Forecast Pressure

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Forecast Pressure
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• ASOS Pressure Sensor the best we have in the
  operational system.

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VOS-Voluntary Observing Ship Program-generally
aneroid barometer calibrated when in U.S. ports
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Ship Pressures

• Often seriously in errorbut substantial
  calibration is possible when they cross other
  ships, pass a buoy, or come into port.

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Moored Buoys
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Drifting Buoy
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Effects of resolution on pressure forecasts

• Most apparent in terrain.

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12-km
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I
MM5
WRF
Pressure initialization dont look the same for a
number of reasons
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An example of a short-term pressure forecast error
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48-hr Forecasts Valid 00 UTC 8 February 2002
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24-Hr Forecasts Valid 00 UTC 8 February 2002
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Station Locations
Tatoosh Is.
Cape Arago
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24 h Coastal Errors
TTI, WA
Cape Arago, OR
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48-h Errors
48h errors much larger and frequent than 24-h
errors
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GFS vs. Eta
24-h errors
NCEP GFS better than Eta on average
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48-h errors
Eta under forecasts
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West Coast
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