Summer 2010 Forecast. Outline Review seasonal predictors Focus on two predictors: ENSO Soil moisture Summer forecast Look back at winter forecast Questions

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


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.


Equatorial Pacific

Warm sea surface temperature anomalies dominatethe eastern equatorial Pacific though anomalies are weakening.


ENSO Forecast

Forecast models all predicting El Niño conditions to wane during the spring and summer.


Soil Moisture

Wet in the South, the East Coast and the Plains with dry in the West and the Great Lakes.


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


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



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


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


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


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


City Forecasts


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


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 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!

Documents

Summer 2010 Forecast. Outline Review seasonal predictors Focus on two predictors: ENSO Soil moisture Summer forecast Look back at winter forecast Questions