Area Forecast Discussion
Issued by NWS Jackson, KY

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000
FXUS63 KJKL 190300 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1100 PM EDT Tue Jun 18 2019

.UPDATE...
Issued at 1100 PM EDT TUE JUN 18 2019

The lull in the storms has continued for most of the area this
evening and should stay that way through the night, though a few
stray storms will still be possible at just about anytime through
dawn. Any of these storms could have heavy rains and training
conditions that will keep up a threat for localized high water
issues. Have updated the grids to mainly adjust the PoPs and QPF
through dawn Wednesday along with adding in the latest obs and
trends for the T/Td grids. These updates have been sent to the
NDFD and web servers. A freshened set of zones, HWO and FFA will
be issued shortly.

UPDATE Issued at 840 PM EDT TUE JUN 18 2019

00z sfc analysis shows general low pressure through the area,
though centered more to the west of the JKL CWA. This is south of
a persistent and wavy frontal boundary well north of the Ohio
River. With light winds, temperatures are running in the mid 70s
while dewpoints remain elevated in the upper 60s to lower 70s -
perpetuating high PW (1.8 inches or so) air in place over the
area. As a result, eastern Kentucky has plenty of moisture in
place along with enough fuel for convection this evening and
through the night. Ongoing convection has thus far been weaker and
less widespread this evening and that is expected to continue
overnight compared to the past few nights given lower CAPE values
and some convective inhibition in place. Still with such low FFG
across the area any heavier showers or training could result in
additional flood concerns. For this reason the Flood Watch was
extended into Thursday night for most of the area. Have updated
the forecast through the night to incorporate the CAMs consensus
for PoPs and QPF into the early morning hours of Wednesday. Have
also added in the latest obs and trends for the T/Td grids. These
updated grids have been sent to the NDFD and web servers.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 529 PM EDT TUE JUN 18 2019

The latest surface map features a stationary frontal boundary
aligned from southern New England across the Ohio Valley and then
down along the Mississippi River. Aloft, broader troughing is
taking shape across the central and northern Plains, with flatter
flow to the east. Clouds have been prevalent across eastern
Kentucky through today, with only some isolated convection
currently redeveloping across locations west of I-75.

The models are in generally good agreement through the short term,
with less organized convection expected through Wednesday, with
weaker forcing involved. Expect some scattered convection to
uptick through the next few hours in response to the limited
heating we have received this afternoon. Otherwise, thunder
chances will diminish after midnight, with some low clouds and fog
developing towards dawn. Lows will be in the mid to upper 60s.

Wednesday will feature a cloudy start to the day, before these mix
out in the afternoon. A weakly capped environment will allow for
scattered convection to refire. Storm motions will be around 15
kts or so, allowing for a continued threat of heavy rainers. Highs
will be around 80.

The better forcing will arrive later Wednesday night, as a
healthier short wave trough moves east across the Mississippi
Valley, genning up deeper surface low pressure, which will ride
east across the Ohio Valley. A better surge of moisture will be
pulled in from the southwest, with PWATs peaking at around 1.8
inches, renewing the flash flooding potential. Given this, have
extended the flash flood watch through Thursday. Have also
expanded this further southeast, as several areas across far
southeastern Kentucky have received some healthier rainfall totals
from convection that occurred earlier today. Lows Wednesday night
will be similar to tonight, generally in the mid to upper 60s.

.LONG TERM...(Thursday through Tuesday)
Issued at 347 PM EDT TUE JUN 18 2019

A shortwave trough will be in the vicinity of eastern Kentucky at
the start of the period with showers and thunderstorms expected
through the first part of Thursday. High PW`s will keep the threat
of heavy rain going through the day allowing the flash flood watch
to continue. A cold front should eventually sweep across the area
Thursday afternoon, with the rain threat ending by Thursday
evening. This will allow for the only dry day of the extended
portion of the forecast on Friday with cooler and less humid air
over the region.

Upper level ridge axis will spread across the area on Friday and
eventually shift just to the east by Saturday morning. As this
happens, the baroclinic zone will be located over the area with a
possible MCS plowing southeast across the area early Saturday with
the low level jet. Still some uncertainty on the exact placement
and track of the MCS, but there is at least a chance for some
active weather returning to the area early Saturday. With heat and
humidity returning Saturday, the threat for shower and storm
redevelopment into the afternoon/evening hours will remain
possible. How much activity we see in the afternoon and evening
will be dictated by the morning MCS activity. The weather will
remain unsettled again from Sunday through Tuesday as several
shortwaves progress along the northern fringes of the upper level
ridge, keeping the weather very unsettled. This will also lead to
a continued threat of flash flooding as PW`s will again be on the
high side. While best chances will be during the daytime hours,
the timing of the shortwaves could allow for better rain chances
even at night. Thus, will maintain the higher rain chances through
much of the extended.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 815 PM EDT TUE JUN 18 2019

Expect the areal coverage of additional convection this evening to
remain scattered enough to not include any prevailing conditions
at the TAF sites - but did go with a tempo in the near term.
Most of the model guidance points towards developing an IFR/MVFR
stratus deck between 09 and 12z tonight. Given the low dew point
depressions heading into tonight, this seems reasonable and have
allowed it in the TAFs pre-dawn and for a few hours after.
Conditions should improve to MVFR by late Wednesday morning, with
scattered convection refiring in the afternoon. South to southwest
winds will average around 5 kts or less through the period.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Thursday evening for KYZ044-050>052-
058>060-068-069-080-085>088-104-106>120.

&&

$$

UPDATE...GREIF
SHORT TERM...GEOGERIAN
LONG TERM...KAS
AVIATION...GEOGERIAN/GREIF


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