SPC AC 030114
DAY 1 CONVECTIVE OUTLOOK CORR 1
NWS STORM PREDICTION CENTER NORMAN OK
0814 PM CDT SAT MAY 02 2009
VALID 030100Z - 031200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...LOWER TO MID MS VALLEY AND CNTRL GULF COAST STATES......
CORRECTED TO REVERSE ARROWS FOR 5 % LINES IN NC
...NE TX/FAR SRN AR/NRN LA/NCNTRL MS/NRN AL...
A SERIES OF SEVERE STORM CLUSTERS ONGOING FROM NEAR DALLAS EWD
ACROSS FAR SRN AR TO NEAR WINONA MS IS LOCATED ON A QUASI-STATIONARY
FRONTAL BOUNDARY WHERE THE RUC SHOWS INCREASING LOW-LEVEL
CONVERGENCE. THE AIRMASS SOUTH OF THE BOUNDARY IS MODERATELY
UNSTABLE WHICH COMBINED WITH STRONG LARGE-SCALE ASCENT ASSOCIATED
WITH AN APPROACHING SHORTWAVE TROUGH SHOULD SUSTAIN A SEVERE THREAT
ALONG THE BOUNDARY THROUGH LATE THIS EVENING. STRONG VERTICAL SHEAR
PROFILES ASSOCIATED WITH A 45 TO 50 KT MID-LEVEL JET CENTER ANALYZED
BY THE RUC OVER SERN AR WILL CONTINUE TO BE FAVORABLE FOR SUPERCELLS
AND BOWING LINE-SEGMENTS.
A WELL-DEVELOPED BOWING LINE-SEGMENT CURRENTLY ONGOING IN SW AR IS
LOCATED JUST NORTH OF THE GREATEST INSTABILITY AND IS LOCATED JUST
AHEAD OF A WELL-DEFINED VORTICITY MAX. THE BOW MAY BE THE START OF A
DERECHO WHICH IS FORECAST TO TRACK EWD ACROSS THE REMAINDER OF SRN
AR INTO WRN MS. SIGNIFICANT WIND DAMAGE AND A FEW TORNADOES WILL BE
LIKELY WITH THIS BOWING LINE-SEGMENT. IF A WELL-DEVELOPED SUPERCELL
CAN PERSIST AHEAD OF THE LINE...A STRONG TORNADO COULD OCCUR.
FURTHER EAST ACROSS NCNTRL MS...CELLS ARE DISCRETE AND SEVERAL
SUPERCELLS ARE ONGOING. INCREASING LOW-LEVEL FLOW THIS EVENING
SHOULD SUSTAIN A THREAT FOR A FEW TORNADOES FOR A FEW MORE HOURS.
THERMODYNAMIC AND SHEAR PROFILES SHOULD ALSO BE FAVORABLE FOR LARGE
HAIL AND ISOLATED WIND DAMAGE.
...CNTRL AND NORTH TX...
A COLD FRONT IS CURRENTLY MOVING SEWD THROUGH THE TX HILL COUNTRY
WITH THE RUC ANALYZING STRONG INSTABILITY AHEAD OF THE BOUNDARY
ALONG THE INTERSTATE-35 CORRIDOR. AS LARGE-SCALE ASCENT INCREASES
AHEAD OF AN APPROACHING SHORTWAVE-TROUGH...ISOLATED TO SCATTERED
THUNDERSTORM INITIATION SHOULD OCCUR LATE THIS EVENING ALONG THE
INSTABILITY AXIS. PROFILERS AND WSR-88D VWPS CURRENTLY SUGGEST
MODERATE TO STRONG VERTICAL SHEAR EXISTS IN ECNTRL TX. THIS ALONG
WITH STEEP MID-LEVEL LAPSE RATES SHOULD BE FAVORABLE FOR SUPERCELLS
WITH LARGE HAIL POTENTIAL. AS STORMS EXPAND EWD ACROSS PARTS OF EAST
AND NE TX DURING THE OVERNIGHT PERIOD...AN ISOLATED WIND DAMAGE AND
TORNADO THREAT SHOULD ALSO DEVELOP.
...ERN CAROLINAS...
A CLUSTER OF THUNDERSTORMS IS ONGOING IN SRN NC AND ERN SC NEAR A
MAXIMUM IN INSTABILITY ANALYZED BY THE RUC. THE LATEST REGIONAL
WSR-88D VWPS SHOW ABOUT 30 KT OF VERTICAL SHEAR. ALTHOUGH THE
THERMODYNAMIC AND SHEAR PROFILES SHOULD SUPPORT AN ISOLATED SEVERE
THREAT FOR ANOTHER 1 TO 2 HOURS...WEAK LOW-LEVEL CONVERGENCE AND
FALLING SFC TEMPS SHOULD RESULT IN AN OVERALL DECREASE IN THE SEVERE
THREAT.
..BROYLES.. 05/03/2009
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0600Z
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