Severe Thunderstorm Warning 20, NWS Memphis, TN

773 
WWUS54 KMEG 010421
SVSMEG

Severe Weather Statement
National Weather Service Memphis TN
1021 PM CST TUE FEB 28 2017

ARC021-010431-
/O.CAN.KMEG.SV.W.0020.000000T0000Z-170301T0445Z/
Clay AR-
1021 PM CST TUE FEB 28 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CLAY COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has weakened.
moved out of the warned area. Therefore the warning has been 
cancelled.

A tornado watch remains in effect until 400 AM CST for eastern
Arkansas...and southeastern Missouri.

LAT...LON 3663 8996 3655 8995 3645 8996 3640 9008
      3641 9014 3643 9014 3645 9013 3648 9014
      3648 9016 3649 9016 3650 9022 3654 9021
      3655 9019 3659 9018 3660 9016 3661 9017
      3663 9015
TIME...MOT...LOC 0421Z 237DEG 54KT 3658 8996 

$$

MOC069-010445-
/O.CON.KMEG.SV.W.0020.000000T0000Z-170301T0445Z/
Dunklin MO-
1021 PM CST TUE FEB 28 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1045 PM CST
FOR NORTHEASTERN DUNKLIN COUNTY...

At 1021 PM CST, a severe thunderstorm was located over Malden, moving
northeast at 60 mph.

HAZARD...60 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees. 

Locations impacted include...
Malden, Campbell, Clarkton, Glennonville, Brian, Valley Ridge, Baird,
Providence, Mc Guires, Wilhelmina and Townley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A tornado watch remains in effect for the warned area. Tornadoes can
develop quickly from severe thunderstorms. Although a tornado is not
immediately likely, if one is spotted act quickly and move to a place
of safety inside a sturdy structure, such as a storm shelter or small
interior room.

For your protection move to an interior room on the lowest floor of a
building.

&&

A tornado watch remains in effect until 400 AM CST for eastern
Arkansas...and southeastern Missouri.

LAT...LON 3663 8996 3655 8995 3645 8996 3640 9008
      3641 9014 3643 9014 3645 9013 3648 9014
      3648 9016 3649 9016 3650 9022 3654 9021
      3655 9019 3659 9018 3660 9016 3661 9017
      3663 9015
TIME...MOT...LOC 0421Z 237DEG 54KT 3658 8996 

HAIL...1.00IN
WIND...60MPH
 
$$

Area Forecast Discussion
National Weather Service Memphis TN
802 PM CST Tue Feb 28 2017

.UPDATE...

Update regarding evolution of evening and overnight severe weather
potential.

&&

.DISCUSSION...

Scattered supercell thunderstorms across northern Arkansas this
evening have been driven by warm advection and increased low level
moisture. These storms have shown varying degrees of intensity
through the evening. The overall background environment remains
quite favorable for severe weather with steep mid level lapse
rates along with increasing low level and deep layer shear. In
addition...low level winds remain backed near the surface across
the forecast area this evening helping to increase helicity with
0-1 km SRH now around 300-400 m2/s2. The main limiting factor
through the evening has been lingering capping inversion as noted
on 00z soundings from KJAN...KSHV.

Latest short-term high resolution model guidance continues to
suggest at least scattered convection moving into northeast
Arkansas and the Missouri Bootheel over the next hour and
spreading into portions of west Tennessee...mainly north of
Interstate 40 towards midnight and beyond. A severe weather threat
will be possible with any of these storms with all storm hazards
possible including damaging winds...large hail...and a few
tornadoes. This initial activity should lift northeast out of
forecast area later tonight. This severe threat will strongly
hinge on the ability of the capping inversion to diminish which is
still somewhat uncertain.

A secondary focus for convection will be prior to sunrise to the
west of the Mississippi River with storms focusing along an
approaching cold front. This convection will also be supported by
falling mid level heights associated with a mid level shortwave.
The development of this convection is much more certain.
Considering the degree of background instability and shear along
with steep mid level lapse rates should support a greater severe
weather potential with this activity. Low level winds may tend to
veer late tonight with an increasingly unidirectional deep layer
flow. The primary severe threats with this activity will be
damaging winds and large hail. This activity will likely be more
linear in nature with embedded QLCS rotations. Isolated tornadoes
will still be possible with any of these rotations. This activity
should spread east of the Mississippi River towards the morning
rush hour and across the remainder of the forecast area through
early afternoon.

Updated grids and forecast products have been sent. Be prepared
and ready to act if any warnings are issued tonight or Wednesday
for your location.

