Severe Storm Outlook Narrative (AC)
Issued by NWS
ACUS11 KWNS 210405
SPC MCD 210404
Mesoscale Discussion 0081
NWS Storm Prediction Center Norman OK
1004 PM CST Fri Jan 20 2017
Areas affected...extreme southeast Texas through southwest and south
Concerning...Tornado Watch 9...
Valid 210404Z - 210600Z
The severe weather threat for Tornado Watch 9 continues.
SUMMARY...Thunderstorms will remain capable of producing large to
very large hail, damaging wind and a few tornadoes into the early
morning. Greatest threat next few hours will exist across southwest
through south-central LA, but threat will eventually expand into
southeast LA and southern MS later tonight into early Saturday.
DISCUSSION...Late this evening a warm front extends along the Gulf
Coast through southern LA. As this boundary continues moving slowly
north and steeper mid-level lapse rates advect east, the atmosphere
will destabilize farther inland with MLCAPE generally from 500 to
1000 J/kg over southern LA. Cluster of storms continues developing
through southwest and south-central LA generally along and north of
the warm front. However, additional discrete cells have developed in
warm sector. The strengthening low-level jet and forcing for ascent
in response to the ejecting shortwave trough will continue to
promote thunderstorm development next several hours. Moreover, a
gradual increase in hodograph size has been observed on the Lake
Charles VWP with 0-1 km storm-relative helicity exceeding 200 m2/s2
and effective bulk shear near 65 kt.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 30519352 30939276 31259225 31069176 30199158 29659117
29579215 29749300 29859367 30519352