============================================================== Revised: 30 May 2023 Added access instructions. ============================================================== Revised: 29 April 2022 Added lists of missing and partial files after the additional data set details below. ============================================================== Revised: 10 January 2020 Notice - Pre-March 21, 2017, the PBLH values tend to be too high. (HYSPLIT can estimate PBLH using a method specified by the KMIXD variable as described at https://ready.arl.noaa.gov/hysplitusersguide/S410.htm). ============================================================== Revised: 22 March 2017 Effective March 21, 2017, coinciding with an NCEP NAM upgrade, the order of the fields were changed in the nam12 archive. A "bridge" file such as ../archives/gdas1/gdas1.mar17.w3 can be in the CONTROL file to allow HYSPLIT to continue between the files. Effective October 1, 2014, coinciding with a HYSPLIT upgrade at NCEP, PBLH was added. ============================================================== Revised: 26 July 2013 Coinciding with NCEP's change from one supercomputer to another, these additional surface fields were added beginning with the file valid July 25, 2013: TMPS SOLT SOLW WESD CSNO CICE CFZR CRAI VSBY TCLD CAPE CINH LISD LIB4 ============================================================== NAM 12 km Forecast Data Archive Revised: 10 January 2004 ________________________________________________________________________________ Access - The NAM 12 km archive may be accessed by a ftp client or by a web browser: 1) If you want to use a ftp client, Windows PC users may use WinSCP, FileZilla, etc. that support passive mode. MacOS and Linux users may use the ftp command. Connect your ftp client to ftp.arl.noaa.gov using anonymous and your email address for the username and password, respectively and change directory to /archives/nam12. Note if you are using multiple ftp connections, limit the number of concurrent connections equal to or less than two. Otherwise, your access to our ftp server may be blocked off. 2) If you are using a web browser, point it to https://www.ready.noaa.gov/data/archives/nam12. It may take a few minutes or longer for the webpage to display. ________________________________________________________________________________ Overview - NOAA ARL began an archive of the first 3 hours of NAM 12km meteorological data from NOAA NCEP in May 2007. An extraction procedure was implemented to concatenate the initial field (+0 h forecast) and the +3 h forecast for each cycle, four times daily, into daily files that can be accessed as a pseudo analysis archive. ________________________________________________________________________________ Additional Data Set Details 12.191 km lambert conformal grid ((different grid than CONUS files in /pub/archives/nams) 614x428 points Spatial domain: 12.19N 133.46W to 57.329N 49.4167W 31-day rotating archive with output every 3 hours 26 Levels (hPa): 1000,975,950,925,900,875,850,825,800,775,750,725,700, 650,600,550,500,450,400,350,300,250,200,150,100,50 Sfc Variables: 14 SHGT MSLP TPPT CPPT T02M RH2M U10M V10M PRSS LHTF SHTF USTR RGHS DSWF Upper Levels: 7 HGTS TEMP UWND VWND WWND RELH TKEN MODEL TYPE: NAM VERT COORD: 2 POLE LAT: 90.000 POLE LON: 0.0000 REF LAT: 25.000 REF LON: -95.00 REF GRID: 12.190 ORIENTATION: 0. CONE ANGLE: 25.0 SYNC X: 1. SYNC Y: 1. SYNC LAT: 12.190 SYNC LON: -133.46 NUMB X: 614 NUMB Y: 428 NUMB LEVELS: 26 ________________________________________________________________________________ Missing (3 files as of April 29, 2022): 20071212_nam12 20130817_nam12 20151129_nam12 Partial (1 file as of April 29, 2022): 20070526_nam12 (lacks the 21z data).