Texas Water Conservation Association powerpoint from presentation by Bob Rose, LCRA Meteorologist. 10/14/2011 www.twca.org

1. Historical Texas
Drought Update
TWCA Fall Conference
October 14, 2011
Bob Rose, LCRA Meteorologist

3. Worst Drought in Texas History
“Texas has experienced its most severe
one-year drought on record”
John Nielsen-Gammon, Texas State Climatologist.
Driest October-September on record
with 7.18 inches. Normal is 14.94.
Record low was 7.35 inches
Oct 1901-Sep 1902.

4. Worst Drought in Texas History
“Texas has experienced its most
severe one-year drought on record”
John Nielsen-Gammon, Texas State Climatologist.
Hottest June, July and August on record. August
was the hottest month ever recorded with an
average temperature of 88.1 degrees, beating
July 2011with 87.1 degrees. Hottest month for
any state ever in the US!

6. Texas Rainfall, Oct.-Sep.
7.35 in. 7.18 in.

7. Rainfall Oct 2010-Sep 2011

8. Rainfall Departure from Normal
October 2010-September 2011

9. Record Low Palmer Drought Index
-7.80
-7.97

10. The 2011 Drought in
Historical Context
1789, -5.14 -4.88 Lowest
Most Persistent -5.37

11. Soil Moisture Anomaly

12. Unprecedented Summer
Heat!!!

16. Temperature Departure
from Normal, 6/1-8/31

17. Record Setting Summer Heat
• Many cities recorded their hottest
June, July and August on record.
• Dozens of Texas cities recorded their
longest stretch of consecutive 100-
degree days.
• A multitude of Texas cities recorded a
record number of 100-degree days.
• Second hottest summer on record for
any state in any year.

20. Rainfall, October 7-9

23. Percent Area of Texas in
Drought, Jan 2001-Sep 2011

24. Going into Second Year of La Niña
January 6th
October 13th

25. Typical Patterns Associated
with La Niña

26. Trending Back into La Niña
El Niño
La Niña

27. Dry Wet

28. Temperature Precipitation

29. NWS Winter into Spring Rainfall Outlook

30. Drought Outlook through December

31. Jan-Mar Anomalies Based
on 2nd Year La Niña

32. Apr-May Anomalies Based
on 2nd Year La Niña

33. Ending Drought in 1 Month

34. Rain Needed to End the
Drought in 6 Months

36. Pacific Decadal Oscillation

37. Similar Conditions to the 1950s?

38. The 2011 Atlantic Hurricane
Season

39. An Active Season, but Not
for Texas

40. Historical Hurricane Tracks
after September 24th

41. Take Home Points
• No clear end in sight to the ongoing
drought; could last well into 2012.
• Scattered rains possible this fall but not
heavy enough to temper the drought.
• Intense droughts are hard to break.
• Tropical storms rains not likely.
• La Niña is back. Late fall and winter
expected to be drier than normal.
• Dry years interspersed with wet years.

42. Bob Rose
Meteorologist, LCRA
bob.rose@lcra.org
512-473-3350