Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
000
ACUS01 KWNS 160547
SWODY1
SPC AC 160545

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1145 PM CST Fri Dec 15 2017

Valid 161200Z - 171200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated thunderstorms are possible from the coastal Plain of Texas
into western Louisana.

...TX/LA...

Late-evening satellite imagery suggests mid-level trough has reached
its lowest latitude over northwest Mexico and will begin to eject
toward the Rio Grande Valley by 17/00z. This feature is expected to
induce a weak surface wave along a notable but stalled front over
the northwest Gulf Basin.  Models suggest this boundary will advance
north during the latter half of the period but likely struggle to
move inland as substantial surface ridging remains dominant across
the Gulf States and any precipitation north of the wind shift will
reinforce cool stable boundary layer. While surface-based
thunderstorms are not expected along the TX/LA coast, elevated
instability should increase such that isolated thunderstorms are
anticipated within stronger-forced region north of the warm front.
Forecast soundings suggest parcels lifted near 850mb will be
adequately buoyant for deep updrafts capable of generating
lightning. While environmental shear would support organized
convection the lack of significant instability does not support a
meaningful threat for severe thunderstorms.

..Darrow/Leitman.. 12/16/2017

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.