Severe Thunderstorm Warning 18, NWS Jackson, KY

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
205 AM EDT Sat Apr 1 2023

.UPDATE...
Issued at 1130 PM EDT FRI MAR 31 2023

We continue to see weaker showers and thunderstorms moving through
eastern Kentucky ahead of the main line that is expected to arrive
closer toward 2 am per the latest CAMs. Severe weather still looks
to be possible depending on the strength of the main line as it
comes through and whether it can establish a QLCS as it moves
through. Nevertheless, just synoptic flow will be enough for
strong wind gusts through the night, but even stronger if a
portion of the jet can mix down with convection. For this reason,
the elevated severe threat continues for another several hours
peaking between 2 and 5 am. Have updated the forecast based on
this idea while also adding in the current obs and trends for the
T/Td/Sky grids. These adjustments have been sent to the NDFD and
web servers along with a forthcoming freshening of the ZFP and
SAFs.

UPDATE Issued at 835 PM EDT FRI MAR 31 2023

00Z sfc analysis shows a very deep spring storm system well to
the northwest of the area but its large reach is conjuring
tornadic storms from southern Wisconsin to Arkansas with eastward
movement through the evening. Already some of those tornado
producing supercells are crossing the Mississippi River and moving
into western Tennessee with additional strong storms just west of
Kentucky. Locally, the initial round of much weaker convection
has moved east through the JKL CWA while another one is starting
to press into the Cumberland Valley from the west. The rain and
plenty of clouds led to a cool day as temperatures are currently
in the mid 50s northeast to the low and mid 60s in the south
limiting instability. Meanwhile, dewpoints are generally in the
low to mid 50s, amid south southwest winds of 10 to 15 mph with
higher gusts. The latest CAMs guidance continues to suggest this
current batch of mainly showers pushes east through the area until
later in thr evening while the strongest convection will be
closer to a front arriving just after midnight. Should these,
mostly linear, storms hold together in the face of the paltry
instability over eastern Kentucky the kinematics will be enough
for a continued severe threat - primarily in the form of damaging
wind gusts but also a small risk for QLCS tornadoes - diminishing
quickly east of the Cumberland Valley. Amid the storm threat
through the night, synoptic wind gusts will push 40 to 45 mph at
times into Saturday with the wind advisories now in effect. Have
updated the forecast mainly to fine tune the timing of that
convective line but also including the current obs and trends for
the T/Td/Sky grids. These tweaks have been sent to the NDFD and
web servers along with a freshening of the zones.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 500 PM EDT FRI MAR 31 2023

Late this afternoon, an upper level low was centered near the NE
and SE border with an associated shortwave trough extending south
into the Southern Plains region while upper level ridging was
centered over the southeast Gulf of Mexico. Eastern KY and the OH
Valley is currently in the warm sector, with weaker shortwaves in
the southwest flow between the upper ridging in the Gulf and the
trough over the Plains leading to convection across portions of
the OH Valley. At the sfc, low pressure centered of IA continues
to develop with a cold front trailing to the southern Plains and
warm front extending east to the southern Great Lakes. Locally,
rounds of showers and some thunderstorms continue to cross eastern
KY at this time, especially near and south of the Mtn Pkwy. The
rounds of showers and some thunderstorms late last night and today
have been in the 0.40 inch to about 1.5 inches, with the higher
totals from Pulaski and Rockcastle County east to Knott County.

This evening and tonight, the upper level low will track east to
the western Great Lakes with the associated shortwave trough
nearing the MS Valley. The upper low will move east to upstate NY
by evening with the shortwave trough axis crossing the area during
the day on Saturday. Behind the departing shortwave trough and
secondary cold front, mid level height rises are anticipated with
high pressure building into the region. Meanwhile the sfc low will
deepen as it tracks into the Great Lakes tonight, before tracking
to the St Lawrence Valley on Saturday. The trailing cold front
will enter the Commonwealth later this evening and cross the
remainder of the state overnight. Also, a secondary cold front is
expected to develop over the Plains/MS Valley later this evening
and tonight closer to the shortwave trough axis. This front is
expected to cross most of the Commonwealth on Saturday.

