re: Tornado! Threat Continues Overnight then Shifts East Tomorrow

New watch coming for SW LA to replace the current watch



Mesoscale Discussion 0411
NWS Storm Prediction Center Norman OK
0807 PM CDT Sun Apr 02 2017

Areas affected...Portions of southern/central Louisiana and extreme
southeastern Texas

Concerning...Tornado Watch 110...

Valid 030107Z - 030230Z

The severe weather threat for Tornado Watch 110 continues.

SUMMARY...The threat for damaging winds and a few tornadoes may
increase some across the discussion area over the next 2-3 hours. A
new watch will be issued prior to the 02Z expiration of Tornado
Watch 110 across the Lake Charles, LA county warning area.

DISCUSSION...Opposing propagation and advection vectors have led to
a relatively stationary southwest-northeast band of strong/severe
convection this evening over extreme southeast Texas and
southern/central Louisiana. The 00Z LCH sounding sampled deep
southerly flow which is continuing to transport ample moisture
towards this linear system. Additionally, relatively steep 700-500mb
lapse rates (around 7 C/km) are contributing to MLCAPE values around
2000-3000 J/kg along and to the south of the ongoing complex.

As large-scale forcing for ascent amplifies in response to an
approaching impulse (noted over south-central Texas in water-vapor
imagery), ascending parcels along the southwest edge of this line
should be able to reach their LFC more efficiently. The band will
then likely re-orient in a more meridional fashion as it advances
eastward, encountering an unstable environment with effective SRH
around 200-300 m2/s2. In turn, a threat for damaging winds and a few
embedded tornadoes may increase somewhat within the next 2-3 hours.
A new watch will be issued to replace Watch 110 in the Lake Charles
CWA.