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000
NOUS41 KWBC 251510
PNSWSH

Service Change Notice 17-59
National Weather Service Headquarters Silver Spring MD
1110 AM EDT Thu May 25 2017

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

From:  Dave Myrick
  NWS Office of Science and Technology Integration

Subject:  Upgrade of experimental National Blend of Models
  guidance effective July 11, 2017, and request for
  comments

On or about Wednesday, July 11, 2017, beginning with the 1200
Coordinated Universal Time (UTC) model run, the NWS
Meteorological Development Laboratory (MDL) will implement an
update to the experimental National Blend of Models (NBM)
guidance over the CONUS, OCONUS (Alaska, Hawaii, Puerto Rico),
and Oceanic National Digital Forecast Database (NDFD) domains.

1. Background

This upgrade will incorporate additional global and mesoscale
models over the CONUS and OCONUS domains.  The upgrade will
enable the NBM to routinely generate key aviation weather
elements for digital aviation services, fire weather and several
meteorological fields used to derive a predominant weather grid
at local Weather Forecast Offices. The location and cycle
availability of all NBM products is outlined in
Sections 4-6 below.

2. NBM Elements

A list of weather elements that will be available at hourly time
steps through 36 hours is provided below:

    1. 2-m temperature
    2. 2-m dewpoint
    3. 10-m wind speed
    4. 10-m wind direction
    5. 10-m wind gust
    6. Sky Cover
    7. Ceiling height (CONUS Only)
    8. Lowest cloud base height (CONUS Only)
    9. Visibility (CONUS Only)
   10. Precipitation potential index (CONUS Only)
   11. Quantitative precipitation amount (1-hour, CONUS Only)
   12. 2-m relative humidity (NDGD only, No SBN)
   13. 2-m apparent temperature (NDGD only, No SBN)

The following NBM weather elements will be available over the
CONUS and OCONUS domains at 3-hour time steps between 39-192
hours and every 6 hours thereafter through 264 hours:

    1. 2-m temperature
    2. 2-m dewpoint
    3. Daytime 2-m Maximum temperature
    4. Nighttime 2-m Minimum temperature
    5. 10-m wind speed
    6. 10-m wind direction
    7. 10-m wind gust
    8. Sky Cover
    9. Precipitation potential index (6-hour)
   10. Probability of precipitation (12-hour)
   11. Quantitative precipitation amount (6-hour)
   12. 2-m Maximum relative humidity (12-hour)
   13. 2-m Minimum relative humidity (12-hour)
   14. 2-m relative humidity (NDGD only, No SBN)
   15. 2-m apparent temperature (NDGD only, No SBN)

For CONUS only, the following NBM weather grid elements will be
available at hourly time steps between 1-36 hours, every 3 hours
between 36-192 hours, and every 6 hours through 264 hours:

    1. Maximum wet-bulb temperature aloft
    2. Bourgouin positive area/energy
    3. Bourgouin negative area/energy
    4. Probability of cloud ice present
    5. Conditional probability of rain
    6. Conditional probability of snow
    7. Conditional probability of freezing rain
    8. Conditional probability of sleet
    9. Conditional probability of refreeze sleet
   10. Snow-liquid ratio
   11. Snow level
   12. 3-h prob. of a thunderstorm (3-hourly, 3-78 hours)
   13. 6-h prob. of a thunderstorm (6-hourly, 84-180 hours)

3. This upgrade will incorporate additional global and mesoscale
models and statistically post-processed guidance over the CONUS
and OCONUS domains:

Current inputs:

1.    NAM (North American Mesoscale Forecast System - 12km)
2.    NAMNest (NAM 3km high resolution nest)
3.    GFS (Global Forecast System)
4.    GEFS (Global Ensemble Forecast System)
5.    GDPS (CMC - Environment Canada Global Deterministic -
PoP12/QPF06 only)
6.    GEPS (CMCE - Environment Canada Global Ensemble)
7.    EKDMOS (Ensemble Kernel Density Model Output Statistics)
8.    Gridded GFS MOS (GMOS or MOSGuide)

New inputs:

  9. HRRR (High Resolution Rapid Refresh), CONUS only
 10. RAP (Rapid Refresh)
 11. Gridded LAMP (GLMP Localized Aviation MOS Product), CONUS
     only)
 12. HiResWindow ARW NCEP (High-Resolution Window Forecast
     System (HIRESW))
 13. HiResWindow NMMB NCEP (High-Resolution Window Forecast
     System (HIRESW))
 14. SREF (Short Range Ensemble Forecast) CONUS, Alaska,
     Puerto Rico sectors
 15. NAVGEME (Navy FNMOC Global Ensemble)

The CONUS NBM products will be disseminated on a 2.5-km Lambert
Conformal grid with dimensions NX=2345 and NY=1597.  This
represents an expansion to the west by 200 grid lengths compared
to the current operational NBM domain to provide coverage for
the Nearshore Wave Prediction Model (NWPS) along the
U.S. West Coast.

NBM products for Alaska will be produced on a 3-km Polar
Stereographic grid with dimensions NX=1649 and NY=1105. The
Hawaii NBM products will be produced on a 2.5-km Mercator grid
with dimensions NX=625 and NY=561. Products for Puerto Rico will
be produced on a 1.25-km Mercator grid with dimensions NX=353
and NY=257.

4. NBM Oceanic Products

NBM guidance for the Oceanic domain will now incorporate all
ensemble members from the Global Ensemble Forecasting System
(GEFS) and the Canadian Meteorological Centre Ensemble (CMCE).
This upgrade provides additional 10-m wind speed percentile
thresholds and a blended wind direction field using a clustering
technique. The Oceanic products will continue to be produced on
a 10-km Mercator grid with dimensions NX=2517 and NY=1817.
Guidance for the following elements will be available for the
0000 and 1200 UTC cycles at 3-hourly time steps between 3-192
hours and at 6-hourly time steps thereafter through 264 hours:

    1. 10-m wind speed 10th Percentile
    2. 10-m wind speed 25th Percentile
    3. 10-m wind speed 50th Percentile
    4. 10-m wind speed 75th Percentile
    5. 10-m wind speed 90th Percentile
    6. 10-m blended wind direction

5. SBN/NOAAPORT Dissemination

While the NBM will run every hour and produce output to 264
hours with each run, only a subset will be sent across the
Satellite Broadcast Network (SBN) and NOAAPORT due to bandwidth
limitations. Products will be disseminated in GRIB2 format and
will contain individual WMO headers. On implementation day,
current NBM products going across the SBN/NOAAPORT will no
longer contain superheaders. The schedule for SBN/NOAAPORT
dissemination is as follows:

 NBM Window      Disseminated Cycles (UTC)
 ----------------------      ------------------------------

 Short-term: 1-18h      0100,0200,0400,0800,1000,1100,
      1300,1400,1600,2000,2200,2300

 Short-term: 1-36h      0300,0600,0900,1500,1800,2100

 Short-term and
 medium-range: 1-84h      0500,1700

 Short-term and
 extended-range: 1-264h      0000,0700,1200,1900

 Oceanic products -
 through 264h      0000,1200

6. TGFTP/NDGD Dissemination

Output for the 0000, 0700, 1200 and 1900 UTC cycles will be
placed in the experimental area of the National Digital Guidance
Database (NDGD) in GRIB2 format at the following locations:

ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndgd/GT.b
lend/AR.conus/(CONUS)
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndgd/GT.b
lend/AR.alaska/  (Alaska)
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndgd/GT.b
lend/AR.hawaii/  (Hawaii)
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndgd/GT.b
lend/AR.puertori/  (Puerto Rico)
ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/DC.ndgd/GT.b
lend/AR.oceanic/  (Oceanic)

Each domain directory will contain subdirectories for each valid
period as follows:

    VP.001/  Day 1
    VP.002/  Day 2
    VP.003/  Day 3
    VP.004/  Day 4
    VP.005-007/  Days 5-7
    VP.008-450/  Days 8 and beyond

Each element-specific GRIB2 file will reside in the appropriate
valid period subdirectory and contain individual WMO headers.
On implementation day, NBM files residing in NDGD will no longer
contain superheaders.  A listing of GRIB2 file names for all NBM
elements that will reside on TGFTP is provided in Table 1 below.

Table 1. GRIB2 file names for NBM elements that will reside on
TGFTP/NDGD in the appropriate valid period subdirectory.

  CONUS/ALASKA/HAWAII/PR PRODUCTS:
  GRIB2 FILE NAME     NBM ELEMENT NAME
  ---------------     -----------------------------
  ds.skymean.bin      Sky cover (mean)
  ds.wdirmean.bin     Wind direction (mean)
  ds.wspdmean.bin     Wind speed (mean)
  ds.pop12.bin        12-h probability of precipitation
  ds.tempmean.bin     2-m temperature (mean)
  ds.tdmean.bin       2-m dewpoint temperature (mean)
  ds.maxtmean.bin     Daytime maximum temperature (mean)
  ds.mintmean.bin     Nighttime minimum temperature (mean)
  ds.qpf06.bin        6-h quant. precipitation amount
  ds.rhmean.bin       2-m relative humidity (mean)
  ds.apptmean.bin     2-m apparent temperature (mean)
  ds.wgustmean.bin    Wind gust (mean)
  ds.ppi.bin       Precipitation potential index
  ds.maxrhmean.bin    12-h maximum relative humidity (mean)
  ds.minrhmean.bin    12-h minimum relative humidity (mean)

