Special Weather Statement, NWS Shreveport, LA

Area Forecast Discussion
National Weather Service Shreveport LA
1251 PM CDT Wed Apr 7 2021

.UPDATE.../This Afternoon/

Quick update to issue Tornado Watch 75. KSHV 18Z sounding shows
this morning's cap has all but been flattened, indicating the
anticipated increase in instability as the cold front approaches.
As such, severe storms becoming more likely to develop as we move
into the aftn/evening hours. /12/

&&

.PREV DISCUSSION... /issued 1212 PM CDT Wed Apr 7 2021/

AVIATION...

Widespread MVFR conditions continue across the TAF sites at this
time. A cold front, that is knocking on our CWA border, will
bring a line of showers and thunderstorms to the area by this
afternoon. Have mention of VCTS at all terminals with TEMPO
thunderstorms at all sites. Some of the storms could be strong to
severe within the line, with high winds, hail, and even tornadoes
possible. There will also be a drop to IFR/LIFR as the
thunderstorms pass through the TAF sites. Winds will diminish in
wake of the front and thunderstorms, along with clearing skies.
This will result in VFR conditions overnight, prevailing through
the end of the TAF period. /20/

PREV DISCUSSION... /issued 1147 AM CDT Wed Apr 7 2021/

UPDATE...

A line of showers have developed along a pre-frontal trough
moving across the region this morning. However, this is only the
start of a very busy short-term period. The Storm Prediction
Center has expanded an Enhanced Risk to include all of North
Louisiana and our adjacent South Arkansas counties along and south
of the Interstate 30 corridor.

At 1030 AM, a closed upper trough was located across Western
Kansas, with a cold front trailing along the I-35 corridor of
Oklahoma and Texas. As this trough and associated cold front
continues to move eastward today, a line of showers and
thunderstorms will initially develop across East Texas and
adjacent SE Oklahoma early this afternoon, and eventually move
across the remainder of the region. The 12z sounding this morning
had a strong cap in place, but large scale forcing with the
frontal boundary should be enough for convection to develop. Ahead
of the front, the synoptic situation is setting up very favorable
for all modes of strong to severe storms. Good instability should
be in place, as MLCape will climb to near 1500 J/kg along with
dewpoints in the mid 60s areawide. Lapse rates are also
favorable, with mid and low-level rates approaching 7 C/km along
with effective bulk shear near 50 kts. A QLCS event will likely
evolve with this set-up, resulting in possible severe wind gusts
in bowing features along the squall line. And with sfc-1km shear
forecasted to be greater than 20 kts along with Effective SRH
values around 200 m2/s2, a tornado or two will be very possible.
Hail is also in play, with wet bulb zero heights between 8-10 kft.

Other than a few minor adjustments to POPs to account for current
trends, the remainder of the forecast remains on track.  /20/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  74  53  81  60 /  90  10  10  20
MLU  78  56  81  60 /  60  70   0  20
DEQ  74  47  78  52 /  60   0   0  20
TXK  74  52  78  58 /  80   0   0  20
ELD  74  50  79  52 /  80  20   0  20
TYR  76  52  81  62 /  60   0  10  20
GGG  74  50  80  59 /  80   0  10  20
LFK  75  54  83  63 /  80  20  10  20

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&

12/20

Hazardous Weather Outlook
National Weather Service Shreveport LA
324 AM CDT Wed Apr 7 2021

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-
TXZ096-097-108>112-124>126-136>138-149>153-165>167-081200-
Sevier-Howard-Little River-Hempstead-Nevada-Miller-Lafayette-
Columbia-Union-Caddo-Bossier-Webster-Claiborne-Lincoln-De Soto-
Red River-Bienville-Jackson-Ouachita-Sabine-Natchitoches-Winn-
Grant-Caldwell-La Salle-McCurtain-Bowie-Franklin-Titus-Camp-
Morris-Cass-Wood-Upshur-Marion-Smith-Gregg-Harrison-Cherokee-Rusk-
Panola-Nacogdoches-Shelby-Angelina-San Augustine-
324 AM CDT Wed Apr 7 2021

This Hazardous Weather Outlook is for portions of south central
Arkansas, southwest Arkansas, north central Louisiana, northwest
Louisiana, southeast Oklahoma, east Texas and northeast Texas.

