SPC AC 281633

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1133 AM CDT THU MAY 28 2015

   VALID 281630Z - 291200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PORTIONS OF THE TX SOUTH
   PLAINS/BIG COUNTRY/PERMIAN BASIN VICINITY...

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM PORTIONS OF NEB SWD TO THE
   RIO GRANDE VALLEY...

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS MUCH OF NEW ENGLAND AND
   INTO SERN NY/NERN PA/NRN NJ...

   ...THERE IS A MRGL RISK OF SVR TSTMS ENCOMPASSING MUCH OF THE PLAINS
   AND INTO THE LOWER MS VALLEY/CENTRAL GULF COASTAL AREA...

   ...THERE IS A MRGL RISK OF SVR TSTMS SURROUNDING THE NEW ENGLAND
   SLIGHT RISK AREA...

   ...SUMMARY...
   SCATTERED SEVERE THUNDERSTORMS WITH LARGE HAIL...WIND DAMAGE...AND
   PERHAPS A TORNADO OR TWO WILL DEVELOP ACROSS PARTS OF THE SOUTHERN
   AND CENTRAL HIGH PLAINS TODAY. OTHER STRONG TO SEVERE THUNDERSTORMS
   ARE FORECAST ACROSS PARTS OF NEW ENGLAND THIS AFTERNOON WHERE STRONG
   WIND GUSTS WILL BE POSSIBLE.

   ...SYNOPSIS...
   BROAD MID-LEVEL TROUGHING...COMPRISED OF SEVERAL SMALLER-SCALE
   CIRCULATIONS -- BOTH CONVECTIVE AND SYNOPTIC -- WILL CONTINUE
   SHIFTING ACROSS THE ROCKIES AND PLAINS STATES TODAY...WITH A
   SIMILARLY BROAD ZONE OF ENHANCED MID-LEVEL WLYS AFFECTING THE
   CENTRAL AND SRN ROCKIES/CENTRAL AND SRN PLAINS.  DOWNSTREAM...
   RIDGING WILL PREVAIL OVER MUCH OF THE E...WHILE STILL FARTHER
   DOWNSTREAM A VIGOROUS SHORT-WAVE TROUGH CROSSES SERN CANADA AND THE
   ADJACENT NERN CONUS.

   AT THE SURFACE...A COLD FRONT WILL CONTINUE SHIFTING EWD ACROSS THE
   NORTHEAST IN CONJUNCTION WITH THE AFOREMENTIONED SHORT-WAVE FEATURE.
    FARTHER W...A SURFACE TROUGH IS PROGGED TO SHIFT GRADUALLY EWD
   ACROSS WRN PORTIONS OF THE PLAINS...WITH SEVERAL BOUNDARIES/OUTFLOWS
   EVIDENT ACROSS THE WARM SECTOR FROM KS SWD TO TX.

   ...WRN PORTIONS OF THE CENTRAL AND SRN PLAINS...
   A VERY COMPLEX CONVECTIVE EVOLUTION IS EXPECTED OVER THE CENTRAL SRN
   PLAINS VICINITY TODAY...AS SEVERAL CLUSTERS OF ONGOING STORMS
   PERSIST ATTM...ALONG WITH WIDESPREAD CLOUD COVER AND SEVERAL 
   CONVECTIVE BOUNDARIES ARE EVIDENT ACROSS KS/OK/TX.  A LARGE
   CONVECTIVE SYSTEM CROSSING THE ERN OK VICINITY HAS TEMPORARILY
   STABILIZED THE AIRMASS OVER OK...BUT VERY STEEP LAPSE RATES ALOFT
   AND A MOIST BOUNDARY LAYER WILL COMBINE WITH DAYTIME HEATING TO
   RESULT IN POCKETS OF STRONGLY UNSTABLE AIR.  ONE PARTICULAR AREA OF
   ENHANCED DESTABILIZATION WILL OCCUR OVER PORTIONS OF THE WRN HALF OF
   TX...PARTICULARLY AWAY FROM ONGOING CLUSTERS OF CONVECTION.

