WW 714 TORNADO AR KY MS TN 091735Z - 100100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 714
NWS Storm Prediction Center Norman OK
1135 AM CST Sat Dec 9 2023
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Southeast Arkansas
Western and Central Kentucky
Northern Mississippi
Western and Middle Tennessee
* Effective this Saturday morning and evening from 1135 AM until
700 PM CST.
* Primary threats include...
A few tornadoes likely
Scattered damaging wind gusts to 70 mph possible
Isolated large hail events to 1 inch in diameter possible
SUMMARY...Strong to severe thunderstorms will continue to develop
and increase through early afternoon near an eastward-moving cold
front, with additional/more isolated development also possible ahead
of it later this afternoon. Increasingly low-level moisture and
strong shear will support the potential for severe storms including
a few tornadoes.
The tornado watch area is approximately along and 85 statute miles
east and west of a line from 30 miles north of Bowling Green KY to 5
miles east southeast of Monticello AR. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.
&&
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 24040.
...Guyer
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WW 0714 Status Updates
STATUS REPORT ON WW 714
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 S JBR TO
40 ENE DYR TO 35 W HOP TO 40 NNW HOP TO 20 SW OWB.
..SQUITIERI..12/09/23
ATTN...WFO...LZK...MEG...LMK...PAH...JAN...OHX...
STATUS REPORT FOR WT 714
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ARC001-011-013-025-035-039-041-043-069-077-079-095-103-107-123-
092040-
AR
. ARKANSAS COUNTIES INCLUDED ARE
ARKANSAS BRADLEY CALHOUN
CLEVELAND CRITTENDEN DALLAS
DESHA DREW JEFFERSON
LEE LINCOLN MONROE
OUACHITA PHILLIPS ST. FRANCIS
KYC003-009-031-047-061-085-087-093-099-107-123-141-169-171-177-
183-213-219-221-227-092040-
KY
. KENTUCKY COUNTIES INCLUDED ARE
ALLEN BARREN BUTLER
CHRISTIAN EDMONSON GRAYSON
GREEN HARDIN HART
HOPKINS LARUE LOGAN
METCALFE MONROE MUHLENBERG
OHIO SIMPSON TODD
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No Mesoscale Discussions are in effect as of Sat Dec 9 19:11:12 UTC 2023.
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1036 AM CST Sat Dec 09 2023
Valid 091630Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE LOWER
MISSISSIPPI VALLEY...GULF COAST...TENNESSEE VALLEY...
...SUMMARY...
A few tornadoes, damaging thunderstorm wind gusts, and isolated
severe hail are possible today and tonight from portions of the Ohio
Valley southward to the Lower Mississippi Valley and middle Gulf
Coast.
...Gulf Coast/Lower Mississippi Valley/Tennessee Valley...
Region is being increasingly influenced by height falls but
otherwise resides between larger scale influences of an upper trough
over the Upper Midwest and a positive-tilt trough over the southern
High Plains. Increasing warm-sector moisture (generally lower to
some middle 60s F surface dewpoints) ahead of a southeastward-moving
cold front, along with considerable deep-layer/low-level shear, will
be favorable factors for a long-duration severe risk through the
afternoon into tonight. However, the likelihood of a complex/mixed
quasi-linear convective mode casts uncertainty regarding the
magnitude of the severe risk, particularly regarding a
supercell-related sustained/focused tornado risk. It is also noted
that some guidance suggests that 1-3km AGL winds may somewhat weaken
by late afternoon/early evening within the warm sector, while noting
SRH will still remain favorable for rotating/severe storms.
Storms should continue to increase in coverage through early
afternoon, initially near the front across Arkansas northeastward
into western portions of Tennessee/Kentucky. Sufficiently steep
mid-level lapse rates will support some hail potential, especially
the first part of the day, but the tendency for storm clustering
will otherwise limit this overall potential, as well as limiting
prospects for more consequential hail magnitudes. As the boundary
layer warms this afternoon, the potential for initially
semi-discrete supercells will increase along with related damaging
wind risk as well as tornado potential, which will persist through
the afternoon/evening even with a quasi-linear convective mode.
As warm-sector inhibition further weakens later this afternoon,
additional deepening convection may develop within weak pre-frontal
convergence/confluence regime, mainly across Mississippi into
Alabama, with this development eventually merging with or taking
over as the main convective band this evening. Similarly,
pre-frontal confluence may support isolated supercellular
development along the Gulf Coast/Florida Panhandle vicinity through
late night hours/early Sunday, within a somewhat separate regime
capable of a few severe storms.
..Guyer/Weinman.. 12/09/2023
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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1135 AM CST Sat Dec 09 2023
Valid 101200Z - 111200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
SOUTHEAST AND TOWARD PARTS OF THE MID ATLANTIC...
...SUMMARY...
Isolated severe thunderstorms will be possible through Sunday
evening across parts of the Southeast States, mainly in the form of
sporadic damaging winds and a few brief tornadoes.
...Synopsis...
A highly amplified upper trough will move from the MS Valley toward
the East Coast on Sunday, with a primary embedded speed max ejecting
quickly from the northern Gulf Coast toward the Mid Atlantic. At the
surface, a cold front will push east across the Appalachians during
the afternoon, with the strongest frontal surge across the Southeast
late in the day and into the evening.
