Area Forecast Discussion
Issued by NWS Jackson, KY

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FXUS63 KJKL 200551
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1251 AM EST Tue Nov 20 2018

.UPDATE...
Issued at 1055 PM EST MON NOV 19 2018

Did a quick update to fine tune the PoPs and Sky cover through the
rest of the night. Also updated the temps and dewpoints with the
latest Shortblend guidance along with the current obs and trends.
It looks like temperatures will stay too warm through eastern
Kentucky tonight to see any snow flakes toward dawn even in the
northwest. These have been sent to the NDFD and web servers.

UPDATE Issued at 640 PM EST MON NOV 19 2018

23z sfc analysis shows a cold front pressing south through eastern
Kentucky this evening. Scattered to numerous patches of light rain
precede and trail - along with some sprinkles - this boundary in
its wake. CAA follows as well with the winds switching from the
southwest at 5 to 10 mph to the west northwest at around 10 mph
behind it. As such, temperatures currently vary from the mid 40s
in the north and west to the low and mid 50s in the east.
Dewpoints, meanwhile, are generally in the mid to upper 40s with
some patchy fog accompanying the light rain. We still look on
track for light pcpn through the night with a small potential for
flurries mixing in with the sprinkles or drizzle in the northwest
parts of the area towards dawn Tuesday with no impact for the
morning commute. Have updated the forecast through the evening
mainly to add in the latest obs and trends for the T/Td grids
along with a slight adjustment to the Wx grids and the potential
for sprinkles.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 348 PM EST MON NOV 19 2018

A cold front, slowly migrating southeast across north central
into western Kentucky, will continue to bring periods of light
rain to eastern Kentucky this evening and tonight as a sheared out
upper trough keeps cyclonic flow in place from Hudson Bay to the
Gulf of Mexico. Rainfall amounts through tonight should only top
out near or just over a tenth of an inch as moisture profiles
remain shallow, mainly below 6-7k feet. The threat of any
frozen/wintry precipitation looks extremely low given the lack of
any saturation in the dendritic growth zone.

Lingering drizzle/sprinkles look possible through Tuesday as a
post-frontal upslope regime remains in play behind the upper
trough axis. Moisture trapped below H85 will keep low clouds
locked in place through the day, keeping temperatures confined to
the low 40s. Surface ridging building in from the Mississippi
Valley late Tuesday and Tuesday night will eventually bring
clearing skies, allowing temperatures to cool into the mid-upper
20s by daybreak Wednesday. Earlier clearing could end up spelling
temperatures reaching the low 20s in portions of the Cumberland
Valley Wednesday morning.

.LONG TERM...(Wednesday through Monday)
Issued at 351 PM EST MON NOV 19 2018

The extended portion of the forecast begins on Wednesday with a
progressive upper level pattern in place. To begin, mid level ridging
sets up over the OH Valley and will remain in place through
Friday. At the surface, high pressure develops and moves in from
the northwest bringing a round of cooler air in from Canada. The
combination of these lower and upper level feature will keep the
region dry through the first part of the extended. As the high
pressure system shifts off to the east, southerly flow will allow
temperatures to trend warmer heading into the weekend.

By Friday evening a shortwave will track across the Mid MS Valley
and into the OH and TN Valley. The front developing to the
southeast will bring overrunning precip to the area Friday night
into Saturday. With warmer air in place at the surface, expecting
precip to fall as rain. At this time, the superblend seems to be a
bit conservative on the QPF compared to the Euro. This may be a
position of adjusting as the event approaches but a bit more QPF
may be needed in the forecast, especially with the southerly flow
set up. This rainfall is expected to last into Saturday night.
This feature shifts out of the region to the northeast by Sunday
with another front quickly following behind from the southwest.
This will bring another round of showers to the area. Once again
some differences between the Euro and superblend as this feature
comes through a bit quicker than what the Euro has. Overall, a
rather benign pattern in place with no hazards expecting in the
extended part of the forecast.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
ISSUED AT 1252 AM EST TUE NOV 20 2018

The cold front that impacted the region throughout the day has now
moved east of the state. However, another weak reinforcing cold
front is on its heels and will begin to traverse eastern KY late
tonight, dissipating as it does. This, in conjunction with an
upper level wave, will keep low CIGS in the forecast throughout
the overnight. TAF sites are currently bouncing between IFR and
MVFR, and should continue to do so throughout the night, though
models are pointing at IFR being the predominate category. While
most of the rain showers have dissipated, light drizzle will still
be possible at all TAF sites overnight with these low clouds, but
should pose little impact to VIS. Given their spotty nature, did
not include in TAF sites at this time. Drier air will filter into
the region by mid-morning, ending drizzle and allowing CIGS to
slowly lift to MVFR throughout the day. Clouds will finally begin
to scatter out by late evening, giving way to VFR skies to finish
out the TAF period. Winds will generally remain W to NW under 10
knots throughout the period.

&&

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

$$

UPDATE...GREIF
SHORT TERM...GUSEMAN
LONG TERM...SHALLENBERGER
AVIATION...JMW


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