Ahead of the initial front in the warm sector, convection will
remain possible in eastern KY this evening, but upstream trends
and recent convective allowing models point toward somewhat of a
lull in the activity for the early evening hours. As the cold
front nears from the west late this evening into the overnight,
chances for convection in eastern KY will peak as convection,
perhaps a line of storms, that develops to the west moves from
central KY into eastern KY. Recent convective allowing model
guidance has trended a little waker with this convection as it
gets into eastern KY, however. With eastward extent, the degree
of instability will decrease substantially, but shear will be more
than ample and the convective line should mix down higher
momentum from aloft leading to some stronger gusts. Some damaging
wind gusts are possible, especially over the western portions of
the CWA, and given the degree of shear and potential orientation
to the line, a tornado cannot be completely ruled out. Outside of
storms, some gusts up to 45 mph are anticipated. If repeated
rounds of convection were to move across the area that received
the heavier rain since midnight, some locally high water would be
possible in low lying and poor drainage areas.

Behind the initial cold front, chances for showers will diminish
from northwest to southeast, late tonight to near dawn. Then in
the dry slot of the low pressure system passing to the north as
the shortwave trough approaches and with the secondary front,
deeper mixing should occur and mix down higher momentum aloft.
This should lead to gusts well into wind advisory criteria and
gusts of 55 mph or more are possible, mainly across the north and
east per some of the high resolution models and 12Z HREF. The
peak of the mixing and associated gusts should begin a little
after sunrise in the north, closer to 9 AM and then with heating
shift east and southeast toward the WV border through early on
Saturday afternoon. Even if mixing falls just short of 58 to 60
mph or stronger gusts being measured, the wet ground from the
recent rainfall combined with gusts to around 55 mph should lead
to some downed tree impacts and power outages. With this in mind,
the Wind Advisory remains in effect from 8 AM to 8 PM for the
entire region, but in the area more likely to experience the
higher wind advisory to high wind warning gusts in the north and
east, a High Wind Warning has been issued. The strongest gusts
should generally occur in areas of more open terrain and on the
higher ridgetops. Behind the front as the shortwave trough nears,
late in the afternoon to early Saturday evening, clouds are
expected to increase and the degree of mixing decrease while winds
aloft will also decrease leading to a decrease in wind gusts late
in the afternoon to early on Saturday evening.

Some low level moisture and associated low cloud cover will
likely linger behind the front into Saturday evening and on
Saturday night, with partial clearing or scattering of the clouds
in the west. In valley locations where skies clear, temperatures
should drop to near the freezing mark and some frost will be
possible.

.LONG TERM...(Sunday through Friday)
Issued at 332 PM EDT FRI MAR 31 2023

High pressure will bring dry and pleasant weather to eastern
Kentucky to begin the extended period on Sunday. Temperatures will
be cold enough to allow for patchy frost to be in place early
Sunday morning, but this should melt quickly once the sun comes
up. The rest of the week, however, looks to be quite active, as a
couple of storm systems move across the eastern half of the CONUS.
The first system will push a couple of frontal boundary's through
our neck of the woods Monday through Wednesday. Showers and storms
will affect our area Monday through Wednesday, with the best
chance for storms from late Tuesday through Wednesday. In fact, it
appears that we may have a combination of both good instability
and wind shear present while a cold front moves through the region
on Wednesday, which would be ideal for thunderstorms to fire up
across the area during that time. We will be monitoring this
situation very closely over the next several days for the
potential for strong thunderstorms next Wednesday. A second area
of low pressure moving by to our south is forecast to bring more
rain to the area toward the end of the week. Each of these low
pressure systems will of course bring the potential for gusty
winds to eastern Kentucky.

Temperatures should be quite warm through out the extended. The
coolest days will see highs in the low to mid 60s, while the
warmest days will warm into the upper 70s to lower 80s. The rest
of the period should see highs ranging from the upper 60s to lower
70s around the area. Nightly lows will range from the 40s on the
coolest nights, to the 50s and low to mid 60s on the warmer
nights.

