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TECHNICAL IMPLEMENTATION NOTICE 07-90 AMENDED

NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC

1055 AM EDT TUE MAR 11 2008

TO: Family of Services (FOS) Subscribers\...NOAAPort

Subscribers\...Other National Weather Service (NWS)

Partners and Other Users\...NWS Employees

FROM: Jason Tuell

> Chief\...Science Plans Branch
>
> Office Of Science And Technology (OST)

SUBJECT: Amended: Addition of NCEP RTMA Grids for the Alaska

Region: Effective March 13 2008

REFER TO: Technical Implementation Notice (TIN) 07-90 Transmitted

on November 13 2007

Amended to delay the implementation date of Real Time Mesoscale Analysis
(RTMA) addition to the National Digital Guidance Database (NDGD) from
January 22 2008 to March 13 2008. Addition of RTMA to NOAAPort proceeded
on January 24 2008.

Effective Thursday march 13 2008\...at approximately 1500

Coordinated Universal Time (UTC)\...the national centers for

Environmental prediction (NCEP) will begin disseminating RTMA for the
Alaska region via NDGD.

RTMA for Alaska consists of a set of gridded surface analyses

Corresponding to the 10 parameters listed below in table 1.

Similar to the CONUS RTMA products already provided via NOAAPort and
NDGD\...these new Alaska region grids are also intended for

distribution in near real time. Thus in the generation of these

grids\...NCEP ingests as much satellite\...radar\...ASOS\... Mesonet

\...and other sensor data as it can acquire in near real time. The

Sensor data are analyzed and interpolated to a 6 km resolution

Alaska region polar stereographic grid and encoded in grib2.

NCEP generates one set of Alaska region RTMA grids each hour.

Each hourly grid has a valid time corresponding to an

even hour (i.e. 0000\...0100\...0200\...thru 2300). The Alaska RTMA
grids will become available on NDGD at approximately 45 minutes after
the valid time hour.

The hourly data volume is approximately 6 megabytes /MB/.

The daily data volume is approximately 144 MB.

All of the grids listed in Table 1 are already carried on NOAAPort.

TABLE 1: WMO Headings Assigned to the Alaska Region RTMA Grids

WMO Heading RTMA Parameters

LTAA98 KWBR: Temperature Analysis

LTAA98 KWBR: Temperature Analysis Uncertainty

LRAA98 KWBR: Dewpoint Temperature Analysis

LRAA98 KWBR: Dewpoint Temperature Analysis Uncertainty

LNAA98 KWBR: Wind Speed Analysis

LNAA98 KWBR: Wind Speed Analysis Uncertainty

LNAA98 KWBR: Wind Direction Analysis

LNAA98 KWBR: Wind Direction Analysis Uncertainty

LUAA98 KWBR: U Wind Component Analysis (NOAAPort Only)

LVAA98 KWBR: V Wind Component Analysis (NOAAPort Only)

All of the grids listed in Table 1 are already flowing on NOAAPort. All
of the grids listed in Table 1\...except for U and V winds\...will
become available in NDGD on March 13 2008. The grids will be in grib2
format in subdirectories:

<ftp://tgftp.nws.noaa.gov/SL.us008001/ST.expr/DF.gr2/dc.ndgd/GT.rtma/AR.alaska>

<http://weather.noaa.gov/pub/SL.us008001/ST.expr/DF.gr2/.ndgd/GT.rtma/AR.alaska/>

There are 24 subdirectories beneath the ar.alaska directory

\...one for each hour of the day: rt.00\...rt.01\...rt.02\...through

rt.23. Each hourly subdirectory will store the RTMA files for

that nominal hour. The RTMA files in each hourly subdirectory

will be named as shown in Table 2:

Table 2: NDGD File Names for Alaska Region RTMA Grids

File Name RTMA Parameter

DS.TEMP.BIN Temperature Analysis

DS.UTEMP.BIN Temperature Analysis Uncertainty

DS.TD.BIN Dewpoint Temperature Analysis

DS.UTD.BIN Dewpoint Temperature Analysis Uncertainty

DS.WSPD.BIN Wind Speed Analysis

DS.UWSPD.BIN Wind Speed Analysis Uncertainty

DS.WDIR.BIN Wind Direction Analysis

DS.UWDIR.BIN Wind Direction Analysis Uncertainty

The residence time of NDGD RTMA files will be approximately one

day. Each hour new files will be written to the most recent

hourly directory\...overwriting the files corresponding to the

same hour on the previous day.

NCEP has created the following web site for previewing up-to-date

Alaska RTMA:

<http://www.emc.ncep.noaa.gov/mmb/rtma/alaska/>

For questions about the technical content or generation of these

products\...please contact:

Geoff Dimego

NWS NCEP Environmental Modeling Center

Camp Springs Maryland

Phone: 301 763 8000 Ext 7221

Email: <geoff.dimego@noaa.gov>

For questions about the NCEP dataflow aspects of these data sets

\...write the NCEP/NCO/PMB dataflow help desk email address below.

Email: <ncep.pmb.dataflow@noaa.gov>

For questions concerning the NDGD activation of these products\...please
contact:

Brian Gockel

NWS Office of Science and Technology

Silver Spring Maryland

Phone: 301 713 0304 Ext 158

Email: brian.gockel@noaa.gov

NWS Technical Implementation Notices are online at:

<http://www.nws.noaa.gov/om/notif.htm>

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