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

2. 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 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.

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

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

5. 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.

6. 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…

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

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

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

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

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

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

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

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

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

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

17. 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.

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

19. Last Winter’s Outlook
Verified temperature
Forecast temperature

20. Last Winter’s Outlook
Verified precipitation
Forecast precipitation

21. 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.