Special Weather Statement, NWS Jackson, KY

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
455 PM EDT Mon Aug 9 2021

.SHORT TERM...(This evening through Tuesday night)
Issued at 455 PM EDT MON AUG 9 2021

20Z sfc analysis shows an area of high pressure just to the east
of Kentucky while low pressure is moving in from the northwest.
This is accompanied by a cluster of storms that are weakening
over our area and some stronger ones still sustaining themselves
to the southwest of the CWA. Otherwise, under partial sunshine,
temperatures across eastern Kentucky managed to climb into the
mid 80s most places before falling back in the rain to the low
70s. Meanwhile, the dewpoints are elevated in the upper 60s to
lower 70s. The pressure gradient between the systems has kept a
steady flow of air moving from the southwest into the JKL CWA at
around 10 mph with some occasional gusts up to 20 mph away from
storms but as high as 50 mph with the gust fronts crossing the
region. This is keeping the heat and humidity up over the area -
providing ample fuel for the storms to feed upon.

The models are in good agreement aloft through the short term
portion of the forecast. They all depict a slowly building ridge
from the southern half of the nation expanding north into the
southern Ohio Valley through Wednesday morning. North of this, a
retreating shortwave passes through the Great Lakes taking some of
its energy along with it tonight - brushing eastern Kentucky as it
departs. The next strong trough upstream, looks to steer clear of
the region by moving more northeastward from the Northern Plains
into Central Canada through 12Z Wednesday allowing those rising
heights to be the story for Kentucky. Given the relatively small
model spread aloft have favored the NBM as the starting point to the
grids, though with a strong lean on the current radar trends and
CAMs consensus in the near term through Tuesday afternoon.

Sensible weather will feature conditions favorable for convection
through much of the short term portion of the forecast. Heat and
humidity will be in place as fuel while a smidge of upper level
support looks be more than enough to sustain the current convection
into this evening and the again on Tuesday. Some of the models
continue to show activity staring up before dawn Tuesday. Given
the subtle features that will dominate the mesoscale through the
next 36 to 48 hours will allow for higher than climo PoPs and sky
cover. As such, the normal ridge to valley temperature split is
likely to be muted tonight along with the worse of the river
valley fog into dawn Tuesday. The severe potential will be
at least marginal both for the rest of today and on Tuesday
mainly dependent on the diurnal instability available - up to 1500
J/kg currently to perhaps 3000 J/kg at peak heating Tuesday -
though some storm scale dynamics and organization will also
support the threat. Given the high freezing levels the main
threat from the stronger storm clusters will be damaging wind
gusts. In addition, despite some recent dryness, any training
of the stronger cells will have the potential for localized
excessive rainfall and a concern for flooding - particularly on
account of PW over 1.8 inches supporting bouts of torrential
rain. Things should be settling by Tuesday evening but a renewed
pcpn threat by dawn Wednesday could also limit the terrain
distinctions in low temperatures while muting the worse of the
fog.

Only made small terrain and spot specific adjustments to the NBM
temperatures through the period given the clouds and convection
around. As for PoPs - generally adjusted them for current radar
and CAMs trends through Tuesday afternoon.

.LONG TERM...(Wednesday through Monday)
Issued at 301 PM EDT MON AUG 9 2021

The first part of the period will feature summer pattern with hot
and muggy conditions expected. This as dome of ridging sets up in
the southern parts of the lower 48 and any upper level troughs
becoming more subtle. However, given the flatter pattern overall
in the Ohio Valley expect weaker embedded shortwaves to lead to a
fairly active pattern across the Lower Ohio Valley. These bouts of
showers and thunderstorms will be most prevalent in the afternoon
and evening hours when instability from daytime heating is
maximized. The greatest threat for stronger storms looks to be
Thursday and Friday given approaching cold front and high
instability. However, isolated strong storm threat still possible
Wednesday and daily chances of heavier rain through Friday given
the PWATs climb closer to nearly 2 inches for some locations and
slow storm motions. The warm air will be noticeable with the muggy
conditions, as highs soar into the upper 80s to lower 90s through
Friday. The overnight lows will be quite warm, with some nights
getting close to maximum min records.

This weekend has been a bit more volatile in the guidance suites,
with what looks like a better consensus on a cold front settling
south and becoming more stationary across the Lower Ohio Valley
and Tennessee Valley. This would bring some drier air and cooler
temperatures for the weekend into early next week, but not as dry
as you might want given the lack of better frontal push. This
boundary would also be the anchor for afternoon convection in
parts of southeast Kentucky through the weekend if it sticks
around. Given the uncertainty in these previously mentioned items
and the various guidance suites backing off the idea of the front
making it south will lean close to the NBM for this part of the
period. Afternoon highs are expected to stay in the low to mid 80s
and afternoon dewpoints in the mid to upper 60s will provide some
relief.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
ISSUED AT 200 PM EDT MON AUG 9 2021

Convection this afternoon is now the main concern with a self-
sustaining cluster of storms expected to affect most of the TAF
sites through 00Z. Accordingly, have maintained VCTS through then
with a tempo for worse prevailing conditions at all sites mainly
from 18-22Z. Otherwise, VFR conditions will prevail through the
majority of the forecast; however, any locations that see a
direct impact from thunderstorms will see temporary IFR or worse
conditions, along with gusty winds of up to 30 kts. Convection is
expected to generally diminish by sunset, before upticking once
again towards dawn Tuesday. Fog will likely be at a minimum for
most of the night - to MVFR at worst - dependent on any clearing
of the clouds. Winds will be out of the south and southwest at 5
to 10 kts through the early evening, before diminishing towards
dusk.

&&

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

SHORT TERM...GREIF
LONG TERM...DJ
AVIATION...GEOGERIAN/GREIF

Hazardous Weather Outlook...UPDATED
National Weather Service Jackson KY
410 PM EDT Mon Aug 9 2021

KYZ044-050>052-058>060-068-069-079-080-083>088-104-106>120-102315-
Fleming-Montgomery-Bath-Rowan-Estill-Powell-Menifee-Rockcastle-
Jackson-Pulaski-Laurel-Wayne-McCreary-Whitley-Knox-Bell-Harlan-
Elliott-Morgan-Johnson-Wolfe-Magoffin-Floyd-Lee-Breathitt-Knott-
Owsley-Perry-Clay-Leslie-Letcher-Martin-Pike-
Including the cities of Flemingsburg, Camargo, Jeffersonville,
Mount Sterling, Owingsville, Morehead, Irvine, Ravenna,
Clay City, Stanton, Frenchburg, Brodhead, Mount Vernon, McKee,
Annville, Burnside, Somerset, London, Monticello, Stearns,
Whitley City, Corbin, Williamsburg, Barbourville, Middlesboro,
Pineville, Cumberland, Harlan, Sandy Hook, West Liberty,
Paintsville, Campton, Salyersville, Prestonsburg, Wheelwright,
Beattyville, Jackson, Hindman, Pippa Passes, Booneville, Hazard,
Manchester, Hyden, Jenkins, Whitesburg, Inez, Coal Run,
Elkhorn City, Pikeville, and South Williamson
410 PM EDT Mon Aug 9 2021

This hazardous weather outlook is for portions of eastern Kentucky.

.DAY ONE...Tonight.

Scattered to numerous thunderstorms will continue into the
evening. Some of the storms could be strong with gusty winds and
heavy rainfall.

There is also a small chance of a storm through the rest of the
night.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Thunderstorms are possible at times through the period. Some of
the stronger storms will be capable of producing gusty winds and
torrential downpours through Friday. Isolated cases of wind damage
and high water will be possible.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report thunderstorm wind damage and
flooding to the National Weather Service.

GREIF/DJ