SPC AC 160600

   DAY 2 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1200 AM CST TUE DEC 16 2014

   VALID 171200Z - 181200Z

   ...NO SVR TSTM AREAS FORECAST...

   ...SUMMARY...
   THE RISK OF SEVERE STORMS CURRENTLY APPEARS NEGLIGIBLE FOR WEDNESDAY
   THROUGH WEDNESDAY NIGHT.

   ...SYNOPSIS/SOUTHWEST INTO SOUTHERN PLAINS...
   DESPITE AN APPARENT TENDENCY FOR INCREASING BLOCKING WITH THE
   DEVELOPMENT OF A PROMINENT UPPER HIGH CENTER TO THE EAST OF THE
   CANADIAN ROCKIES...WITHIN THE NORTHERN BRANCH OF SPLIT WESTERLIES
   EMERGING FROM THE PACIFIC...THE LARGE-SCALE PATTERN APPEARS LIKELY
   TO REMAIN PROGRESSIVE THROUGH THIS PERIOD.  MODELS CONTINUE TO
   INDICATE THAT A SIGNIFICANT PERTURBATION EMANATING FROM AN INTENSE
   MID/UPPER JET OVER THE WESTERN AND CENTRAL PACIFIC WILL SUPPORT
   STRONG LOW/MID-LEVEL CYCLOGENESIS WHILE PROGRESSING ACROSS THE
   NORTHEASTERN PACIFIC THROUGH WEDNESDAY/WEDNESDAY NIGHT.  AS THIS
   OCCURS...AND DOWNSTREAM RIDGING BUILDS ALONG THE NORTH AMERICAN
   PACIFIC COAST...AMONG OTHER INFLUENCES...LARGE-SCALE TROUGHING IN
   THE SOUTHERN STREAM IS FORECAST TO SHIFT INLAND OF THE CALIFORNIA
   COAST.

   WITHIN THIS LATTER CYCLONIC FLOW REGIME...IT NOW APPEARS THAT ONE
   SIGNIFICANT IMPULSE WILL PROGRESS INLAND ACROSS SOUTHERN CALIFORNIA
   BY 12Z WEDNESDAY...BEFORE WEAKENING WHILE CONTINUING EASTWARD INTO
   THE SOUTHERN ROCKIES THROUGH THE REMAINDER OF THE PERIOD.  IN ITS
   WAKE...ANOTHER SIGNIFICANT IMPULSE MAY DIG MORE STRONGLY SOUTHWARD
   OR SOUTHEASTWARD...TOWARD THE LOWER COLORADO VALLEY AND NORTHERN
   BAJA.  DOWNSTREAM...ANOTHER IMPULSE IS FORECAST TO MIGRATE NORTHEAST
   OF THE SOUTHERN ROCKIES...THROUGH THE CENTRAL PLAINS BY LATE
   WEDNESDAY NIGHT.

   IN RESPONSE TO THESE DEVELOPMENTS...COOLING ALOFT PROBABLY WILL
   CONTRIBUTE TO STEEPENING MID-LEVEL LAPSE RATES OVER A FAIRLY BROAD
   AREA FROM THE SOUTHWEST THROUGH THE SOUTHERN PLAINS.  AT THE SAME
   TIME...30 TO 40 KT SOUTHERLY 850 MB FLOW FORECAST TO DEVELOP ACROSS
   THE SOUTHERN PLAINS IS EXPECTED TO CONTRIBUTE TO SUBSTANTIVE GULF
   MOISTURE RETURN.  HOWEVER...TO THE NORTH OF A REMNANT SURFACE
   FRONTAL ZONE ACROSS THE LOWER RIO GRANDE VALLEY INTO MID/UPPER TEXAS
   COASTAL AREAS...THIS WILL OCCUR ABOVE A COOL/STABLE SURFACE BASED
   LAYER.  CAPE IS EXPECTED TO BECOME SUFFICIENT FOR SCATTERED
   THUNDERSTORM DEVELOPMENT WITH THE AID OF FORCING FOR LARGE-SCALE
   ASCENT.  BUT THE RISK FOR STORMS CAPABLE OF PRODUCING SEVERE HAIL
   STILL SEEMS NEGLIGIBLE AT THIS TIME...AS STRONGER MID-LEVEL FORCING
   GENERALLY SHIFTS WELL NORTH OF THE MORE FAVORABLE MOISTURE RETURN
   AND DESTABILIZATION.

   ALTHOUGH MOIST INFLOW OFF THE PACIFIC IS EXPECTED TO BECOME CUT OFF
   NEAR THE SOUTHERN CALIFORNIA COAST EARLY IN THE
   PERIOD...DESTABILIZATION IS STILL EXPECTED TO BECOME SUFFICIENT TO
   SUPPORT THE RISK FOR WIDELY SCATTERED THUNDERSTORM ACTIVITY ACROSS
   MUCH OF THE SOUTHWEST DURING THE DAY WEDNESDAY.

   ..KERR.. 12/16/2014

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

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