Storm Surge Watches and Warnings are not issued for southern California. Any departure in the forecast from the actual track, size, or intensity of a hurricane can dramatically change its impacts. Through the implicit use of probability data, color-coded HTI graphics depict the potential conditions to protect against with accompanying descriptions of potential impacts needed for effective preparations.
The HTI graphics account for the latest forecast at specific locations while also including a reasonable safety margin to account for any forecast errors. What hazards are described by the HTI Graphics? Tropical wind, storm surge, flooding rain, and tornadoes are the hazards addressed within the HTI graphics suite. Since the Cone Graphic only reveals the most probable track of the center of the storm, it provides little to no information about projected impacts.
The HTI graphics, however, show the geographic extent of associated hazards; their level of threat and potential impacts. Impacts often extend well-beyond the area depicted in the Cone Graphic alone. The HTI color-scale corresponds to increasing levels of threat and is graduated from warm to hot colors. Examining the wind graphic above; left , locations colored in purple have the potential to experience winds greater than mph when accounting for both the forecast and forecast error. It is not a mere depiction of forecast conditions to be expected.
Rather, it indicates that these locations should be ready for winds in excess of mph, when taking into account the latest forecast and knowing that although skilled the forecast isn't perfect. Simply put, locations in purple are being threatened by major hurricane force winds greater than mph at least Category 3 force , locations in red are being threatened by hurricane force winds between mph Category 1 or 2 force , and so on. A similar approach is used for depicting each of the remaining hazards.
HTI is designed to help make preparedness actions more effective. For additional information about hurricane preparedness, please see ready. The HTI Graphics suite can be accessed using the following web portal: weather. The links will be made readily accessible from most WFO front pages during active hurricane or tropical storm events. Click on the Threats and Impacts tab to display HTI information similar to what is shown below on the left side of Figure 3.
