ZCZC SPCSWOD48 ALL
   ACUS48 KWNS 050857
   SPC AC 050857
   
   DAY 4-8 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0357 AM CDT TUE MAY 05 2009
   
   VALID 081200Z - 131200Z
   
   ...DISCUSSION...
   00Z GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT TRACKING A SHORTWAVE
   TROUGH ESEWD THROUGH THE NRN PLAINS/UPPER MS VALLEY ON DAY 4 /FRI
   MAY 8/...AND THEN REMAINING PROGRESSIVE ON DAY 5 /SAT MAY 9/ WITH
   THIS SYSTEM MOVING THROUGH THE GREAT LAKES TO NERN STATES.  BROAD
   CYCLONIC AND FAST MID/UPPER LEVEL FLOW REGIME WILL PERSIST THROUGH
   THE MIDDLE PART OF THE EXTENDED PERIOD /DAY 6...SUN MAY 10/ FROM THE
   NRN INTERMOUNTAIN WEST THROUGH THE CENTRAL PLAINS TO MID ATLANTIC
   STATES.  MODELS INDICATE AMPLIFICATION OF THIS FLOW REGIME SHOULD
   OCCUR BY DAY 8 /TUE MAY 12/ AS A BROAD TROUGH AMPLIFIES EWD ACROSS
   THE NRN/CENTRAL ROCKIES AND NRN/CENTRAL PLAINS.  THIS WILL RESULT IN
   WSWLY FLOW DEVELOPING ACROSS THE PLAINS STATES.
   
   ...DAY 4 /FRI MAY 8/...
   GFS/ECMWF BOTH AGREE THAT TSTMS SHOULD DEVELOP ACROSS ERN PORTIONS
   OF THE SRN PLAINS /ERN OK AND NERN TX/ INTO AR FRIDAY AFTERNOON
   ALONG THE SRN PERIPHERY OF AN EARLY MORNING MCS.  STRONG INSTABILITY
   WILL LIKELY BE JUXTAPOSED WITH STRONG DEEP LAYER SHEAR SUPPORTING
   ORGANIZED SEVERE STORMS ACROSS THIS AREA...WITH ANOTHER MCS LIKELY
   DEVELOPING FROM THE SRN PLAINS TO THE MID SOUTH FRIDAY NIGHT.
   
   ...BEYOND DAY 4...
   THE EFFECTIVE SURFACE BOUNDARY FOCUSING TSTMS SHOULD EXTEND FROM THE
   SRN PLAINS TO THE CAROLINAS...BUT THIS WILL TEND TO BE LOCATED S OF
   STRONG FLOW ALOFT/SHEAR.  ALTHOUGH SEVERE STORMS MAY DEVELOP
   THROUGHOUT THIS CORRIDOR...UNCERTAINTY EXISTS WITH THE OVERALL
   SEVERITY AND PRECLUDES THE INTRODUCTION OF A REGIONAL SEVERE WEATHER
   AREA BEYOND DAY 4.
   
   ..PETERS.. 05/05/2009

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