Mesoscale Discussion 1912

Issued

Oct 27, 2021, 9:08 AM CDT (14:08 UTC)

Expired

Oct 27, 2021, 10:45 AM CDT

In force

97 min

Issued by

the Storm Prediction Center

Concerning

Tornado watch 540

Counties Hardin County, TX, Jasper County, TX, Jefferson County, TX, Newton County, TX, Orange County, TX, Tyler County, TX

The Lake Charles radar (KLCH), 96 km from the middle of the area, began a volume at 14:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

712 
ACUS11 KWNS 271408
SWOMCD
SPC MCD 271408 
LAZ000-TXZ000-271545-

Mesoscale Discussion 1912
NWS Storm Prediction Center Norman OK
0908 AM CDT Wed Oct 27 2021

Areas affected...southeast Texas and far southwest Louisiana

Concerning...Tornado Watch 540...

Valid 271408Z - 271545Z

The severe weather threat for Tornado Watch 540 continues.

SUMMARY...The greatest threat for tornadoes through 16Z will persist
with discrete storms developing from southeast TX and possibly far
southwest LA.

DISCUSSION...Early this morning a warm front extends through
southwest LA north of Lake Charles into southeast TX near Jasper,
then farther northwest where it intersects the squall line which
extends southward through the Houston metro area and beyond. The
warm sector to the south and east of these boundaries is very moist
with low to mid 70s F dewpoints along with temperatures in the upper
70s F. The 12Z RAOBs and latest objective analysis show the
atmosphere in this area to be moderately unstable with around 1500
J/kg MLCAPE. VWP data from Lake Charles also indicates sizeable
low-level hodographs with 250-300 m2/s2 storm relative helicity
based on current storm motions. This strongly sheared, low-LCL
environment will remain favorable for low-level mesocyclones and
tornadoes next couple hours as discrete supercells continue moving
northeast through the warm sector. Some interaction with the warm
front is also likely, potentially augmenting the tornado threat.

Farther west, damaging wind will remain the primary threat along the
squall line, but a couple of brief tornadoes cannot be ruled out
with any embedded mesovortices.

..Dial.. 10/27/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LCH...HGX...

LAT...LON   31029405 30739340 30189340 29759405 29889481 30609464
            30929444 31029405

Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.