Univ of AZ WRF Model Verification

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Univ of AZ WRF Model Verification
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Method

• NCEP Stage IV data used for precipitation
  verification
• Stage IV is composite of rain fall observations
  and radar estimates
• Data has a resolution of 4km
• http//www.emc.ncep.noaa.gov/mmb/ylin/pcpanl/stage
  4/
• Nearest neighbor is used to move stage iv data to
  model data to observation site
• Verification was performed on 12 hour
  accumulations at various forecast hours
• For the 24 hr model forecast, verified the
  amount of precipitation accumulated for the 12 hr
  period ending at the time the 24 hour forecast is
  valid (i.e. for a 24 hr fcst from a 15 Nov 00Z
  model run, verify the precipitation that fell
  during the period 15 Nov 12Z 16 Nov 00Z
• Statistics generated for several precipitation
  thresholds gt1mm, gt6.25mm(.25in),
  gt12.5mm(.5in),gt25mm(1in)

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Nov 25 12Z Model RunWRF 5.4 km

• On the following displays, the solid color is the
  model forecast
• Dots and other symbols are the Stage IV
  precipitation observations
• The color and shape of observations symbols
  represent the amount of precipitation accumulated
  in a 12 hour period ending at the forecast valid
  time
• Statistics calculated for data displayed in the
  image

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Model Run 20081125 12Z Forecast
18hr Accumulation Period 20081125 18Z 20081126
06Z
Model Run 20081125 12Z Forecast
24hr Accumulation Period 20081126 00Z 20081126
12Z
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Model Run 20081125 12Z Forecast
30hr Accumulation Period 20081126 06Z 20081126
18Z
Model Run 20081125 12Z Forecast
36hr Accumulation Period 20081126 12Z 20081127
00Z
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Model Run 20081125 12Z Forecast
42hr Accumulation Period 20081126 18Z 20081127
06Z
Model Run 20081125 12Z Forecast
48hr Accumulation Period 20081127 00Z 20081127
12Z
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Nov 25 12Z Model RunWRF 1.8 km
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Model Run 20081125 12Z Forecast
18hr Accumulation Period 20081125 18Z 20081126
06Z
Model Run 20081125 12Z Forecast
24hr Accumulation Period 20081126 00Z 20081126
12Z
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Model Run 20081125 12Z Forecast
30hr Accumulation Period 20081125 06Z 20081126
18Z
Model Run 20081125 12Z Forecast
36hr Accumulation Period 20081126 12Z 20081127
00Z
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Model Run 20081125 12Z Forecast
42hr Accumulation Period 20081126 18Z 20081127
06Z
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Domain Verification

• Period of verification is from 15 Oct 28 Nov
  2008
• During this period there were two major
  precipitation events over the area of interest
• Not sure why the 30hr forecast shows higher skill
  compared to other forecasts
• Probably due to the limited number of forecasts
  with precipitation for period

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