  CONUS-ONLY PRODUCTS:
  GRIB2 FILE NAME     NBM ELEMENT NAME
  ---------------     -----------------------------
  ds.pts03.bin        3-h Probability of a thunderstorm
  ds.pts06.bin        6-h Probability of a thunderstorm
  ds.vismean.bin      Visibility (mean)
  ds.cigmean.bin      Ceiling height (mean)
  ds.cldbsemean.bin   Cloud base height (mean)
  ds.qpf01.bin        1-h Quant. precipitation amount
  ds.cprbfzrain.bin   Cond. probability of freezing rain
  ds.cprbsnow.bin     Cond. probability of snow
  ds.cprbrain.bin     Cond. probability of rain
  ds.cprbsleet.bin    Cond. probability of ice pellets
  ds.prbrefzslt.bin   Probability of refreeze sleet
  ds.probcldice.bin   Probability of cloud ice present
  ds.negemean.bin     Bourgouin negative area/energy (mean)
  ds.posemean.bin     Bourgouin positive area/energy (mean)
  ds.slrblend.bin     Snow-liquid ratio (mean)
  ds.snowlvlmean.bin  Snow level (mean)
  ds.maxwbmean.bin    Maximum wet-bulb temp. aloft (mean)

  OCEANIC PRODUCTS:
  GRIB2 FILE NAME     NBM ELEMENT NAME
  ---------------     -----------------------------
  ds.wdirmean.bin     Wind direction (mean)
  ds.wspd10p.bin      Wind speed - 10th percentile
  ds.wspd25p.bin      Wind speed - 25th percentile
  ds.wspd50p.bin      Wind speed - 50th percentile
  ds.wspd75p.bin      Wind speed - 75th percentile
  ds.wspd90p.bin      Wind speed - 90th percentile


7. NCEP Web Dissemination

On implementation day, the NBM output for all cycles, elements,
and projections will now be made available on NCEP web services
sites:

http://nomads.ncep.noaa.gov/pub/data/nccf/com/blend/prod/
http://ftp.ncep.noaa.gov/data/nccf/com/blend/prod/
ftp://ftp.ncep.noaa.gov/pub/data/nccf/com/blend/prod

8. WMO Headers

Unique originating center IDs have been assigned to each
geographic region. A listing of the originating center IDs is
given in Table 2 below.  WMO headers for all NBM elements and
discontinued superheaders are listed below in Tables 3 and 4,
respectively.

A document outlining the new WMO header scheme for NBM products
can be found here:

 http://www.weather.gov/media/mdl/NBM_WMO_header.pdf

Table 2. List of originating center IDs (CCCC) for NBM products

Two IDs are assigned to each geographic region to accommodate
all weather elements. Oceanic products are disseminated under
KWEA.

  Geographic Region  Originating Center (CCCC)
  -----------------  ------------------------
  CONUS and Oceanic  KWEA and KWEB
  Alaska  KWEC and KWED
  Hawaii  KWEE and KWEF
  Puerto Rico  KWEG and KWEH

Table 3. WMO headers for all NBM products that will be
disseminated over the SBN/NOAAPORT and placed on TGFTP/NDGD

Listed below are representations of the WMO headers where xxx is
a placeholder for the forecast valid day and hour (see header
document linked above for further details).

  CONUS Products (CCCC=KWEA)
  WMO Header     Element Name
  ----------     -----------------------------
    YAAxxx     Sky cover (mean)
    YBAxxx     Wind direction (mean)
    YCAxxx     Wind speed (mean)
    YDAxxx     12-h Probability of precipitation
    YEAxxx     2-m temperature (mean)
    YFAxxx     2-m dewpoint temperature (mean)
    YGAxxx     Daytime maximum temperature (mean)
    YHAxxx     Nighttime minimum temperature (mean)
    YIAxxx     6-h Quant. precipitation amount (mean)
    YJAxxx     6-h Probability of a thunderstorm
    YMAxxx     Precipitation potential index
    YPAxxx     Visibility (mean)
    YQAxxx     Ceiling height (mean)
    YRAxxx     Relative humidity (mean) - NDGD only
    YTAxxx     Apparent temperature (mean) - NDGD only
    YVAxxx     1-h Quant. precipitation amount (mean)
    YWAxxx     Wind gusts (mean)
    YYAxxx     3-h Probability of a thunderstorm

