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Summer 2010 Forecast
Dr. Judah CohenAtmospheric & Environmental Research, Inc.
April 15, 2010
Outline
Review seasonal predictorsFocus on two predictors:
ENSOSoil moisture
Summer forecastLook back at winter forecastQuestions
© AER 2010 – All Rights Reserved
© AER 2010 – All Rights Reserved
Seasonal Forecasting Tools Climatology - Past history is used to predict the
future. Persistence - Extrapolating recent past into the
future.
El Nino/Southern Oscillation - The most important recent discovery which has improved seasonal climate forecasts.
Trends - Extrapolating multi-year and multi-decadal trends into the future.
Soil moisture - In summer dry soil is associated with warm temperatures and vice versa.
Atmospheric precursors – Using regional anomalies in sea level pressure, wave energy, etc. to predict future large-scale atmospheric patterns.
Snow cover (winter months only) - Extensive snow cover is conducive to cold air masses.
© AER 2010 – All Rights Reserved
Equatorial Pacific
Warm sea surface temperature anomalies dominatethe eastern equatorial Pacific though anomalies are weakening.
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ENSO Forecast
Forecast models all predicting El Niño conditions to wane during the spring and summer.
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Soil Moisture
Wet in the South, the East Coast and the Plains with dry in the West and the Great Lakes.
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Summer Temperature ForecastAnomaly (deg F) of the Mid-value of the 3-month
Temperature Outlook Distribution for JJA 2010Anomaly (deg F) of the Mid-value of the 3-month
Temperature Outlook Distribution for JJA 2010
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Summer Precipitation ForecastAnomaly (inches) of the Mid-value of the 3-month
Precipitation Outlook Distribution for JJA 2010Anomaly (inches) of the Mid-value of the 3-month
Precipitation Outlook Distribution for JJA 2010
Verification of Winter Forecast
© AER 2010 – All Rights Reserved
© AER 2010 – All Rights Reserved
October Siberian Snow CoverDuring the last 3 weeks of October 2009 there was a rapid increase in
Siberian snow cover…
…that was equivalent to the snow cover advance
across North America from September through
January
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2009/10 Winter Temperatures Forecasted Temperature Anomaly Dec-Jan-Feb 2010
Forecast made the 2nd week of November Observed Temperature Anomaly Dec-Jan-Feb 2010 Forecasted Temperature Anomaly Dec-Jan-Feb 2010
Forecast made the 1st week of October
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El Niño, Snow & Winter TemperaturesRegression of ENSO with US surface temps
Regression of snow cover with US surface temps
Observed Temperature Anomaly Dec-Jan-Feb 2010
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Anomaly Correlation - a measure of how well the forecast compares to the observations at one point for all the available forecasts. For the real-time forecasts there are a total of 37 forecasts.
• 37 years of hindcasts for sCast model
Skill Score – a measure of how well the forecast compares to a forecast derived from climatology.
forecast
climatology
1MSE
SSMSE
Forecast Verification
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City Forecasts
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2009/10 Winter Temperatures Forecasted Temperature Anomaly Dec-Jan-Feb 2010
Forecast made the 2nd week of November Observed Temperature Anomaly Dec-Jan-Feb 2010
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2009 Winter Precipitation
Forecasted Precipitation Anomaly Dec-Jan-Feb 2010 Forecast made the 2nd week of November Observed Precipitation Anomaly Dec-Jan-Feb 2010
© AER 2010 – All Rights Reserved
AER Summer Forecast
Weakening El Nino is predicted for the summer, this is usually associated with less heat ridging in the interior US and somewhat wetter, consistent with model precipitation forecast.
Soil moisture is wet in the South and in the Plains with dry in the Great Lakes and in the Pacific Northwest. This favors warmer temperatures in the Northeastern quadrant of the country and the West with cooler in the South and the Plains.
Thank You!
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