HR: 09:15h
AN: A31A-04    [Abstracts]
TI: The Synoptics of Subseasonal Forecasting: Lessons From Weather-Climate Monitoring
AU: * Weickmann, K M
EM: klaus.weickmann@noaa.gov
AF: NOAA-CIRES Climate Diagnostics Center, R/CDC1 325 Broadway, Boulder, CO 80305-3328 United States
AU: Berry, E
EM: edward.berry@noaa.gov
AF: NOAA National Weather Service, 104 Airport ROAD, Dodge City, KS 67801 United States
AB: The synoptic events that encompass the subseasonal time band are generally vague and little studied. Variability beyond an individual storm involves a rapidly increasing spatial domain and the interaction of multiple time scales. The events range from the fast local interactions of baroclinic wavetrains and tropical convective flare-ups to the medium time scale interactions of the MJO, teleconnection patterns and surface soil moisture/snow cover to the slow times scales of seasonal SST changes including ENSO. The MJO occupies a unique niche in the time band as it organizes tropical convection at 30-60 day periods, influences mid-latitudes, and can affect both higher and lower frequency variability. Fast dynamical processes (e.g., baroclinic life cycles, wave-mean flow interaction) dominate the variability slowly giving way to MJO time scales (e.g., tropical heating) and then coupled ocean atmosphere dynamics. When boundary forcing is weak seasonal anomalies are often the residual of large amplitude subseasonal events. Since northern Fall 2003 an experimental MJO website has been online (www.cdc.noaa.gov/MJO) gathering and posting subseasonal predictions from a variety of models. Weeks 1 and 2 and day 11 are emphasized on the site although predictions to 30-45 days are being planned. A subseasonal synoptic model has been used to help monitor and analyze synoptic behaviors as part of a ~monthly weather-climate discussion, also available online. Selected events will be used to illustrate the forecasting problem from a synoptic perspective. These will be discussed in the context of signal to noise, linear versus nonlinear and coupled versus uncoupled variability.
DE: 3319 General circulation
DE: 3346 Planetary meteorology (5445, 5739)
DE: 3374 Tropical meteorology
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly