MESOSCALE DISCUSSION 0472
NWS STORM PREDICTION CENTER NORMAN OK
0428 AM CDT WED APR 27 2016
AREAS AFFECTED...PORTIONS NRN/WRN LA...SE/S-CENTRAL TX.
CONCERNING...SEVERE THUNDERSTORM WATCH 113...
VALID 270928Z - 271100Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 113
CONTINUES.
SUMMARY...MOST OF WW 113 MAY BE CLEARED BEHIND LINE AND/OR ALLOWED
TO EXPIRE AS SCHEDULED. MRGL SVR THREAT MAY STILL EXIST A COUPLE
HOURS BEYOND INITIAL WW WITH BOWING SEGMENTS ACROSS PORTIONS SE
TX...ACROSS TOLEDO BEND RESERVOIR REGION INTO WRN LA. NEW WW DOES
NOT APPEAR LIKELY ATTM...GIVEN LIMITED COVERAGE AND MRGL NATURE OF
THREAT...HOWEVER LOCAL EXTENSION IS BEING DONE FOR SOME COUNTIES IN
PROJECTED PATH OF SE TX CONVECTION.
DISCUSSION...AS OF 915Z...TWO PRIMARY/WELL-ORGANIZED BOWING SEGMENTS
HAVE DISTILLED FROM EARLIER EXTENSIVE QLCS -- ONE APCHG OCH/LFK AND
ANOTHER APCHG UTS/CXO CORRIDOR. EACH IS INTERACTING WITH...AND AT
LEAST PARTLY BEHIND...GUST FRONTS FROM EARLIER ACTIVITY. SFC
MESOANALYSIS SHOWS 4-5 MB/2-HR PRESSURE RISES WITH THESE SEGMENTS.
PRIND AREA OF 50+ KT INBOUND VELOCITIES APPARENT IN RADAR DATA
ATOP/ABOVE BOUNDARY LAYER CONTAINS CONSIDERABLE HORIZONTAL
MOMENTUM...BUT THAT COMBINATION OF CONTINUING/PRECONVECTIVE SFC
DIABATIC COOLING AND GUST-FRONT-INDUCED STABILIZATION FROM EARLIER
CONVECTION WILL SUBSTANTIALLY MITIGATE POTENTIAL FOR DOWNWARD
MOMENTUM TRANSFER. THIS IS REFLECTED TO SOME EXTENT IN MODIFIED RAP
SOUNDINGS SHOWING INCREASING MLCINH WITH EWD EXTENT AWAY FROM THIS
CONVECTION...WITHIN FREE WARM SECTOR. SRN SEGMENT PRODUCED SUB-SVR
GUSTS DURING PAST HOUR -- E.G. 43 AND 44 KT AT CLL AND 11R
RESPECTIVELY AND LESS AT SURROUNDING OBS SITES. STILL...ISOLATED
DAMAGING GUSTS APCHG SVR LIMITS ARE POSSIBLE EWD FROM ONGOING BOWING
SEGMENTS AS LOCALIZED VERTICAL CIRCULATIONS PROPEL STG WINDS THROUGH
STABLE LAYER TO SFC.
THOUGH CONVECTION FARTHER W ACROSS S-CENTRAL TX IS WELL BEHIND SFC
GUST FRONT...ISOLATED HAIL NEAR SVR LIMITS STILL IS POSSIBLE.
..EDWARDS.. 04/27/2016
ATTN...WFO...LCH...SHV...HGX...CRP...EWX...