JLH

&&

.PREV DISCUSSION... /issued 359 PM CST Tue Feb 28 2017/

Potentially active severe weather event tonight and early
Wednesday, as the Midsouth is on the southern periphery of a more
potent severe weather area over the Mid-Mississippi River valley,
into the Ohio River valley. For the short term, will need to watch
central AR closely, as the HRRR suggests this may be a source
region for discrete supercells that may lift into northeast AR
toward mid- evening. Hail threat and storm coverage will
simultaneously increase overnight, as falling midlevel heights and
steepening lapse rates overspread a strongly sheered and unstable
airmass. Storms should exit northeast MS by midafternoon, after
possibly undergoing a reintensification due to daytime heating.
See the latest Hazardous Weather Outlook for area-specific timing
and severe weather threats.

Dry and cooler air will spread through the Midsouth late
Wednesday afternoon and evening, setting the stage for low
afternoon daytime humidity levels late in the week. This dry air
will remain until more humid maritime air returns late Sunday into
the early part of the upcoming work/school week. Low end rain
chance prevail until the arrival of a cold front on Tuesday, which
bring the region's best chances of rain beyond tonight and
early Wednesday.

PWB

&&

.AVIATION...
00z TAFs

VFR weather to start again...with best timing of thunderstorms on
station bringing conditions down to IFR/MVFR and higher wind gust
potential. More than one round of storms is possible...especially
at JBR. Outside of storms south to southwest winds will be strong
with frequent gusts of 20-28kts. Low level wind shear is also a
concern through the night at JBR...MEM and MKL. Cold front to push
through late with improving weather...with gusty winds veering
west through northwest. Winds will taper off by 02/00z.

JAB

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&

Hazardous Weather Outlook
National Weather Service Memphis TN
822 PM CST Tue Feb 28 2017

ARZ008-009-017-018-026>028-035-036-048-049-058-MOZ113-115-
MSZ001>017-020>024-TNZ001>004-019>022-048>055-088>092-020430-
Alcorn-Benton MS-Benton TN-Calhoun-Carroll-Chester-Chickasaw-Clay-
Coahoma-Craighead-Crittenden-Crockett-Cross-DeSoto-Decatur-
Dunklin-Dyer-Fayette-Gibson-Greene-Hardeman-Hardin-Haywood-
Henderson-Henry-Itawamba-Lafayette-Lake-Lauderdale-Lawrence-
Lee AR-Lee MS-Madison-Marshall-McNairy-Mississippi-Monroe-Obion-
Panola-Pemiscot-Phillips-Poinsett-Pontotoc-Prentiss-Quitman-
Randolph-Shelby-St. Francis-Tallahatchie-Tate-Tippah-Tipton-
Tishomingo-Tunica-Union-Weakley-Yalobusha-
822 PM CST Tue Feb 28 2017

This hazardous weather outlook is for portions of East Arkansas...
the Missouri Bootheel...North Mississippi...and West Tennessee.

.DAY ONE...Tonight

There is a Moderate Risk of severe thunderstorms over far northeast
Arkansas and the northern Missouri bootheel. An Enhanced Risk of
severe storms extends to the north of a Wynne Arkansas to
Covington and Paris Tennessee line. A Slight Risk of severe storms
prevails along the the Interstate 40 corridor.

Scattered thunderstorms this evening will move across northeast
Arkansas...the Missouri Bootheel...and west Tennessee mainly north
of Interstate 40. These storms will have a potential to become
severe with a threat of damaging winds, large hail, and a few
tornadoes.

A secondary threat for severe thunderstorms will develop late
tonight before sunrise across areas west of the Mississippi River.
The primary threats with this activity will be damaging winds and
large hail. Isolated tornadoes will also be possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Beginning at 6 am CST Wednesday, there is a Slight Risk of severe
thunderstorms along and east of the Mississippi River. There is
an Enhanced Risk of severe thunderstorms east of a Bolivar to
Paris Tennessee line, and east of an Aberdeen to Pontotoc to
Ashland Mississippi line.

Thunderstorms, some possibly severe, will be ongoing at daybreak
Wednesday. Damaging winds and large hail will be the primary
severe weather threats. Isolated brief tornadoes will be possible,
associated with any stronger segments of an eastward-moving
developing squall line. Thunderstorms will exit west Tennessee and
primarily affect northeast Mississippi into early Wednesday
afternoon. With the heating of the day, conditions may be
favorable for an increase in severe weather potential over
northeast Mississippi, with large hail, damaging winds and a
tornado or two possible. Storms should exit northeast Mississippi
by Wednesday mid afternoon.

Following a strong cold frontal passage Wednesday afternoon and
evening, breezy conditions and low humidity will spread through
the Midsouth. North Mississippi and west Tennessee will likely
experience elevated levels of wild fire danger Thursday and
Friday, due to low relative humidity levels.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed for the remainder of
tonight through early afternoon Wednesday.

JLH