Limited Area Fine Mesh (LFM) Model Analyses and Forecasts for North America

BRIEF

These analyses and forecasts are associated with what is called the 'Early Run' (ERL), the first in a series of daily forecast models operated by the National Meteorological Center (NMC). The ERL which is run twice daily is intended to provide a 'quick look' U.S. regional forecast update using an early data cutoff. A 1-hour 30-minute data cutoff (i.e. data are used which are received within 1-hour and 30-minutes of the nominal synoptic observation time) is employed to assure that the majority of North American mandatory level rawinsonde reports are included. The parameters include geopotential height, temperature, u and v winds, humidity, vorticity, vertical velocity, and precipitation. Data sources include NWS observations, surface observations from the Federal Aviation Administration (FAA), international observations received on the World Meteorological Organization (WMO) Global Telecommunications System (GTS), and satellite products provided by the National Environmental Satellite Data and Information Service (NESDIS).

The ERL run analyses are based on the original Cressman (1959) analysis method and is produced by making corrections to the 6-hour forecast fields generated in the previous cycle's 'Final Run' (FNL). The corrections are then interpolated onto a regularly spaced grid and added to the first-guess fields to produce the analyses. The corrections are applied at the 10 constant pressure levels through 100 mb on a 129 X 129 point 190.5 km mesh polar stereographic grid covering the Northern Hemisphere. The analyses are then subset to a 53 X 45 point grid and interpolated vertically from the analyzed constant pressure levels into the boundary layer, the three tropospheric layers, and the three stratospheric layers (i.e. 7-layer model). An analysis of moisture in the boundary layer and the lower two tropospheric layers is also performed. All pre- and post-processing for the ERL run is performed on the NAS 9000 computers, while the 48-hour forecasts are computed on the CYBER using the limited-area fine mesh model (LFM) described by Gerrity (1977) and Newell and Deaven (1981), using lateral boundary conditions supplied from the 12--60 hour forecasts from the previous 'Aviation Run' (AVN). The CYBER version of the LFM, operational since 1983, contains revisions including improved frictional boundary layer parameterization and executes in about 5 minutes. A backup version of the LFM executes on the NAS 9000 when the CYBER is unavailable, however the forecasts require a considerably larger amount of time and do not include the improved boundary layer parameterization.

ATTRIBUTES

Entry_ID: NMC_69 (MD Identifier: 269)
 
Temporal Coverage:
     From: 1971-10-31                 TO:  
 
Geographic Coverage:
     Southwest Extent: 5N,180E     Northeast Extent:  90N,20W
 
Storage Media:
     Magnetic Tapes 1600 bpi
 
Discipline, Subdiscipline:
     EARTH SCIENCE                   > ATMOSPHERE
     EARTH SCIENCE                   > OCEAN
 
Location Keyword:
     ATLANTIC OCEAN
     BOUNDARY LAYER
     EQUATORIAL
     MID-LATITUDE
     PACIFIC OCEAN
     POLAR
     STRATOSPHERE
     TROPOSPHERE
 
Parameter Group, Parameter:
     ATMOSPHERIC COMPOSITION         > HUMIDITY
     ATMOSPHERIC DYNAMICS            > ATMOSPHERIC TEMPERATURE
        Temperature
 
     ATMOSPHERIC DYNAMICS            > GEOPOTENTIAL HEIGHT
     ATMOSPHERIC DYNAMICS            > HUMIDITY
     ATMOSPHERIC DYNAMICS            > PRECIPITATION
     ATMOSPHERIC DYNAMICS            > PRESSURE
     ATMOSPHERIC DYNAMICS            > STORMS
     ATMOSPHERIC DYNAMICS            > WINDS
     OCEAN DYNAMICS                  > WINDS
 
General Keywords:
     ANALYSES
     CLIMATOLOGY
     FORECASTS
     GRID DATA
     IDN_NODE GSFC/NCAR
     LFM
     MODEL
     SURFACE
     UPPER AIR
 
Revision Date: 1992-10-07

DATACENTER

Archive: 
   NCAR>National Center for Atmospheric Research
   Data Set ID: DS 69.0 
 
   Contact: JOSEPH, DENNIS 
            National Center for Atmospheric Research
            Data Support Section
            P.O. Box 3000
            Boulder, CO  80307
            USA
 
            Electronic Mail: INTERNET> JOSEPH@BIERSTADT.SCD.UCAR.EDU
 
            Phone: 303-497-1216
 
Archive: 
   NOAA/NWS/NMC>National Meteorological Center, NOAA
 
   Contact: STACKPOLE, JOHN D.
            NOAA/NWS/NMC
            5200 Auth Road
            Washington, DC 20233
            USA
 
            Phone: (301) 763-8115
 
Archive: 
   NSSDC>National Space Science Data Center, NASA
   Data Set ID: GN-31A 
 
   Contact: COORDINATED REQUEST & USER SUPPORT OFFICE,  
            National Space Science Data Center
            Mail Code 633.4
            NASA/Goddard Space Flight Center
            Greenbelt, MD 20771
            USA
 
            Electronic Mail: INTERNET> request@nssdca.gsfc.nasa.gov
                             NSI/DECNET> 15548::REQUEST
                             NSI/DECNET> 15578::REQUEST
 
            Phone: (301) 286-6695
                   FAX (301) 286-1771

PERSONNEL

Tech Contact: JENNE, ROY 
              National Center for Atmospheric Research (NCAR)
              P.O. Box 3000
              Boulder, CO 80307-3000
              USA
 
              Electronic Mail: OMNET> R.JENNE
 
              Phone: (303) 497-1215
 
Entry Author: SCIALDONE, JOHN N.
              Hughes STX
              7701 Greenbelt Road, Suite 400
              Greenbelt, MD  20770
              USA
 
              Electronic Mail: INTERNET> SCIALDONE@NSSDCA.GSFC.NASA.GOV
                               NSI/DECnet> NCF::SCIALDONE
 
              Phone: (301) 441-4214
 
 
Information in this entry provided by NCAR

REFERENCE


Cressman, G.P., 1959: An Operational Objective Analysis System. Mon. Wea. Rev.,
87, 367-374

Gerrity, J.G., 1977: The LFM Model--1976: A Documentation. NOAA Tech. Memo. No.
60, NWS, NMC, 68 pp.

Newell, J., and D.G. Deaven, 1981: The LFM-II. NOAA Tech. Memo. No. 66, NWS,
NMC, 20 pp.

Petersen, R.A., and J.D. Stackpole, 1989: Overview of the NMC Production Suite.
Weather and Forecasting, 4, 313-322.

SUP_MENU

   1. Data Center: NCAR>National Center for Atmospheric Research
  
   2. Data Center: NSSDC>National Space Science Data Center, NASA