MESOSCALE DISCUSSION 0921
NWS STORM PREDICTION CENTER NORMAN OK
1158 AM CDT SUN JUN 13 2010
AREAS AFFECTED...PARTS OF ERN PA...NJ...AND THE NORTHERN DELMARVA
VICINITY
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 131658Z - 131900Z
THE NEED FOR A WW IS NOT ANTICIPATED...BUT TRENDS WILL BE MONITORED.
A MOIST BOUNDARY LAYER WITH SURFACE DEW POINTS NEAR 70F IS BECOMING
MODERATELY UNSTABLE EAST OF THE ALLEGHENY MOUNTAINS AND ALONG A
SURFACE FRONT EXTENDING ACROSS NORTHERN PENNSYLVANIA THROUGH CENTRAL
NEW JERSEY. THIS IS BEING ACCOMPANIED BY SLOWLY
INCREASING/INTENSIFYING CONVECTIVE DEVELOPMENT...PERHAPS AIDED BY
FORCING ASSOCIATED WITH A WEAK SHORT WAVE TROUGH DEVELOPING EAST
SOUTHEASTWARD OUT OF THE LOWER GREAT LAKES REGION. THERMODYNAMIC
PROFILES ARE RATHER WARM...WHICH MAY MINIMIZE THE RISK FOR LARGE
HAIL...BUT LOW-LEVEL LAPSE RATES ARE STEEPENING...AND 30-35 KT WEST
NORTHWESTERLY 500 MB FLOW IS CONTRIBUTING TO MODEST DEEP LAYER
SHEAR...PERHAPS SUFFICIENT FOR ORGANIZED CONVECTION. AN ISOLATED
SUPERCELL OR SMALL STORM CLUSTER ACCOMPANIED BY STRONG SURFACE WIND
GUSTS DOES NOT APPEAR OUT OF THE QUESTION...PARTICULARLY ALONG THE
FRONT NEAR ALLENTOWN THROUGH CENTRAL NEW JERSEY...BETWEEN NOW AND
18-20Z.
..KERR.. 06/13/2010