Public Information Statement
Issued by NWS National HQ
Issued by NWS National HQ
003 NOUS41 KWBC 311720 PNSWSH Service Change Notice 24-62 National Weather Service Headquarters Silver Spring MD 120 PM EDT Fri May 31 2024 To: Subscribers: -NOAA Weather Wire Service -Emergency Managers Weather Information Network -NOAAPort Other NWS Partners, Users and Employees From: Gregory Schoor, Chief Marine, Tropical and Tsunami Services Branch Subject: Limiting Tropical Information in High Seas Forecasts from 120 Hours to Only the First 48 Hours: Effective June 26, 2024 The NWS National Centers for Environmental Prediction (NCEP)s Ocean Prediction Center (OPC), the National Hurricane Center (NHC)s Tropical Analysis and Forecast Branch (TAFB), and the Weather Forecast Office (WFO) Honolulu, Hawaii (HFO) are limiting tropical cyclone information in the High Seas Forecast (HSF) text product to only the first 48 hours of the forecast period starting on Wednesday, June 26, 2024. The HSF, detailed in NWS Instruction (NWSI) 10-311, describes the marine weather forecast and warning period as extending through the first 48 hours, in accordance with international standards and requirements. For tropical systems, it is noted that the highest tropical cyclone-based warning information is to be included for the 48-hour forecast. Limiting tropical cyclone information to the required 48 hours would reduce the HSF text product and broadcast time length and match NWS policy. Alternative sources of data: High seas mariners and customers will continue to have the entire 120-hour tropical cyclone information available via Inmarsat-C SafetyNet and Iridium Safetycast. The Tropical Cyclone Forecast/Advisory (TCM), available at the same frequency as high seas forecasts of up to four times daily for each active tropical cyclone, contains the cyclone position, intensity, direction, and speed of motion. It also includes the current maximum radial extent of 12-foot seas, as well as the maximum radial extent of winds of 34, 50, and 64 knots in each of four quadrants around the storm. The forecast/advisory contains quantitative forecast information on the track and intensity of the cyclone valid 12, 24, 36, 48, 60, 72, 96, and 120 hours from the forecasts nominal initial time, with size information forecast out to 72 hours. By reducing redundancy with the TCM, HSF broadcasts will be more streamlined. The TCM can be found as follows: Product Title WMO Header AWIPS Identifier ------------ --------- --------------- Atlantic NHC WTNT/21-25/KNHC TCMAT/1-5/ Atlantic WPC WTNT/21-25/KWNH TCMAT/1-5/ Eastern North Pacific NHC WTPZ/21-25/KNHC TCMEP/1-5/ Eastern North Pacific WPC WTPZ/21-25/KWNH TCMEP/1-5/ Central North Pacific CPHC WTPA/21-25/PHFO TCMCP/1-5/ There will be no changes to dissemination or product information for either the HSF or the TCM.Text products in this proposed change include: AWIPS Identifier WMO Header Geographic Descriptor --------------- ---------- -------------------- HSFAT1 FZNT01 KWBC High Seas Forecast METAREA IV HSFAT2 FZNT02 KNHC High Seas Forecast ATLANTIC FROM 07N TO 31N W OF 35W INCLUDING CARIBBEAN SEA AND GULF OF MEXICO HSFEPI FZPN02 KWBC High Seas Forecast METAREA XII HSFEP1 FZPN01 KWBC High Seas Forecast PACIFIC N OF 30N AND S OF 67N E OF A LINE FROM BERING STRAIT TO 50N 160E HSFEP2 FZPN03 KNHCHigh Seas Forecast E PACIFIC FROM THE EQUATOR TO 30N E OF 140W AND 03.4S TO THE EQUATOR E OF 120W HSFNP FZPN40 PHFO High Seas Forecast NORTH PACIFIC EQUATOR TO 30N BETWEEN 140W AND 160E HSFSP FZPS40 PHFO High Seas Forecast SOUTH PACIFIC EQUATOR TO 25S BETWEEN 120W AND 160E A public comment period (ref PNS 24-18) from March 11 through April 11, 2024 resulted in the majority supporting the change. Any additional comments can be sent to: Darin Figurskey Operations Branch Chief Ocean Prediction Center College Park, MD darin.figurskey@noaa.gov John Hurley Director of Operations WFO Honolulu Honolulu, HI john.hurley@noaa.gov Chris Landsea Operations Branch Chief NHC Tropical Analysis and Forecast Branch Miami, FL chris.landsea@noaa.gov Melinda Bailey National Weather Service Marine Program Manager National Weather Service Headquarters Silver Spring, MD melinda.bailey@noaa.gov National Service Change Notices are online at: https://www.weather.gov/notification/