National Hurricane CenterThe National Hurricane Center (NHC) is the division of the United States' NOAA/National Weather Service responsible for tracking and predicting tropical weather systems between the Prime Meridian and the 140th meridian west poleward to the 30th parallel north in the northeast Pacific Ocean and the 31st parallel north in the northern Atlantic Ocean.
Extreme wind warningAn extreme wind warning (SAME code EWW) is an alert issued by the National Weather Service for areas on land that will experience sustained surface winds 115 miles per hour (100 kn; 185 km/h; 51 m/s) or greater within one hour. As of 2025, it has only been used for the eyewalls of major hurricanes when they pass near-shore, and during and shortly after landfall, but it is also intended as a general "short-fused" warning for any immediate occurrence of such winds.
Tropical cycloneRapidly rotating storm systemHurricane Florence viewed from the International Space Station in 2018. The eye, eyewall, and surrounding rainbands are characteristics of tropical cyclones.A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls.
Central Pacific Hurricane CenterThe Central Pacific Hurricane Center (CPHC) of the United States National Weather Service is the official body responsible for tracking and issuing tropical cyclone warnings, watches, advisories, discussions, and statements for the Central Pacific region: from the equator northward, 140°W–180°W, most significantly for Hawai‘i. It is the Regional Specialized Meteorological Center (RSMC) for tropical cyclones in this region, and in this capacity is known as RSMC Honolulu.
140th meridian westLine of longitude 140° 140th meridian west (interactive map) The meridian 140° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole. The line is the divider in the area of warning responsibility between the National Hurricane Center and the Central Pacific Hurricane Center in the north Pacific Ocean.
American SamoaAmerican territory in PolynesiaUnincorporated and unorganized U.S. territory in the United StatesAmerican Samoa is a self-governing, unincorporated and unorganized territory of the United States located in the south Pacific Ocean, within the Polynesia subregion of Oceania.
Pacific OceanLargest ocean on EarthThe Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It stretches from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the continents of Asia and Australia in the west and the Americas in the east.
Atlantic OceanThe Atlantic Ocean is the second largest of the world's five oceans, with an area of about 85,133,000 square kilometers (32,870,000 sq mi). It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for separating the New World of the Americas (North America and South America) from the Old World of Afro-Eurasia (Africa, Asia, and Europe).
GuamU.S. territory in MicronesiaUnincorporated and organized U.S. territory in the United StatesGuam ( ; Chamorro: Guåhan) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, and the most populous village is Dededo.
MicronesiaMicronesia (UK: , US: ) is a subregion of Oceania, consisting of approximately 2,000 small islands in the Northwestern Pacific Ocean. It has a close shared cultural history with three other island regions: Maritime Southeast Asia to the west, Polynesia to the east, and Melanesia to the south—as well as with the wider community of Austronesian peoples. The region has a tropical marine climate and is part of the Oceanian realm.
Weather forecastingApplication of science and technologyForecast of surface pressures five days into the future for the North Pacific, North America, and the North Atlantic OceanWeather forecasting or weather prediction is the application of science and technology to predict the conditions of the atmosphere for a given location and time. People have attempted to predict the weather informally for thousands of years and formally since the 19th century.
Central AmericaSubregion of North AmericaCentral America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually defined as consisting of seven countries: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama, and also, in specialized contexts, including Mexico.*As an Amazon Associate I earn from qualifying purchases.