# Presentation: 233803

## North American Drought Briefingfor July and MJJ 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

## Drought  monitor: 

- Droughts:
- Southeast
-  Southern Plains including Texas
- California, Nevada
-  4. North Dakota
- 5.Eastern  Colorado and western Kansas

- Outlook:
- Improvement over
- Southeast and southern Plains
- Persistence over California, Nevada, Dakota

## P anomalies 

- Highlights
- Positive P anomalies persisted from May-July over Iowa, Mo,& Illinois
- Dryness over the Southeast & Texas
- This pattern persisted from April-July
- Good North American monsoon
- Rain over Florida relieved  drought conditions there.

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

- 2. Dry: Southeast, southern Texas, California
-  3. Wet: Central U. S. and the upper Missouri basin (RFC 2 area)

- Standard Precip Indices   for 2008 July

## Streamflow indicates :

- a) Wet Mississippi River basin,
- b) Dry: Southeast , but in  comparison  with June conditions, anomalies were slightly weaker
- The ensemble runoff anomaly captures the streamflow pattern well.

- June 2008

- Ensemble: Noah, Mosaic and SAC

- July 2008

- Runoff ensemble anomalies

## Standardized Runoff index

- U. Washington August 4

- The ensemble mean agrees with the streamflow (USGS well).
- In comparison with U. Washington, differences are over Texas (no drought) and California (stronger drought)

- VIC model

## Soil Moisture percentiles

- Base:1979-2006

- University of Washington ensemble:

- Base: 1920-2003

- Both ensemble and U. Washington agree with the Drought  Monitor  for most drought areas except north Dakota

## The NLDAS drought indices pick up most dry areas. The SPI does not show drought over California, because this is not their raining season

- Overall, the drought monitor issued on July 1 and August 5 are similar
- There are improvements
- Over Southern Texas & New Mexico
- And persistence : California, Nevada and Southeast

- Changes of SM
- Increase SM over the Southwest due to good monsoon,
- Florida drought improved
- Dryness over the Pacific Northwest & RFC 2 area

## Drought impact: Fire weather Keetch Byrarm index (WFAS)

- Watch out:
- Southeast;
- Texas, California
- Nevada
- North Dakota
- Fire Danger

## Recent Conditions 

- August 2-8,2008

- Panom

- SM  anomaly

- Northern Plains: started to dry
- Southeast: still dry
- Over the AZNM, monsoon continued

- SM anomaly did not change much except some improvement over California

- SM anom

## Monsoon over AZNM

- mm/day

- Onset 3Jul2008

- Monsoon onset 3 Jul
- Overall a good monsoon

- P max:
- 11jul
- 20Jul
- 27Jul

## Monsoon onset (AZNM) July 3

- Eastern Pac tropical storms (unisys)

- Boris: 27Jun-01Jul
- Douglas 02-04 Jul
- Tropical depression 05E (05-07Jul)
- Elida (12-19 Jul)Fausto (14-22 July)
- Genevieve (21-27Jul)

- North American monsoon update

- Moisture surge events for 2008 & tropical storms in the E. Pacific
- A good correspondence

- Boris

- 05E

- Elida

- Fausto

- Genevieve

- Tstorms
- Passing GoC long

## SSTA  

- Cold ENSO ended and the CPC predicts ENSO neutral conditions through summer and fall.
- Negative SSTas along the West coast of North America
- Warm SSTAs in the North Atlantic
- This pattern persisted from June to  July 2008

- P  Fcst from 8-14 DAY

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

##  SM % from the Princeton downscaling from the CFS fcsts using VIC model IC 200807

- Jul 08

- Jul08

- Aug08

- California: drought persists for 2 months and then improves in Oct
- Southeast: about the same.
- Texas: getting better in September.

##  SM % from the ESP seasonal Fcst IC=20080802

- Month 1

- Month 2

- Month 3

- California: Dry conditions persist for 2 months
- Texas: improvement in the next 2 months
- Southeast: conditions improve by the end of summer

- University of Washington

- Month 2

## Seasonal forecasts from NSIPP

- California: Drought Persists for 2 months then iweakens
- Southeast : no relieve until Nov.
- Texas: persists for 2 months and then drought weakens

## 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 through the next 2 months then improves:  summer is not their raining season and P has a strong seasonal cycle. When rainfall season starts in Oct-Nov, drought should improve (no COLD ENSO, the MJO may bring rain)
- Southern Plains:  Drought conditions will continue for one-two months and then improve since ENSO will be neutral
- Southeast: The ENSO neutral condition may mean that drought will last until the end of summer.