John W. Neilson-Gammon's PowerPoint Presentation from the Panhandle Groundwater Conservation Districts Inaugural Texas Panhandle Water Conservation Symposium

1. What’s Next After the Worst
One-Year Drought?
John W. Nielsen-Gammon
Texas State Climatologist
Texas A&M University
n-g@tamu.edu

5. Rainfall Amount 
Rainfall Duration 

6. Rainfall Amount 
Rainfall Duration 

7. Rainfall Amount 
Rainfall Duration 

8. Rainfall Amount 
Rainfall Duration 

9. Rainfall Amount 
Rainfall Duration 

10. Sea Surface Temperature Departures from Normal
La Niña Years El NiñoYears

12. Dryness contribution to hot summer: 4.0 +/- 0.6 °F

15. Official La Niña
threshold
One Year Now
Ago

16. Fall Winter Spring Summer Fall

17. February
through April

18. April
through June

19. Driest in Tenth-driest Tenth-wettest Wettest in
30 years in 30 years in 30 years 30 years
33% 34% 33%
45% 34% 21%

20. Driest in Tenth-driest Tenth-wettest Wettest in
30 years in 30 years in 30 years 30 years
33% 33% 33%

21. Source: IPCC AR4 Working Group 1 SPM http://www.ipcc.ch

22. PANHANDLE
AND PLAINS
WEST EAST
CENTRAL NORTH
TEXAS
TEXAS CENTRAL
TEXAS
FAR WEST
TEXAS SOUTH
CENTRAL
TEXAS
SOUTHEAST
TEXAS
SOUTH
TEXAS

25. PDO/ENSO Pattern History since 1900

26. Red: Dry
Green:
Wet
Different
models
agree: La
Niña is
dry for
south-
central
US

27. PDO/ENSO Pattern History since 1900

29. Pacific
(PDO)
Shading: Droughty periods
Texas
Precip
Atlantic
(AMO)

30. 1900 1940 1980 2020 2060
Time 
Temperature 

31. Drought Outlook
• Departing La Niña
– Drought likely to continue in most of state
– Almost half of all 2-year La Niñas get a third year
• Period of drought susceptibility
– Ocean temperature patterns favor drought
– Period will last another 3-15 years
• Longer Term
– More rain if we’re lucky
– Warmer temperatures and more evaporation: very
likely

32. Contact Information
• John W. Nielsen-Gammon
• n-g@tamu.edu
• 979-862-2248
• http://atmo.tamu.edu/osc
• http://blog.chron.com/climateabyss