eruption, or extreme global warming. I Indirect Hit Generally refers to locations that do not experience a direct hit from a tropical cyclone, but do experience hurricane-force winds (either sustained or gusts) or tides of at least 4 feet above normal. Inland Tropical Storm Warning The equivalent of a Tropical Storm Warning for inland counties, put into use after multiple Tornado Warnings were issued for Hurricane Katrina, when tornadoes were not present, but winds were the equivalent of EF0-2 tornadoes. These are issued by local NWS forecast offices, not the NHC. Inland Hurricane Warning The equivalent of a Hurricane Warning for inland counties, put into use after multiple Tornado Warnings were issued for Hurricane Katrina, when tornadoes were not present, but winds were the equivalent of EF0-2 tornadoes. These are issued by local NWS forecast offices, not the NHC. Intertropical Convergence Zone A zonally elongated axis of surface wind confluence of northeasterly and southeasterly trade winds in the tropics. Inundation The flooding of normally dry land, primarily caused by severe weather events along the coasts, estuaries, and adjoining rivers. These storms, which include hurricanes and nor'easters, bring strong winds and heavy rains. The winds drive large waves and storm surge on shore, and heavy rains raise rivers. (A tsunami — a giant wave caused by earthquakes or volcanic eruptions under the sea or landslides into the sea — is another kind of coastal inundation, but should not be confused with storm surge). Invest A weather system for which a tropical cyclone forecast center (NHC, CPHC, or JTWC) is interested in collecting specialized data sets (e.g., microwave imagery) and/or running model guidance. Once a system has been designated as an invest, data collection and processing is initiated on a number of government and academic web sites, including the Naval Research Laboratory (NRL) and the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies (UW-CIMSS). The designation of a system as an invest does not correspond to any particular likelihood of development of the system into a tropical cyclone; operational products such as Tropical Weather Outlooks or Significant Tropical Weather Advisories should be consulted for this purpose. K Kelvin wave An eastward moving atmospheric wave that can enhance deep convection and contribute to tropical cyclogenesis, especially over the Pacific Ocean. It moves towards the east at about 10° to 20° longitude per day. L Landfall The intersection of the surface center of