Contact:  Wallace Clark
March 23, 2012

NWS Western Region Science Webinar on Object Analysis of Atmospheric Rivers

At the request of the National Weather Service (NWS) Western Region, a webinar was held March 7, 2012, at 10 AM MST. The webinar was hosted by Brian Garcia with Wallace Clark and Tara Jensen presenting, with a focus on object analysis relevant to Western Region coastal forecasting.

Topics Covered

  • Delineating significant meteorological entities and events (e.g., ARs and AR landfalls) via object analysis.
  • Measuring biases and uncertainties in event size, location, and intensity using metrics based on object attributes.
  • Strategic use of multiple domains.
  • Real-time postprocessing with the Developmental Testbed Center's MODE object analysis package.

Highlights

  • Because IWV and IVT objects are synoptic scale or larger, the full Northeast Pacific (NEP) domain is needed for
    • Meaningful comparison of SSMIS and model IWV data.
    • Addressing longer lead-time forecasting by development of indexes of the wetness and amount of flux over the NEP domain.
  • A narrow coastal-strip domain, when applied to frequent (~hourly) observational and/or model output, provides:
    • Landfall detection
    • Measures of latitudinal location and track
    • Measures of event intensity
    • Times of arrival and duration.
  • A broader (~1000 km longitudinally) coastal strip domain:
    • Allows visual comparison of forecast to observational objects as they come ashore.
    • Aids physical interpretation of events detected as narrow coastal-strip objects.
    • Causes difficulties in interpreting the built in MODE object attributes due to object truncation by the seaward domain boundary.
    • New special-purpose attributes need to be developed for this domain.
Contributors: Wallace Clark*, Tara Jensen, Brian Garcia*, Ed Tollerud, Ellen Sukovich

*Primary contacts

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