NOUS41 KWBC 071835 AAA

PNSWSH

 

Technical Implementation Notice 16-22 Amended

National Weather Service Headquarters Washington DC

235 PM EST Wed Dec 7 2016

 

To:      Subscribers:

         -NOAA Weather Wire Service

         -Emergency Managers Weather Information Network

         -NOAAPORT

         Other NWS Partners and NWS Employees

 

From:    David Myrick

         Office of Science and Technology Integration

 

Subject: Amended:  The Nearshore Wave Prediction System (NWPS)

         data will be provided over the Satellite Broadcast

         Network (SBN) and NOAAPORT on or about November 17,

         2016, for Western, Pacific and Alaska Region WFOs

 

Amended to reflect GRIB2 file packing modifications and update

parallel data availability.

 

Effective on or about Thursday, November 17, 2016, additional

NWPS data will be added to the SBN and NOAAPORT. The NWPS is run

2-4 times per day, on-demand, depending on the coastal Weather

Forecast Office (WFO). On November 17, 2016, data for 13

additional coastal WFO domains (Western, Pacific and Alaska

Regions) was made available. This addition appends the data from

the 23 Eastern and Southern Region WFOs implemented in February

2016, bringing the total to 36 coastal WFO domains. The 3-hourly

grids will be disseminated in GRIB2 format. Grid resolutions

will be dependent upon individual coastal WFO. This upgrade also

features minor modifications to the GRIB2 file encoding and the

output directory structure of all 36 domains.

 

The parameters associated with the messages at these resolutions

are:

 

Q - Wind Speed

R - Wind Direction

Z - Current speed

Z - Current direction

Z - Water level

C - Wave Height

D - Water Depth

J - Peak Frequency/Period

K - Peak Direction

Z - Wave Length

O - Wave height of swell waves

O - Partitioned swell wave height

Y - Partitioned swell peak period

P - Partitioned swell mean direction

 

Data volume will vary, depending on coastal WFO. The average

total data volume is approximately 65 MB per cycle, 2 times per

day, for each of the remaining 13 coastal WFO domains.

 

CG grids are described as follows:

CG0 grid: partition output on overall computational domain 

(low- resolution) for a given WFO

 

CG1 grid: integral output on overall computational grid for a

given WFO

 

CG2 grid: integral output on first nested grid where applicable

 

CG3 grid: integral output on second nested grid where

applicable

 

CG4 grid: integral output on third nested grid where applicable

 

CG5 grid: integral output on fourth nested grid where

applicable

 

 

Each WFO may produce up to 5 grids. Not all WFOs are producing

all 5 grids for their County Warning Area (CWA).

 

CG0 grid messages are approximately 8 MB per WFO. The total

volume (13 coastal WFOs) is 104 MB per cycle, 2 times per day.

 

CG1 grid messages are approximately 29 MB per WFO. The total

volume is 377 MB per cycle, 2 times per day.

 

CG2 grid messages are approximately 7 MB per WFO. The total

volume is 91 MB per cycle, 2 times per day.

 

CG3 grid messages are approximately 7 MB per WFO. The total

volume is 91 MB per cycle, 2 times per day.

 

CG4 grid messages are approximately 7 MB per WFO. The total

volume is 91 MB per cycle, 2 times per day.

 

CG5 grid messages are 7 MB per WFO. The total volume is 91 MB

per cycle, 2 times per day.

 

The total volume (13 coastal WFOs) for all resolution files is

approximately 845 MB per cycle, 2 times per day.

 

The following summarizes the generic WMO Headers for the NWPS

data: T1T2A1A2iiCCCC, where:

 

T1 = E

 

T2 specifies the parameters (stated above)

 

A1 = A for CG0 grid; B for CG1 grid; C for CG2 grid; D for CG3

grid; E for CG4 grid, and F for CG5 grid

 

A2 specifies forecast hours: A=00, B=03, C=06, D=09, E=12, F=15,

G=18, H=21, I=24 and 27, J=30 and 33, K=36 and 39, L=42 and 45,

M=48 and 51, X=54 and 57, N=60 and 63, Y=66 and 69, O=72, 75, 78

and 81, P=84, 87, 90 and 93, Q=96, 99, 102

 

ii = 88 (specifies surface)

 

For CONUS offices, CCCC corresponds to K, appended by the 3-

letter AWIPS code for the generating the 7 coastal WFO domains:

 

SEW - Seattle, Washington

PQR - Portland, Oregon

MFR - Medford, Oregon

EKA - Eureka, California

MTR - Monterey, California

LOX - Los Angeles, California

SGX - San Diego, California

 

For OCONUS offices, CCCC corresponds to P, appended by the 

3-letter AWIPS code for generating the six coastal WFO domains:

 

HFO - Honolulu, Hawaii

GUM - Tiyan, Guam

AJK - Juneau, Alaska

AER - Anchorage, Alaska

ALU - Anchorage (Aleutian Islands), Alaska

AFG - Fairbanks, Alaska

 

 

OUTPUT DATA:

 

In addition to NOAAPORT, data will be available through the NCEP

ftp/http services:

 

  http://nomads.ncep.noaa.gov

  ftp://ftp.ncep.noaa.gov

 

On Implementation Day the data for the new domains was made 

available at:

 

  /pub/data/nccf/com/nwps/prod

 

The modified file format is the following:

 

For each of the 2-character regional codes (sr, er, wr, pr, ar)

the GRIB2 files are listed under date (YYYYMMDD), 3-character

WFO code (listed above, in lower case), run cycle (CC) and model

domain (CG = CG1, CG2, CG3, CG4, CG5; or CG0). The run cycle

always corresponds to the analysis time of the run (HH). All

output variables pertaining to the run domain are stored in a

single GRIB2 file. Note that since the runs are on demand, not

all CC cycles will be produced during a given YYYYMMDD.

 

REGION.YYYYMMDD/WFO/CC/CG/WFO_nwps_CG_YYYYMMDD_HH00.grib2

 

REGION.YYYYMMDD/WFO/CC/CG0/WFO_nwps_CG0_Trkng_YYYYMMDD_HH00.grib

2

 

GRIB2 ENCODING CHANGES:

 

The encoding of exception values has been changed from various

codes (-9.0, -99.0, -999.0) to a consistent value of 9.999e+20,

covering the full domain, which is interpreted as "NO DATA"

values by the AWIPS2 Grib2Decoder. For the CG0 GRIB2 files, this

results in a switch from the use of "NO BIT-MAP" to "with BIT-

MAP 0" in the encoding (see GRIB2 - Section 6). Furthermore, the

decimal precision at which the CG0 GRIB2 files are packed have

been increased.

 

The NWPS website is located at:

 

http://polar.ncep.noaa.gov/nwps/

 

For additional information regarding GRIB2 files, visit:

 

http://www.nco.ncep.noaa.gov/pmb/docs/grib2/

 

For questions pertaining to NWPS data, please contact:

 

Nicole P. Kurkowski

NWS STI Modeling Lead

NOAA/NWS/Office of Science and Technology Integration

Silver Spring, MD 20910

nicole.kurkowski@noaa.gov

 

For questions regarding the model, please contact:

 

Michael Farrar

NCEP/Director, Environmental Modeling Center

College Park, MD 20746

301-683-3748

michael.farrar@noaa.gov

 

For questions regarding data flow aspects, please contact:

 

Carissa Klemmer

NCEP/NCO Dataflow Team

College Park, MD 20746

301-683-0567

ncep.list.pmb-dataflow@noaa.gov

 

National Technical Implementation Notices are online at:

 

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

 

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