Author: HURREVAC Support

Emergency managers in the Mid-Atlantic now have access to updated storm surge modeling in HURREVAC. The National Hurricane Center’s Storm Surge Unit published new SLOSH data for the Chesapeake Bay and Delaware basins in July 2025.  The associated high-resolution MEOWs are available in HURREVAC’s Storm Surge (SLOSH) Explorer to help users understand their storm surge risk for both planning and operational decision-making. The Chesapeake Bay basin, identified as cp6, is intended for use between the Virginia-North Carolina border and Maryland-Delaware border, including all of Virginia, Maryland, the District of Columbia, and some western portions of Delaware. This replaced the cp5 SLOSH data throughout the Chesapeake Bay region. The Delaware basin, identified as de4, is intended for use between the Maryland-Delaware border and Sandy Hook, New Jersey, including most of Delaware, the Philadelphia area, and the southern two-thirds of New Jersey. Refer to the latest basin outlines on the accompanying map to see which data set is most appropriate for use in your area of interest. The SLOSH basin outlines are also available in HURREVAC’s Resources tab and referenced whenever a user defines their base location in the program. Questions pertaining to the new SLOSH data should be directed to Cody.Fritz@noaa.gov at the National Hurricane Center. General questions about storm surge tools in HURREVAC should be directed to support@hurrevac.com. New shortcut to generate Evacuation Timing Report HURREVAC can now save users a few clicks when they are ready to evaluate protective actions along with the latest forecast data. ● First, make sure that your storm of interest is plotted on the tracking map. ● In the Evacuation Timing window, enter your Evacuation Scenarios and/or custom Timeline Actions. ● Then, click the new Create Report button in the lower right portion of the window. This instantly opens the right side panel and generates an Evacuation Timing Report. The report is the same as before, and lists results for all stored evacuation scenarios and timeline actions for areas with valid wind timing data. In other words, it is not necessary to select specific scenarios or actions to populate the report. HURREVAC incorporates extension of NHC/CPHC hurricane-force wind radii forecasts to day 3 As announced in NHC’s product updates for 2025, the Forecast Advisory (TCM) now includes a prediction of the extent of hurricane-force winds out to day 3. Previously, the forecasts for that 74 mph threshold were issued out to day 2 and extrapolated to day 3 in HURREVAC when applicable. This new information is used when drawing HURREVAC’s map layers (Forecast Wind Field, Wind Swath – Deterministic) and the Deterministic Wind Timing Report. As in years past, the size and shape and timing of the hurricane wind field (red) is not depicted beyond three days for systems in the Atlantic, eastern Pacific and central Pacific, even if the track forecast indicates a hurricane four or five days into the future. Wind radii forecasts are available up to five days beyond the advisory time for the tropical storm (blue) and strong tropical storm (yellow) thresholds. For storms tracked by the JTWC, 64 kt (typhoon or cyclone) winds are explicitly forecast out to five days and shown on the map when applicable.

HURREVAC now highlights active selections in the Toolbox, which is located in the lower left corner of the workspace. For example, this behavior indicates whenever the Tropical Weather Outlook is turned on by default when the program loads. Other tools like Text Advisories, Evacuation Timing and Training are also highlighted when clicked and their respective windows are open. Tools that open from the right side panel – Reports, Storm Surge (SLOSH) Explorer, and Storm Simulator – are also highlighted in the same way when you click on them. The right side panel now has a slightly different look, which removes the tabs at the top and only shows one tool at a time. It is still possible to switch between these three panel-based features using the toolbox. Other recent program changes Tropical Weather Outlook: storm icons are shown for all systems except the one that is actively selected (the ‘working’ storm). The TWO is beneficial for situational awareness, but we also recommend turning off the TWO layer when focused on tracking a particular storm unless you want to show its track in relation to other areas of potential development. Wind watches and warnings: improved caching now lets new information populate on the map without needing to restart the browser. This layer is often published shortly after the other advisory text products, so there can be a period of a few to several minutes where the HURREVAC map does not yet show a wind watch/warning line to match the text. Deterministic winds for JTWC areas of responsibility: added an exception to the recent program changes to show the 64kt (typhoon or cyclone) winds on the map throughout the 5 day period when applicable, as that threshold is explicitly forecast in JTWC advisories. The deterministic wind timing report still limits specific results for the 64-kt threshold to 3 days in all areas. Note to users in South Carolina: the state’s latest Hurricane Evacuation Study (HES) data has been implemented in the program during recent weeks and months. This includes new Evacuation Zones and clearance times in the Evacuation Timing window. New HES documents for the Resources tab are coming soon.