September’s Extreme Weather - Colorado Mesa University · NOAA HPC 7-day Quantitative Precipitation Forecast (QPF) issued 6pm 9/8/2013 for 9/9 through 9/15

http://wwa.colorado.edu

Jeff Lukas, Senior Research Associate

CIRES Western Water Assessment

Upper Colorado River Basin Forum

Colorado Mesa University

November 7, 2013

September’s Extreme Weather: How the weather system that flooded Colorado’s

Front Range affected the Upper Colorado River

Basin



Acknowledgements

• Klaus Wolter, Kelly Mahoney, and Joe

Barsugli (CIRES/NOAA PSD)

• Nolan Doesken and Wendy Ryan

(Colorado Climate Center, CSU)

• Imtiaz Rangwala, Ben Livneh, and Eric

Gordon (CIRES/WWA)

• Martin Hoerling and George Kiladis

(NOAA PSD)


NOAA HPC 7-day Quantitative Precipitation Forecast

(QPF) issued 6pm 9/8/2013 for 9/9 through 9/15

http://wwa.colorado.edu Upper-air (500mb) pattern – September 11, 2013

L


Water vapor and atmospheric circulation at 11:15 pm MDT, September 11, 2013. (Satellite image: CIMSS, University of Wisconsin)

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Total atmospheric precipitable water (PW) over Denver on

Sept. 11, 2013, compared to all values from 1948-2012

Denver 1.44”


Total atmospheric precipitable water (PW) over Grand Jct. on

Sept. 10, 2013, compared to all values from 1948-2012

Max

99th 9/10/2013

Pre

cip

itab

le W

ate

r, in

che

s

Grand Jct. 1.28”


L


L


L


L


L


L


L


CoCoRAHS total precipitation from September 9–15, 2013

(Map: Colorado Climate Center, CSU)

Grand Junction

1.7

Denver (Stapleton)

13.3


Near-surface (850mb) winds, September 12, 2013


CoCoRAHS total precipitation from September 9–15, 2013

Steamboat Spgs

2.5

Grand Jct

1.7

Durango

3.0 Pagosa Spgs

2.5

Glenwood

1.4

Gunnison

1.6 Norwood

2.0

Dillon

2.0

Cortez

2.0

Aspen 1.8

(Map: Colorado Climate Center, CSU)


CoCoRAHS total precipitation from September 9–15, 2013 (Map: Colorado Climate Center, CSU)

1”-2”

2”-4”

2”-4”

2”-4”

2”-6”


SNOTEL precipitation (in.), September 2013 with Sept. 9-16 shaded

0

2

4

6

8

10 Willow Park

0

2

4

6

8

10 Tower

0

2

4

6

8

10 Loveland Basin

0

2

4

6

8

10

Hoosier Pass

3.2” 6.0” 2.4”

5.1”


0

2

4

6

8

10

0

2

4

6

8

10

12

SNOTEL precipitation (in.), September 2013 with Sept. 9-16 shaded

Columbus Basin

0

2

4

6

8

10

Wolf Creek Summit

Weminuche Creek

0

2

4

6

8

10 McClure Pass

2.1”

6.4” 7.3” 2.3”


CoCoRAHS

September 2013 precipitation as % of normal (Map: Colorado Climate Center, CSU)


PRISM monthly Western CO (Div. 2) precipitation, 2000–2013

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Jan- 2000

Jan- 2001

Jan- 2002

Jan- 2003

Jan- 2004

Jan- 2005

Jan- 2006

Jan- 2007

Jan- 2008

Jan- 2009

Jan- 2010

Jan- 2011

Jan- 2012

Jan- 2013

Pre

cip

itat

ion

, in

che

s

September 2013

4.17”

September 2013: wettest month since April 1999 3rd wettest September on record 13th wettest month on record


Upper Colorado Basin streamflow percentiles

September 8, 2013 September 15, 2013


Upper Colorado Basin hydrographs for September 2013










Navajo Reservoir contents - September 1st-30th, 2013

Co

nte

nts

(ac

re-f

eet)

September

800,000

850,000

900,000

950,000

1,000,000

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29

Net Gain:

~100,000 AF


Lake Powell Daily Inflows - September 2013


Lake Powell change in reservoir level - September 1st-30th

Elev

atio

n, f

eet

September

3587

3588

3589

3590

3591

3592

1 8 15 22 29

Net gain:

~4 feet

~250,000 AF


US Drought Monitor for Colorado – before and after the rain event

September 17, 2013 September 3, 2013


VIC simulated soil moisture percentiles – before and after


How unusual was the September

2013 event for the Western

Slope?


• Sept. 3-7, 1909

• Sept. 3-4, 1927

• Sept. 18-23, 1941

• Sept. 27-30, 1959

• Sept. 20-24, 1961

• Sept. 4-6, 1970

• Sept. 19-21, 1997

• Sept. 6-10, 2003

Previous September/October multiday

Western Slope precipitation events

• Oct. 10-15, 1894

• Oct. 4-6, 1911

• Oct. 19-20, 1972

• Oct. 10-12, 1986

• Focus of these

events is usually

San Juans


(Data: NCAR/NCEP and NOAA 20th Century Reanalyses)

Sept. 12-14, 2013 Sep. 4-6, 1970

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Upper-level (500 Mb) pattern, averaged over ~3-day period of

peak of rainfall in two West Slope heavy precip events


Total atmospheric precipitable water (PW) over Denver from

1948-2012, compared to the measurement for 6pm MDT on

September 11, 2013 (red dot) (Plot adapted from NOAA NWS.)

Climate change?


Total atmospheric precipitable water (PW) over Denver from

1948-2012, compared to the measurement for 6pm MDT on

September 11, 2013 (red dot) (Plot adapted from NOAA NWS.)

Climate change?


Summary of the September 2013 event

• Surges of subtropical monsoon-like moisture persisted for ~1 week due to near-stationary upper-level pattern

• Western Slope and UCRB received widespread beneficial precipitation without the severe flooding (except NW NM)

• Event contributed to September 2013 being wettest month for Western Slope since 1999

• Precipitation fell as rain at all elevations: increase in runoff, reservoir levels, and soil moisture

• Similar widespread fall precipitation events on West Slope have occurred every ~10 years

• Not clear how climate change may alter frequency of these events – but each event will likely be wetter


Comments? Questions? Please contact me at [email protected]

Thank you!

Documents

September’s Extreme Weather - Colorado Mesa University · NOAA HPC 7-day Quantitative Precipitation Forecast (QPF) issued 6pm 9/8/2013 for 9/9 through 9/15