There are two types of GRIB output files on AWIPS Grid 212: AWIP3Dtt.tmXX (3-D atmospheric fields) AWIPSFtt.tmXX (2-D surface, subsurface, or near surface fields) In the above generic file names, the value of "tt" is either "00", denoting an analysis field, or a value ranging from "03" to "36", denoting a forecast length in hours. The "XX" denotes the number of hours PRIOR to the GMT time of the directory name that the INITIAL state for this field is valid. For example in directory T12Z: AWIPSF00.tm00 Analysis at 12Z (i.e. 12 GMT) AWIPSF00.tm03 Analysis at 09Z AWIPSF00.tm06 Analysis at 06Z AWIPSF00.tm09 Analysis at 03Z AWIPSF00.tm12 Analysis at 00Z (Caution: this file should not be used, since it is a 'cold-start' analysis based on global analysis. Instead of this file, use AWIPSF00.tm00 from the previous cycle). The first 4 files above (and their AWIP3D counterparts) are the primary analysis fields of chief interest to many users. Along with the corresponding 4 files in directory T00Z, one has eight analyses that span the 24-hour period at intervals of 3 hours. Continuing with directory T12Z: AWIPSF03.tm12 3-hour forecast from 00Z (valid at 03Z) AWIPSF03.tm09 3-hour forecast from 03Z (valid at 06Z) AWIPSF03.tm06 3-hour forecast from 06Z (valid at 09Z) AWIPSF03.tm03 3-hour forecast from 09Z (valid at 12Z) These 4 files (and their AWIP3D counterparts) are important intermediate steps in the data assimilation cycle (steps known as the "first-guess" for the following analysis). Finally in directory T12Z: AWIPSF06.tm00 6-hour forecast starting from 12Z AWIPSF12.tm00 12-hour forecast starting from 12Z AWIPSF18.tm00 18-hour forecast starting from 12Z AWIPSF24.tm00 24-hour forecast starting from 12Z AWIPSF30.tm00 30-hour forecast starting from 12Z AWIPSF36.tm00 36-hour forecast starting from 12Z These 6 files (and their AWIP3D counterparts) represent the mainline Early Eta forecasts of interest to many users. In either directory T00Z or T12Z, one can determine the last update time of all entries in the directory by acquiring and examing the 24-character ASCII label in file "nmcdate". Characters 03-10 given the date and GMT time in YYMMDDHH format (YY-year, MM-month, DD-day, HH - GMT hour either 00Z or 12Z).
Format (from 19 Nov 1999 on. For earlier inventory format, scroll down to just before the 'For run cycles 12Z 3 Nov 1998 --' section): Columns Meaning 1- 4 Field number in file 6- 9 Parameter number 10-16 Parameter name 17-66 Height and time description 68-78 Min. value 80-90 Max. value
Prior to 28 Sep 1999, two types of grib inventories are listed. You might wish to look at both. awip212.range.* files give the min and max values for each field (for that particular run cycle and output time), while awip212.invnt.* files give the names of the output fields and some raw PDS (product definition section) header information for each record.
For the 3-hr guess valid at tm00 (AWIP3D03.tm03 and AWIPSF03.tm03): 03+tm03.invnt.98110312-xxxxxxxx 03+tm03.range.98110312-xxxxxxxx For the analysis valid at tm00 (AWIP3D00.tm00 and AWIPSF00.tm00): 00+tm00.invnt.98110312-xxxxxxxx 00+tm00.range.98110312-xxxxxxxx For the 24-hour forecast (AWIP3D24.tm00 and AWIPSF24.tm00): 24+tm00.invnt.98110312-xxxxxxxx 24+tm00.range.98110312-xxxxxxxxxxxxxxxx: indeterminate. Somewhere between 1998111712 and 1999092712.
