SPC AC 240600

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0100 AM CDT TUE MAY 24 2016

   VALID 241200Z - 251200Z

   ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PORTIONS OF NORTHEASTERN
   COLORADO...WESTERN NEBRASKA...AND A SMALL PORTION OF SOUTHWEST SOUTH
   DAKOTA...

   ...THERE IS AN ENH RISK OF SVR TSTMS ACROSS PARTS OF THE TEXAS AND
   OKLAHOMA PANHANDLES...AND INTO WESTERN OKLAHOMA AND SOUTHWEST/SOUTH
   CENTRAL KANSAS...

   ...THERE IS A SLGT RISK OF SVR TSTMS COVERING MUCH OF THE CENTRAL
   AND INTO THE SRN PLAINS...

   ...THERE IS A MRGL RISK OF SVR TSTMS OVER MOST OF THE CENTRAL THIRD
   OF THE COUNTRY...

   ...SUMMARY...
   SEVERE THUNDERSTORMS ARE LIKELY TUESDAY AFTERNOON AND EVENING FROM
   THE NORTHEASTERN COLORADO AND WESTERN NEBRASKA VICINITY...SOUTH AND
   SOUTHEASTWARD ACROSS THE CENTRAL PLAINS AND INTO OKLAHOMA AND
   EASTERN PORTIONS OF THE TEXAS PANHANDLE.  THE PRIMARY THREAT IN
   THESE AREAS WILL BE VERY LARGE HAIL. OTHER SPORADIC MARGINALLY
   SEVERE STORMS ARE POSSIBLE OVER A WIDE AREA FROM THE UPPER AND
   MIDDLE MISSISSIPPI VALLEY SOUTHWARD INTO TEXAS.

   ...SYNOPSIS...
   AS AN UPPER LOW MOVES GRADUALLY NWD ACROSS THE MID-ATLANTIC REGION
   AND INTO NEW ENGLAND...A SECOND LOW/TROUGH WILL REMAIN IN PLACE OVER
   THE WRN STATES.  IN BETWEEN...A BROAD ZONE OF SWLY FLOW ALOFT WILL
   EXTEND FROM THE SWRN STATES NEWD INTO THE MID AND UPPER MS VALLEY
   REGION.

   AT THE SURFACE...THE MAIN FEATURE WITH RESPECT TO CONVECTIVE RISK
   WILL BE A BROAD LEE LOW...AND DRYLINE EXTENDING SWD ACROSS THE SRN
   HIGH PLAINS DURING THE AFTERNOON AND EVENING HOURS.

   ...CENTRAL HIGH PLAINS SEWD ACROSS MUCH OF NEB/KS/OK AND VICINITY...

   A VERY COMPLEX SCENARIO IS EVOLVING ACROSS THE PLAINS TODAY...AS
   STORMS NOW DEVELOPING OVER NERN CO AND INTO NRN KS ARE FORECAST TO
   GROW UPSCALE INTO AN MCS AND SHIFT ESEWD ACROSS THE KS/NRN OK
   VICINITY AND LATER INTO MO AND POSSIBLY AR.  EXACT
   EVOLUTION/TRACKING OF THIS CONVECTION WITH TIME REMAINS
   UNCERTAIN...AS WILL THE LOCATION OF REMNANT OUTFLOW -- COLLECTIVELY
   PROGGED TO BE SHIFTING SWD ACROSS KS INTO OK THROUGH THE DAY.  THE
   EVOLUTION OF THIS CONVECTION WILL ALTER BOTH THE THERMODYNAMIC
   ENVIRONMENT...AS WELL AS THE FAVORED ZONES FOR NEW/AFTERNOON
   CONVECTIVE INITIATION.

