
SPC AC 100559
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1259 AM CDT TUE JUN 10 2008
VALID 101200Z - 111200Z
...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF NY...VT...PA AND
NJ...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NEW
ENGLAND...NY...MID-ATLANTIC AND THE CNTRL APPALACHIAN MTNS...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SE MT...NRN WY...SD AND
SW ND...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF SRN WI AND
LOWER MI...
...NERN STATES...
AN UPPER-LEVEL TROUGH OVER THE UPPER MIDWEST WILL ACCELERATE NEWD
ACROSS THE GREAT LAKES TODAY. IN RESPONSE...A COLD FRONT WILL MOVE
EWD ACROSS THE REGION. SFC DEWPOINTS IN THE MID TO UPPER 60S F AHEAD
OF THE FRONT SHOULD RESULT IN MODERATE INSTABILITY ACROSS MOST OF
THE WARM SECTOR. STRONG FORCING DUE TO THE FRONT AND LARGE-SCALE
ASCENT ASSOCIATED WITH THE TROUGH WILL RESULT IN WIDESPREAD
THUNDERSTORM DEVELOPMENT. A SQUALL-LINE SHOULD ORGANIZE AND MOVE
QUICKLY EWD ACROSS THE MODERATE RISK AREA.
FORECAST SOUNDINGS ACROSS THE MODERATE RISK AREA INCREASE VERTICAL
SHEAR PROFILES AS A 60 TO 75 KT MID-LEVEL JET MOVES NEWD INTO THE
NRN APPALACHIAN MTNS THIS AFTERNOON. THE SHEAR SHOULD BE SUPPORTIVE
OF NUMEROUS SEVERE STORMS AS A LINEAR MCS DEVELOPS. SUPERCELLS WILL
BE POSSIBLE UPON INITIATION BUT THE STRONG FORCING SHOULD FAVOR
LINEAR DEVELOPMENT. STRONG LOW-LEVEL FLOW AND STEEP LAPSE RATES
BELOW 3 KM SHOULD PRODUCE A WIDESPREAD WIND DAMAGE THREAT WITH
BOWING LINE SEGMENTS.
FURTHER SOUTH ACROSS THE MID-ATLANTIC AND NC...THUNDERSTORMS SHOULD
NOT BE AS WIDESPREAD DUE TO WEAKER LARGE-SCALE ASCENT.
HOWEVER...MODEL FORECASTS DEVELOP VERY STEEP LOW-LEVEL LAPSE RATES
AND MODERATE TO STRONG INSTABILITY. THIS SHOULD SUPPORT AN ISOLATED
SEVERE THREAT AS STORMS DEVELOP IN THE CNTRL APPALACHIAN MTNS THIS
AFTERNOON AND MOVE INTO THE ATLANTIC COASTAL PLAINS BY EARLY THIS
EVENING.