NHC changes for the 2024 hurricane season

The National Hurricane Center (NHC), is making some changes to the way it handles tropical systems.  These changes to their products and services, will be implemented on an experimental basis for the 2024 hurricane season. This stems from the need to better inform the public on the potential multiple impacts that a tropical cyclone may deliver. The changes are…

(1  Spanish Text Products

(2 Watches and Warnings on Intermediate Advisories

(3  Extension of Tropical Storm Wind Radius Forecast

(4 Website Links in Advisories

(5 Forecast Cone with Inland Watches and Warnings

(6  Rainfall Graphics

(7  New marine forecast for offshore waters

(8  Change to the Time zone Reference in the Eastern Pacific

Spanish Text Products…

The National Hurricane Center will expand information provided in Spanish to include:

All public advisories.

The tropical cyclone discussion.

The tropical cyclone update.

Key messages.

The NHC will be using AI to generate the Spanish-language documents.

 

Watches and Warnings on Intermediate Advisories…

The NHC said watches and warnings could now be adjusted more frequently and not during the set times of 5 A.M., 11 A.M., 5 P.M., and 11 P.M. when the full advisory packages are typically issued.

This change will allow for flexibility when issuing tropical storm, hurricane and storm surge watches and warnings and more current and valid watches and warnings to be posted more frequently.

Extension of Tropical Storm Wind Radius Forecast…

The National Hurricane Center currently issues tropical storm wind radius forecasts out three days.

Starting in 2024, those forecasts will extend out five days.

 

Website Links in Advisories…

The public advisory for the 2024 hurricane season will include links that provide "graphical hazard information."

The links are "intended to help reduce the length of the Tropical Cyclone Public Advisory ... and to direct the focus to the most significant and impactful storm surge and rainfall hazards and areas," the NHC said.

 

Forecast Cone with Inland Watches and Warnings…

The NHC will be making changes to its cone of uncertainty, adding watches and warnings for interior areas starting around Aug. 15, 2024. Previously, watches and warnings were issued only for coastal areas.

With this experimental product, both coastal and inland watches and warnings will be shown with the forecast cone to illustrate that storm hazards can extend beyond the inside of a forecast cone.

Here is an example of the experimental version of the cone graphic.

 

The National Hurricane Center warns that since this is an experimental product, it may not be available at the same time that the current cone of uncertainty graphic is released but it should appear within 30 minutes of the advisory release.

 

Rainfall Graphics…

An experimental rainfall graphic for the Caribbean and Central America will be available in the 2024 Atlantic hurricane season.

The graphic will provide forecast rainfall totals for tropical cyclones or disturbances for a particular time period.

 

New marine forecast for offshore waters…

This change starts ahead of hurricane season

The current offshore waters forecast for the southwest and tropical north Atlantic will be divided into two forecasts starting March 26, 2024.

The new offshore waters forecast will consist of:

Offshore waters forecast for Southwest North Atlantic Ocean: Consists of all the Atlantic zones currently north of 19N.

Offshore waters forecast for the Caribbean Sea and Tropical North Atlantic: Consists of the remaining zones in the Caribbean Sea and Atlantic waters south of 19N.

 

 

Change to the Time zone Reference in the Eastern Pacific…

This won’t affect us here in the Northeast.

Most of Mexico no longer observes Daylight Saving

Time, therefore Central Standard and Mountain Standard time will be used in lieu of Daylight

Saving Time within those two time zones. Since Daylight Time is used within portions of Baja

California and the southwestern United States, Pacific Daylight Time will continue to be used

within that time zone when Daylight Saving Time is observed. The time zone of reference in

NHC tropical cyclone products is based on the initial position of the tropical cyclone at the

advisory issuance time, except for the caveat noted below. The time zone that appears in

eastern Pacific tropical cyclone products will be determined by the initial longitude of the tropical

cyclone as follows:

Central Standard Time: longitude at advisory time is east of 106.0W.

Mountain Standard Time: longitude at advisory time is between 106.0W to 114.9W.

During Daylight Saving Time, Pacific Daylight Time: when the longitude at advisory time is

west of 115.0W. Otherwise, Pacific Standard Time will be used. Please note that this

guidance applies to tropical cyclones that may affect Southern California.

CAVEAT: If the final forecast point for a tropical cyclone in the Tropical Cyclone

Forecast/Advisory (TCM) is west of 140W, the advisory will use Hawaii Standard Time.