Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 230733
AFDJKL

Area Forecast Discussion
National Weather Service Jackson KY
333 AM EDT MON MAY 23 2016

.SHORT TERM...(Today through Tuesday)
Issued at 244 AM EDT MON MAY 23 2016

Early this morning, a trough over the Canadian Maritimes continues
to pull further on off to the northeast as the southern end of the
trough has closed off in response to this and shortwaves that
dropped south across the Great Lakes, Appalachians and Mid
Atlantic States on Sunday. This closed low is meandering over
southern VA and northeast NC and clouds around the western edge of
this circulation are mostly east of the region although a few of
these have affected locations as far west as the Big Sandy Region
over the past few hours. The axis of a mid and upper level ridge
extends from Mexico to the Arklatex region to the Upper MS Valley
and western Great Lakes. Meanwhile a trough encompassed much of
the Western US and Canada and into the Plains. At the sfc, a low
pressure system extended from the Canadian Maritimes south and
south southwest off the Eastern Seaboard and then into South FL.
Meanwhile a ridge of high pressure extended from Ontario across
the Central Great Lakes and south into the MS Valley region. A
drier airmass is working into the Ohio Valley at this time. Valley
fog has formed across the region and in some non valley locations
nearer to the WV border where rain was observed on Sunday.

The Upper level low will meander a bit further southeast before
turning north off the Mid Atlantic States and track toward Cape
Cod in response to a trough moving from central into Eastern
Canada. Meanwhile the axis of the relatively narrow ridge will shift
slowly east through the period and start to shift east of the area
by the end of the period. This ridge will also flatten as well as
the trough moves across Canada and shortwaves eject northeast
toward the area from the trough over the Western Conus into the
Plains. With the mid and upper level ridge dominating and sfc
high pressure in place, but moving east of the area on Tue a
period of drier weather which has been rather rare so far this
May is expected. Rain has been recorded at Jackson on 18 of the 22
days so far this month. The drier weather should linger until
about midweek.

Valley fog formation will be monitored for the remainder of the
night and highlighting it in an SPS and Graphical Nowcast may be
needed over the next few hours. After the valley fog lifts and
dissipates early this morning, cu should develop by the midday to
early afternoon hours, especially across eastern sections closer
to the Upper Low. The fog will probably linger the longest in
valleys nearer to the VA border where rain was observed on Sunday.
However, with high pressure dominating, dry weather is expected
for today. Temperatures should average about the same as highs on
Sunday, perhaps a degree warmer in some locations.

Fog should be less prevalent tonight after a day of drying in all
locations. At this time, we are expecting it to be confined to the
river valleys. A ridge/valley temperature split is anticipated
again tonight, likely a couple of degrees wider than this morning.
Valley locations in the east should reach the mid to upper 40s
while ridges bottom out in the mid 50s.

Temperatures will moderate to above normal levels on Tuesday, a
change from what has occurred so for much of the month of May. The
highs at the Jackson and London airports will likely reach 80 or
above for only the fourth time so far this month. A few cumulus
should again develop, but should be even flatter than today due to
a subsidence inversion descending. High clouds may increase late
on Tuesday in the west in advance of an approaching shortwave
trough as the axis of the upper ridge shifts to the east of the
area.

.LONG TERM...(Tuesday night through Sunday)
Issued at 332 AM EDT MON MAY 23 2016

The models were not in the best of agreement in the extended, with
timing differences between the GFS and ECMWF models, along with
differences in onset of precipitation and areal coverage of
precipitation associated with weather systems toward the end of
the week and into the upcoming weekend. That being said, decided
to go with 20 to 30 percent chance of showers and storms across
eastern Kentucky from Tuesday night on through the weekend. This
was done to account for each of the aforementioned models
different takes on precipitation timing and coverage through out
the week. Temperatures during the extended look to be well above
normal, with daily readings maxing out in the 80s across the
board. Overnight lows should only be falling into the 60s most
nights across the area this week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 155 AM EDT MON MAY 23 2016

After considerable sunshine on Sunday and drier air within the
boundary layer overall, fog is not expected to be as prevalent
tonight as it was Sun morning at least at the TAF sites despite
high pressure building in. However, valley fog continues to form
and should eventually affect LOZ and SME with MVFR vis. Fog is
likely more prevalent nearer to the WV border where convection
occurred on Sunday. Fog has developed locally at SJS and
additional fog may lift in overnight. Vis and or indefinite ceiling
near or below airport mins are expected there until after 12Z.
Winds will be light but generally out of the north to east through
the period.

&&

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

$$

SHORT TERM...JP
LONG TERM...AR
AVIATION...JP



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