Post by siagreg on Nov 28, 2016 18:50:53 GMT -6
MESOSCALE DISCUSSION 1834
NWS STORM PREDICTION CENTER NORMAN OK
0636 PM CST MON NOV 28 2016
AREAS AFFECTED...PORTIONS OF SOUTHWEST AL...SOUTHEAST MS...SOUTHEAST
LA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 290036Z - 290300Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...THE RISK FOR SEVERE THUNDERSTORMS AND PERHAPS A COUPLE OF
TORNADOES WILL CONTINUE SPREADING EASTWARD TONIGHT...AND THIS COULD
WARRANT NEW WATCH ISSUANCE.
DISCUSSION...LOW-LEVEL MOISTENING CONTINUES TO THE SOUTH OF A MERGED
SQUALL LINE/SURFACE TROUGH EXTENDING FROM EAST-CENTRAL MS TO
SOUTHWEST LA. WHERE SURFACE WINDS HAVE NOT APPRECIABLY VEERED...
SUFFICIENT ASCENT MAY CONTINUE TO FOSTER THUNDERSTORM CLUSTERS
WITHIN THE MOISTENING BOUNDARY LAYER THROUGH THE OVERNIGHT HOURS...AS
DEWPOINTS CLIMB THROUGH THE LOWER/MIDDLE 60S. BUOYANCY SHOULD REMAIN
RATHER LIMITED AS NOCTURNAL COOLING OCCURS...WHILE THE STRONGEST
PRESSURE RISE/FALL COUPLET IS ANALYZED WELL TO THE NORTH OF THE
REGION. REGARDLESS...SUFFICIENT ASCENT WITHIN THE RIGHT-ENTRANCE
REGION OF A HIGH-LEVEL SPEED MAXIMUM WILL CONTINUE TO RESIDE OVER
THE AREA THROUGH THE OVERNIGHT HOURS FOR A POSSIBLE PERSISTENT RISK
OF MATURING CONVECTION ALONG LOW-LEVEL CONFLUENCE AXES.
GIVEN THE ABUNDANT DEEP SHEAR -- E.G....EFFECTIVE SHEAR AROUND 60 KT
PER THE 00Z LIX RAOB -- ORGANIZED CONVECTION INCLUDING SUPERCELL
STRUCTURES COULD CONTINUE THROUGH THE OVERNIGHT HOURS. DAMAGING WIND
GUSTS MAY OCCUR. STRONG LOW-LEVEL SHEAR AIDED BY A VERTICALLY
VEERING WIND PROFILE MAY SUPPORT THE RISK FOR A COUPLE OF TORNADOES.
ULTIMATELY...WITH THE STRONGEST LARGE-SCALE UPWARD MOTION CONTINUING
TO DEPART MORE APPRECIABLE BUOYANCY...AND GIVEN THE POOR MID-LEVEL
LAPSE RATES SAMPLED BY THE LIX RAOB...THERE IS UNCERTAINTY REGARDING
THE SUSTAINABILITY OF DEEP CONVECTION THROUGH THE OVERNIGHT HOURS.
CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED.
..COHEN/HART.. 11/29/2016
However, tomorrow might be a different story.