   GIVEN THE POTENTIALLY VOLATILE AIRMASS LIKELY TO EVOLVE IN AREAS
   WHERE HEATING IS MAXIMIZED...THE KINEMATIC ENVIRONMENT -- FEATURING
   30 TO 35 KT MID-LEVEL WLYS SPREADING ATOP GENERALLY SELY
   BOUNDARY-LAYER WINDS -- WILL SUPPORT ROTATING/SUPERCELL STORMS. 
   ALONG WITH RISK FOR LOCALLY DAMAGING WINDS...VERY LARGE HAIL WILL BE
   POSSIBLE -- PARTICULARLY ACROSS PORTIONS OF THE WRN HALF OF TX.  A
   FEW TORNADOES WILL ALSO BE POSSIBLE -- PARTICULARLY IN
   VORTICITY-RICH AREAS NEAR AND N OF NWRN/WRN TX CONVECTIVE OUTFLOWS
   WHERE LOW-LEVEL FLOW IS MOST BACKED.

   WITH TIME...STORMS WILL LIKELY EVOLVE INTO ONE OR MORE LARGE
   MCS...WITH HEAVY RAIN POTENTIAL TO INCREASE ALONG WITH ONGOING
   SEVERE THREAT.

   SEVERE RISK WILL LIKELY REMAIN SOMEWHAT MORE ISOLATED NWD INTO NRN
   PORTIONS OF THE OUTLOOK AREA...WHERE A SLIGHTLY LESS
   UNSTABLE/SLIGHTLY LESS-SHEARED ENVIRONMENT IS EXPECTED. 
   STILL...STORMS DEVELOPING INVOF THE ADVANCING TROUGH MOVING OUT OF
   THE CENTRAL HIGH PLAINS WILL BE CAPABLE OF PRODUCING LARGE HAIL AND
   DAMAGING WINDS LOCALLY.

   ...NEW ENGLAND INTO SERN NY/NWRN PA/NRN NJ...
   THUNDERSTORMS HAVE BEGUN DEVELOPING FROM WRN AND CENTRAL ME SWWD
   INTO THE CHAMPLAIN VALLEY...AND WILL CONTINUE TO INCREASE IN
   COVERAGE THIS AFTERNOON ACROSS THE RISK AREA AHEAD OF AN ADVANCING
   COLD FRONT.  DESTABILIZATION OF A MOIST BOUNDARY LAYER ACROSS THE
   AREA HAS PUSHED MIXED-LAYER CAPE INTO THE 500 TO 1000 J/KG RANGE AT
   MIDDAY...WITH ADDITIONAL AFTERNOON HEATING/DESTABILIZATION TO
   SUPPORT THE ANTICIPATED CONVECTIVE INCREASE.  

   DEEP-LAYER FLOW REMAINS FAIRLY STRONG ACROSS THE AREA /40 TO 50 KT
   WSWLYS INDICATED AT MID LEVELS PER VWP AND RAOB DATA/ ON THE SRN
   SIDE OF THE SHORT-WAVE TROUGH SHIFTING NEWD ACROSS THE SRN QUEBEC
   VICINITY.  THIS WILL SUPPORT ORGANIZED CONVECTION -- MAINLY IN THE
   FORM OF LINEAR/BOWING SEGMENTS BUT ALSO WITH POTENTIAL FOR ROTATION
   IN STRONGER CELLS.  LOCALLY DAMAGING WINDS WILL ACCOMPANY STRONGER
   STORMS/LINE SEGMENTS AS CONVECTION SHIFTS EWD TOWARD THE NEW ENGLAND
   COAST -- IN CONJUNCTION WITH THE SURFACE FRONT -- LATER THIS
   AFTERNOON.

   ..GOSS.. 05/28/2015

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z