.DAY ONE...Today and Tonight...

Strong to severe thunderstorms will become likely later today
through this evening across at least the eastern half of the Four
State Region which would include all of Southern Arkansas and all
of Northern Louisiana. A more conditional threat exists across
Southeast Oklahoma and Northeast Texas. Conditions will be
conducive for damaging wind gusts, large hail and isolated
tornadoes this afternoon through this evening where severe
thunderstorms develop. The severe weather threat should end across
Northeast Louisiana after midnight.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday...

After a relatively quiet day on Thursday, more severe
thunderstorms are back in the forecast for Friday Afternoon
through Friday Evening once again. Look for the possibility of
very large hail, damaging thunderstorm wind gusts and isolated
tornadoes once again during this time frame along and ahead of a
cold front that should move through the region late Friday Night
into early Saturday.

.SPOTTER INFORMATION STATEMENT...

Activation of emergency management personnel...amateur radio
operators...and storm spotters will likely be needed this
afternoon into this evening. Please relay any information about
observed severe weather to the NWS while following all local,
state, and CDC guidelines.

13

Special Weather Statement
National Weather Service Shreveport LA
132 PM CDT Wed Apr 7 2021

TXZ110-111-124>126-136-071915-
Upshur TX-Smith TX-Camp TX-Marion TX-Wood TX-Morris TX-
132 PM CDT Wed Apr 7 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN SMITH...NORTHWESTERN
MARION...SOUTHEASTERN WOOD...UPSHUR...SOUTHERN MORRIS AND CAMP
COUNTIES UNTIL 215 PM CDT...

At 132 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Newsome to near Rosewood to near Hoard.
Movement was east at 35 mph.

Penny size hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Gladewater, Gilmer, Pittsburg, Leesburg, Daingerfield, Lone Star, Big
Sandy, Hawkins, Ore City, Rosewood, Jenkins, Newsome, West Mountain,
Cedar Springs, Midway, Holly Springs, Lafayette, Center Point, Bettie
and Grice.

A Tornado Watch remains in effect until 800 PM CDT for northeastern
Texas.

LAT...LON 3273 9522 3297 9513 3302 9488 3301 9486
      3300 9485 3298 9482 3303 9482 3306 9465
      3289 9465 3278 9468 3279 9470 3276 9470
      3256 9498 3253 9541
TIME...MOT...LOC 1832Z 258DEG 29KT 3292 9511 3274 9517 3260 9531

44

Special Weather Statement
National Weather Service Shreveport LA
150 PM CDT Wed Apr 7 2021

LAZ001-010-TXZ151-153-071930-
De Soto LA-Caddo LA-Panola TX-Shelby TX-
150 PM CDT Wed Apr 7 2021

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN DE SOTO AND SOUTHWESTERN
CADDO PARISHES...SOUTHEASTERN PANOLA AND NORTHEASTERN SHELBY COUNTIES
UNTIL 230 PM CDT...

At 150 PM CDT, Doppler radar was tracking a strong thunderstorm over
Joaquin, or 14 miles northeast of Center, moving northeast at 45 mph.

Penny size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Mansfield, Stonewall, Logansport, Joaquin, South Mansfield, Keachi,
Grand Cane, Longstreet, Stanley, Gloster, Keat Chie, Carmel,
Frierson, Kingston, Kickapoo, Keithville and Reeds Store.

A Tornado Watch remains in effect until 800 PM CDT for northwestern
Louisiana...and eastern and northeastern Texas.

LAT...LON 3182 9403 3202 9424 3239 9385 3210 9354
TIME...MOT...LOC 1850Z 229DEG 39KT 3198 9406

44