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NOUS41 KWBC 101835

Service Change Notice 19-101
National Weather Service Headquarters Silver Spring MD
235 PM EST Tue Dec 10 2019

To:  Subscribers:
  -NOAA Weather Wire Service
  -Emergency Managers Weather Information Network
  Other NWS partners and NWS employees

From:  Mary Mullusky
    Chief, Water Resources Services Branch

Subject: Implementation of Wireless Emergency Alerts (WEA)
Changes for Flash Flood Warnings on or after January 8, 2020

Beginning on or after January 8, 2020, the NWS will issue
Wireless Emergency Alerts (WEA)for Flash Flood Warnings (FFW)
based on damage threat tags.

WEAs will only be sent for FFWs with a damage threat tag of
either "considerable" or "catastrophic" using the new
90-character messaging. FFWs labeled with these tags are life-
threatening and require urgent action. Because these tags are
applied to FFWs relatively rarely, this change will limit the
number of FFW WEAs distributed. WEAs will also be issued for
Flash Flood Statements that exhibit an increase in damage threat
(e.g., base [no tag] to considerable, base [no tag] to
catastrophic, and considerable to catastrophic).

This change will not affect key information in the FFW segment
header block, including the Valid Time Event Code (VTEC) and
Hydrologic VTEC (H-VTEC) strings, nor will it affect changes to
the existing criteria for warning dissemination. All FFWs will
still be issued and distributed via NOAA Weather Radio, the
Emergency Alert System, on radio and TV broadcasts,
and through dissemination systems to our emergency managers and
partners.  Information about the specific changes to WEA
Messages for FFWs can be found in the Product Description
Document (PDD):

The characterization of the flash flood damage threat, source
information and causative event, along with examples of FFWs in
Impact-Based Warnings (IBW) format, are contained in the PDD:

Based on feedback from the public survey referenced in the

and approvals for the broader IBW effort, NWS is proceeding to
implement the WEA changes for FFWs.

WEA is a joint effort between the Federal Communications
Commission, the Federal Emergency Management Agency, and the
wireless industry that allows emergency alerting authorities to
geographically target emergency messages to mobile devices
(primarily cell phones). The NWS will provide messages to WEA
for hazards believed to be life-threatening and that have
consequences that can be mitigated or minimized by immediate
action.  More information about WEA can be found at:

NWS has also solicited public feedback on a proposed expansion
of weather warnings to the new 360-character maximum and the
proposed content of the NWS messages carried by WEA in English
and Spanish. Based on the positive feedback received, we have
now  finalized those messages. This Service Change Notice will
be updated once an implementation date for 360-character FFW WEA
messages in English and Spanish has been established.

For more information, please email:

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.