# Presentation: 516804

## North American Drought Briefingfor June and AMJ 2008 conditions

- Climate Prediction Center/NCEP/NOAA
- _[http://](http://www.cpc.ncep.noaa.gov/products/Drought)__[www.cpc.ncep.noaa.gov](http://www.cpc.ncep.noaa.gov/products/Drought)__[/products/Drought](http://www.cpc.ncep.noaa.gov/products/Drought)_

## Current Partners

**CPC:** Kingtse Mo, Wanru Wu, Muthuvel Chelliah, Wesley Ebisuzaki, Yun Fan, Huug van den Dool, Wei Shi
**EMC:** NLDAS Team: Ken Mitchell, Youlong Xia, Jesse Meng, Helin Wei
**EMC:** NAEFS Team: Zoltan Toth, Yuejian Zhu
**NASA/GSFC:** Randy Koster, Gregory Walker
**Princeton Univ.:** Eric Wood, Lifeng Luo, Justin Scheffield
**Univ. of Washington:** Dennis Lettenmaier
**Web Masters:** Viviane Silva, Joe Harrison
**Project Funded by NOAA CPPA** & NASA

## outlines

- Objective drought indicators from the NLDAS: Drought indices –SPI, and ensemble SRI and Soil moisture percentiles.
- Mississippi flooding
- Update on the North American monsoon
- Droughts over the Southeast and Texas and relationships with ENSO
-  Forecasts

## Drought  monitor: 

- Drought  monitor:
- Droughts:
- Southeast
-  Southern Plains including Texas
- California, Nevada
-  4. North Dakota

- A cold ENSO pattern

- Outlook:
- Improvements over
- Southeast and southern Plains
- Persistence over California

## P anomalies 

- Heavy flooding over Iowa, Mo,& Illinois in June
- Dryness over the Southeast & Texas and California
- This pattern persisted from April

## 1. Rainfall over the Mississippi basin influenced all SPI indices. 

- 1. Rainfall over the Mississippi basin influenced all SPI indices.
- 2. Dry: Southeast, southern Texas and  California
- 3. Wet: Central U. S. and the upper Missouri basin (RFC 2 area)

## Streamflow indicates :

- a) Wet Mississippi River basin,
- b) Dry: Southeast, Texas and California
- The ensemble runoff anomaly captures the streamflow pattern well.

- June 2008

- Ensemble: Noah, Mosaic and SAC

## Standardized Runoff index

- All models capture
- Wetness over the Mississippi, Upper Missouri ,
- Dryness over the Southeast,  southern Texas and California, North Dakota

## Soil Moisture percentiles

- Base:1979-2006

- University of Washington ensemble:

- Base: 1920-2003

## Drought:  Southeast, Southern Plains California, north Dakota

- Overall, the drought monitor is consistent with all three drought indices: SPI, SRI and SM percentiles:

## Conditions 

- Conditions
- 28Jun-5Jul2008

- Panom

- SM  anomaly

- Northern Plains: started to dry
- Southeast: still dry
- Some rainfall over  Southern Texas
- Over the AZNM, monsoon started

- SM anomaly does not change much

## Monsoon  daily rainfall (thanks to  Wei Shi)

- New Mexico: 105-110W

- Arizona 110-105W onset July 3

- Eastern Pac tropical storms (unisys)

- Boris: 27Jun-01Jul
- Douglas 02-04 Jul
- Tropical depression 05E (05-07Jul)

- North American monsoon update

## comparison with 1993 floods

**comparison with 1993 floods**

- Floods over the Mississippi River

- SM percentiles

- 2008 May

- 1993 Jun

- Both had:
- Heavy P over the central U. S.
- Dryness over the Southeast, Texas
- Wet soil moisture the previous month

## A

- C

- Two patterns are in quadrature with each other
- Over North America

- Vertically integrated moisture flux
- (qu;qv) - vector
- GPLLJ- (qv) colored

## SSTA  

- Heavy rainfall area for 2008 was located eastward from the areas of  the 1993 floods.
- The associated Z500 anomalies are in quadrature with  each other.
- SSTA patterns for these two years are almost opposite in phase

- SSTA

## Droughts and ENSO relationships

- ENSO Composites (cold-warm)
- Composites for JFM, AMJ, JAS and OND for  SPI6, SM anomalies  and SRI6 were obtained using the VIC model outputs from 1903-2006.

- Monitor shows a cold ENSO signal except the Southeast

- ENSO composite (cold-warm)

- SPI6

- SM anom

- SRI 6

## Drought over the Southeast

- ENSO composites of P and SPI6  (cold-warm) for winter and summer seasons

- ENSO composite of P shows negative P anomalies over the Southeast for winter, but positive anomalies for summer.
- Therefore, drought over the Southeast is likely to occur during cold ENSO winters, but persistent ENSO from winter to summer does not mean persistent drought

- (Mo and Schemm 2008 GRL)

## Drought over Texas

- From SPI6 over the RFC 10, drought events were selected when SPI6<-0.8 more than 4 months.
- Composites of SSTAs were computed for periods under drought.

- It shows a cold ENSO for
- both winter and summer

## North Atlantic: getting warmer. Cold ENSO: weakening

- North Pacific: A PDO with warming over the N-PAC.

- SSTA for Mar-May 2008

## CFS forecasts of SSTAs

- Neutral conditions from now  to Dec 2009,
- Warm North Atlantic and  the PDO stay through Dec

- P  Fcst from 6- 10DAY

- Soil Moisture from Leaky Bucket model
- Yun Fan and Huug vandenDool

##  SM % from the Princeton downscaling from the CFS fcsts using VIC model IC 200806

- Jul 08

- Jul08

- Aug08

- Sep08

- Jun08

##  SM % from the ESP seasonal Fcst IC=20080705

-  SM % from the ESP seasonal Fcst IC=20080705
- Month 1

- Month 2

- Month 3

- California: Dry conditions persist through JAS
- Texas: some improvement due to the weakening of the  cold ENSO
- Southeast: improve by the end of summer

- University of Washington

## Conclusions

- We start to use drought indices for drought assessment. They are consistent with the official drought monitor.
- California: Dry condition is likely to continue because summer is not their raining season and P has a strong seasonal cycle.
- Southern Plains:  Drought is largely influenced by cold ENSO. Dry conditions are likely to improve since ENSO will be neutral for summer
- Southeast: The ENSO neutral condition may mean drought will last until the end of summer.