NOUS41 KWBC 231930



Service Change Notice 18-20

National Weather Service Headquarters Silver Spring, MD

1130 AM EST Fri Feb 23 2018


To:          Subscribers:

             -NOAA Weather Wire Service

             -Emergency Managers Weather Information Network


             Other NWS Partners and NWS Employees


From:        Allison Allen

             Chief, Marine, Tropical and Tsunami Services Branch


Subject:     NHC and CPHC to begin issuing 48-hour 64-knot wind

   radii forecasts effective on or around May 15, 2018


Effective on or around May 15, 2018, the NWS National Hurricane

Center (NHC) and the Central Pacific Hurricane Center (CPHC)

will begin issuing a 64-knot wind radii forecasts at the 48-hour

forecast time. These wind radii will be provided in the Tropical

Cyclone Forecast/Advisory (TCM) product.


Currently, NHC and CPHC issue TCM products for ongoing and

potential tropical cyclones, subtropical cyclones, post-tropical

cyclones, and remnants of tropical cyclones up to forecast 

Day 5. TCM products include track, intensity, size and tropical

cyclone type (i.e., tropical depression, hurricane, etc.)

forecasts. Through the 2017 hurricane season, the TCM included a

forecast of 64-knot wind radii through 36 hours in each quadrant

of the storm. Beginning in the 2018 hurricane season, a new line

will be added to the 48-hour forecast to provide a forecast of

64-knot wind radii in all quadrants when applicable. 


An example of a 2018 TCM product that includes a 64-knot wind

radii 48-hour forecast is provided at:


A full description of NWS Tropical Cyclone Forecast Center

Products is provided in NWSI 10-607, which is available on the

Internet at:


For questions regarding this notice, please contact:


Jessica Schauer

NWS Tropical Service Program Lead

NWS Marine, Tropical and Tsunami Services Branch

National Hurricane Center

Miami, FL

Telephone: 305-229-4476



Wayne Presnell

NWS Marine, Tropical and Tsunami Services Branch

Silver Spring, MD  20910

Telephone:  301-427-9390



National Service Change Notices are online at: