Ocean Prediction Center - Overview
The OPC strives to provide the world's best marine weather forecasts, preventing loss of life and property at sea. It an integral component of the National Centers for Environmental Prediction (NCEP) located at the National Center for Weather and Climate Prediction in College Park, Maryland.
OPC originates and issues marine warnings and forecasts, continually monitors and analyzes maritime data, and provides guidance of marine atmospheric variables for purposes of protection of life and property, safety at sea, and enhancement of economic opportunity. These products fulfill U.S. responsibilities with the World Meteorological Organization and Safety of Life at Sea Convention (SOLAS) [International Convention for the Safety of Life at Sea, 1960 and 1974].
OPC also provides forecast points in coordination with the National Hurricane Center (NHC) for Tropical Cyclones in the Atlantic Ocean E of 60W and N of 20N. In emergency situations OPC acts as a backup to the National Hurricane Center (NHC) and the Honolulu National Weather Service Office taking over the marine functions. Those offices also act as backups to OPC's marine functions.
The Ocean Prediction Center (OPC), established in 1995, was one of the National Centers for Environmental Prediction's (NCEP's) original six service centers. However, the basis for OPC's mission can be traced back to the sinking of the Titanic in April 1912. In response to that tragedy, an international commission was formed to determine requirements for safer ocean voyages. In 1914, the commission's work resulted in the Safety of Life at Sea Convention; the United States is one of the original signatories. The National Weather Service (NWS), through OPC, assumed the U.S. obligation to issue warnings and forecasts for portions of the North Atlantic and North Pacific oceans.
Current Operations and Responsibilities
OPC's Ocean Forecast Branch issues warnings and forecasts in print (bulletins) and graphical formats, on a 24x7 basis up to five days in advance. Over 100 of these products are issued daily. They cover the North Atlantic Ocean from the west coast of Europe to the U.S. and Canadian east coast and the North Pacific Ocean from the U.S. and Canadian west coast to the east coast of Asia. OPC weather forecasts and warnings for these areas primarily ensure the safety of ocean-crossing commercial ships and other vessels on the high seas. Imbedded in these high seas areas are smaller offshore zones off the Atlantic and Pacific coasts. These zones extend from near the coast seaward to just beyond the U.S. Exclusive Economic Zones, out to about 250 nm. OPC services ensure the safety of the extensive commercial and recreational fishing, boating, and shipping activities in these offshore waters.
Areal extent: Region of coverage is the over marine areas of the Northern Hemisphere S of 67N to 15 degrees S (except Indian Ocean).
Temporal extent: Guidance and forecasts are issued for time periods where useful skill exists out to 96 hours for seas and 120 hours for weather systems.
Application activities: Conducted to support the civilian maritime community and other government agencies in support of safety of life at sea , ie. U.S. Coast Guard.
Product suite: Support for transoceanic, fishing, and recreational marine users, coastal communities, marine navigation, and other marine interests.
Product distribution: Direct support for all national and international marine users. MPC produces principal guidance for National Weather Forecast Offices with offshore and coastal responsibilities, and other marine related programs.
In addition to being available online through the Ocean Prediction Center homepage, the graphical products described below are transmitted directly to vessels at sea and the public along coastal areas via High Frequency (HF) short-wave radiofacsimile through transmitters of the U.S. Coast Guard at Marshfield, MA, and Point Reyes, CA. The Coast Guard transmits these products at scheduled times throughout the day.
Short wave Radio Broadcast
Also, a brief version of the High Seas Forecast (HSF), which covers the North Pacific Ocean E of 140W and North Atlantic W of 35W is broadcast via High Frequency (HF) short-wave radio station, WWV in Fort Collins, Colorado. The Atlantic forecast is broadcast in two parts at HH+08 and HH+09 minutes. The Pacific forecast is broadcast at HH+10 minutes. These warnings and forecasts are updated every six hours at 0500 UTC, 1100 UTC, 1700 UTC, and 2300 UTC. WWV transmits on 2.5 MHz, 5.0 MHz, 10.0 MHz, 15.0 MHz, and 20.0 MHz continuously 24 hours a day. In addition WWV marine broadcasts can be heard at these times at (303) 499-7111.
