160 likes | 326 Vues
Essential Components of the MOS Process. Verify Respond. Observe. Develop/ Evaluate. Archive. Distribute. NWP Model. Post-Process MOS. Statistical Post-Processing. Advantages Removal of systematic model bias Reliable probabilities from a single run
E N D
Essential Components of the MOS Process Verify Respond Observe Develop/ Evaluate Archive Distribute NWP Model Post-Process MOS
Statistical Post-Processing Advantages Removal of systematic model bias Reliable probabilities from a single run Can forecast what the model does not – i.e. thunderstorms Suitable to a wide-range of predictands (max/min temperature, sky cover, probability of precipitation…) Challenges Availability and quality of observations Short samples Changing NWP models
Operational MOS Guidance Suite • GFS (MAV) (00,06,12,18Z) – 3.5 days • GFS Ext. (MEX) (00, 12Z) – 7 days • NAM (MET) (00,12Z) – 3.5 days • NGM (FWC) (00,12Z) – 3 days – Turn off March 3 • Specialized products – marine and co-op messages, SHEF max/min products for RFCs to 10 days. • Variety of formats: text bulletins, NDGD, GRIB/2 and BUFR messages, graphics …
Midway, US Wake, US Saipan, ROM Western Pacific MOS Guidance NSTU GFS MOS GUIDANCE 11/07/2008 1200 UTC DT /NOV 7/NOV 8 /NOV 9 /NOV 10 HR 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12 TMP 84 85 85 85 82 82 81 79 80 83 84 83 81 81 80 79 81 84 86 82 80 DPT 77 77 78 77 76 77 76 75 77 78 77 77 76 77 76 75 77 78 77 77 76 WDR 08 08 08 09 08 07 05 04 06 07 08 07 05 02 35 01 02 07 07 08 10 WSP 17 17 15 13 11 08 07 07 07 08 09 08 07 05 04 04 04 08 09 06 06 P06 36 37 47 46 50 43 25 35 43 30 31 P12 60 66 60 59 47
Observational Data SourcesRequires archives, metadata, QC • METAR • Marine - buoy and c-man • Lightning data • Vaisala’s National Lightning Detection Network • Bureau of Land Management (source of data over Alaska) • Storm reports • NCDC cooperative observer data – (COOP) • Satellite Cloud Product (SCP) • Supplementary Climate Data (SCD) • Mesonets – work in progress • Geophysical data – terrain, land cover, climatology We strive for one coherent archive, not many small datasets
METAR, marine, mesonet, COOP, RFC sites Now over 10500 stations with site-specific guidance used as input to gridded MOS analysis
Gridded MOS MOS guidance needed on a grid commensurate with the resolution being used by local forecasters in producing their local grids • Surface Temperature • Dew Point • Max/Min Temperature • Relative Humidity • Wind Speed/Direction • Wind Gusts • Probability of Precipitation • Precipitation Amount • Opaque Sky Cover • Snowfall Amount • Thunderstorms Method 1: Develop regression equations that apply to observation sites and analyze them to a grid.
Gridded Guidance - continued Method 2: Develop regression equations that can be applied at gridpoints, make the forecasts directly on the grid
Gridded MOS refinementsmos_info, e-mail, callsmany thanks to Dave Novak • grid expansions • land/water mask edits • non-representative station removals Forecasters reported max temperatures to be a few degrees higher in areas surrounding Chamberlain Bridge Removing suspect stations provides a more useful product http://www.weather.gov/mdl/synop/gmos.php
Early Ensemble MOS product • NO development using ensemble members as input • MOS equations developed from higher resolution run applied to each member • Applications developed by users to create graphics and AWIPS summary products
Recent Major Milestones • June 2008 - Implemented grids over Alaska of daytime max, nighttime min, 2-m temperature and dewpoint, 3-, 6-, 12-hr probability of thunderstorms • December 9, 2008 – Replaced Eta MOS with new NAM MOS • December 16, 2008 – Implemented sky cover, PoP and wind grids over Alaska • COMING SOON March 3, 2009 – Remove NGM and all of its associated post-processed products Additional minor implementations to improve the quality of the guidance (removal of “bad” stations, updated masks…)
Current Development Efforts • enhancements to the CONUS gridded analysis software, allow variable radius of influence • Refresh equations and increase stations in GFS-based products • increase mesonet sites to increase spatial details • Add snowfall and QPF grids to Alaska gridded MOS • Add precipitation type and weather grids to the GFS-based gridded MOS suite • Add NAM MOS grids http://www.nws.noaa.gov/mdl/synop/products.php
Discussion Items • General issue: coordination of requirements • OCWWS? e-mails? phone calls? • quality of mesonet data • Do you require… • projections of max/min grids to day 8 for Alaska? • new max/min definition in Alaska? • 4 cycles of extended-range gridded guidance? • 6-h snowfall grids derived from 24-h snowfall guidance? • More MOS probability guidance, in addition to the expected values or best categories? • aviation elements (ceiling, visibility) beyond day 1? • NAM MOS grids: 2 cycles a day? 4 cycles a day?