Severe Thunderstorm Warning 488, NWS Shreveport, LA

Area Forecast Discussion
National Weather Service Shreveport LA
204 PM CST Mon Nov 20 2023

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(This evening through Tuesday Night)
Issued at 1259 PM CST Mon Nov 20 2023

A tornado watch remains in place across much of the area through
01z Tuesday...

The upper level pattern this afternoon is characterized by a
longwave trough extending from the Rockies southward into the
Southern Plains and into the Midwest, with a closed area of
circulation centered across the Central Plains and numerous
shorter wave perturbations rotating about. Near the surface, a
cyclone is located across S/SE OK near the Red River, with a warm
front draped to the E/SE over SW AR and N LA and a cold front
draped to the S/SW across C TX.

This evening, a potent area of mid level vorticity will be
rotating around the SE periphery of the aforementioned longwave
trough and ejecting NE into AR/Missouri Valley, continuing to
supply PVA across the ArkLaTex. Meanwhile, the surface low will
begin to move along the AR/LA border, with convection within the
warm sector and near and along the cold front ongoing. Model
guidance is suggestive that an area of MLCAPE of around
500-1000J/kg will be maintained into the evening hours as dewpoint
temperatures remain in the 60s, with effective bulk shear values
of around 60kts and 0-1 SRH values between 100-200m2/s2.
Convection will likely consist of several multicell
clusters/linear segments with a few embedded supercells, carrying
a threat for tornadoes and damaging winds. While hi-res model
guidance is still suggestive of the bulk of the warm sector
activity pushing east of the CWA in the 00z-03z timeframe, there
looks to be slightly better development along the actual cold
front, which may result in a more isolated severe or strong storm
threat slightly beyond 03z. Do expect any cold frontal convection
to wane towards 06z given loss of the most favorable thermodynamic
environment as well as the best upper level forcing as the vort
lobe and closed area of mid level circulation begin to slowly
pivot NE.

Expect generally quiet weather conditions after midnight and
through the overnight period tonight, with just a few light
showers across N LA, SW AR, and NE OK and low level cloud cover
filtering in from N to S, associated with wrap-around moisture.
Despite some CAA, a pronounced pressure gradient will lead to
sufficient vertical mixing overnight and keep a somewhat stiff NW
wind. Breezy winds and low level cloud cover combined will keep
temps from falling too dramatically in the wake of the cold front,
so expecting low temps to range from the mid 40s to low 50s
areawide.

On Tuesday, the closed area of mid level low pressure will
continue its journey NE, with another closed area of low pressure
in its wake diving straight south into the Four State Region from
the Northern Plains/Upper MS Valley. This may bring a few light
showers to portions of AR and OK late in the day, however,
stronger CAA will hold strong enough to prevent much in the way of
QPF. An enhanced pressure gradient will remain in place on
Tuesday as high pressure builds into the Plains, making it a
chilly day across the area with highs in the 50s and breezy winds.
Stronger CAA and clearing skies Tuesday night will then allow low
temps to drop into the mid to upper 30s across most of the area
(isolated freezing temps possible in portions of McCurtain Count
and potentially into far SW AR).

Kovacik

&&

.LONG TERM...
(Wednesday through next Sunday)
Issued at 1259 PM CST Mon Nov 20 2023

The long term period will feature a split-flow pattern across the
E CONUS as a deep polar low strengthens over the Hudson Bay and
ridging over the N Plains gives way to a longwave trough over the
Eastern CONUS with a closed area of circulation over the Deep
South. Near the surface, the pressure gradient will have relaxed
some across the area as high pressure settles deeper into the
Southern Plains/TX and low pressure makes it way along the Eastern
Seaboard. Wednesday will be dry and sunny across the local area,
with winds finally relaxing as sfc high pressure pushes east
across into the area. High temps won't recover too much with a NW
wind remaining in place.

Conditions then change for the Thanksgiving holiday, at least
towards the latter half of the day and into Friday. The longwave
trough over the south will move east, with arguably a weak ridge
moving in ahead of a closed low moving across Northern Mexico.
With higher pressure over the area through much of the day, most
of the day will be dry with cloud cover quickly increasing from
south to north and a return to S/SE winds and highs near 60. By
Thursday evening and into Thursday night, expect rain chances to
increase, although moisture does not look as pronounced as it did
in previous runs. Nevertheless, showers will be possible through
the first half of Friday.

Then next weekend, ensemble guidance shows another trough
developing across the Rockies. This currently looks to bring the
prospect of another frontal passage across the Four State Region.
It's too early to determine if a severe threat will be associated
with it. Temperatures look to remain on the cool side with highs
in the 50s.

Kovacik

&&

.AVIATION...
(18Z TAFS)
Issued at 1114 AM CST Mon Nov 20 2023

Ceilings remain MVFR and IFR across much of E TX and SW AR late
this morning, with VFR noted and associated with more sun breaks
across much of LA. The severe weather threat will impact aviation
through much of the rest of today, with all TAFs carrying a VCTS
and many TEMPOs for -TSRA. Expect very gusty winds to be the main
threat at airport terminals. The threat will end from west to east
from mid afternoon (TX terminals) to mid to late evening (C and E
LA terminals), with a brief period of SCT VFR or clear skies
anticipated. This break in cloud cover will be short lived with
MVFR cloud cover quickly filtering in and remaining in place thru
Tues morning. Winds will be breezy out of the S/SW much of the
afternoon (erratic and gusty within or in vicinity of TSRA),
shifting to the W/NW through the evening and remaining breezy,
10-15kts gusting 20-25kts.

