Area Forecast Discussion
Issued by NWS Jackson, KY

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967
FXUS63 KJKL 191900
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
300 PM EDT Sat May 19 2018

.UPDATE...
Issued at 1158 AM EDT SAT MAY 19 2018

Showers currently continue to stream northeast across portions of
eastern Kentucky, with additional activity expected to both
develop and move out of central Kentucky this afternoon
along/ahead of an upper trough. Diabatic heating early this
afternoon will promote updraft growth, but anemic mid level lapse
rates and support from wind fields aloft should negate much in the
way of robust development. That being said, storm motions of 30
mph or greater will allow for cells to progress enough to negate a
widespread flooding potential.

UPDATE Issued at 815 AM EDT SAT MAY 19 2018

Showers have already started to redevelop, mainly over central KY,
but will be shifting eastward. For this update, have followed the
suggestion of the NAM and HRRR. This initial batch of showers
swings through this morning, followed by a bit of a lull at mid
day, followed by more development with the trough axis during peak
heating this afternoon.

&&

.SHORT TERM...(Today through Sunday)
Issued at 505 AM EDT SAT MAY 19 2018

The diurnal precip pattern is continuing, with very few showers
remaining early this morning. They will pick up again during the
day as destabilization occurs, but will also be aided by a weak
trough passing through during peak heating. Low pressure or
troughing at all levels was centered over southern IL and southern
IN early this morning, and will move slowly east northeast. The
combination of instability and upper level support will favor high
coverage of precip this afternoon, and likely to categorical POPs
were used. The trough axis will depart to our east early this
evening, and in combination with loss of heating, will result in
the dissipation of convection for the night.

No change in air mass will occur, so daytime heating on Sunday
will again build instability. However, less favorable conditions
for precip aloft (ridging and geopotential height rises) should
result in much less coverage, and POPs of only 10-30% were used.

Most storms should be garden variety. Modest flow of 20-35 kts
aloft today is not impressive. However, with enough instability
and perhaps cell interactions, isolated hail or strong wind can`t
be ruled out. As in recent days, cell training in the moist
atmosphere could again result in isolated heavy rainfall.

.LONG TERM...(Monday through Saturday)
Issued at 300 PM EDT SAT MAY 19 2018

The extended will feature periods of showers and thunderstorms,
mainly during the afternoon and early evening hours, through
Wednesday. A ridge of high pressure is then forecast to bring a
short period of dry weather to eastern Kentucky from Wednesday
night through early Friday morning. A series of weak areas of low
pressure passing by to the south of the area may bring more rain
to eastern Kentucky Friday afternoon into Friday night, but with
the model data being a bit uncertain with this part of the
forecast, only small chances of rain have been included for next
Friday. Temperatures will be running well above normal across the
area, with daily highs maxing out in the low to mid 80s and
nightly lows only falling into the low to mid 60s.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 157 PM EDT SAT MAY 19 2018

Showers and thunderstorms will continue to develop and spread
northeast across eastern Kentucky this afternoon into this evening
as an upper level disturbance moves overhead. Have inserted TEMPO
groups from this afternoon into early this evening as these storms
will be short-lived and transient in nature. May see a brief
reduction to MVFR criteria underneath any of these, along with
variable and gusty winds up to 30-40 knots or so. Outside of
thunderstorms, southwesterly gusts of 15-20 knots will occur this
afternoon with mainly low-end VFR ceilings prevailing. Showers and
storms will dissipate this evening as VFR conditions largely
prevail at all sites. Will see fog in locales that see more
rainfall today and in valleys overnight, but not enough certainty
at this time to insert any reductions to visibility at any given
site.

&&

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

$$

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



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