&&

.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
ISSUED AT 205 AM EDT SAT APR 1 2023

A broken line of strong thunderstorms is working east tonight,
with the expectation of these to work through from west to east
toward dawn. Reductions into the MVFR category for visibilities or
ceilings will be possible as these work through. Storms that
directly pass over a TAF site could see briefly reduced
visibilities and ceilings, IFR or lower, along with erratic wind
gusts. This will primarily be from the 7z to 10z timeframe. As the
convective line moves east and the initial cold front pushes
through, VFR conditions will return from west to east into
Saturday morning with showers exiting the far southeast by 12z.
Additionally, winds of 12-22 kts and gusts between 28 and 38 kts
will be possible along and ahead of this advancing front. A
secondary cold front is then expected to traverse the area through
the day, bringing breezy winds when higher momentum from a strong
LLJ transfers to the sfc, especially after 14Z. Gusts in excess
of 40 kts out of the southwest to west are forecast by midday as a
result. Winds will begin to slacken as the pressure gradient
relaxes toward the end of the TAF period. Low clouds will also be
possible by periods end, particularly for sites north of SME and
LOZ, which could result in MVFR conditions in these locations.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 8 AM EDT this morning for KYZ044-050>052-059-
060-104-106>110-112-113-118>120.

High Wind Warning from 8 AM this morning to 6 PM EDT this
evening for KYZ044-050>052-059-060-104-106>110-112-113-118>120.

Wind Advisory until 6 PM EDT this evening for KYZ058-068-069-079-
080-083>088-111-114>117.

&&

UPDATE...GREIF
SHORT TERM...JP
LONG TERM...AR
AVIATION...BB

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Special Weather Statement
National Weather Service JACKSON KY
208 AM EDT Sat Apr 1 2023

KYZ068-079-083-084-010715-
McCreary KY-Wayne KY-Rockcastle KY-Pulaski KY-
208 AM EDT Sat Apr 1 2023

...A strong thunderstorm will impact portions of Wayne, Pulaski,
McCreary and southern Rockcastle Counties through 315 AM EDT...

At 208 AM EDT, Doppler radar was tracking a strong thunderstorm 8
miles southeast of Columbia, or 23 miles northwest of Monticello,
moving east at 35 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Faubush, Naomi, Mill Springs, Nancy, Betsey, Pulaski County Park,
  Frazer, Quinton, Kidder, Somerset, Burnside, Bronston, Elihu,
  General Burnside S.P., Somerset Pulaski Airport, Tateville, Ruth,
  Sloans Valley, Grade, Alpine and Dykes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3696 8494 3695 8490 3700 8484 3705 8491
      3712 8490 3736 8456 3733 8451 3738 8449
      3731 8414 3722 8427 3704 8430 3702 8433
      3700 8431 3695 8437 3694 8430 3678 8435
      3659 8423 3663 8500 3676 8501 3686 8506
TIME...MOT...LOC 0608Z 268DEG 29KT 3700 8522

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

GREIF

Special Weather Statement
National Weather Service JACKSON KY
210 AM EDT Sat Apr 1 2023

KYZ050-058>060-068-069-010715-
Jackson KY-Montgomery KY-Menifee KY-Estill KY-Rockcastle KY-
Powell KY-
210 AM EDT Sat Apr 1 2023

...A strong thunderstorm will impact portions of Powell, southeastern
Montgomery, Estill, Jackson, Rockcastle and southern Menifee Counties
through 315 AM EDT...

At 210 AM EDT, Doppler radar was tracking a strong thunderstorm 8
miles north of Lancaster, or 16 miles west of Richmond, moving east
at 40 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
  Harris Ferry, Fox, Winston, Rice Station, Kings Station,
  Blackburn, Palmer, Iron Mound, Cressy, Calloway Crossing,
  Sandhill, Weedon, Wiseman Crossing Station, North Irvine, West
  Irvine, Wisemantown, Hargett, Witt, Kimbrell, Irvine, Ravenna,
  Willow Tree, Cow Creek, Hardwick, South Irvine, Doe Creek, Vaughns
  Mill, Wagersville, Pitts, Fitchburg, Cottage Furnace, Pryse,
  Texola, Shade, Cobhill, Patsey, Furnace, Rogers Chapel, Knowlton,
  See, Pilot, Natural Bridge S.P., Slade, Nada and Lombard.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3748 8444 3754 8435 3757 8409 3781 8410
      3781 8412 3782 8410 3784 8400 3797 8399
      3793 8345 3783 8353 3783 8362 3762 8387
      3754 8391 3734 8378 3726 8390 3725 8402
      3734 8412 3727 8422 3728 8445 3733 8450
TIME...MOT...LOC 0610Z 271DEG 37KT 3774 8459

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

GREIF