Post by Briella - Houma on Mar 15, 2014 15:05:55 GMT -6
MESOSCALE DISCUSSION 0184
NWS STORM PREDICTION CENTER NORMAN OK
0340 PM CDT SAT MAR 15 2014
AREAS AFFECTED...PORTIONS OF SERN AND ERN TX
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 152040Z - 152315Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...STORMS MAY INCREASE IN COVERAGE AND INTENSITY THIS EVENING
ACROSS PARTS OF ERN TX. POTENTIAL EXISTS FOR THE DEVELOPMENT OF
SUPERCELLS WITH DAMAGING WIND AND ISOLATED TORNADOES THE MAIN
THREATS. TIMING OF ANY WW ISSUANCE IN THIS AREA IS UNCERTAIN...BUT
WILL ULTIMATELY DEPEND ON CONVECTIVE TRENDS.
DISCUSSION...LOW 60S DEWPOINTS HAVE ADVECTED THROUGH MUCH OF THE ERN
TX WARM SECTOR. HOWEVER...BOUNDARY LAYER DESTABILIZATION HAS BEEN
LIMITED BY WIDESPREAD MULTI-LAYER CLOUDS AND AREAS OF ONGOING RAIN
AND THUNDERSTORMS WITHIN A GENERAL WARM ADVECTION REGIME. MORNING
RAOB DATA FROM CORPUS CHRISTI TX AND LAKE CHARLES LA SHOWED A
PRONOUNCED CAPPING INVERSION BETWEEN 850-700 MB...AND INDEED BASED
ON MOTION AND CHARACTER OF THE CONVECTION THUS FAR...ACTIVITY DOES
NOT APPEAR TO BE BASED WITHIN THE SFC LAYER. THE STRONGER FORCING
FOR ASCENT ASSOCIATED WITH A COMPACT...BUT VIGOROUS SHORTWAVE TROUGH
CURRENTLY MOVING THROUGH NWRN TX WILL REMAIN NORTH OF SERN TX...BUT
WILL AFFECT ECNTRL THROUGH NERN TX THIS EVENING. THIS SUGGESTS THAT
SHALLOW CONVECTION DEVELOPING ALONG CONVERGENCE BANDS MAY IN TIME
DEEPEN AS IT LIFTS NWD. MEANWHILE...THE LLJ IS FORECAST TO
STRENGTHEN TO NEAR 50 KT ACROSS ERN TX WITHIN ZONE OF HEIGHT FALLS
ASSOCIATED WITH THE PROGRESSIVE SHORTWAVE TROUGH. HOUSTON VWP HAS
SHOWN A SUBSTANTIAL INCREASE IN 0-1 KM SHEAR DURING THE PAST COUPLE
HOURS. WHILE WEAK INSTABILITY MAY REMAIN A LIMITING
FACTOR...INCREASING HODOGRAPH SIZE COINCIDENT WITH POTENTIAL FOR
DEEPENING CONVECTION POSES A RISK FOR SUPERCELLS WITH LOW-LEVEL
MESOCYCLONES TO DEVELOP DURING THE EVENING.
..DIAL/CORFIDI.. 03/15/2014
