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  • Author or Editor: Samuel Penn x
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Samuel Penn

An explanation is offered for a case of violent and prolonged non-frontal thunderstorms in New England. The thunderstorms occurred in the vicinity of an upper level trough. An analysis of the situation points to the development of marked divergence in the upper troposphere and convergence at middle levels. The resulting vertical motions acted to decrease the stability of the air mass. The increased divergence-convergence aloft resulted from an intensification of the ridge to the west and not from any deepening of the trough in the thunderstorm area.

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Samuel Penn
,
Charles Pierce
, and
James K. McGuire

Some features of the squall line situation of June 9, 1953 and accompanying tornadoes in central and eastern Massachusetts are discussed. From radarscope photographs, it is pointed out (1) that the Worcester tornado and the Franklin-Wrentham tornado each occurred in the right-rear quadrant of a squall-line thunderstorm cell, and (2) that this relative position, with an associated tail or hook in the radar echo, is similar to that of the Illinois tornado of April 9, 1953. A tentative explanation is suggested for tornado formation in this position.

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