SPC AC 210614
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1214 AM CST FRI NOV 21 2014
VALID 221200Z - 231200Z
...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF CNTRL TX AND
THE TX GULF COAST...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN PLAINS
AND LOWER MS VALLEY...
...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...LOWER MS VALLEY AND CNTRL GULF COAST...
...SUMMARY...
NUMEROUS STRONG TO SEVERE STORMS ARE EXPECTED TO DEVELOP FROM
CENTRAL TEXAS SOUTHEASTWARD TO THE TEXAS GULF COAST ON SATURDAY.
OTHER SEVERE STORMS ARE POSSIBLE FROM SOUTHERN LOUISIANA INTO
SOUTHERN MISSISSIPPI SATURDAY NIGHT. PRIMARY THREATS WILL BE
DAMAGING WIND AND A FEW TORNADOES...BUT LARGE HAIL WILL ALSO BE
POSSIBLE MAINLY OVER TEXAS.
...SRN PLAINS/LOWER MS VALLEY...
AN UPPER-LEVEL TROUGH WILL MOVE EWD ACROSS NRN MEXICO ON SATURDAY AS
A LOW-LEVEL JET REMAINS OVER SRN PLAINS. AT THE SFC...SOUTH TO
SOUTHEASTERLY FLOW ACROSS THE SRN PLAINS WILL MAINTAIN LOW-LEVEL
MOISTURE ACROSS MUCH OF CNTRL AND ERN TX WHERE DEWPOINTS ARE
FORECAST TO BE IN THE LOWER TO MID 60S F. ELEVATED THUNDERSTORMS MAY
BE ONGOING AT THE START OF THE PERIOD ON THE NOSE OF THE LOW-LEVEL
JET IN NORTH TX AND SRN OK. AS SFC TEMPS WARM DURING THE
DAY...SCATTERED THUNDERSTORM DEVELOPMENT IS EXPECTED TO TAKE PLACE
SWD ACROSS THE TX HILL COUNTRY AND SEWD ONTO THE TX COASTAL PLAIN.
SEVERAL THUNDERSTORM CLUSTERS OR PERHAPS MCS DEVELOPMENT MAY OCCUR
DURING THE LATE AFTERNOON INTO THE EVENING.
MODEL FORECASTS SUGGEST THE GREATEST CHANCE FOR ORGANIZED CONVECTION
WILL BE JUST AHEAD OF THE UPPER-LEVEL TROUGH EARLY SATURDAY EVENING
FROM THE TX COASTAL PLAINS SEWD TO THE TX GULF COAST. FORECAST
SOUNDINGS AT SAN ANTONIO AND HOUSTON AT 00Z/SUN SHOW MLCAPE NEAR
1000 J/KG WITH 0-6 KM SHEAR OF 50 TO 60 KT. THIS ENVIRONMENT SHOULD
SUPPORT SUPERCELL DEVELOPMENT WITH STORMS THAT HAVE ACCESS TO
MAXIMIZED INSTABILITY. THE POTENTIAL FOR SUPERCELLS AND POSSIBLY A
TORNADO OR TWO MAY BE GREATEST ALONG THE MIDDLE TX COAST JUST AHEAD
OF A 60 TO 70 KT MID-LEVEL JET ROUNDING THE BASE OF THE TROUGH.
SUPERCELLS MAY ALSO PRODUCE ISOLATED LARGE HAIL. SOME MODELS SUGGEST
THAT A LINE OF STRONG TO SEVERE STORMS WILL DEVELOP IN CNTRL TX JUST
AHEAD OF THE APPROACHING UPPER-LEVEL TROUGH. IF THIS SCENARIO PANS
OUT...THEN A WIND DAMAGE THREAT WOULD DEVELOP LATE SATURDAY
AFTERNOON MOVING EWD FROM THE TX HILL COUNTRY TO THE VICTORIA AND
HOUSTON AREA WHERE A 30 PERCENT SEVERE PROBABILITY HAS BEEN
MAINTAINED.
...LOWER MS VALLEY...
AN UPPER-LEVEL TROUGH WILL MOVE FROM NRN MEXICO INTO THE RIO GRANDE
VALLEY ON SATURDAY. LOW-LEVEL MOISTURE ADVECTION AHEAD OF THE
APPROACHING SYSTEM SHOULD INCREASE SFC DEWPOINTS ACROSS THE LOWER MS
VALLEY INTO THE LOWER TO MID 60S F. A SUBTLE LEAD SHORTWAVE TROUGH
IN THE CNTRL GULF COAST STATES LATE SATURDAY AFTERNOON MAY PROVIDE
ENOUGH LARGE-SCALE ASCENT FOR ISOLATED TO SCATTERED THUNDERSTORM
DEVELOPMENT. MODERATE INSTABILITY NEAR THE COAST ALONG WITH ABOUT 50
KT OF DEEP-LAYER SHEAR EVIDENT ON FORECAST SOUNDINGS SHOULD BE
ENOUGH FOR A SEVERE THREAT FROM LATE SATURDAY AFTERNOON THROUGH
SATURDAY NIGHT. ALTHOUGH A TORNADO THREAT COULD DEVELOP WITH
ISOLATED ROTATING CELLS THAT MOVE ONSHORE...THE GREATER THREAT COULD
BE FOR WIND DAMAGE AS A LINE OF STRONG STORMS MOVES INTO THE REGION
FROM THE WEST SATURDAY NIGHT.
..BROYLES.. 11/21/2014
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
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