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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: is the U.S. government's official web portal to all federal, state and local government web resources and services.