Coastal Frontogenesis and Precipitation during ERICA IOP 2

Abstract

The inverted trough and coastal front that occurred during ERICA IOP 2 were studied in order to assess the ability of an operational mesoscale model, the Canadian Regional Finite Element Model, to provide credible forecast guidance concerning the regional distribution of precipitation associated with such events. The observed distribution of the heaviest precipitation was dependent on the orientation and inland penetration of the coastal front and its associated (geostrophic) frontogenetic forcing, although considerable local variability was evident. The observations indicate that the front penetrated inland along a line west of Boston through east-central Connecticut. The model, which performed exceptionally well in forecasting the eventual development of the main cyclone, correctly forecast the existence and general location of the inverted trough and coastal front and thereby gave indications of the development of heavy snowfall within the coastal region of New York?New England 18?24 h in advance. However, detailed modeling of the coastal front itself is still beyond the scope of current operational models. In the case studied, the position of the regional environment in which the coastal front forms was forecast incorrectly, preventing a precise regional forecast of the precipitation distribution.