Correlation coefficients of precipitation anomaly (P) and temperature

anomaly (T) in North Central Texas and major climate indices (AMO,

PDO, SOI, NAO) during El Nino climate condition from 1960 to 2014.

Climate Forecast-Aided Drought Decision Support for North Central Texas

Sunghee Kim1, Hossein Sadeghi1, D.-J. Seo1, Andrew Philpott2, Frank Bell2, Tyler Fincannon3, Arne Winguth3, Reza Ahmad Limon1, Laura Blaylock4, James Brown5, Nick Fang1, Glenn Clingenpeel6

1Dept. of Civil Eng, The Univ. of Texas at Arlington, Arlington, TX, USA, 2West Gulf River Forecast Center, NOAA/NWS, Fort Worth, TX, USA, 3Dept. of Earth & Environ. Sciences, The Univ. of Texas at

Arlington, Arlington, TX, USA; 4Tarrant Regional Water District, Fort Worth, TX, USA, 5Hydrologic Solutions Limited, Southampton, UK, 6 Trinity River Authority of Texas, Arlington, TX, USA

Background

Extreme events pose increasingly large challenges

for water supply and flood control to the Dallas-Fort

Worth Metroplex (DFW) and North Central Texas,

exacerbated by rapid population growth, urbanization

and climate change.

To meet the growing demand for water supply, large

raw water suppliers such as the Tarrant Regional

Water District (TRWD) operate systems of reservoirs

interconnected by extensive networks of pipelines.

Approach – Phase 1

594, Wednesday, January 13, 2016 02:30 PM - 04:00 PM, AMS 96th Annual Meeting, New Orleans, LA

Perform hindcasting experiments using weather and

climate reforecasts from the Global Ensemble Forecast

System (GEFS), Coupled Forecast System Model

Version 2 (CFSv2) and conditional ensemble

streamflow prediction using climate indices

Produce streamflow ensemble hindcasts using the

Hydrologic Ensemble Forecast Service (HEFS) on the

NWS Community Hydrologic Prediction System

(CHPS)

Input ensemble streamflow hindcasts to the TRWD’s

decision support tool, RiverWare

Conclusions

• The use of medium-range ensemble

precipitation forecast can substantially

increase lead time and skill of inflow

forecast in North Central Texas

‒ Significant skill observed in

weekly inflow volume forecast out

to 2 weeks into the future

Acknowledgments This work is supported by the Sectoral Applications Research Program (SARP) of the NOAA Climate

Program Office (CPO) Grant NA15OAR4310109. This support is gratefully acknowledged.

Objectives

Utilize weather and climate forecast-forced

ensemble streamflow forecast in water resources

management practices in North Central Texas

‒ Currently, the NWS West Gulf River Forecast

Center (WGRFC) provides only short-range (~3

days) single-valued precipitation forecast (QPF)

Assess predictive skill and economic value of

weather and climate forecasts for integrated decision

support for reservoir management and water supply

operations in North Central Texas

Advance understanding of the role of weather and

climate forecasts in improving reliability, efficiency

and resilience of a complex water supply system in a

large and rapidly growing urban area

Method Study area

Preliminary Results

Using GEFS-forced, post-processed ensemble

streamflow forecasts as inflows, the TRWD

model simulates the reservoir and water

transfer operations, evaluating the effectiveness

and benefits of weather and climate forecast-

aided decision support.

Perc

ent

Non-E

xceedance

Dollars in Millions

Annual Cost

Savings Additional

Annual Cost

(1) Climate indices

(2) Skill in precipitation hindcasts:

Medium-range (GEFS) vs. Short-range (WGRFC QPF)

(4) Skill in total inflow volume

(3) Skill in ensemble streamflow hindcasts

Skill in weekly inflow volume

hindcasts remains significant up

to about 14 days into the future

NWS Hydrologic Ensemble Forecast Service (HEFS) on Community Hydrologic Prediction System (CHPS)

TRWD model

GEFS reforecasts (Ensemble mean)

MEFP

MEFP parameters

Ensemble precipitation hindcasts

Hydrologic &

reservoir models

Raw ensemble streamflow hindcasts

EnsPost parameters

EnsPost

Post-processed ensemble streamflow hindcasts

Meteorological Ensemble Forecast

Processor

Ensemble Post Processor

Lead time (hours)

Co

rre

latio

n c

oe

ffic

ien

t

Lead time (hours)

Co

rre

latio

n c

oe

ffic

ien

t GEFS ensemble

mean

RFC single-valued

QPF

Streamflow (cfs)

Obs. CDF

Forecast CDF

Cu

mu

lative

De

nsity

CR

PS

S

Lead time (hours)

CRPSS (relative to climatology)

remains significant for about 10

days into the future

Co

rre

latio

n c

oe

ffic

ien

t

Lead time (hours)

Mean Continuous Ranked Probability:

𝑪𝑹𝑷𝑺 = { 𝑭𝒀 𝒒 − 𝑭𝑿 𝒒𝟐 𝒅𝒚

Ongoing work

• Use the weather and climate

forecast-aided ensemble inflow

volume forecast in TRWD’s decision

support tool

‒ CFSv2 via HEFS

‒ Climate indices via conditional

ESP using HEFS

TRWD’s water supply system

NA

O

SO

I

PD

O

A

MO

P(J

AK

T2

)

P

(DF

W)

T(D

FW

)

T(DFW) P(DFW) P(JAKT2) AMO PDO SOI NAO

• Regional mean areal precipitation anomaly, P(JAKT2) shows

statistically significant correlation with indices PDO (=0.57),

NAO (= 0.31), AMO (= -0.31), and SOI (= -0.35).

• P(JAKT2) has moderate correlation with temperature

anomaly in the DFW area (=-0.23).

An example of cost-benefit analysis