Posted by JAC on 4/17/2009, 10:35 am, in reply to "Next Severe Weather: Tuesday 4/21, SE Coast"

ZCZC SPCSWOD48 ALL ACUS48 KWNS 170853 SPC AC 170853 DAY 4-8 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0353 AM CDT FRI APR 17 2009 VALID 201200Z - 251200Z ...SEVERE STORMS POSSIBLE ACROSS MUCH OF THE MIDDLE AND SOUTHERN ATLANTIC COAST STATES MONDAY /APRIL 20/... MEDIUM RANGE FORECAST GUIDANCE APPEARS IN REASONABLE ENOUGH AGREEMENT WITH THE LARGE-SCALE PATTERN EVOLUTION INTO EARLY NEXT WEEK. AMPLIFICATION OF THE UPPER FLOW REGIME IS PROGGED TO CONTINUE...WITH A VIGOROUS SHORT WAVE TROUGH DIGGING SOUTH SOUTHEASTWARD THROUGH THE UPPER HALF OF THE MISSISSIPPI VALLEY INTO THE LOWER OHIO VALLEY MONDAY/MONDAY NIGHT. CONSOLIDATION WITH A REMNANT CLOSED LOW/TROUGH EMANATING FROM THE SOUTHWESTERN U.S. APPEARS LIKELY TO CONTRIBUTE TO A LARGER SCALE TROUGH ENCOMPASSING MOST AREAS EAST OF THE MISSISSIPPI VALLEY. DOWNSTREAM OF THE UPPER TROUGH AXIS...AND IN THE WARM SECTOR OF A DEEPENING SURFACE CYCLONE LIFTING THROUGH THE UPPER OHIO VALLEY/ LOWER GREAT LAKES REGION...STRONG LOW-LEVEL AND DEEP LAYER SHEAR IS EXPECTED TO DEVELOP WITHIN A DESTABILIZING ENVIRONMENT TO THE LEE OF THE CENTRAL/SOUTHERN APPALACHIANS. A SECONDARY SURFACE LOW MIGRATING NORTHEASTWARD TO THE LEE OF THE APPALACHIANS...TOWARD NORTHERN MID ATLANTIC COASTAL AREAS...MAY BE ACCOMPANIED BY SEVERE STORM DEVELOPMENT...INCLUDING A FEW SUPERCELLS...WITH ADDITIONAL STORMS PROBABLY FORMING SOUTHWARD ALONG A LEE SURFACE TROUGH... AND PERHAPS ALONG SEA BREEZES...INTO GEORGIA/NORTHEAST FLORIDA COASTAL AREAS. ..KERR.. 04/17/2009