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About OPC's Hurricane Force Low Climotology

Introduction to Hurricane Force Lows

During cold weather months, continental polar and arctic air masses originating from the mid to high latitudes will move over the North Atlantic and North Pacific Oceans and interact with lower latitude marine tropical air masses to produce large temperature gradients and strong frontal boundaries. Extratropical low pressure centers that form along these boundaries will intensify using the temperature contrast as one of the main ingredients for development. This differs from the driving force behind tropical cyclones which are fueled by organized convection.

Forecasters at the Ocean Prediction Center (OPC) analyze and classify low pressure systems on the unified surface analysis four times per day. OPC started issuing extratropical hurricane force wind warnings in late 2000 when QuikSCAT data became routinely available. Prior to that, forecasters did not have the ability to identify hurricane force systems with certainty due to insufficient data. The first North Pacific extratropical low center classified as "hurricane force" by OPC was analyzed on the 1800 UTC January 13, 2001 surface analysis (below).

Systems that are classified as "hurricane force" can have devastating effects on life and property in their path. Each year nearly $2 trillion dollars worth of imports and exports pass through U.S. seaports aboard 60,000 ocean fearing vessels. Additionally over 11 million Americans board cruise ships annually. Marine hazards such as hurricane-force winds and the waves that they create threaten the safety of everyone at sea. This makes understanding and predicting these storms of the utmost importance to forecasters at the OPC and mariners everywhere. Data on hurricane force low centers has been collected since January 2005, and will help us better understand the issue.

Explore the data using the tabs at the top of the page.