NOUS41 KWBC 211155



Technical Implementation Notice 13-4

National Weather Service Headquarters Washington DC

656 AM EST Thu Feb 21 2013


To:†††††††† Subscribers

††††††††††† -Family of Services

††††††††††† -NOAA Weather Wire Service

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

††††††††††† -NOAAPORT

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


From:†††††† Richard J. Vogt

††††††††††† Director, WSR-88D Radar Operations Center


Subject:††† WSR-88D Software Build 14 Changes That May Impact

WSR-88D Product and Data Users starting January 2014


The NEXRAD Program will implement software changes in Weather

Surveillance Radar-1988, Doppler (WSR-88D) Radar Data

Acquisition/Radar Product Generator (RDA/RPG) Build 14, that may

impact data/product users and user systems. Beta testing of Build

14 will begin at 5 sites in October 2013.The software is

scheduled for release starting in January 2014.Three of the

changes will slightly change the format of Level 3 products and

Level 2 data.These changes are described below:


1.A new, dynamic scanning method called Supplemental Adaptive

Intra-Volume Low-Level Scan (SAILS) will be introduced. When

SAILS" is selected by the radar operator, one supplemental "Split

Cut scan (lowest elevation of the VCP, normally 0.5į) is inserted

into the "middle" of existing severe weather VCPs 12 and 212. To

evenly space the time intervals between low-level updates, the

"middle" of the VCP is determined each volume scan based on the

termination angle assigned by the Automated Volume Scan

Evaluation and Termination (AVSET) function. SAILS will extend

volume scan completion times by approximately 35 seconds and

double the number of low-level scans.


2.Radial-by-Radial Noise Estimation will be introduced. Noise

can vary within elevation scans and over time. The new

algorithmís noise power estimate comes from radial data rather

than the current separate test, resulting in a unique noise value

for each radial. This change prevents over- or under-estimation

of noise and improves signal recovery, resulting in more accurate

Reflectivity, Differential Reflectivity, Spectrum Width, and

Correlation Coefficient values.

3.Base Products, Base Data, and General Status Message (GSM)

changes in Build 14:


- Base Products:The RPG will support generating base products

DR (94), DV (99), SDR (153), SDV (154), and SDW (155) from the

SAILS added Split Cut.For these products, the volume scan

time/date fields will be set to the start time/date of the added

Split Cut. The volume scan time/date fields for all other

products will continue to be the start time/date of first radial

of the volume scan. While SAILS is active, the supplemental

products N0Q(94/DR) and N0U(99/DV) will be provided via the NWS

Radar Product Central Data Collection Dissemination Service

(RPCCDS) and NOAAPort.

- Level 2 Base Data: The legacy base moments and Dual Pol

variables from SAILS supplemental scans will be in the Level II

base data stream. Radial-by-Radial Noise Estimation requires the

Horizontal and Vertical channel dBZ0 values to be added to the

Radial Data Block within Message Type 31, resulting in a Major

Version change from 1 to 2.

- General Status Message (GSM): The GSM length is increasing to

200 bytes. GSM Halfword 58, Bit 15 is set when AVSET is enabled,

Bit 14 will be used to identify when SAILS is active, and Bit 13

will be set if a site-specific VCP is in use. Bit 14 is set when

SAILS is enabled and a SAILS VCP is active and is not set all

other times. Bit 13 will only be set for the KLGX (Langley Hill,



The following tools are available to assist userís transition to

the Build 14 changes:


1.Draft Build 14 Interface Control Documents (ICDs) describing

the new data format and data stream (RPG to Class 1, RDA to RPG,

and Product Specification) are available at:


2.Dates/times of archived test Level 2 data sets, available

from NCDC, using the new format and SAILS and/or AVSET are

available at:


3.Real-time Level 2 data from the ROC test bed WSR-88D (KCRI)

will be available during Build 14 Operations Test at select

periods beginning in July. The ROC will issue another TIN in June

with information on how to obtain the data from the NWS Level 2

Data Collection and Distribution network and when the data will

be available with SAILS and/or AVSET operating.


4.An early version of Build 14 Software, executable and source

code, will be available from the NWS Common Operations and

Development Environment (CODE) beginning in June 2013 at:


More detailed descriptions of AVSET and SAILS are available at:


If you have questions concerning these changes, please contact:


†††† Mike Istok

†††† NWS Office of Science & Technology



†††† Joe Chrisman

†††† WSR-88D Radar Operations Center


National Technical Implementation Notices are online at: