NHC Publishes 2026 New Products and Services Document

Earlier this week the National Hurricane Center (NHC) published their “National Hurricane Center Products and Services Update for 2026 Hurricane Season”. This document includes more information on the forecast-cone graphics developments that I discussed yesterday. It also includes information on:

• Storm Surge Watches and Warnings, Peak Storm Surge Graphic, and Potential Storm Surge Flooding Map for Hawaii,

• Mobile-friendly front page of the NHC website,

• Updated symbology of disturbances in the Graphical Tropical Weather Outlook for which development is not expected,

• Annual update to the track forecast error cone,

• Experimental Graphical Marine Wind Warning.

NHC Updates Forecast-Cone Graphics for 2026 Hurricane Season

Yesterday the National Hurricane Center (NHC) published an update for the expected use of their forecast-cone graphics. The NHC has been updating these graphics over the last couple of seasons to visually provide more information. Most of this newly added information was trialed last season as an optional experimental graphic.

The new information includes:

Incorporates all land-based (coastal and inland) tropical storm and hurricane watches and warnings in effect for the continental United States, Hawaii, Puerto Rico, and the U.S. Virgin Islands;

Uses single shading for the entire 5-day outlook cone;

Legend depicts symbols for areas where a hurricane watch and tropical storm warning are both in effect (represented by diagonal pink and blue lines); and

Full and intermediate Tropical Cyclone Advisories are/will be publicly available on hurricanes.gov.

This season’s experimental graphics will change how the NHC determines the dimensions of the cone graphics. On the experimental version instead of using a set of circles set at a 67% experimental error to determine the width of the cone, yesterday’s update notes that:

“Beginning in 2026, the experimental cone will use ellipses anchored at each NHC forecast point, allowing for the experimental cone to capture a range of possibilities for both the speed and direction of the tropical cyclone’s forecast path. NHC will experiment changing two aspects of the cone using ellipses (instead of circles) to account for errors in speed and direction, and the cone will include 90% of forecast track possibilities, instead of the traditional 67% forecast error.”

This should mean that the experimental cones will be larger. The increase in width of the cone will probably be the most noticeable difference, but the overall length of the cone should also increase.

NHC Updates 2025 Hurricane Season Products and Services Guidance

The National Hurricane Center (NHC) has published a link to their “NHC New Products/Updates 2025” document on their landing page. This document provides a summary of the changes that are being made (some on an experimental basis) to the information that they will provide on tropical cyclones during the 2025 Hurricane Season. The changes discussed include:

• Experimental Cone Graphic with a depiction of inland watches and warnings for the United States,

• U.S. Rip Current Risk Map For Active Tropical Cyclones,

• Updated Issuance Criteria for Potential Tropical Cyclone Advisory Products,

• Updates to the Forecast/Advisory (TCM) product including the extension of hurricane-force (74 mph, 64 kt) wind radii forecasts to day 3,

• Probabilistic Storm Surge for the Hawaiian Islands,

• Annual update to the track forecast error cone,

• Issuance of U.S. watches and warnings on Intermediate advisories,

• Pronunciation of storm names, and

• Social Media information.

Here’s an interesting idea for an AI product that would provide helpful information on tropical cyclone forecasts. Provide a clickable link for each 10-mile-square data set within the warning/watch areas on each track forecast diagram issued for tropical cyclones. That link would provide a summary of NHC data for that location, including forecast arrival time of tropical storm/hurricane winds, top wind speed, 3-hour rainfall, storm surge (for coastal areas), flood potential, and tornado probabilities. Under the current regime, NOAA is certainly not going to be funded to provide such information, but the gross data is available from current NOAA data sets and would be useful for planning purposes.

NHC Publishes New Product Update for 2024 Hurricane Season

Today, NOAA’s National Hurricane Center published a New Product Update, explaining new sources of information and changes to information presentation for the 2024 Hurricane Season. It provides information on the following topics:

• Spanish language advisory text products,

• Issuance of U.S. watches and warnings on Intermediate advisories,

• Extension of tropical storm (39 mph, 34 kt) and 58 mph, 50 kt)) wind radii forecasts to days 4 and 5,

• Weblinks in the Public Advisory,

• Change to the time zone reference in the eastern Pacific,

• Experimental Cone Graphic with a depiction of inland watches and warnings for the United States,

• Experimental international tropical cyclone rainfall graphics,

• New Marine Forecast Product “Offshore Waters Forecast for the southwestern North Atlantic Ocean”,

• Pronunciation of storm names,

• Social Media, and

• Find us on the Web

NOAA Expands Hurricane Forecasts to 7-Days

Just noticed a change on the NOAA National Hurricane Center web site for the 2023 Hurricane Season, they have replaced the 5-day Graphical Tropical Weather Outlook page that has been available for quite some time with a 7-day Graphical Tropical Weather Outlook page. This will provide a longer outlook on the potential formation of tropical systems.

There is not currently an explanation of the change on the NHC Tropical Cyclone Graphical Product Descriptions page. That site still lists the 5-day outlook.