Southern Company Winter 2017-18 Outlook Presented by Climate Impact Company October 26, 2017

The Climate Impact Company Winter 2017-18 Outlook & Summer 2017 Review Nationally, extremes dominated. Worst tropical cyclone season since 2005. Southern Company verification was much wetter than normal therefore not as hot as forecast. Winter 2017-18 Outlook A La Nina Winter is likely. U.S. averages cold West and warm East. Southern Company outlook is warm but not as warm as last year. Winter storm track affects western Alabama but Georgia is dry.

Extremes (Records) Dominated Summer 2017 Record hot in California and Nevada Wettest in 123 years in Mississippi

Southern Company Summer Forecast Verification Temperature forecast a little too hot Precipitation forecast not wet enough

Tropical Cyclone Season Was Most Destructive Since 2005 Tropical cyclone tracks in 2017…Most active in U.S. since 2005. The Climate Impact Company forecast…Needed a western Gulf track.

Most of East/South U.S. Affected in 2017 Aerial coverage of hurricane and tropical storm force wind… La Nina climate develops late summer causing 10 consecutive hurricanes…

The Winter 2017-18 Outlook… La Nina is developing NOW and will last through winter… Warm subtropical Pacific and North Atlantic bias South & East U.S. warm…

La Nina Wintertime Climatology Temperature: Cold North-Central and warm Gulf States/East… Precipitation: Wet Northwest and Ohio Valley while South is dry…

U.S. Meteorological Winter 2017-18 Outlook Temperature: Cold West, warm East… Precipitation: Stormy Northwest/East- Central & Dry far Southeast/Southwest…

November 2017 Forecast Temperature Regime: Northwest chill, mild East… High Impact Weather: East- Central/Northeast storm track.

December 2017 Forecast Temperature: Cold/snow bias Northwest, East is warm. Precipitation: Mid-South storms, 1-2 Central cold outbreaks.

January 2018 Forecast Temperature: Widening snow/cold West, East is warm. Precipitation: Snowy West, storm track Midwest…

February 2018 Forecast Temperature: Cold lock West, East stays warm (low confidence)… Precipitation: Big storm track East- Central continues…

March 2018 Forecast Temperature Regime: Late season snow cover sustains northern cold… High Impact Weather: Drier/warmer South…

Southern Company Winter 2017-18 Outlook Temperature: Warmer than normal each month… Precipitation: Alabama near to wetter than normal; Georgia drier than normal…

Southern Company Winter Outlook Gas home heating population weight HDD forecast for Alabama Gas home heating population weight HDD forecast for Georgia

Projecting Number of Cold Mornings for Winter 2017-18 Number of days <32 are below normal. However, number of days <32 are greater than last winter. Probably 1 or 2 very cold days (teens) most likely in January.

Climate Impact Co. Vs. NOAA Winter 2017-18 Outlook CIC: Cold West, warm East… NOAA: Cold Northwest, warm South/East…

Last Winter’s Outlook Verified temperature Forecast temperature

Last Winter’s Outlook Verified precipitation Forecast precipitation

Southern Company Winter 2017-18 Outlook Southern Company is forecast warmer than normal. Not nearly as warm as last year. Volatility! A few cold days separated by longer periods of mild weather is characteristic of upcoming winter. Alabama on edge of storm track while Georgia is drier than normal. Nationally, the Northwest/North-Central is cold and snowy while South and East are mild. Summer 2017 was wetter and less hot than forecast. Summer 2017 produced extremes: Record heat CA/NV, dryness WA and wet weather in the Gulf States. Most destructive tropical cyclone season since 2017.