Surface data is crucial for mesoscale weather forecasting because its
time and space resolution is unmatched among in situ observations.
The Mesoscale Analysis and Prediction System (MAPS) and the Rapid
Update Cycle (RUC) Surface Assimilation Systems (MSAS/RSAS) exploit
the resolution of surface data by providing timely and detailed
surface analyses. RSAS (also known as the RUC Surface or "RUCS"
system) runs operationally at the NWS's National Centers for
Environmental Prediction (NCEP). MSAS runs operationally at NWS
Forecast Offices as part of the AWIPS workstation, and contributes
quality control information to the Quality Control
and Monitoring System (QCMS).
RSAS also runs
quasi-operationally in the ESRL/GSD Central Facility.
The ESRL/GSD RSAS is also used to
quality control surface observations distributed through the Meteorological Assimiliation Data Ingest System
(MADIS), and as the development system where new advances can be
incorporated before being put into operations at NCEP. Grids from the
ESRL/GSD RSAS are also made available via MADIS to interested parties in
real-time by ftp, LDM, or OPenDAP. For a list of the analyzed and
derived grids, see the Surface Analysis Description link below.
MADIS subscribers can receive the real-time ESRL/GSD RSAS grids by
requesting an ftp, LDM, or OPeNDAP account.
In general, users who require a
continuous datafeed will get better performance by accessing the data
via ftp or LDM. All of the analyzed and derived grids are output in
a single netCDF file, and we provide software that can be used to
read the file and output the desired grids in a simple text format
that can then be read in by your application.
Grids valid at the top of the hour are updated every 15 minutes to
incorporate newly arriving observations. The exact schedule of when the
grids are available is difficult to predict, because of the varying and
ever-increasing volume of observations being handled by the system. Therefore,
LDM is the best method to receive the data. For those
wishing to use ftp or OPeNDAP, however, here are the range of times when
the RSAS grids were available on March 3, 2005:
|Update Cycle|| ||Available at Minutes
Past the Hour|
|1|| ||22 - 25|
|2|| ||35 - 40|
|3|| ||52 - 54|
|4|| ||66 - 71|
Animated GIFs are available to loop the latest 8 hours of surface analysis
grids. Single GIF images are also available for the grids from the current
MSAS/RSAS Production Error Reporting
Last updated 30 October 2013.