Ahead of the cold front, a surface trough will gradually deepen from
MD southwestward to the FL Panhandle, with 40-50 kt southerly 850 mb
flow aiding moistening. Front-parallel winds aloft as well as modest
destabilization will likely lead to scattered storms, with a few
becoming severe across the region.
...Parts of the Southeast and East Coast...
Scattered storms are likely to be ongoing along the front from
southern AL and the western FL Panhandle across northern GA and the
Appalachians Sunday morning, with substantial low clouds across much
of the region. Lack of appreciable heating will generally reduce
available instability, but sufficient boundary layer moisture with
low to perhaps mid 60s F dewpoints will result in a few hundred J/kg
MLCAPE ahead of the cold front. The strongest cooling aloft will
occur behind the boundary, as the upper trough will be quite
amplified with meridional flow aloft.
Storms across the Southeast may eventually become linear as the cold
front accelerates, and this may yield a few damaging gusts.
Low-level shear may also favor isolated supercells with brief
tornado threat, with the main mitigating factor being lack of
heating. Any pockets of strong heating that do develop could yield
mesocale areas of higher potential, and the southeastern area will
be monitored going into the Day 1 period.
Farther north into the Mid Atlantic, boundary layer stability will
likely reduce severe potential to Marginal Risk levels due to the
combination of weak lift/convergence combined with the
cloudy/saturated profiles. Still, strengthening mean winds in the
lowest few km may support strong to perhaps damaging gusts.
..Jewell.. 12/09/2023
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1041 AM CST Sat Dec 09 2023
Valid 091700Z - 101200Z
The previous forecast remains on track with no changes required.
Latest surface observations within the southern CA coastal ranges
show areas of elevated to critical fire weather conditions with
winds gusting between 25-50 mph and RH in the upper teens and low
20s. Such conditions will likely persist through tonight and into
early Sunday morning. Across southern TX, dry conditions are noted
in recent observations with a gradual increase in winds still likely
this afternoon. See the previous discussion below for additional
information.
..Moore.. 12/09/2023
.PREV DISCUSSION... /ISSUED 1141 PM CST Fri Dec 08 2023/
...Synopsis...
An upper-level trough will amplify as it moves into the Southeast
today. This will push a cold front through the Plains to near the
Appalachians. Surface high pressure will increase within the Great
Basin and Four Corners regions.
...Southern California...
Offshore winds will likely be maximized early this morning. Winds of
20-25 mph (with higher gusts) will overlap with at least marginally
reduced RH. RH values will fall to near 10-15% in some locations by
the afternoon. Winds will slowly lose some intensity with time, but
should remain 15-20 mph for several hours. Lower elevation fuels
will be the primary driver of fire spread. However, these fine fuels
are only marginally dry at present. Elevated fire weather concerns
are possible where these fuels are driest.
...Texas...
Elevated fire weather is possible within part of the Permian Basin
into the Edwards Plateau. Post-frontal winds will be 15-20 mph amid
15-20% RH. Locally lower RH could occur where a greater downsloping
wind component exists. Fine fuels are marginally dry and will
support a low-end threat for a large fire. Cold advection will tend
to limit the fire weather threat, particularly farther north, as RH
will likely remain above critical thresholds in those areas.
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0103 PM CST Sat Dec 09 2023
Valid 101200Z - 111200Z
An Elevated risk area is introduced for portions of coastal southern
CA for Sunday. Latest observations show areas of elevated to
critical fire weather conditions ongoing within the coastal ranges.
Recent deterministic solutions indicate that the regional pressure
gradient driving these winds will persist well into Sunday morning
and perhaps into Sunday afternoon. This idea is supported by
ensemble guidance, which has increased confidence in multiple hours
of at least elevated fire weather conditions Sunday, warranting a
risk area. Other forecast concerns outlined in the previous
discussion (below) remain on track.
..Moore.. 12/09/2023
.PREV DISCUSSION... /ISSUED 1142 PM CST Fri Dec 08 2023/
...Synopsis...
The upper-level trough will continue through the Southeast before
lifting into the Mid-Atlantic on Sunday. The surface high in the
West will move into the southern Plains and Gulf of Mexico. A belt
of strong mid-level northwesterly winds will remain in the central
Rockies. Modest lee troughing may occur in the southern/central High
Plains as a result.
...Southern California...
Offshore pressure gradients will continue to diminish. The strongest
winds will again be early in the day. RH recovery during Saturday
night may only be modest. Though some elevated fire weather may
occur early in the period, diminishing coverage and intensity of
winds, a slight offset of the lowest RH with the strongest winds,
and winds becoming more confined to the terrain where fuels are less
receptive should keep the bulk of fire weather concerns localized.
...Southern High Plains...
As the surface high shifts east and a weak lee trough develops, some
modestly dry and breezy conditions are possible in parts of eastern
New Mexico into the Texas Panhandle/South Plains. With both winds
and RH being marginal, fire weather concerns that exist should
remain rather localized.
...Please see www.spc.noaa.gov/fire for graphic product...
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