Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 262218

Area Forecast Discussion
National Weather Service Jackson KY
618 PM EDT THU MAY 26 2016

Issued at 618 PM EDT THU MAY 26 2016

Current conditions feature a weakening line of showers and
thunderstorms moving into eastern Kentucky. These storms will
continue with a weakening trend through the evening as they
continue to move into a more unfavorable environment. In fact, hi
resolution models indicate a complete dissipation by 06z. Have
adjusted the forecast to account for this and updated the current
obs as the rain cooled air has dropped temps across the area this
evening. Later tonight, a warm front looks to lift north through
the area as some weak forcing may be enough for a few showers to
develop over the north towards dawn. Have put in a slight chance
of showers for this possibility.


.SHORT TERM...(This evening through Friday night)
Issued at 359 PM EDT THU MAY 26 2016

Strong troughing across the southwest conus and ridging for the
southeast conus has led to SW to NE flow aloft across the
mississippi and Ohio River Valley. Several short waves continue to
eject ne along this flow and into the Ohio River Valley, including
the one that spawned a strong line of showers and thunderstorms this
morning over western KY and Illinois. This line has sustained itself
throughout the day and is now traversing central KY. Decent
instability present, along with good mid level drying, have led to
several of these storms going severe. Most of the hi res models have
had a fairly good handle on this system through the afternoon, with
preference for the HRRR which has been initializing well since this
morning. They also all have this line weakening as it moves into our
western CWA, then quickly dissipating as it moves east late this

Forecast soundings show good CAPE, LI`s -6 to -8, and steep lapse
rates. However our shear is lacking, and strong storms will likely
not be able to sustain themselves. As such, agree with models to a
certain degree. We could still see some isolated embedded cells that
could pop up to severe limits, or produce small hail at the least.
But do agree that there will be a diminishing trend as we head into
the evening.

By overnight, this line of showers and thunderstorms will move
eastward out of the region. High pressure will take hold, generally
to our southeast, leaving southerly flow across the region. The
continued moisture influx, in addition to the lingering moisture and
a night time inversion taking hold, could lead to fog development
across the CWA, especially in the valley locations.

High pressure will remain in control tomorrow. However southerly
flow will continue, allowing temps to easily climb into the mid and
even upper 80s by the afternoon. With that southerly flow will also
come moisture, so diurnal CU development will be likely. Afternoon
instability will also be in place, so scattered showers and
thunderstorms may develop for the afternoon.

.LONG TERM...(Saturday through Thursday)
Issued at 330 PM EDT THU MAY 26 2016

We begin the period more influenced by the upper level ridge
extending west out of the Mid Atlantic Coast, while upper level
closed low resides in the Central Plains states. Overall better
PVA will remain east of the region, but enough influence to
include some higher chance pops mainly toward the northern and
western portion of the CWA on Saturday and Sunday. Now moving into
the first part of the work week more uncertainty exists with
regard to waves and any residual down stream storm complexes that
hold together. Also another complication exists in the tropics
with potential for a developing tropical system near the Carolina
Coast line. Right now the GFS has been the most volatile with
little continuity run to run, while the ECMWF seems to be more
consistent. The influence from this overall should reside latter
portion of the long term period, therefore for now will stick with
model blend approach for now. This especially as shear will be nil
through the long period leading to little if any organization of
storms. Toward the very end of the period ridging breaks down more
allowing for more height falls. This will lead to higher chance
pops by Thursday given this looks to be the overall best synoptic
feature we have seen. Given the ridging a more summer time feel
will remain in place through the long term period.


.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)

While a few lingering showers are ongoing across eastern KY a
the time of TAF issuance, attention turns to a strong line of
showers and thunderstorms currently moving across western and
central KY. Convection is now also occurring ahead of the main
line. Timing this out, expect the western most TAF sites
(KSME/KLOZ) to be affected first, likely between 22 and 23z. The
line is then expected to lose overall intensity as it continues
eastward toward the other TAF sites through around 3z. At present
time, it is hard to know exact impacts on each TAF site, so will
likely need to update TAFs as we see storms are nearing the
airports. Ongoing threats to our west include hail, torrential
rains, frequent lightning, and gusts between 30 and 40kts. After
the line moves through later tonight, high pressure and some
possible clearing will take hold. This may lead to some fog
development at the TAF sites, though confidence on exact VIS
restrictions is lows, especially considering it will be very much
correlated with when and how much rain occurs this evening. Any
fog should clear out by morning, with (VFR) diurnal CU developing
as we head into the early afternoon.


.JKL Watches/Warnings/Advisories...


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