Apr 18, 2015 0600 UTC Day 1 Convective Outlook

 DAY 1 CONVECTIVE OUTLOOK  

   NWS STORM PREDICTION CENTER NORMAN OK
   1241 AM CDT SAT APR 18 2015

   VALID 181200Z - 191200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL/SRN PLAINS
   INTO THE CNTRL GULF STATES...

   ...THERE IS A MRGL RISK OF SVR TSTMS IMMEDIATELY SURROUNDING THE
   SLGT RISK...

   ...SUMMARY...
   SCATTERED STRONG/LOCALLY SEVERE THUNDERSTORMS CAPABLE OF PRODUCING
   HAIL AND LOCALLY DAMAGING WINDS WILL BE POSSIBLE SATURDAY FROM THE
   CENTRAL PLAINS SOUTHWARD ACROSS TEXAS...AND EASTWARD ACROSS THE GULF
   COASTAL STATES.

   ...CENTRAL/SRN PLAINS...

   BROAD REGION OF MID-LEVEL HEIGHT FALLS WILL OVERSPREAD THE PLAINS AS
   CO UPPER LOW...AND ASSOCIATED TROUGH SHIFT INTO THE HIGH PLAINS
   DURING THE AFTERNOON HOURS.  MODEST MID-LEVEL FLOW SHOULD EXTEND
   ACROSS THE WARM SECTOR SUCH THAT ANY STORMS THAT DEVELOP FROM
   NEBRASKA...SWD INTO TX WILL BE SUFFICIENTLY SHEARED FOR POTENTIAL
   STORM ORGANIZATION.  LATEST THINKING IS THE PRIMARY FOCI FOR
   CONVECTIVE DEVELOPMENT SHOULD BE ALONG A WARM FRONT DRAPED ACROSS
   THE CNTRL PLAINS...AND ALONG DRY LINE THAT WILL EXTEND SWD FROM SFC
   LOW OVER WRN KS INTO THE EDWARDS PLATEAU OF WEST TX.  LATEST MODEL
   GUIDANCE SUGGESTS STRONG BOUNDARY-LAYER HEATING WILL ALLOW SFC-3KM
   LAPSE RATES TO EXCEED 9 C/KM WEST OF THE DRY LINE AS SFC
   TEMPERATURES WARM THROUGH THE 70S.  CONVECTION SHOULD EASILY DEVELOP
   AHEAD OF SFC LOW WITHIN WARM ADVECTION ZONE OVER THE CNTRL
   PLAINS...POSSIBLY DEVELOPING BY 20Z.  DRY LINE INITIATION MAY BE
   DELAYED A FEW HOURS AS CONVECTIVE TEMPERATURES MAY NOT BE BREACHED
   UNTIL 22Z.  SFC-6KM SHEAR CERTAINLY FAVORS SUPERCELL DEVELOPMENT AND
   GREATEST SEVERE THREAT SHOULD BE LARGE HAIL.  ALTHOUGH...SOMEWHAT
   STRONGER LOW-LEVEL SHEAR MAY PROVE SUPPORTIVE OF A FEW TORNADOES
   ACROSS THE CENTRAL PLAINS.

   ...CENTRAL GULF COAST...

   LOW-LATITUDE MID-LEVEL SPEED MAX IS EXPECTED TO EJECT FROM THE BASE
   OF THE WRN U.S. TROUGH ACROSS NERN MEXICO INTO THE NCNTRL GULF OF
   MEXICO BY LATE AFTERNOON.  MODELS SUGGEST A WEAK SFC LOW COULD FORM
   IN RESPONSE TO THIS FEATURE OVER THE LOWER MS VALLEY REGION BY MID
   DAY THEN LIFT SLOWLY NEWD.  IF QUALITY AIR MASS CAN ADVANCE INLAND
   ACROSS THIS REGION AN INCREASINGLY SHEARED ENVIRONMENT WOULD SEEM
   SUPPORTIVE OF ORGANIZED THUNDERSTORMS.  ONE CONCERN EARLY THIS
   MORNING IS THE EXPANSIVE MCS THAT HAS DEVELOPED ACROSS THE TX
   COASTAL PLAIN INTO SRN LA.  THIS ACTIVITY SHOULD PROPAGATE EWD AND
   DISRUPT BUOYANCY/LOW-LEVEL FLOW AHEAD OF APPROACHING SPEED MAX. 
   EVEN SO...HAVE OPTED TO INCREASE/EXPAND SEVERE PROBABILITIES EWD
   ACROSS THE CNTRL GULF COAST TO ACCOUNT FOR ORGANIZED SEVERE
   CONVECTION IF AIR MASS RECOVERS.  ISOLATED SUPERCELLS COULD PRODUCE
   WIND GUSTS IN EXCESS OF 50KT OR PERHAPS A FEW TORNADOES WITHIN MORE
   BUOYANT ENVIRONMENT.