   WHILE ONGOING STORMS WITHIN THE ANTICIPATED MCS MAY POSSIBLY POSE A
   LOCAL/ISOLATED SEVERE RISK AT THE START OF THE PERIOD...AND POSSIBLY
   CONTINUING THROUGH THE DAY...TWO FAVORED AREAS FOR NEW STORM
   INITIATION APPEAR TO BE:

   1.  ALONG A DRYLINE MIXING EWD ACROSS THE TX PANHANDLE TOWARD WRN OK
   -- AND POSSIBLY IN PARTICULAR NEAR THE INTERSECTION OF THIS DRYLINE
   AND THE ANTICIPATED/SWD-MOVING CONVECTIVE BOUNDARY

   2.  ACROSS THE NERN CO/ERN WY VICINITY AS A VERY WEAK/SUBTLE
   MID-LEVEL TROUGH/VORT MAX CROSSES UT AND SHIFTS INTO WY/CO DURING
   THE AFTERNOON

   WITH CONTINUED ADVECTION OF VERY STEEP LAPSE RATES ALOFT INTO THE
   PLAINS ATOP A MOIST BOUNDARY LAYER...A VERY HIGH-CAPE ENVIRONMENT IS
   AGAIN ANTICIPATED E OF THE DRYLINE AND S OF AREAS CONTAMINATED BY
   ONGOING/PRIOR CONVECTION.  WEAKER -- BUT SUFFICIENT -- LOW-LEVEL
   MOISTURE ACROSS THE CENTRAL HIGH PLAINS SHOULD COMBINE WITH DIURNAL
   HEATING TO YIELD 1000 TO 2000 J/KG MIXED-LAYER CAPE IN THIS REGION.

   WITH MODERATE MID-LEVEL WSWLYS PERSISTING ACROSS THE CENTRAL U.S.
   AHEAD OF THE PERSISTENT WRN TROUGH...AND LOW-LEVEL SLYS
   BENEATH...SHEAR SUPPORTIVE OF ROTATING UPDRAFTS SUGGESTS SUPERCELLS.
   LARGE HAIL WILL LIKELY BE THE PRIMARY SEVERE THREAT ACROSS THE
   ENTIRE RISK AREA...THOUGH LOCALLY DAMAGING WINDS AND A COUPLE OF
   TORNADOES WILL ALSO BE POSSIBLE.  GREATEST TORNADO RISK WOULD LIKELY
   EXIST NEAR THE POTENTIAL CONVECTIVE OUTFLOW/DRYLINE
   INTERSECTION...WITH SECONDARY POTENTIAL OVER THE CENTRAL HIGH
   PLAINS.  

   SEVERE RISK WILL LIKELY CONTINUE THROUGH THE EVENING...WITH STORMS
   LIKELY GROWING UPSCALE -- POSSIBLY EVOLVING INTO MCS/S OVER THE
   SD/NEB VICINITY...AS WELL AS THE KS/OK/OZARKS REGION.

   ...TX...
   S OF THE RED RIVER/TX PANHANDLE...THUNDERSTORM DEVELOPMENT REMAINS
   UNCERTAIN DUE TO WEAK LARGE-SCALE SUBSIDENCE ASSOCIATED WITH
   SHORT-WAVE RIDGING ALOFT -- AND THUS A PERSISTENTLY CAPPED BOUNDARY
   LAYER.  ANY UPDRAFT WHICH WOULD DEVELOP/BECOME MAINTAINED WOULD --
   GIVEN VERY STEEP LAPSE RATES/STRONG INSTABILITY ABOVE THE CAPPING
   LAYER AND AMPLY WSWLY MID-LEVEL FLOW -- BECOME SEVERE...POSING A
   RISK FOR MAINLY LARGE HAIL.  HOWEVER...WITH THE NAM AND AVAILABLE
   CAM GUIDANCE DEPICTING A LACK OF CONVECTION...WILL MAINTAIN ONLY A
   CONDITIONAL/MRGL RISK ACROSS THIS AREA.

   ...UPPER MS VALLEY AREA...
   SHOWERS AND SCATTERED THUNDERSTORMS ARE FORECAST TO REDEVELOP ACROSS
   THE UPPER MS VALLEY/WRN UPPER GREAT LAKES AREA DURING THE
   AFTERNOON...AS MODEST AIRMASS DESTABILIZATION OCCURS INVOF A WEAK
   COOL FRONT PROGGED TO TRAIL ROUGHLY W-E ACROSS THE AREA.  MODERATE
   WLY MID-LEVEL FLOW COMBINED WITH AMPLE CAPE EXPECTED THROUGH PEAK
   DIURNAL HEATING SUGGESTS THAT HAIL AND/OR LOCALLY GUSTY WINDS WILL
   BE POSSIBLE THROUGH EARLY EVENING.

   ..GOSS/ROGERS.. 05/24/2016

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