DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1150 PM CST MON NOV 14 2011
VALID 151200Z - 161200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS
AND LOWER MS VALLEY...
...TX COASTAL PLAINS/SABINE RIVER VALLEY/LOWER MS VALLEY...
AN UPPER-LEVEL TROUGH WILL MOVE ACROSS THE RIO GRANDE VALLEY THIS
MORNING WITH A LINE OF THUNDERSTORMS ONGOING ON THE TX COASTAL
PLAINS AT 12Z. THIS LINE IS FORECAST TO MOVE EWD ACROSS SCNTRL AND
SE TX DURING THE MORNING JUST AHEAD OF A WELL-DEFINED VORTICITY MAX.
FORECAST SOUNDINGS ON THE TX COASTAL PLAINS AT 15Z TO 18Z SHOW A
MODERATELY UNSTABLE AIRMASS WITH SFC DEWPOINTS IN THE UPPER 60S F
AND 0-6 KM SHEAR VALUES IN THE 40 TO 50 KT RANGE. THIS ENVIRONMENT
MAY SUPPORT A WIND DAMAGE THREAT AS A LINEAR MCS MOVES EWD INTO THE
CORPUS CHRISTI AND HOUSTON AREAS AROUND MIDDAY. THE UPPER-LEVEL
TROUGH AND ASSOCIATED MID-LEVEL JET MAX IS FORECAST TO MOVE INTO THE
LOWER MS VALLEY THIS AFTERNOON. AHEAD OF THE TROUGH...A BAND OF
LARGE-SCALE ASCENT AND A SLOWLY DESTABILIZING AIRMASS MAY ENABLE THE
CONVECTIVE LINE TO PERSIST THIS AFTERNOON WITH A WIND DAMAGE THREAT
DEVELOPING EWD INTO LA AND MS. THE MAIN ISSUE WITH THIS FORECAST IS
THAT THE MODELS DO NOT SHOW MUCH FOCUS WITH THIS SYSTEM. THIS
SUGGESTS THE WIND DAMAGE THREAT COULD BE INTERMITTENT AND DEPENDENT
UPON HOW MUCH DESTABILIZATION OCCURS ACROSS THE LOWER MS VALLEY.
THERE IS A POSSIBILITY THAT THE SEVERE THREAT COULD BE SPLIT INTO
SEPARATE AREAS WHERE INSTABILITY BECOMES MAXIMIZED.
THUNDERSTORM DEVELOPMENT WILL ALSO BE POSSIBLE THIS AFTERNOON
FURTHER NORTH ACROSS THE ARKLATEX AND IN THE SRN OZARKS.
HOWEVER...MODEL FORECASTS SHOW A WEAKNESS IN DEEP LAYER SHEAR ACROSS
MUCH OF AR AND NE TX SUGGESTING THE WIND DAMAGE THREAT SHOULD REMAIN
MARGINAL THERE. FURTHER TO THE EAST ACROSS THE TN VALLEY...FORECAST
SOUNDINGS BY LATE AFTERNOON SHOW STRONG DEEP LAYER SHEAR DUE TO A
BELT OF 50 TO 60 KT WINDS IN THE MID-LEVELS. THIS ALONG WITH WEAK
DESTABILIZATION AND 30 TO 40 KT AT 850 MB MAY BE ENOUGH FOR A
MARGINAL WIND DAMAGE THREAT AS THUNDERSTORMS DEVELOP IN THE LATE
AFTERNOON AND EARLY EVENING.
..BROYLES/GARNER.. 11/15/2011
Bookmarks