Public Information Statement
Issued by NWS National HQ

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NOUS41 KWBC 231520

Public Information Statement 19-24
National Weather Service Headquarters Silver Spring MD
1120 AM EDT Fri Aug 23 2019

To:  Subscribers:
  -NOAA Weather Wire Service
  -Emergency Managers Weather Information Network
  Other NWS Partners and NWS Employees

From: Michelle Hawkins, Chief
 Severe, Fire, Public, and Winter Weather Services

Subject: Soliciting comments on experimental provision of Wet
Bulb Globe Temperature (WBGT) grids in the NDFD through
September 30, 2020

Effective on or about August 23, 2019, and continuing through
September 30, 2020, the NWS is seeking user feedback on
experimental Wet Bulb Globe Temperature (WBGT) grids in the
National Digital Forecast Database (NDFD).

NWS currently uses the Heat Index to convey heat risk during
summer heat events. While the heat index is useful for sedentary
populations, research has proven that the WBGT is a more
effective means of assessing heat risk to persons involved in
physical activity. The WBGT is a composite parameter that
estimates the effect of temperature, humidity, wind chill, and
solar radiation on humans, while Heat Index only takes into
account temperature and humidity.

Based upon engagement with core partners, particularly emergency
management officials, the NWS has identified the need to provide
WBGT forecasts because it is becoming an increasingly needed
parameter by partners in Impact-based Decision Support Services
(IDSS) activities. In particular, WBGT is important for those
partners who need a numerical (finite) value, rather than a
threat index, to determine necessary modifications to their
respective activities in the interest of protecting life.

To better meet users` needs, NWS will provide gridded forecasts
of WBGT in the NDFD on an experimental basis for the Continental
United States (CONUS), Hawaii, Guam and Puerto Rico. CONUS data
will be available hourly out to 36 hours from NDFD issuance
time, then every 3 hours out to 72 hours from 0000 Coordinated
Universal Time (UTC) Day 1, then every 6 hours out to 168 hours
from 0000 UTC Day 1.  Data for Hawaii, Guam and Puerto Rico will
be available every 3 hours out to 72 hours from 0000 UTC Day 1,
then every 6 hours out to 168 hours from 0000 UTC Day 1.

WBGT data for forecast days 1-3 and forecast days 4-7 will be
made available via https and ftp from the following URLs:

Please see NWS Product Description Document (PDD) for more

NDFD GRIB2 files can be downloaded and displayed by the user
with software available for download at the following URL:

Users are encouraged to provide feedback on this experimental
service by using the brief survey and comment form available
online at:

Questions related to WBGT can be directed to:
Lisa Schmit
NOAA/National Weather Service Forecast office
Chanhassen, MN 55317
Phone: (952) 361-6671

Policy questions related to WBGT can be directed to:
Andy Horvitz
NOAA/NWS/Analyze Forecast and Support Office
Silver Spring, MD 20910
Phone: 301-427-9357

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