Now this is interesting...

SPC AC 220536
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1236 AM CDT TUE MAR 22 2011
VALID 231200Z - 241200Z
...THERE IS A SLGT RISK OF SVR TSTMS WEDNESDAY INTO WEDNESDAY
EVENING ACROSS MUCH OF THE OHIO AND TENNESSEE VALLEYS
...CENTRAL/SOUTHERN APPALACHIANS AND SOUTHERN MID ATLANTIC COAST
STATES...
...SYNOPSIS...
A BLOCKING PATTERN WILL CONTINUE TO EVOLVE OVER NORTH AMERICA
THROUGH THIS FORECAST PERIOD. WITHIN BROAD UPPER TROUGHING NEAR THE
PACIFIC COAST...MODELS SUGGEST THAT A SERIES OF SIGNIFICANT SHORT
WAVE IMPULSES WILL STILL BE IN THE PROCESS OF DIGGING OFFSHORE...BUT
ONE IS PROGGED TO MIGRATE INLAND ACROSS THE CALIFORNIA COAST...INTO
THE GREAT BASIN BY LATE WEDNESDAY NIGHT. THE PROGRESSION OF THIS
LATTER FEATURE...COUPLED WITH A ANOTHER IMPULSE PIVOTING AROUND THE
NORTHERN/WESTERN PERIPHERY OF A BROAD CYCLONIC CIRCULATION TO THE
SOUTHEAST OF HUDSON BAY...APPEAR LIKELY TO CONTRIBUTE TO THE
SOUTHEASTWARD ACCELERATION OF A CLOSED LOW/UPPER TROUGH INITIALLY
OVER THE MID/UPPER MISSISSIPPI VALLEY AT 12Z WEDNESDAY. AS THIS
IMPULSE IS FORCED INTO AN INCREASINGLY CONFLUENT REGIME...AN
ASSOCIATED MID/UPPER JET STREAK IS PROGGED TO INTENSIFY /90-100+ KT
AT 500 MB/ AND GRADUALLY VEER FROM WESTERLY TO NORTHWESTERLY AS IT
NOSES EAST OF THE OZARK PLATEAU TOWARD THE SOUTH ATLANTIC SEABOARD.
AT LOWER LEVELS...GUIDANCE SUGGESTS THAT A SUB-1000 MB SURFACE LOW
WILL TRACK ALONG A STALLED SURFACE FRONT SOUTH OF THE GREAT LAKES
INTO THE NORTH CENTRAL APPALACHIANS DURING THE DAY
WEDNESDAY...BEFORE STRONGER SURFACE CYCLOGENESIS TAKES PLACE OFF THE
MID ATLANTIC COAST WEDNESDAY NIGHT. AHEAD OF A COLD FRONT TRAILING
TO THE WEST SOUTHWEST OF THE INITIAL LOW...BOUNDARY LAYER MOISTENING
IS EXPECTED ACROSS THE LOWER OHIO AND TENNESSEE VALLEYS...AS SURFACE
RIDGING WEAKENS AND RETREATS AWAY FROM THE EASTERN GULF OF MEXICO.
BENEATH THE REMNANTS OF ELEVATED MIXED LAYER AIR EMANATING FROM THE
MEXICAN/U.S. PLATEAU REGION...THIS IS EXPECTED TO CONTRIBUTE TO WEAK
TO MODERATE CONDITIONAL AND CONVECTIVE INSTABILITY...WHICH LIKELY
WILL PROMOTE WIDESPREAD CONVECTIVE DEVELOPMENT...INCLUDING THE RISK
FOR SEVERE STORMS.
...OHIO/TENNESSEE VALLEYS INTO THE MID ATLANTIC COAST...
INITIAL STORM DEVELOPMENT MAY BE FOCUSED IN THE WARM SECTOR NEAR THE
LOW...AND ALONG THE FRONTAL ZONE TO THE EAST SOUTHEAST OF THE
LOW...PERHAPS AS EARLY AS MID DAY ACROSS PARTS OF SOUTHEASTERN
INDIANA INTO OHIO. THIS MAY INCLUDE SUPERCELLS...BUT UPSCALE GROWTH
INTO AN EVOLVING MESOSCALE CONVECTIVE SYSTEM APPEARS
POSSIBLE...WHICH SHOULD DEVELOP SOUTHEASTWARD THROUGH THE CENTRAL
APPALACHIANS BY LATE AFTERNOON.
AS THIS OCCURS...AND AN AREA OF STRONG MID/UPPER FORCING FOR UPWARD
VERTICAL MOTION BEGINS TO OVERSPREAD THE REGION WITH THE APPROACHING
UPPER JET STREAK...ADDITIONAL STORM DEVELOPMENT IS EXPECTED
SOUTHWESTWARD ALONG AN EFFECTIVE DRY LINE TYPE STRUCTURE NEAR AND TO
THE SOUTHEAST OF THE OHIO RIVER. THIS ACTIVITY MAY TEND TO REMAIN
DISCRETE IN THE PRESENCE OF FAVORABLE SHEAR FOR SUPERCELLS.
TORNADIC POTENTIAL...PARTICULARLY WITH THE DISCRETE STORMS...
REMAINS THE PRIMARY UNCERTAINTY FOR THIS FORECAST...AND APPEARS
LIKELY TO HINGE ON THE CHARACTER OF THE BOUNDARY LAYER. WHILE
LOW-LEVEL HODOGRAPHS IN GENERAL MAY NOT BECOME PARTICULARLY LARGE
AND CLOCKWISE CURVED...THE SHEAR STILL APPEARS SUFFICIENT.
HOWEVER...FORECAST SOUNDINGS AMONG THE MODELS DO EXHIBIT SOME
VARIABILITY CONCERNING THE BOUNDARY LAYER MOISTURE CONTENT. IF
SURFACE DEW POINTS APPROACH 60F...AND THE SURFACE DOES NOT HEAT TOO
STRONGLY AND SUPPORT DEEPER MIXING...THE TORNADO POTENTIAL MAY BE
HIGHER...AND THE SEVERE THREAT PERHAPS GREATER THAN REFLECTED BY THE
CURRENT SLIGHT RISK. CURRENTLY...IT SEEMS MORE PROBABLE THAT
SLIGHTLY DRIER BOUNDARY LAYER CONDITIONS WILL PREVAIL...PROMOTING
PRIMARILY A LARGE HAIL AND DAMAGING WIND THREAT.
MODEST DESTABILIZATION AND INCREASING LARGE-SCALE ASCENT COULD ALSO
PROMOTE STRONG/SEVERE STORM DEVELOPMENT TO THE LEE OF THE CENTRAL
APPALACHIANS BY LATE AFTERNOON. BUT IT ALSO SEEMS POSSIBLE THAT THE
MESOSCALE CONVECTIVE SYSTEM MAY MAINTAIN STRENGTH ACROSS THE
APPALACHIANS...WITH A CONTINUING SEVERE THREAT ACROSS PARTS OF
VIRGINIA AND NORTH CAROLINA DURING THE EVENING HOURS. COOL/COLD AIR
TO THE NORTH OF A STALLED FRONTAL ZONE MAY MITIGATE THE SEVERE STORM
POTENTIAL NEAR CHESAPEAKE BAY AND ACROSS NORTHERN VIRGINIA.
..KERR.. 03/22/2011
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z
CURRENT UTC TIME: 1400Z (10:00AM), RELOAD THIS PAGE TO UPDATE THE TIME