NOUS41 KWBC 171630



Service Change Notice 17-49

National Weather Service Headquarters Silver Spring MD

1230 PM EDT MON Apr 17 2017

To:††††† Subscribers:

†††††††† -NOAA Weather Wire Service

†††††††† -Emergency Managers Weather Information Network

†††††††† -NOAAPORT

†††††††† Other NWS Partners and NWS Employees

From:††† Allison Allen

†††††††† Chief, Marine, Tropical and Tsunami Services Branch

Subject: Changes to the appearance of the graphics

†††††††† accompanying Tropical Cyclone Advisory packages

†††††††† effective on or about May 15, 2017


Effective on or about May 15, 2017, the appearance of the

graphics accompanying tropical cyclone advisory packages issued

by the National Hurricane Center (NHC) and Central Pacific

Hurricane Center (CPHC) will change. These changes are required

for the NHC and CPHC to begin issuing forecasts and

watches/warnings for potential tropical cyclones.


A potential tropical cyclone is a disturbance that is not yet a

tropical cyclone but one for which the NWS has begun issuing

tropical cyclone watches or warnings because it poses the threat

of bringing tropical storm or hurricane conditions to land areas

within 48 hours.


In addition, three new Keyhole Markup Language (KML) files will

be available and the wind speed probability Geographic

Information System (GIS) files will be available at higher

resolution. This resolution change will make the data smoother

when plotted, but it will neither change how it is plotted nor

will affect a userís ability to display the data.

Summary of changes:

-All tropical cyclone graphics will use a common map

background and color scheme.

-The estimated extent of tropical-storm-force and hurricane-

force winds at advisory time will be depicted on the 5-day and

3-day track forecast/uncertainty graphic with the following


--Orange: estimated extent of tropical-storm-force winds

--Brown: estimated extent of hurricane-force winds

Users will have the option to toggle the initial wind extents

overlay on and off.

-The estimated extent of 34-kt, 50-kt, and 64-kt winds at

advisory time, as well as the forecast extent of 34-kt, 50-kt,

and 64-kt winds, will now be available in shapefile and KML

format. In addition, the estimated cumulative wind swath of

hurricane-force and tropical-storm-force winds will be available

in KML format. Previously, these files were only available in

shapefile format.

-The 5-day probability of 34-kt, 50-kt and 64-kt winds in KML

and shapefile format will be available on a 5 km grid.

Previously, these files used 10 km grid spacing. The resolution

of the model used to generate the input data did not change.

-The static Uniform Resource Locators (URL) of the latest-

available graphics from NHC for a given tropical cyclone will

change. A complete list of URL changes for NHC products is

provided on the NHC website at:


CPHC provides products on dynamic URLs that change for each

tropical cyclone. These products can be found for active

tropical cyclones in the central North Pacific on the CPHC



Examples of the graphics that will accompany CPHC tropical

cyclone advisory packages in 2017 can be found at:


The Public Information Statement (PNS) issued on March 8,

2017 to collect comments on this proposed change is online at:


No negative comments were received, so implementation of

these changes will be effective on or about May 15, 2017.


The effective date of this change is slightly sooner than

specified by NWS Policy (NWS Instruction 10-1805). The reduction

of the lead time was approved to ensure this change is made

before the tropical season begins.


If you have questions, please contact:


Jessica Schauer

NWS Marine, Tropical and Tsunami Services Branch

National Hurricane Center

Miami, FL 33165

Telephone: 305-229-4476



Wayne Presnell

NWS Marine, Tropical and Tsunami Services Branch

Silver Spring, MD20910

Telephone: 301-427-9390


National Service Change Notices are online at: