The Harrisburg NC tornado of 3 March 2012

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1142 PM CST THU MAR 01 2012
   
   VALID 021200Z - 031200Z
   
   ...THERE IS A MDT RISK OF SVR TSTMS FROM THE OH VALLEY TO THE CNTRL
   GULF STATES...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK FROM
   THE UPPER OH VALLEY TO THE CNTRL GULF COAST...
   
   ...A SIGNIFICANT SEVERE WEATHER EPISODE IS EXPECTED FRIDAY ACROSS
   MUCH OF THE OH VALLEY...SWD INTO THE CNTRL GULF STATES...
   
   A VERY STRONG JET CORE AT MID-HIGH LEVELS WILL INTENSIFY IN EXCESS
   OF 110KT AS IT OVERSPREADS SRN MO INTO THE OH VALLEY LATER TODAY. 
   IN RESPONSE TO THIS FEATURE A SFC LOW OVER NCNTRL OK EARLY THIS
   MORNING WILL TRACK NEWD AND DEEPEN OVER MO INTO CNTRL IL BY MID DAY.
    BOUNDARY LAYER MOISTURE IS RECOVERING RAPIDLY ACROSS ERN OK ATTM
   WITH 60F DEW POINTS NOW SPREADING NORTH OF I-40.  THIS MOISTURE
   SURGE WILL ADVECT INTO MO BY SUNRISE AND STRONG WARM ADVECTION IS
   EXPECTED TO INDUCE MULTIPLE CLUSTERS OF ELEVATED SEVERE
   THUNDERSTORMS...CAPABLE OF PRODUCING LARGE HAIL...AHEAD OF SFC LOW
   ALONG/NORTH OF RETREATING WARM FRONT.  SUBSEQUENT EXPANSION NEWD
   WITH RECOVERING AIRMASS WILL ALLOW SEVERE WARM ADVECTION STORMS TO
   SPREAD ACROSS MUCH OF THE OH VALLEY BY 18Z.  WHILE LARGE HAIL WILL
   LIKELY BE THE PREDOMINANT THREAT EARLY...A FEW TORNADOES ARE
   POSSIBLE AS AIRMASS MOISTENS.  IN THE WAKE OF THIS ACTIVITY BOUNDARY
   LAYER DEW POINTS WILL RISE INTO THE LOWER 60S AHEAD OF SFC COLD
   FRONT AND LOW LEVEL LAPSE RATES SHOULD STEEPEN SUCH THAT PRE-FRONTAL
   SUPERCELL DEVELOPMENT WILL LIKELY EVOLVE NEAR OR SHORTLY AFTER 18Z
   ACROSS IL.  FORECAST SOUNDINGS ACROSS THE WARM SECTOR OVER SRN IL
   SUGGEST MUCAPE SHOULD BE ON THE ORDER OF 2000 J/KG WITHIN AN
   OTHERWISE VERY STRONGLY SHEARED ENVIRONMENT.  THIS PRE-FRONTAL
   CONVECTION SHOULD THEN EXPAND IN AREAL COVERAGE DOWNSTREAM ACROSS
   IND/KY BEFORE DEVELOPING SWWD ALONG THE WIND SHIFT ACROSS TN INTO
   NRN AL/MS.
   
   AFTER THE INITIAL WARM ADVECTION CONVECTION ACROSS THE MID MS/OH
   VALLEY REGION...THE PRIMARY FOCUS WILL BE WITH ACTIVITY THAT EVOLVES
   AFTER 18Z AHEAD OF COLD FRONT.  WITH QUITE STEEP LAPSE RATES IN
   PLACE...ENVIRONMENTAL CONDITIONS FAVOR LARGE HAIL IN ADDITION TO
   POSSIBLY STRONG TORNADOES WITH ANY DISCRETE SUPERCELLS THAT FORM
   ACROSS THE MOIST WARM SECTOR.  WITH TIME A DAMAGING SQUALL LINE
   COULD EMERGE WITH VERY STRONG WINDS.
   
   ...GULF STATES...
   
   DURING THE OVERNIGHT HOURS IT APPEARS THE TRAILING COLD FRONT WILL
   BECOME VERY ACTIVE CONVECTIVE-WISE AS WIND SHIFT ENCOUNTERS MORE
   SIGNIFICANT MOISTURE/INSTABILITY ACROSS THE TN VALLEY/GULF STATES. 
   SHEAR PROFILES ACROSS THIS REGION ALSO FAVOR SUPERCELLS...THOUGH
   FRONTAL CONVERGENCE COULD CERTAINLY ENHANCE THE PROSPECT FOR
   MULTIPLE LINE SEGMENTS.
   
   ...LOWER MI...
   
   WITH THE SFC LOW EXPECTED TO DEEPEN SIGNIFICANTLY OVER LOWER MI
   AFTER 00Z THERE IS SOME CONCERN THAT A STRONGLY FORCED BAND OF LOW
   TOPPED SEVERE THUNDERSTORMS COULD PRODUCE DAMAGING WINDS.  MODELS
   SUGGEST ONLY MEAGER MOISTURE WILL ADVECT INTO THIS REGION AHEAD OF
   COLD FRONT BUT WITH INTENSE FORCING IT/S ENTIRELY POSSIBLE THAT A
   SEVERE SQUALL LINE COULD EXTEND INTO SERN LOWER MI DURING THE
   EVENING HOURS.
   
   ..DARROW/SMITH.. 03/02/2012
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z