NOUS41 KWBC 191705

PNSWSH

 

Technical Implementation Notice 15-27

National Weather Service Headquarters Washington DC

105 PM EDT Tue May 19 2015

 

To:      Subscribers:

         -Family of Services

         -NOAA Weather Wire Service

         -Emergency Managers Weather Information Network

         -NOAAPORT

         Other NWS Partners, Users and Employees

 

From:    Timothy McClung

         Chief Operating Officer

         NWS Office of Science and Technology Integration

 

Subject: Upgrade to HIRES Window and Introduction of

         High-Resolution Ensemble Forecast: Effective

         June 30, 2015

 

Effective June 30, 2015, beginning with the 1200 Coordinated

Universal Time (UTC) run, the National Centers for Environmental

Prediction (NCEP) will upgrade the High-Resolution Window

Forecast System (HIRESW). This upgrade includes:

 

-Changes to the model components

-Increase in vertical resolution

-Modifications to parameterized physics

-New product fields

-File name changes

-New High-Resolution Ensemble Forecast (HREF) suite of products. 

 

Model Changes:

 

The HIRESW model will be updated from Weather Research and

Forecasting (WRF) version 3.5 code to 3.6.1 code for the Advanced

Research WRF (ARW) member. The Nonhydrostatic Multiscale Model on

B-grid (NMMB) will be updated from a late 2013 to early 2015

version of the code, but it will retain the microphysics used

with the current HIRESW system.  

 

The number of vertical levels will increase from 40 to 50 in both

the WRF-ARW and NMMB systems.

 

Physics Changes:

 

The WRF Single Moment 6-Class (WSM6) microphysics of the WRF-ARW

will be modified to decrease the amount of falling graupel, which

will leave more moisture for snow production in the anvil region.

 

Post-processing Changes:

 

Simulated radar reflectivity for the WRF-ARW model will now be

generated by the post-processing code rather than by the model

microphysics.  This change tends to reduce reflectivity at the

melting layer, which primarily impacts the composite

reflectivity.

 

Simulated reflectivity (instantaneous and hourly maximum) and

echo top height fields will be defined in this upgrade by the

nearest-neighbor value on the model grid rather than through

bilinear interpolation as was done previously.

 

The bitmapping of echo top heights for which no point in the

column has a sufficient value of reflectivity to define a height

will be removed.  A zero height value will be assigned instead.

 

Output Product Changes:

 

The order of records within the gridded output files will change

due to significant software changes in how the products are

produced.

 

The hourly maximum and minimum temperature and relative humidity

fields at 2 meters above ground will now be labeled in Grib2 as

temporal maxima and minima.

 

New fields only for 5 km output grids:

 

- Cloud ceiling height

- Simulated radar reflectivity at -10 C level

 

Changes to content of the 2.5-3 km NDFD output grids:

 

- Duplicate fields of surface height, land-sea mask, and Haines

Index in the three hourly files will be removed.

 

- A total cloud percentage will be uniformly defined for all

forecast hours.  This replaces a surface total cloud percentage

field that was previously only in three hourly files.

 

- The one and two hour old 2 m temperature and dew point

temperature fields will be included for forecasts valid at 00Z

and 12Z.  This was previously included for all three hourly

output except at those valid times.      

 

-  A best (4 layer) lifted index field will be added to the three

hourly output.  This field was previously in the non-three hourly

output only.

 

- Precipitation type and 2 m temperature and dew point

temperature fields will be removed from the non-three hourly

output in the NMMB run over Hawaii.

 

- A bug that was leading to incomplete Guam output files every

six hours will be corrected.  The following fields will be added

to the incomplete Guam files:

 

Accumulated precipitation

Probability of wetting rain

Planetary Boundary Layer (PBL) depth

2 m dew point temperature

Surface wind gust

Height of lowest wet bulb 0 C temperature

Surface geopotential height

Surface pressure

Land-sea mask

Maximum and minimum 2 m relative humidity (RH)

Probability of precipitation

Composite reflectivity

Average PBL RH

Snow depth accumulation

2 m specific humidity

Maximum and minimum 2 m temperature

2 m temperatures

10 m U and V winds

Surface visibility

Average PBL wind direction

Average PBL wind speed

Accumulated snow water equivalent

 

File name changes:

 

The filenames of existing output files will change to a new

naming convention.  All output files will now have "hiresw" as

the leading character string.  Legacy "awpreg", "awp5km", and

"smart" strings will be discontinued.  For gridded output, the

output file grid spacing in kilometers will be provided in the

file name, with decimals represented by a "p" (2.5 km is 2p5km in

a file name).  Please reference Table 1 for all Grib2 file name

changes.

 

The BUFR output file names will also change, generally following

the same rules applied for the gridded output.  Please reference

Table 2 for all BUFR file name changes.

 

Addition of new BUFR Sounding Products:

 

BUFR sounding products will be made available for each HIRESW

domain.  The file names for these products will be:

 

hiresw.tCCz.domain[arw|nmmb].bufrsnd.tar.gz

 

where CC is the cycle (00 and 12 for CONUS, Guam, and Hawaii and

06 and 18 for Alaska and Puerto Rico)

and domain is conus, ak, guam, hi, or pr

In addition to the single monolithic files for each model run,

the BUFR output will also be split out by individual station. 

 

The individual station files have names of the format:

 

domain[arw|nmmb]bufr.station.cycle

 

where domain is conus, ak, guam, hi, or pr

where station is the 6-digit identifier

and where cycle is the YYYYMMDDCC formatted time of the model

initial time (YYYY is the 4-digit year, MM is the month, DD is

the day, and CC is the cycle (00, 06, 12, 18)).

 

The new HREF products:

 

The new HREF is a set of probabilistic products generated from

the three most recent HIRESW model runs [both WRF-ARW and NMMB

members] and the five most recent North American Mesoscale (NAM)

model nest runs to create an 11 member time-lagged ensemble.  In

this initial implementation, products will be generated only for

the Contiguous United States (CONUS) domain.  Despite using the

same name, this product has very little in common with the HREF

output previously provided by HIRESW v5. 

 

HREF products will be generated every 6 hours at 00Z, 06Z, 12Z,

and 18Z.  Mean, spread, and probability products will be produced

at 3 hour forecast intervals from 3 h to 36 h.

 

The file names for the mean, spread, and probability product

files will be:

 

href.tCCz.mean.fFF.grib2

href.tCCz.sprd.fFF.grib2

href.tCCz.prob.fFF.grib2

 

where CC is the cycle (00, 06, 12, 18)

and where FF is the forecast hour (03, 06, 09, ..., 30, 33, 36)

 

The contents of the mean and spread files will be:

 

Sea level pressure

500 hPa height

850 hPa height, temperature, U and V winds, and wind speed

700 hPa vertical velocity and relative humidity

500 hPa absolute vorticity

Precipitable water (column total)

Surface visibility

3 h accumulated precipitation

Cloud ceiling height

Surface vertical speed shear

 

The contents of the probability files will be:

 

1000 m AGL simulated reflectivity > 40 dBZ

Hourly maximum 1000 m AGL simulated reflectivity > 40 dBZ

Hourly maximum 2-5 km AGL updraft helicity > 25 m^2/s^2

Hourly maximum updraft over 400-1000 hPa layer (m/s) > (1, 5, 10)

Hourly maximum downdraft over 400-1000 hPa layer (m/s) > 

 (1, 5 10)

Hourly maximum 10 m AGL U wind component > 15.4 m/s

Hourly maximum 10 m AGL V wind component > 15.4 m/s

Precipitable water (column total, kg/m^2) > (25, 37.5, 50)

Surface visibility (m) < (400, 800, 1600, 3200, 6400)

Column maximum (composite) simulated reflectivity (dBZ) > (10,

20, 30, 40, 50)

Echo top height (m) > (1000, 3000, 5000, 7600, 10000)

3 h precipitation (kg/m^2) > (0.24, 6.34, 12.4, 25.1, 50, 75)

Precipitation type: rain, freezing rain, ice pellets, snow

10 m AGL wind speed (m/s) > (10.3, 15.4, 20.6)

80 m AGL wind speed (m/s) > (10.3, 15.4, 20.6)

850 hPa wind speed (m/s) > (10.3, 20.6, 30.9, 41.2, 51.5)

500 hPa wind speed (m/s) > (10.3, 20.6, 30.9, 41.2, 51.5)

250 hPa wind speed (m/s) > (10.3, 20.6, 30.9, 41.2, 51.5)

Flight category (1-4)

Haines Index (2-5, 5-6, 6-7)

Cloud ceiling height (m) < (305, 610, 915, 1372, 1830, 3050)

Surface vertical speed shear (1/s) > 20

Wind speed over 300 to 850 hPa above ground < 5 m/s

 

Data Availability and Schedule Changes:

 

During the 2015 hurricane season, NCEP does not plan to reinstate

the preemption of HIRESW runs, but in subsequent years NCEP may

need to resume preemption based on resources in the NCEP

Production Suite.

