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TRANSCRIPT
Dealing with Water in
Texas’s Climate
John W. Nielsen-Gammon, Texas A&M University
Texas State Climatologist
Topics
• Heavy rain
• Annual rain
• Drought
• Next year’s rain
0
20
40
60
80
100
Oct-14
Nov-14
Dec-14
Jan-15
Feb-15
Mar-15
Apr-15
May-15
Jun-15
Jul-15
Aug-15
Sep-15
Oct-15
Nov-15
Dec-15
PercentDroughtCoverage,TexasOct.7,2014toPresent
D4
D3
D2
D1
D0
0
20
40
60
80
100
Oct-14
Nov-14
Dec-14
Jan-15
Feb-15
Mar-15
Apr-15
May-15
Jun-15
Jul-15
Aug-15
Sep-15
Oct-15
Nov-15
Dec-15
PercentDroughtCoverage,TexasOct.7,2014toJan.5,2016
D4
D3
D2
D1
D0
Weekly number of flood reports
0
2
4
6
8
10
12
1/1/50 1/1/60 1/1/70 1/1/80 1/1/90 1/1/00 1/1/10
NumberofTop-25One-DayRainEventsPerDecade
Freestone Leon Madison Limestone Robertson Brazos
Milam Burleson Lee Bastrop Average
All county-
average one-
day rainfall
totals >5”
since 1950
All county-
average two-
day rainfall
totals >6.5”
since 1950
All county-
average two-
day rainfall
totals >6.5”
plus
Washington
County
All county-
average two-
day rainfall
totals >6.5”
plus
Washington
County and
Thrall
All county-
average two-
day rainfall
totals >6.5”
plus
Washington
County,
Thrall, and
Hearne
ChangeinFrequencyofVeryHeavy*Rainfall
Atenthascommon
Afi hascommon
Athirdascommon
Halfascommon
Almostascommon
Morecommon
Twiceascommon
Three mesascommon
Six mesascommon
Waymorecommon
*about once every 5000 days
Summary: Heavy Rain
• Heavy rain is increasing in general
• Heavy rain is expected to increase
• Local trends are more random
– Don’t trust the local trends!
• Have a plan for Thrall and Hearne
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
1950 1960 1970 1980 1990 2000 2010 2020
WaterYearRainfall,PostOakSavannahGCD
Freestone Leon Madison Limestone Robertson
Brazos Milam Burleson Lee Bastrop
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
1950 1960 1970 1980 1990 2000 2010 2020
WaterYearRainfall,PostOakSavannahGCD
Milam Burleson North-Central East South-Central
0
10
20
30
40
50
60
70
1895 1915 1935 1955 1975 1995 2015
ClimateDivisionWater-YearPrecipita on
North-Central East South-Central
0
10
20
30
40
50
60
70
1895 1915 1935 1955 1975 1995 2015
ClimateDivisionWater-YearPrecipita on
North-Central East South-Central
Linear(South-Central) Linear(North-Central) Linear(East)
0
10
20
30
40
50
60
70
1895 1915 1935 1955 1975 1995 2015
ClimateDivisionWater-YearPrecipita on
North-Central East South-Central NewYorkState
Summary: Annual Rain
• Observed upward trend: 10% per century
• Trend tentatively not expected to continue
-8
-6
-4
-2
0
2
4
6
8
1895 1915 1935 1955 1975 1995 2015Differencefrom20thCenturyAverage(°F)
TX07SeasonalTemperatureAnomalies
Tmaxplus,TminminusTmaxsmoothedsolid,Tminsmootheddo ed
DJF MAM JJA SON DJF MAM JJA SON
DJF MAM JJA SON DJF MAM JJA SON
-8
-6
-4
-2
0
2
4
6
8
1895 1915 1935 1955 1975 1995 2015Differencefrom20thCenturyAverage(°F)
TX03SeasonalTemperatureAnomalies
Tmaxplus,TminminusTmaxsmoothedsolid,Tminsmootheddo ed
DJF MAM JJA SON DJF MAM JJA SON
DJF MAM JJA SON DJF MAM JJA SON
0
10
20
30
40
50
60
70
1895 1915 1935 1955 1975 1995 2015
ClimateDivisionWater-YearPrecipita on
North-Central East South-Central NewYorkState
0
10
20
30
40
50
60
70
1895 1915 1935 1955 1975 1995 2015
ClimateDivisionWater-YearPrecipita on
North-Central East South-Central NewYorkState
Summary: Drought
• Texas is unusually drought-prone
• Drought depends on:
– Rainfall, increasing so far (good)
– Temperature, increasing (not so good)
– Carbon dioxide (good for plants)
• Drought tentatively expected to become
more severe
El Niño
La Niña
Neutral
2016 2017
0
5
10
15
20
25
30
Normal(1981-2010)
TopTwoElNiños
TopSixElNiños
TopTwelveElNiños
2015-2016
AccumulatedPrecipita
on(inches)
TexasPrecipita onDuringStrongerElNiñoEvents
May
April
March
February
January
December
November
October
0
1
2
3
4
5
6
7
8
9
10
Normal(1981-2010) TopSixLaNiñas TopTwelveLaNiñas
TexasLaNiñaRainfall
March
February
January
December
November
Next Year’s Rain
• We’ll see
• Odds tilted toward drier than normal winter
• Strong La Niña very unlikely
Contact Info
• John Nielsen-Gammon
– 979-862-2248
– http://climatexas.tamu.edu
– Climatexas on Facebook