  CONUS Products (CCCC=KWEB)
  WMO Header     Element Name
  ----------     -----------------------------
    YAAxxx     Cond. probability of freezing rain
    YBAxxx     Cond. probability of snow
    YCAxxx     Cond. probability of rain
    YDAxxx     Cond. probability of ice pellets
    YEAxxx     Probability of refreeze sleet
    YGAxxx     12-h Maximum relative humidity (mean)
    YHAxxx     12-h Minimum relative humidity (mean)
    YIAxxx     Probability of cloud ice present
    YNAxxx     Bourgouin negative area/energy (mean)
    YPAxxx     Bourgouin positive area/energy (mean)
    YQAxxx     Cloud base height (mean)
    YRAxxx     Snow-liquid ratio (mean)
    YSAxxx     Snow level (mean)
    YWAxxx     Maximum wet-bulb temp. aloft (mean)

  AK/HI/PR Products (CCCC=KWEC,KWEE,KWEG)
  WMO Header     Element Name
  ----------     -----------------------------
    YAAxxx     Sky cover (mean)
    YBAxxx     Wind direction (mean)
    YCAxxx     Wind speed (mean)
    YDAxxx     12-h Probability of precipitation
    YEAxxx     2-m temperature (mean)
    YFAxxx     2-m dewpoint temperature (mean)
    YGAxxx     Daytime maximum temperature (mean)
    YHAxxx     Nighttime minimum temperature (mean)
    YIAxxx     6-h Quant. precipitation amount (mean)
    YMAxxx     Precipitation potential index
    YRAxxx     Relative humidity (mean) - NDGD only
    YTAxxx     Apparent temperature (mean) - NDGD only
    YWAxxx     Wind gusts (mean)

  AK/HI/PR Products (CCCC=KWED,KWEF,KWEH)
  WMO Header     Element Name
  ----------     -----------------------------
    YGAxxx     12-h Maximum relative humidity (mean)
    YHAxxx     12-h Minimum relative humidity (mean)

  Oceanic Products (CCCC=KWEA)
  WMO Header     Element Name
  ----------     -----------------------------
    OBAxxx     Wind direction (mean)
    OCCxxx     Wind speed - 10th percentile
    OCMxxx     Wind speed - 25th percentile
    OCGxxx     Wind speed - 50th percentile
    OCNxxx     Wind speed - 75th percentile
    OCKxxx     Wind speed - 90th percentile

Table 4. List of WMO superheaders that are being discontinued.
Listed below are representations of the superheaders where ii
represents the valid period of the forecasts (ii=93-98).

  CONUS (CCCC=KWEA):
    LAAZii LBAZii LCAZii LDAZii LEAZii LFAZii
    LGAZii LHAZii LIAZii LRAZii LTAZii LWAZii

  Alaska (CCCC=KWEA):
    MAAZii MBAZii MCAZii MEAZii MFAZii
    MGAZii MHAZii MRAZii MTAZii MWAZii

  Hawaii (CCCC=KWEA):
    ZAAZii ZBAZii ZCAZii ZEAZii ZFAZii
    ZGAZii ZHAZii ZRAZii ZTAZii ZWAZii

  Puerto Rico (CCCC=KWEA):
    YAAZii YBAZii YCAZii YEAZii YFAZii
    YGAZii YHAZii YRAZii YTAZii YWAZii

  Oceanic (CCCC=KWEA):
    HCAZii

Users may find parallel NBM data for download:

http://para.nomads.ncep.noaa.gov/pub/data/nccf/noaaport/blend/
http://para.nomads.ncep.noaa.gov/pub/data/nccf/com/blend/para/

Feedback will be collected through October 15, 2017 via comments
provided on the electronic survey at:

 http://www.nws.noaa.gov/survey/nws-survey.php?code=EXPNBM

Any questions, comments or requests regarding this
implementation should be directed to the contacts below. We will
review any feedback and decide whether to proceed.

For questions regarding the implementation of NBM guidance
please contact:

 David Rudack
 MDL/Silver Spring, Maryland
 301-427-9456
 David.Rudack@noaa.gov

 or

 Jeff Craven
 MDL/Silver Spring, Maryland
 301-427-9475
 Jeffrey.Craven@noaa.gov

For questions regarding the data flow, please contact:

 Carissa Klemmer
 NCEP Central Operations
 301-683-0567
 ncep.list.pmb-dataflow@noaa.gov

A web page describing the NBM can be found at:

 http://w2.weather.gov/mdl/nbm_home

NWS National Service Change Notices are online at:

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



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