 

The HIRESW data is currently available on the NWS FTP server, the

NCEP server, NOMADS, and on NOAAPORT.  The HREF products will

also be available on the NWS FTP server, the NCEP server, and

NOMADS, but they are not available on NOAAPORT. 

 

Product delivery timing of current HIRESW products is not

expected to change as a result of this implementation, although

downscaled (2.5 to 3 km) output from the CONUS and AK domains

will be available somewhat earlier.  Currently it arrives as much

as 30 minutes later than the 5 km gridded output; with this

upgrade that delay will be reduced to about five minutes.

 

More information regarding the current operational HIRESW and

associated products can be found at:

 

http://www.emc.ncep.noaa.gov/mmb/mmbpll/nestpage_4km/

 

A consistent parallel feed of data is currently available on the

NCEP HTTP server at the following URL: 

 

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

 

Table 1:  Grib2 File Name Changes

 

Contiguous United States (CONUS):

conus[arw|nmmb].tCCz.awp5kmfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_5km.fFF.conus.grib2

conus[arw|nmmb].tCCz.smartconusfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_2p5km.fFF.conus.grib2

 

Hawaii:

hi[arw|nmmb].tCCz.awpregfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_5km.fFF.hi.grib2

hi[arw|nmmb].tCCz.smarthifFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_2p5km.fFF.hi.grib2

 

Puerto Rico:

pr[arw|nmmb].tCCz.awpregfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_5km.fFF.pr.grib2

pr[arw|nmmb].tCCz.smartprfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_2p5km.fFF.pr.grib2

 

Alaska:

ak[arw|nmmb].tCCz.awpregfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_5km.fFF.ak.grib2

ak[arw|nmmb].tCCz.smartakfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_3km.fFF.ak.grib2

 

Guam:

guam[arw|nmmb].tCCz.awpregfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_5km.fFF.guam.grib2

guam[arw|nmmb].tCCz.smartguamfFF.grib2 ->

hiresw.tCCz.[arw|nmmb]_2p5km.fFF.guam.grib2

 

where CC is the model cycle (00 or 12 for CONUS, Alaska, and Guam

domains and 06 or 18 for Hawaii and Puerto Rico domains)

and where FF is the forecast hour (00, 01, 02, ..., 46, 47, 48).

 

Table 2: BUFR File Name Changes

 

conusarw.tCCz.class1.bufr  -> hiresw.tCCz.conusarw.class1.bufr

conusnmmb.tCCz.class1.bufr -> hiresw.tCCz.conusnmmb.class1.bufr

hiarw.tCCz.class1.bufr     -> hiresw.tCCz.hiarw.class1.bufr

hinmmb.tCCz.class1.bufr    -> hiresw.tCCz.hinmmb.class1.bufr

prarw.tCCz.class1.bufr     -> hiresw.tCCz.prarw.class1.bufr

prnmmb.tCCz.class1.bufr    -> hiresw.tCCz.prnmmb.class1.bufr

akarw.tCCz.class1.bufr     -> hiresw.tCCz.akarw.class1.bufr

aknmmb.tCCz.class1.bufr    -> hiresw.tCCz.aknmmb.class1.bufr

guamarw.tCCz.class1.bufr   -> hiresw.tCCz.guamarw.class1.bufr

guamnmmb.tCCz.class1.bufr  -> hiresw.tCCz.guamnmmb.class1.bufr

 

where CC is the model cycle (00 or 12 for CONUS, Alaska, and Guam

domains and 06 or 18 for Hawaii and Puerto Rico domains).

 

NCEP encourages all users to ensure their decoders are flexible

and are able to adequately handle changes in content order,

changes in the scaling factor component within the product

definition section (PDS) of the GRIB files, and also any volume

changes which may be forthcoming. These elements may change with

future NCEP model implementations. NCEP will make every attempt

to alert users to these changes prior to any implementations.

 

For questions regarding these changes, please contact:

 

      Matthew Pyle

      NCEP/EMC, Mesoscale Modeling Branch

      College Park, Maryland

      Phone: 301-683-3687

      Email: Matthew.Pyle@noaa.gov

or

      Geoff DiMego

      NCEP/EMC, Mesoscale Modeling Branch

      College Park, Maryland

      Phone: 301-683-3764

      Email: Geoff.Dimego@noaa.gov

 

For questions regarding the dataflow aspects of these data sets,

please contact:

 

     Kelly Kempisty

     NCEP/NCO Dataflow Team

     College Park, Maryland

     Phone:  301-683-0567

     Email:  ncep.list.pmb-dataflow@noaa.gov

 

NWS National Technical Implementation Notices are online at:

 

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

 

$$