Movement of Large Convective Rainstorms in Relation to Winds Aloft

Abstract

By means of hourly rainfall data from the Hydroclimatic Network, the motions of large rainstorms, of the kind associated with squall lines, are examined in relation to the winds aloft. Very little correlation is found between the speed of movement of the rainstorms and the wind speed at any level, although the fastest moving storms were associated with strong winds aloft. Significant correlation is found between direction of motion of rainstorms, and wind direction at 700 mb or higher levels. On the average, the rainstorms move with an appreciable component toward right of the wind direction. The difference between these results, and those from other studies based on small precipitation areas, is ascribed to propagation. The mechanism involved is discussed briefly.

Radar Observations of the Halifax Storm, 19 May 1989

“…The development and progression of the storm corresponds well with the observations of similar multicellular convective storms reported by authors such as Browning and Ludlam (1962), Newton and Katz (1958), and Newton and Fankhauser (1975). The propagation and development of severe local storms is discussed by Sumner (1988).…”

Mechanisms for a Record‐Breaking Rainfall in the Coastal Metropolitan City of Guangzhou, China: Observation Analysis and Nested Very Large Eddy Simulation With the WRF Model

“…Chappell () noted that most flash floods are produced by quasi‐stationary precipitation systems, wherein many convective cells reach maturity and produce their heaviest rainfall over the same area. Newton and Katz () and Chappell () showed that a convective system's motion can be identified as being the vector sum of an advective component approximated by the mean cloud‐layer wind (direction and magnitude) and a propagation component governed by the rate and location of new cell formation relative to existing convection. Based on this idea, a vector‐based forecast technique was developed for predicting the motion of upwind‐ and downwind‐propagating mesoscale convective systems (MCSs; Corfidi, ; Corfidi et al, ).…”

“…Chappell (1986) noted that most flash floods are produced by quasi-stationary precipitation systems, wherein many convective cells reach maturity and produce their heaviest rainfall over the same area. Newton and Katz (1958) and Chappell (1986) showed that a convective…”

Características físicas dos sistemas convectivos de mesoescala que afetaram o Rio Grande do Sul no período de 2004 a 2008

“…Apesar dessa ressalva, os resultados obtidos neste trabalho vão ao encontro daqueles encontrados por diversos autores (Velasco & Fritsch, 1987;Machado et al, 1998;Siqueira, 2004;Vila, 2004;Durkee & Mote, 2009;Sakamoto, 2009;Sakamoto et al, 2009, por exemplo), que mostraram que os SCM subtropicais sul-americanos tendem a se deslocar para leste desde sua gênese até sua dissipação. Isso ocorre porque o movimento do SCMé a soma de uma componente advectiva, dada pelo deslocamento médio das células convectivas, e uma componente de propagação, definida pela taxa de formação e localização de novas células (Newton & Katz, 1958;Newton & Newton, 1959;Bluestein & Jain, 1985). Quantoàs células convectivas individuais imersas nos SCM, estas tendem a se mover a favor do fluxo médio na camada de nuvens.…”