UPDATED 5/2007 
                          REAL-TIME GRIDS
                          ---------------

   The dataset structure for real-time grids (RTGRIDS) has been expanded
   to clarify the availability and location of grid data.  A given grid
   can be accessed through the RTGRIDS/ALL dataset which, as its name
   implies, covers all of the real-time grid data that is available.
   The user may instead opt to use the model-specific datasets e.g. 
   
       RTGRIDS/NAM-ALL, RTGRIDS/GFS-ALL, RTGRIDS/RUC-ALL, etc.

   The use of these datasets will significantly reduce search time as
   far fewer grid files need be searched.  To further reduce search 
   time the user may opt to use the subset datasets for a given model,
   e.g.
   
       RTGRIDS/NGM-USLC, RTGRIDS/NGM-USPS, RTGRIDS/NGM-USPS2, etc.
      
   Every model has an associated "-All" dataset, e.g. RTGRIDS/NGM-ALL,
   which covers all of the data for the given model, in addition,
   those models that generate large numbers of grids per day also have
   subset datasets.  The use of subset datasets further reduces search
   time by focusing only on the desired grids.  An additional benefit
   of using the subset datasets is that the data has been broken down
   such that no knowledge of GRIB ID numbers is necessary in order to
   access the desired data.

   The naming scheme for the RTGRIDS datasets is as follows;

       RTGRIDS/ALL          => all real-time grids may be accessed by using
                               this dataset

       RTGRIDS/OVERFLOW     => any new real-time grids will be placed into this
                               dataset, if the new grids will be a permanent
                               addition to the NOAAPORT datastream then new 
                               datasets will be added to accommodate them

       RTGRIDS/mmm-ALL	    => every model will have its own dataset that
                               allows access to all of its data.  The naming
			       structure will be as indicated where 'mmm' is the
			       three letter abreviation for the model.

       RTGRIDS/aaa-bbccddd => these are the subset datasets, a description of
                               the naming scheme follows;

                               aaa  => McIDAS model abbreviation
                               bb   => geographic coverage
                                          GL = global
                                          NH = northern hemisphere
                                          US = continental United States
                                          NE = north-eastern quadrant
                                          NW = north-western quadrant
                                          AK = Alaska
                                          HI = Hawaii
                                          PR = Puerto Rico
                               cc   => projection
                                          ME = Mercator
                                          PS = polar stereographic
                                          LC = Lambert Conformal
                               dddd => optional further description
                                          2  = double resolution grids
                                          4  = quadruple resolution grids
                                          LRES = low resolution grids (T62 and T170)
                                          SSIF = spectral statistical interpolation
                                                 analysis from the final run
                                          THIN = thinned grids


   Data for the following models are currently available;

      McIDAS
    Abbreviation	Model Description
    ------------	----------------------------------------------
	AWC		National Convective Weather Diagnostic grids
	AWR		Alaska Waters Regional Wave Model grids
	ECM		European Center for Medium Range Forecast grids
        ENP             All Eastern North Pacific Regional Wave Model grid 
	FFG		NWS Flash Flood Guidance System grids
	GFS		Global Forecast System grids (formerly AVN and MRF)
	ICA		Ice Concentration Analysis grids
	ICN		Current Icing Potential grids
	MDR		Manually Digitized Radar grids
	NAH		North Atlantic Hurricane Wave Model grids
	NAM		North American Mesoscale model grids
	NCE		NCEP quantitative precipitation forecast grids
	NGM		Nested Grid Model grids
        NPH             All North Pacific Hurricane Wave Model grids
	RCM		Radar Coded Message grids
	RFC		River Forecast Center mosaic grids
	RUC		Rapid Update Cycle model grids
	SST		Sea Surface Temperature Analysis grids
	UKM		Coastal Ocean Circulation grids
	WHG		Significant height of wind waves grids
	WNA		Western North Atlantic Regional Wave Model grids
	WWF		Global Wind-Wave Forecast grids

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