Daily to Seasonal Higher Latitude North Atlantic Tropical Cyclone Threat Prediction

Tropical cyclones that impact higher latitudes, regardless of their status with respect to the extratropical transition process, result in an array of societal and meteorological impacts to both the region impacted by the cyclone and areas downstream. As with any tropical cyclone impact, preparation for these events – whether immediately prior to or well in advance of an impact – is critical to minimize disruption to businesses, governments, and society. Yet, despite advances made in short-term and seasonal prediction of overall tropical cyclone activity, little focus has been given to analyzing, improving, or developing methods designed to advance the science of higher latitude tropical cyclone prediction.

This study presents several schemes designed to improve daily to seasonal lead time prediction of higher latitude tropical cyclone activity in the entire North Atlantic basin as well as to specific locations (New England, Canadian Maritimes, and Europe) within the basin. These methods include multiple linear regression techniques utilizing relevant climate teleconnection index correlations; anomaly correlations based upon observed and climatological atmospheric weather patterns; single and multiple member ensemble track prediction; and an extended range track prediction scheme based upon official and guidance-based track forecasts coupled with climatology. Statistically significant (to >90% confidence) and skillful (versus all available climatologies) predictions of seasonal and monthly higher latitude activity will be presented along with case studies focusing on signals for enhanced or reduced higher latitude threats in the medium- and long-ranges.