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Service Change Notice 17-112 Updated
National Weather Service Headquarters Silver Spring MD
420 PM EST Fri Jan 19 2018

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

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

Subject: Updated: Polygon-based Snow Squall Warnings to begin on or
 about January 31, 2018, for select offices and Polygon-based
 Dust Storm Warnings and Dust Advisory Product Operational
 Demonstration at select Weather Forecast offices (WFOs) on
 or about June 20, 2018

Updated to amend the beginning date for the Snow Squall Warning
Operational Demonstration to on or about January 31, 2018, for
WFO Cheyenne, WY and to a date to be announced in a future
Service Change Notice for WFO Buffalo. Also updated to amend the
beginning date for the Dust Storm Warnings and Dust Advisory
locations to on or about June 20, 2018.

To provide feedback on Dust Storm Warning and Dust Advisory:
www.nws.noaa.gov/survey/nws-survey.php?code=DSWDSY

To provide feedback on Snow Squall Warnings:
www.nws.noaa.gov/survey/nws-survey.php?code=SQW1718

On January 16, 2018, the NWS began an operational demonstration
to issue the highly localized, polygon-based Snow Squall
Warnings at the following WFOs:

State College, PA
Binghamton, NY
Burlington, VT
Pittsburgh, PA
Detroit, MI

and effective on or about June 20, 2018, the polygon-based Dust
Storm Warnings and Dust Advisory products at WFOs:

Phoenix, AZ
Tucson, AZ

The software that provides the capability to issue these
products will be implemented in a phased manner to all NWS
offices by May 2018. Provision of the new products will commence
according to local office procedures. A Service Change Notice
will be issued before the operational implementation of the
new services.

The products will be issued for a portion of a county or
counties within the warned area, as defined and depicted by the
polygon LAT/LON point pairs. Portions of counties would be
described by ordinal directions (e.g., North, Northeast, East,
Southwest, Central, etc.). After an initial issuance, WFOs would
update the product for an extension of area or time by issuing a
new product. The WFO issuing the initial message would cancel or
allow it to expire when conditions no longer meet criteria.

Snow Squall Warning Product:

The Snow Squall Warning will provide three discrete
information sections segments per the example below when the
following conditions are expected:

HAZARD...White-out conditions in heavy snow and blowing snow
SOURCE...Radar indicated and webcams
IMPACT...Dangerous life-threatening travel

The Snow Squall Warning will use the new SQ.W Valid Time Event
Code (VTEC) with an operational (O) fixed identifier in the
P-VTEC line, and Warning (W) significance code.

The new product will use existing World Meteorological
Organization (WMO) headers and Advanced Weather Interactive
Processing System (AWIPS) identifiers as shown below:

WFO       WMO Header AWIPS Id
--------------------   --------- --------
State College, PA      WWUS51 KCTP SQWCTP
Binghamton, NY       WWUS51 KBGM SQWBGM
Burlington, VT       WWUS51 KBTV SQWBTV
Pittsburgh, PA       WWUS51 KPBZ SQWPBZ
Detroit, MI       WWUS53 KDTX SQWDTX
Cheyenne, WY       WWUS55 KCYS SQWCYS

The Snow Squall Warning product will be available via NOAA
Weather Wire Services, NOAAPort satellite broadcast and other
sources under the WMO Header WWaa5i cccc:

-aa corresponds to US, AK, CA, GM, HW, or ZS
-i is equal to 0 (zero) to 9
-cccc is equal to the WFO 4-character site ID

The Snow Squall Warning product will use the county Universal
Geographic Code (UGC).

The Snow Squall Warning will appear on the weather.gov web page
as well as the local WFO web pages with a priority of number 23
and display color of medium violet red.

Snow Squall Warnings will broadcast over NOAA Weather Radio All
Hazards (NWR) using the NWR Specific Area Message Encoding
(SAME) SVS Event Code according to local policy. The 1050 Hz
Warning Alarm Tone will also be invoked. NWS Offices will be
working with state broadcasters associations and State Emergency
Communications Committees for possible future activations of the
Emergency Alert System (EAS) for the Snow Squall Warning.

Dust Storm Warning Products:

The existing zone-based Dust Storm Warning will be replaced by
two distinct warning products: a polygon-based Dust Storm
Warning and a zone-based Blowing Dust Warning. The polygon-based
Dust Storm Warning will be issued when widespread or localized
blowing dust is forecast to suddenly reduce visibility to less
than one quarter mile with sustained winds greater than 25 mph,
resulting in dangerous and life-threatening travel conditions.
The polygon-based Dust Storm Warning will provide three discrete
information sections segments per the example below when the
following conditions are expected:

HAZARD...Visibility less than one-quarter mile in blowing dust
SOURCE...Radar indicated and webcams
IMPACT...Dangerous and life-threatening travel

The zone-based Blowing Dust Warning will be issued if similar
conditions are forecast over a long duration, generally greater
than 90 minutes.

Dust Advisory Products:

The new polygon-based Dust Advisory will be issued when
widespread or localized blowing dust suddenly reduces visibility
to between one quarter of a mile and 1 mile, resulting in
hazardous travel conditions. The polygon-based Dust Advisory
will provide three discrete information sections, per the
example below, when the following conditions are expected:

HAZARD...Visibility between one-quarter and 1 mile in blowing
dust
SOURCE...Radar indicated and webcams
IMPACT...Hazardous travel

The existing Blowing Dust Advisory will remain a zone-based
product and will be issued if similar conditions persist over a
long duration, generally greater than 3 hours.

All Dust Warning and Advisory products will be available via
NOAA Weather Wire Service (NWWS), NOAAPort satellite broadcast
and other sources under the WMO Header WWaa7i cccc

-aa corresponds to US, AK, CA, GM, HW, or ZS
-i is equal to 0 (zero) to 9
-cccc is equal to the WFO 4-character site ID

The polygon-based (with county UGC) Dust Storm Warning and Dust
Advisory will have an AWIPS Identifier of DSWxxx where xxx is
equal to WFO site ID.

The zone-based (with zone UGC) Blowing Dust Warning and Blowing
Dust Advisory will have an AWIPS Identifer of NPWxxx, where xxx
is equal to 3-character WFO site ID.

The Dust Storm Warning will use the existing VTEC code DS.W and
the Dust Advisory will use the new DS.Y VTEC code. Both of the
warning products will use existing WMO headings (WWUS55 KPSR for
WFO Phoenix and WWUS55 KTWC for WFO Tucson) and AWIPS
Identifiers (DSWPSR for WFO Phoenix and DSWTWC for WFO Tucson)
for dissemination over NOAAPort and NOAA Weather Wire Services.
NWS will broadcast the polygon-based Dust Storm Warning over NWR
and disseminate with both SAME (using the DSW Event Code) and
1050 Hz warning alarm tones. NWS will display the warning
polygon on NWS radar depictions.

The Dust Storm Warning and the Blowing Dust Warning will appear
on the weather.gov web page as well as the local WFO web pages
with a priority of number (40) and display color of bisque. The
Dust Advisory and the Blowing Dust Advisory will appear on the
weather.gov web page as well as the local WFO web pages with a
priority of number (87) and display color of dark khaki.

Common Alerting Protocol:

The Snow Squall Warning and Dust Storm Warning products will be
disseminated in Common Alerting Protocol (CAP) format through
several methods. CAP is pre-parsed and is intended for use by
the weather enterprise and other partners. For more information
on CAP and how to obtain it via NOAAPORT, NWS web file services,
in raw XML format or via a web service API, please see the
following Service Change Notice issued on September 1, 2017:
http://www.nws.noaa.gov/os/notification/scn17-98cap1_2.htm

Examples of these products including more information about
activation of the Emergency Alert System and Wireless Emergency
Alerts can be found in the Product Description Documents linked
below:

Dust Storm Warning/Dust Advisory:
https://nws.weather.gov/products/docs/PDD-
DustStormWarningandAdvisoryProducts.pdf

Snow Squall Warning:
https://nws.weather.gov/products/docs/PDD-
NewSnowSqualWarning.pdf

Additional information on UGC and VTEC can be found in NWS
Instructions (NWSI) 10-1701 and NWSI 10-1703, respectively at:
http://www.nws.noaa.gov/directives/sym/pd01017001curr.pdf
http://www.nws.noaa.gov/directives/sym/pd01017003curr.pdf

To provide feedback on Dust Storm Warning and Dust Advisory:
www.nws.noaa.gov/survey/nws-survey.php?code=DSWDSY

To provide feedback on Snow Squall Warnings:
www.nws.noaa.gov/survey/nws-survey.php?code=SQW1718

For questions or comments on these new products, please contact:

For Snow Squall Warning:
David Soroka, Winter Weather Services Program Lead
NWS Severe, Fire, Public, and Winter Weather Services Branch
Silver Spring, MD
Telephone: 301-427-9346
Email: david.soroka@noaa.gov

For Dust Storm Warning and Dust Advisory:
Andy Horvitz, Public Weather Services Program Lead
NWS Severe, Fire, Public, and Winter Weather Services Branch
Silver Spring, MD
Telephone: 301-427-9357
Email: andy.horvitz@noaa.gov

National Service Change Notices are online at:

http://www.weather.gov/os/notif.htm



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