SPC AC 200559

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1259 AM CDT WED MAY 20 2015

   VALID 211200Z - 221200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS IN THE TX BIG BEND...

   ...THERE IS A SLGT RISK OF SVR TSTMS IN PARTS OF ERN NC/SC...

   ...THERE IS A MRGL RISK OF SVR TSTMS ACROSS THE RIO GRANDE VALLEY...

   ...THERE IS A MRGL RISK OF SVR TSTMS IN PARTS OF CNTRL/ERN NC/SC...

   ...SUMMARY...
   ISOLATED SEVERE STORMS ARE MOST PROBABLE OVER THE BIG BEND AREA OF
   WEST TEXAS AND PARTS OF THE EASTERN CAROLINAS...MAINLY ON THURSDAY
   AFTERNOON.

   ...SYNOPSIS...
   A LOW-AMPLITUDE SHORTWAVE TROUGH SHOULD TRACK FROM THE CNTRL GREAT
   LAKES TO THE NEW ENGLAND COAST...AS A VIGOROUS UPSTREAM IMPULSE
   MOVES FROM JAMES BAY INTO QUEBEC. THESE FEATURES WILL AID IN A BELT
   OF STRONG MID-LEVEL W/SWLYS FROM THE OH VALLEY TO THE
   MID-ATLANTIC/NORTHEAST. IN THE SOUTHWEST...A LEAD MID-LEVEL IMPULSE
   SHOULD EJECT FROM NEAR BAJA CA TO THE SRN ROCKIES...WHILE AN
   UPSTREAM IMPULSE APPROACHES THE SRN CA/BAJA CA BORDER AREA NEAR
   12Z/FRI. AT THE SURFACE...A WEAK FRONTAL WAVE SHOULD TRACK ALONG THE
   BAROCLINIC ZONE OVER THE CAROLINAS DURING THE DAY AND MOVE OFFSHORE
   BY EVENING. TRAILING PORTION OF A COLD FRONT SHOULD DECAY OVER PARTS
   OF S TX AS A BROAD ANTICYCLONE SHIFTS FROM THE CNTRL HIGH PLAINS TO
   THE OZARK PLATEAU.

   ...SE NM/W TX...
   THE 850 MB BAROCLINIC ZONE SHOULD BE INITIALLY WELL-DIVORCED TO THE
   N FROM THE DECAYING SURFACE FRONT /THE LATTER LIKELY MODULATED BY
   CONVECTIVE OUTFLOW ON D1/. SELY FLOW WILL BE MAINTAINED BETWEEN
   THESE FEATURES RESULTING IN 60S SURFACE DEW POINTS PERSISTING FROM
   THE BIG BEND TO EDWARDS PLATEAU THROUGH THE AFTERNOON AND GRADUALLY
   ADVECTING NWWD THU NIGHT. UPSLOPE FLOW/ISENTROPIC ASCENT SHOULD
   FAVOR SCATTERED STORMS FORMING BY LATE AFTERNOON INTO EVENING...AS
   THE LEADING EDGE OF STRENGTHENING MID-LEVEL SWLYS REACHES THE
   TRANS-PECOS. THIS TYPE OF SETUP SHOULD SUPPORT A RELATIVELY SMALL
   CORRIDOR OF POTENTIALLY PERSISTENT SUPERCELLS NEAR THE BIG BEND AREA
   WITH ALL SEVERE HAZARDS POSSIBLE...AND A MORE TRANSIENT/PREDOMINANT
   HAIL RISK FARTHER N.

   ...CAROLINA COASTAL PLAIN...
   AHEAD OF THE WEAK CYCLONE...A MODESTLY UNSTABLE AIR MASS IS
   ANTICIPATED BY EARLY AFTERNOON AS DIABATIC HEATING OCCURS WITHIN A
   WARM SECTOR LARGELY CHARACTERIZED BY MIDDLE TO UPPER 60S SURFACE DEW
   POINTS. GUIDANCE CONTINUES TO DIFFER WITH THE NRN EXTENT OF AT LEAST
   WEAK SURFACE-BASED INSTABILITY...WHICH IS WHERE STRONGER DEEP SHEAR
   WILL LIE ON THE PERIPHERY OF THE MID-LEVEL JET. HOWEVER...GUIDANCE
   HAS TRENDED TOWARDS DEPICTING FASTER 700-500 MB WLYS AND THIS SHOULD
   SUPPORT POTENTIAL FOR AN ORGANIZED SEVERE RISK WITH WIND AS THE
   PRIMARY HAZARD. 

   ...BRUSH COUNTRY/DEEP S TX...
   LOW/DEEP-LAYER FLOW WILL BE WEAK BUT VEERING WIND PROFILES WITH
   HEIGHT COULD FOSTER A COUPLE MULTICELL CLUSTERS IN THE AFTERNOON
   WITH A PERSISTENT MODERATE TO STRONGLY UNSTABLE AIR MASS S OF THE
   DECAYING FRONT. LOCALIZED SEVERE HAIL/WIND SHOULD BE THE MAIN
   HAZARDS.

   ..GRAMS.. 05/20/2015

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   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z