MESO: Mesoscale Discussion 0114

ACUS11 KWNS 161652
SWOMCD
SPC MCD 161651
CAZ000-161815-

MESOSCALE DISCUSSION 0114
NWS STORM PREDICTION CENTER NORMAN OK
1051 AM CST MON FEB 16 2009

AREAS AFFECTED...WRN PARTS OF THE LOS ANGELES BASIN SWD ALONG THE
COAST TO NEAR OR N OF SAN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 161651Z - 161815Z

THE POTENTIAL FOR ISOLATED SEVERE STORMS CAPABLE OF SOME
HAIL...GUSTY WINDS AND PERHAPS A BRIEF TORNADO APPEARS TO BE
INCREASING ACROSS THE DISCUSSION AREA. THIS THREAT IS FORECAST TO
CONTINUE INTO THIS AFTERNOON. CURRENTLY...A WW IS NOT ANTICIPATED.

LATEST MESOSCALE ANALYSIS INDICATES THAT LARGE-SCALE UPPER-LEVEL
PATTERN HAS SUPPORTED THE DEVELOPMENT OF A LOW-LEVEL CONVERGENCE
ZONE EXTENDING GENERALLY W-E FROM N OF CATALINA ISLAND EWD TO NEAR
RAL. TO THE S OF THIS BOUNDARY WINDS HAVE MAINTAINED A SELY
DIRECTION...WHEREAS TO THE N WINDS BACK TO ENELY. LOCAL RADAR
IMAGERY SUGGESTS THAT CONVERGENCE AND DEEPER-LAYER VERTICAL
VORTICITY IS BEING ENHANCED ALONG THIS BOUNDARY NEAR THE COAST BY AN
APPARENT MESOSCALE VORTICITY MAXIMUM CURRENTLY LIFTING NEWD INTO THE
LOS ANGELES METROPOLITAN AREA.

DESPITE THE VERY MARGINAL INSTABILITY...THIS ZONE OF CONVERGENCE HAS
ENHANCED ONGOING CONVECTIVE DEVELOPMENT OVER PORTIONS OF LOS ANGELES
AND NWRN ORANGE COUNTIES TO JUST E OF CATALINA ISLAND. LOCAL VWPS
CONTINUE TO INDICATE RATHER STRONG LOW-LEVEL SHEAR /25-40 KT/ ALONG
AND TO THE S OF THIS CONVERGENCE ZONE...SUGGESTING THE POTENTIAL FOR
EMBEDDED ROTATING CONVECTIVE ELEMENTS CAPABLE OF A BRIEF TORNADO IN
ADDITION TO SOME HAIL AND GUSTY WINDS.

FARTHER S...RADAR IMAGERY SHOWS INTENSIFYING CONVECTION ALONG
FRONTAL BAND TO THE W/SW OF SAN WITH EXTRAPOLATION TAKING THIS
ACTIVITY ONSHORE TO THE N OF SAN BETWEEN 1800-1830Z. HERE TOO...THE
POTENTIAL WILL EXIST FOR HAIL...LOCALLY STRONG WIND GUSTS AND
PERHAPS A BRIEF TORNADO ALONG THE IMMEDIATE COAST. ANY POTENTIAL
FOR A MORE SIGNIFICANT/ORGANIZED SEVERE WEATHER EPISODE IS EXPECTED
TO BE LIMITED BY THE VERY MARGINAL CONVECTIVE INSTABILITY.

..MEAD.. 02/16/2009

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...SGX...LOX...

LAT...LON 33601831 33811842 33961824 33901789 33431728 33231719
33091726 33091748 33411796 33601831

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.