south of the Mountain Parkway
through the same time period, given the ongoing outflow
interaction and some instability still lingering across the area.
Once the convection dissipates, skies will clear out, with patchy
dense fog likely forming once again. Updates have been sent.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 300 PM EDT SAT AUG 27 2016

Hot and muggy weather will continue across eastern Kentucky
through the weekend, as the ridge of high pressure that is
currently parked over the Ohio, Tennessee, and mid Mississippi
valley regions, continues to exert some influence on the region. A
few showers and thunderstorms have formed this afternoon in the
humid and unstable air mass that is in place. These should remain
confined to an area generally along and west of the I-75 corridor.
A few showers and storms will also be present along and north of
the western end of the Mountain Parkway in our forecast area
through sunset this evening. Any showers and storms that form
today should dissipate quickly once the sun goes down. Another
round of showers and storms is expected on Sunday, as the
aforementioned ridge weakens and allows height falls to occur over
the region. The persistently warm and humid air mass will still be
in place, however, and with the ridge weakening, conditions will
be bit more favorable for shower and storm formation on Sunday.
That being said, still only went with 20-40 percent chance of rain
across the area on Sunday, with the best time for rain being
during the afternoon and evening hours. The rain should taper off
Sunday night, with only a few showers or storms ongoing along and
north of I-64 by early Monday morning.

Temperatures tonight and tomorrow night will be very warm and
uncomfortable yet again, with min readings around 70 expected.
Highs on Sunday should easily reach 90 or slightly above for the
entire area once again.

.LONG TERM...(Monday through Saturday)
Issued at 340 PM EDT SAT AUG 27 2016

The period is expected to begin with a general area of ridging
with the axis from the Ohio Valley east to near Bermuda. A
shortwave trough is expected to be moving into the Maritimes and
Northeast CONUS at that time, with a stronger trough extending
toward the Northern Plains from a closed low moving through the
Canadian Plains. A weakness in the ridging is expected to develop
along the Eastern Seaboard by Monday night with upper ridging
becoming centered east of Bermuda and over the Mid MS Valley
Region. The Canadian closed low should progress east across
Ontario and into Quebec through midweek and as this system begins
to merge with another closed low to the Northeast and the center
of the Upper ridge retrogrades into the Plains, a trough will
begin to be carved out over Eastern Canada and into the Great
Lakes and Northeast. This should send a cold front across the
area Wed night and Thursday. Surface high pressure building
across the Great Lakes should then usher in a cooler and drier
airmass.

Another shortwave should move through the Eastern Canada and
Northeast CONUS Thursday into Friday. The axis of this trough
should begin to move east of the area by Thursday night and
Friday. Height rises are expected to begin across the Southeast
CONUS by the end of the period, with some model to model and run
to run difference in timing of individual waves. Overall, a
gradual warming trend should begin around the end of the period.

Monday and Tuesday should average out the warmest days of the
period, with upper 80s to lower 90s common outside of the highest
terrain. Then a reprieve from the recent heat and humidity should
follow through the rest of the period with near normal to a couple
of degrees below normal highs. Dewpoints should fall sufficiently
so that under the influence of high pressure some valley lows may
reach the upper 50s for Thu night and Fri night.

A few locations may be able to break the cap on Monday and or
Tuesday, but with the ridge dominating and little if any mid level
support, coverage should be minimal. Then some height falls and
an approaching shortwave and cold front should lead to at least
isolated coverage on Wednesday. Enough moisture may linger across
the southeastern part of the area for isolated diurnally driven
convection on Thursday, then as the drier airmass becomes more
entrenched dry weather should follow in all areas for Thursday
night and Friday. Uncertainty remains at the end of the period and
as moisture begins to increase, the cap may be able to be broken
in a few locations on Saturday for a few stray showers or
thunderstorms.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
ISSUED AT 219 AM EDT SUN AUG 28 2016

Convection finally died out late in the evening, and a quiet
finish to the night should now be in store. Will look for fog to
develop in the typical valley locations. Expect most TAF sites to
have relatively minimal impacts from it. KSJS stands the greatest
chance of having a period of IFR conditions for a couple hours
around sunrise. Any fog is expected to dissipate by mid morning,
leaving mainly VFR to finish the period. The exception will be
localized IFR in scattered thunderstorms in the afternoon and
early evening. Outside of thunderstorms, winds will generally be
less than 10kts.

&&

.JKL Watches/Warnings/Advisories...
None.
&&

$$

UPDATE...HAL
SHORT TERM...AR
LONG TERM...JP
AVIATION...HAL



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