Office of Coast Survey - Details of Narragansett Bay Local Analysis and Prediction Systems

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Information about the Narragansett Bay LAPS (NBLAPS)

Version:

NBLAPS is based on version 0-17-14 of the NOAA FSL LAPS distribution.

Grid Configuration:

A 125 x 125 grid point mesh centered over the southern New England with a horizontal resolution of 4-km.

Hardware:

NBLAPS runs on a National Weather Service HP, J Class, dual processor workstation located at NWS Baltimore/Washington Weather Forecast Office in Sterling, VA.

Types of Surface Observations:

1. Traditional Surface Observing Networks:

a) Inland Sites (NWS/FAA/DOD):

Automated Surface Observing System (ASOS)

Automated Weather Observing Station (AWOS)

b) Marine Sites:

NWS/NDBC Coastal-Marine Automated Network (C-MAN) stations (www.ndbc.noaa.gov)

NWS/NDBC Fixed Buoys (www.ndbc.noaa.gov)

NOS CO-OPS Physical Oceanographic Real-Time Reporting System (PORTS) (www.co-ops.nos.noaa.gov)

c) Ships

2. Other
Selected NWS Cooperative Climate Stations

Data Cutoff Window:

Data "cut-off" point is at 20 minutes past the hour to ensure that over-water observations from NDBC buoys and C-MAN are available.

Products:

Two-dimensional analyses of surface meteorological variables every hour at a 4-km resolution.

Variables:

surface air temperature

surface dew point temperature

surface (10m AGL) wind velocity

mean sea-level pressure

Format:

Analyses are encoded into WMO general purpose, bit-oriented data exchange format, Gridded Binary (GRIB) using software from the U.S. Dept. of Defense Master Environmental Library. Also available in NetCDF.

Time Availability:

GRIB files containing NBLAPS analyses are usually available by 25 minutes past the hour.

Information about the Narragansett Bay MM5 Model (NBMM5)

General Information:

The PSU/NCAR MM5 mesoscale model is being run once a day at NOAA/NOS/CSDL as a part of the Narragansett Bay NOPP Project in order to provide: surface forcing for estuarine forecast model being developed by NOPP partners high-resolution meteorological fields for weather forecast guidance and forecasts, and other regional applications.

The MM5 model is a complete, full-physics, limited area nonhydrostatic numerical weather prediction system. The model is designed to simulate or predict mesoscale atmospheric phenomena.

Model Configuration:

Domain consists of 82x102 grid points centered over Southern New England.

Horizontal resolution is 4 km.

Vertical resolution is 37 sigma levels.

Non-hydrostatic mode is applied.

Topography (meters) and l and-water mask fields are derived from 30’’ source files.

      Physics parameterization:
          - Grell cumulus parameterization
          - Explicit cloud water and ice scheme
          - MRF Planetary Boundary Layer model
          - Radiation cooling of atmosphere
          - Multi-layer soil temperature model

Initialization:

Initial and boundary conditions are generated from 3-hourly forecast output of the 0000 UTC forecast cycle of NCEP's Eta-12km model.

Sea surface temperatures (SSTs) for the oceans and Great Lakes are obtained from NCEP's daily Real-Time, Global SST (RTG_SST) Analysis which uses both in-situ observations and multi-channel SST retrieval. (http://polar.wwb.noaa.gov/sst/Welcome.html)

Snow cover and depth analyses are obtained from NCEP's EDAS analysis.

Computer resources:

The model is run on NOS/CSDL's SGI Origin 2000 workstation and currently uses 6 CPU’s. The model is parallelized using MPI software. A 24 hours forecast requires 1.5 hours to be completed.

Time availability:

Hourly forecasts out to 24 hours are usually available at 08:35 UTC (04:35 EST). Graphical description of the forecasts are available on the Web page by 10:35 UTC (06:35 EST)

Output format:

The hourly forecast are encoded in netCDF format on a Lambert Conformal grid.

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Revised Monday May 05 2003by OCS Webmaster