Historical Texas Drought Update

LCRA Firm Water Customer MeetingOctober 27, 2011

Bob Rose, LCRA Meteorologist

Worst Drought in Texas History

“This is state’s most severe one-year drought in recorded history”

John Nielsen-Gammon, Texas State Climatologist.

Driest October-September on record with 7.18 inches. Normal is 14.94.

Record low was 7.35 inchesOct 1901-Sep 1902.

7.18 in.7.35 in.

Texas Rainfall, Oct.-Sep.

Austin’s Driest 12-Month Period in History

1. OCT. 2010 TO SEP. 2011 11.202. JAN. 1954 TO DEC. 1954 11.423. OCT. 1924 TO SEP. 1925 11.834. OCT. 1955 TO SEP. 1956 12.185. MAY 1977 TO APR. 1978 14.44 NOV. 1916 TO OCT. 1917 14.446. JUN. 1970 TO MAY 1971 15.067. SEP. 2008 TO AUG. 2009 15.388. SEP. 1878 TO AUG. 1879 15.529. OCT. 1983 TO SEP. 1984 16.8610. JUL. 1993 TO JUN. 1994 17.01

Rainfall Oct 2010-Sep 2011

Rainfall Departure from Normal October 2010-September 2011

Unprecedented Summer Heat!!!

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

Unprecedented Summer Heat

• Second hottest summer ever recorded, for any state. Average temperature 86.7 degrees. (Oklahoma was first with 86.8)

• Austin recorded its hottest April, July, August and September on record. June was second hottest.

• Austin recorded 90 days at or above 100 degrees. 165 days at or above 90 degrees.

Rainfall, October 7-9

Going into Second Year of La Niña

January 6th

October 24th

Typical Patterns Associated with La Niña

La Nina

WetDry

Temperature Precipitation

NWS Winter into Spring Rainfall Outlook

Drought Outlook through January

Jan-March Anomalies Based on 2nd Year La Niña

April-May Anomalies Based on 2nd Year La Niña

June-Aug Anomalies Based on 2nd Year La Niña

Ending Drought in 1 Month

Rain Needed to End the Drought in 6 Months

The 2011 Atlantic Hurricane Season

An Active Season, but Not for Texas

Take Home Points• No clear end in sight to the ongoing

drought; could last well into 2012.• Scattered rains possible this fall and

winter but not heavy enough to temper the drought.

• Intense droughts are hard to break.• Tropical storms rains now not likely.• La Niña is back. Late fall and winter

expected to be drier than normal.• Dry years interspersed with wet years.

Bob RoseMeteorologist, LCRAbob.rose@lcra.org

512-473-3350