A typical warning text format is as
North Pacific Weather east of 140W at 1800
UTC October 11 1995
By 24 hours Gale 56N 138W moving NE 25 knots with winds to 40 knots seas to 24 feet within 900 nautical miles south and southeast quadrants.
Low 39N 127W moving ENE 25 knots. Winds to 30 knots seas to 14 feet within 480 nautical miles south semicircle.
End Of Message.
Two types of graphical products are disseminated. The analysis and forecasts of upper level large synoptic scale flow are based on a computer objective scheme. The surface analysis and forecast charts are produced from a blend of objective and subjective means as determined by a marine forecaster. Times indicated on the charts are in Coordinated Universal Time (UTC). There are two major categories of charts broadcast.
These manually produced charts depict surface features and forecast positions, and define present and future wind and wave conditions.
These are depictions of the computer model analyses and forecasts of ridges and troughs for the 500 mb constant pressure surfaces.
The High Seas Forecast (HSF), which covers the North Atlantic Ocean and North Pacific Oceans is issued four times per day. The text describes initial synoptic scale conditions. The forecast describes conditions of winds/seas associated with significant weather features of concern to Mariners out to 36 hours. It can include areas of dense fog and structural icing.
Also, two Offshore forecast products are issued which describe current and forecast features for the offshore waters of the Western and Eastern US coasts. The Marine Weather Discussion (MWD) based on the current weather conditions and forecast model guidance are issued four times a day, and describe latest weather conditions forecast reasoning for the offshore forecast waters and adjacent areas for the next 5 days.
In 1994, OPC began to quality control global surface marine observations. Using an automated algorithm and interactive system, forecasters examine the latest observations from Voluntary Observing Ships and drifting and moored platforms and compare them against short projection model runs. Worldwide surface marine observations come to OPC via the World Meteorological Organization's global telecommunications system in real time. These quality control measures remove spurious data before the data are ingested into models to initialize forecasts. Several hundred of these observations are interactively examined daily. In addition, the quality controlled data are used by OPC forecasters to determine if gale, storm, or hurricane force wind warnings are warranted.
Advancing Science and Research of Marine Weather Forecasts and Warnings
OPC's Ocean Applications Branch plays a critical role in transitioning science and technological advancements into enhanced OPC operations and services. One example is the adaptation of ocean surface vector wind observed from the QuikSCAT satellite in early 2000. Prior to the QuikSCAT launch, NWS did not have the ability to observe, verify, and warn of hurricane force (HF) wind conditions, areas where wind speed exceeds 64 knots, associated with strong winter ocean storms. With QuikSCAT data routinely available in 2000, OPC began to issue HF wind warnings. In the 2006-2007 winter storm season, over 100 HF warnings were issued for North Pacific and North Atlantic oceans to warn ships of these most severe weather hazard conditions over major shipping routes. Preliminary results from a recent study estimates that in the absence of good information about extra-tropical ocean storms, the annual loss to container and dry bulk shipping would be on the order of more than $500 million. Operational marine warnings and forecasts reduce the above estimated annual loss by nearly a half.
Advancements in science and technology continue to drive OPC's service improvements. OPC began to produce experimental gridded significant wave height forecast in 2006, a first step toward digital marine service for high seas and offshore areas. Additional gridded products such as surface pressure and winds are under development. Recently, OPC began to use the NWS operational extratropical storm surge model output to provide experimental extratropical storm surge guidance for coastal weather forecast offices to assist them in coastal flood warning and forecast operations. OPC has a number of ongoing research-to-operations transition efforts that will lead to a suite of new oceanographic analysis and forecast products such as ocean temperatures and currents based on real time observations and advanced global and basin scale ocean forecasting models.