Data Sources & Additional Information

• This page shows the current day's average weather — temperature, precipitation, wind, and other variables — forecast by the NOAA/NCEP Global Forecast System (GFS). GFS is a numerical modeling framework that uses a 13 km Finite-Volume Cubed-Sphere dynamical core (FV3) to produce 16-day forecasts four times each day. The weather maps here show 1-day average conditions calculated from eight 3-hourly GFS forecast timesclices beginning 0000 UTC. Sea ice concentration is an analysis field produced daily by the NCEP Environmental Monitoring Center. Sea surface temperature is from a NOAA gridded data product described below. All weather and sea ice data are downloaded from the NOAA Operational Model Archive and Data Distribution System (NOMADS). Visualizations are made using NCAR Command Language.


• 2m Temperature refers to air temperature at 2 meters above the surface. 2m Temperature Anomaly refers to the departure of the current day's forecasted temperature from a long-term mean for the same day of the year. The anomalies here are based on a 1979-2000 reference climatology derived from the NCEP Climate Forecast System Reanalysis (CFSR). This 22-year baseline is used instead of the more common 1981-2010 climate normal because 1979-2000 represents conditions prior to significant Arctic warming and sea-ice loss. A comparison of different climate baselines against the historical temperature record is shown here.


• The daily temperature anomaly values shown on these maps reflect current weather patterns, and therefore global and regional means can vary significantly from day-to-day and week-to-week. Climate trends should only be inferred from long-term datasets. Refer to NOAA's Climate at a Glance for monthly, seasonal, and annual global temperature change since 1880. Reanalysis and gridded data products can also be accessed on Climate Reanalyzer's Monthly Reanalysis Timeseries page.


• Temperature anomalies calculated between GFS (forecast) and CFSR (reanalysis) may differ from those calculated entirely within the Climate Forecast System framework (see this NCEP/NWS discussion on model bias). CFS/CFSR daily temperature anomaly estimates are available with a few days lag on the Daily Reanalysis Maps page.


• Sea Surface Temperature (SST) and SST anomaly maps are generated from NOAA Optimum Interpolation SST version 2 (OISST V2). OISST is a 0.25° gridded dataset derived by blending satellite, ship, and buoy measurements. The SST anomalies is based on a 1971-2000 climatology calculated by NOAA.


• The regional values shown at the bottom of the 2m temperature and SST anomaly maps are area-weighted averages for the following domains:
  
  World
  90°S-90°N, 0-360°E

  Northern Hemisphere
  0-90°N, 0-360°E

  Southern Hemisphere
  90°S-0, 0-360°E

  Arctic
  65°N-90°N, 0-360°E

  Antarctic
  90°S-65°S, 0-360°E

  Tropics
  25°S-25°N, 0-360°E

  North Atlantic
  5°N-65°N, 280°E-360°E

  North Pacific
  0-60°N, 130°E-260°E

  Equatorial Pacific
  15°S-15°N, 140°E-290°E

Last updated 7/22/2022