Kovacik

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  50  56  41  56 /  20  10   0   0
MLU  53  58  41  56 /  80  10  10   0
DEQ  45  54  33  53 /  40   0   0   0
TXK  48  53  37  52 /  20   0   0   0
ELD  48  54  37  53 /  40  10   0   0
TYR  49  57  38  54 /  10   0   0   0
GGG  48  57  39  55 /  10   0   0   0
LFK  48  57  40  57 /  20   0   0   0

&&

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

SHORT TERM...23
LONG TERM....23
AVIATION...23

Hazardous Weather Outlook
National Weather Service Shreveport LA
1258 PM CST Mon Nov 20 2023

ARZ050-051-059>061-070-OKZ077-TXZ096-097-108>112-124-125-211900-
Sevier-Howard-Little River-Hempstead-Nevada-Miller-McCurtain-
Red River-Bowie-Franklin-Titus-Camp-Morris-Cass-Wood-Upshur-
1258 PM CST Mon Nov 20 2023

This Hazardous Weather Outlook is for southwest Arkansas, southeast
Oklahoma and northeast Texas.

.DAY ONE...This afternoon and tonight.

Thunderstorm development will increase in coverage this afternoon,
continuing to increase in severity into the late afternoon and
lasting through the evening hours. All modes of severe weather will
be possible including the risk of tornadoes, damaging wind and hail.

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

Chances for rain may return by Thursday as a low approaches the Four
State Region. No severe weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

ARZ071>073-LAZ001>006-010>014-017>022-TXZ126-136>138-149>153-165>167-
211900-
Lafayette-Columbia-Union-Caddo-Bossier-Webster-Claiborne-Lincoln-
De Soto-Red River-Bienville-Jackson-Ouachita-Sabine-Natchitoches-
Winn-Grant-Caldwell-La Salle-Marion-Smith-Gregg-Harrison-Cherokee-
Rusk-Panola-Nacogdoches-Shelby-Angelina-San Augustine-
1258 PM CST Mon Nov 20 2023

...TORNADO WATCH 711 IN EFFECT UNTIL 7 PM CST THIS EVENING...

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

.DAY ONE...This afternoon and tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Tornado Watch.

Thunderstorm development will increase in coverage this afternoon,
continuing to increase in severity into the late afternoon and
lasting through the evening hours. All modes of severe weather will
be possible including the risk of tornadoes, damaging wind and hail.

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

Chances for rain may return by Thursday as a low approaches the Four
State Region. No severe weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed.

Special Weather Statement
National Weather Service Shreveport LA
338 PM CST Mon Nov 20 2023

OKZ077-202215-
McCurtain OK-
338 PM CST Mon Nov 20 2023

...STRONG THUNDERSTORMS WILL IMPACT NORTHERN MCCURTAIN COUNTY THROUGH
415 PM CST...

At 337 PM CST, Doppler radar was tracking a cluster of strong
thunderstorms 16 miles east of Cloudy, or 30 miles southeast of
Clayton, moving northeast at 55 mph.

HAZARD...Wind gusts up to 40 mph and pea size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Plunketville, Smithville, Watson, Bethel, Battiest, Pickens, Mount
Herman, and Sherwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3451 9446 3431 9447 3414 9503 3424 9506
      3425 9505 3451 9505
TIME...MOT...LOC 2137Z 240DEG 49KT 3426 9500

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

44

Special Weather Statement
National Weather Service Shreveport LA
356 PM CST Mon Nov 20 2023

LAZ019-020-022-202230-
Winn LA-La Salle LA-Grant LA-
356 PM CST Mon Nov 20 2023

...STRONG THUNDERSTORMS WILL IMPACT CENTRAL GRANT...NORTHWESTERN LA
SALLE AND SOUTHEASTERN WINN PARISHES THROUGH 430 PM CST...

At 356 PM CST, Doppler radar was tracking strong thunderstorms along
a line extending from 10 miles southeast of Winnfield to near Lena.
Movement was northeast at 45 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Colfax, Olla, Urania, Dry Prong, Tullos, Georgetown, Zenoria, Lake
Iatt, Bentley, Williana, Rochelle, and Standard.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

These storms 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.

A Tornado Watch remains in effect until 700 PM CST for north central
and northwestern Louisiana.

&&

LAT...LON 3154 9239 3146 9271 3147 9271 3148 9269
      3148 9270 3149 9270 3151 9271 3153 9273
      3155 9276 3185 9249 3193 9218
TIME...MOT...LOC 2156Z 233DEG 37KT 3183 9250 3151 9278

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

26

Preliminary Local Storm Report
National Weather Service Shreveport LA
417 PM CST Mon Nov 20 2023

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0326 PM     Tstm Wnd Dmg     5 SSW Midway            31.62N 92.18W
11/20/2023                   La Salle           LA   Law Enforcement

            A few trees and power lines were downed near
            the intersection of Nebo Belah Road and
            Clyde Road.

&&

15

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