For the 3-hr guess valid at tm00 (AWIP3D03.tm03 and AWIPSF03.tm03): 03+tm03.invnt.98060312-98110300 03+tm03.range.98060312-98110300 For the analysis valid at tm00 (AWIP3D00.tm00 and AWIPSF00.tm00): 00+tm00.invnt.98060312-98110300 00+tm00.range.98060312-98110300 For the 24-hour forecast (AWIP3D24.tm00 and AWIPSF24.tm00): 24+tm00.invnt.98060312-98110300 24+tm00.range.98060312-98110300
For the 3-hr guess valid at tm00 (AWIP3D03.tm03 and AWIPSF03.tm03): 03+tm03.invnt.98020912-98060300 03+tm03.range.98020912-98060300 For the analysis valid at tm00 (AWIP3D00.tm00 and AWIPSF00.tm00): 00+tm00.invnt.98020912-98060300 00+tm00.range.98020912-98060300 For the 24-hour forecast (AWIP3D24.tm00 and AWIPSF24.tm00): 24+tm00.invnt.98020912-98060300 24+tm00.range.98020912-98060300
For the 3-hr guess valid at tm00 (AWIP3D03.tm03 and AWIPSF03.tm03): 03+tm03.invnt.97111100-98020900 03+tm03.range.97111100-98020900 For the analysis valid at tm00 (AWIP3D00.tm00 and AWIPSF00.tm00): 00+tm00.invnt.97111100-98020900 00+tm00.range.97111100-98020900 For the 24-hour forecast (AWIP3D24.tm00 and AWIPSF24.tm00): 24+tm00.invnt.97111100-98020900 24+tm00.range.97111100-98020900
For the 3-hr guess valid at tm00 (AWIP3D03.tm03 and AWIPSF03.tm03): 03+tm03.invnt.97071712-97111012 03+tm03.range.97071712-97111012 For the analysis valid at tm00 (AWIP3D00.tm00 and AWIPSF00.tm00): 00+tm00.invnt.97071712-97111012 00+tm00.range.97071712-97111012 For the 24-hour forecast (AWIP3D24.tm00 and AWIPSF24.tm00): 24+tm00.invnt.97071712-97111012 24+tm00.range.97071712-97111012
For the 3-hr guess valid at tm00 (AWIP3D03.tm03 and AWIPSF03.tm03): 03+tm03.invnt.97061012-97071700 03+tm03.range.97061012-97071700 For the analysis valid at tm00 (AWIP3D00.tm00 and AWIPSF00.tm00): 00+tm00.invnt.97061012-97071700 00+tm00.range.97061012-97071700 For the 24-hour forecast (AWIP3D24.tm00 and AWIPSF24.tm00): 24+tm00.invnt.97061012-97071700 24+tm00.range.97061012-97071700
For the 3-hr guess valid at tm00 (AWIP3D03.tm03 and AWIPSF03.tm03): 03+tm03.invnt.97021812-97061000 03+tm03.range.97021812-97061000 For the analysis valid at tm00 (AWIP3D00.tm00 and AWIPSF00.tm00): 00+tm00.invnt.97021812-97061000 00+tm00.range.97021812-97061000 For the 24-hour forecast (AWIP3D24.tm00 and AWIPSF24.tm00): 24+tm00.invnt.97021812-97061000 24+tm00.range.97021812-97061000
1. Total precipitation 2. Convective precipitation 3. Surface runoff 4. Baseflow runoff 5. Snowmelt 6. Snowfall 7. EvaporationThese accumulations are in mm (equivalent to kg/m**2), over the designated accumulation period. In EDAS files, the accumulation period for all the above variables is 3 hours. In ETA files, the accumulation period for variables 3--7 is 6 hours. For the total precipitation and convective precipitation, the accumulation period is 12 hours (this is to maintain consistency with NCEP operational practice for field forecasts). This means that the variables holding the accumulated total precip and accumulated convective precip are 'zeroed out' every 12 hours:
File name Precip is accumulated during hours of AWIPSF06.tm00 0 to 6 AWIPSF12.tm00 0 to 12 AWIPSF18.tm00 12 to 18 AWIPSF24.tm00 12 to 24 etc.If you wish to compute 6-hour precip accumulations for, say, 18-24 hours, just subtract the AWIPSF18.tm00 precip field from the corresponding field in AWIPSF24.tm00.
For the time-averaged surface energy fluxes, the time period for averaging is 3 hours in EDAS, and 6 hours in Eta.
In addition, the output files also contain instantaneous energy fluxes. Please see the inventories for details.