1. Hydro-climate Review for the water year 2008 Kingtse C. Mo and Wanru Wu Climate Prediction Center/NCEP/NWS High lights Drought: Southern Texas, & California, Southeast Floods : Mississippi River basin A good North American monsoon.

2. Drought Briefing http://www.cpc.ncep.noaa.gov/products/Drought Drought briefing on the second Thursday of the month at 11AM eastern time • Monitor atmospheric and hydrological conditions in support of operational Drought Monitor and Drought Outlook • Provide users timely information and analysis on drought. • Bring drought forecasters and products generators together for discussion. • Contact person: Kingtse.mo@noaa.gov

3. objective monitoring many faces of drought • Meteorological drought: Precipitation deficit. Index: Standardized Precipitation Index (SPI) • Hydrological drought: Stream flow or runoff deficit Index: Standardized runoff index (SRI) • Agricultural drought: Total soil water storage deficit Index: soil moisture anomaly percentiles

4. Drought Briefing http://www.cpc.ncep.noaa.gov/products/Drought • Surface conditions including soil conditions, E, P– from the ensemble NLDAS (EMC) and the University of Washington. • Atmospheric conditions and budget terms : NARR • Forecasts: • U. Washington (ESP) • Princeton U (downscaling from the CFS using VIC) • NSIPP (from NSIPP model) Dennis Lettenmaier’s presentation on Wed.

5. Precip anomalies Dryness: California, Southern Texas, Southeast Wetness: Ohio Valley (3 seasons) and central United States, a wet NA monsoon

6. June 2008 AMJ 2008 Drought: local phenomenon • Heavy flooding over Iowa, Mo,& Illinois in June • Dryness over the Southeast & Texas and California • This pattern persisted from April-July Kansas : western Kansas : D3 drought Eastern Kansas: Flood

7. Uncertainties of SM percentiles :Jun2008 Univ. of Washington ensemble: EMC/NCEP 6 model ensemble; P from NCDC stations 1920-2003 3 model ensemble; CPC unified P analysis; Base:1979-2006

8. 6-month SPI (SPI6)

9. Ensemble sm percentiles (EMC)

10. Stream flow anomalies (USGS) Jan Jul Oct Apr

11. ENSO (SST) Cold ENSO OND 2007 through JFM 2008 -> Neutral in JAS Tropical convection: Suppressed convection through summer Jul2008 180

12. P SM • Drought: • California • Southern Texas • Southeast • Floods: • Mississippi River Basin • Northern Plains SRI6 SPI 6

13. California Drought Climatology P Below normal P for winter • Path to drought • OND 2007 –JFM 2008: Below normal rainfall due to cold ENSO • SM below normal • No rainfall after March • SM depreciated even more SM dry SM SM: ensemble NLDAS (EMC) Month Strong seasonal cycle Rain: Nov-March Cold ENSO below normal rainfall

14. Composites Impact of cold ENSO: Dry Southern TexasSoutheast, California SPI6 P Texas, Southern Plains: Cold ENSO drought Southeast: Cold ENSO Drought in winter Relieve in summer Mo and Schemm 2008

15. A very wet monsoon Over the Southwest, this was the 6th wettest season since 1948.

16. June 2008 Mississippi Flood Strong GPLLJ IASLLJ

17. Path to floods Byerle and Paegle 2003 (JGR) Interaction bwt U200 and mountains  GPLLJ GPLLJ Box: (30-50N,100-120W) S200a Colored U200a Contoured

18. A Possible path to floods • SSTAs in the tropical Pacific showed a diminishing cold ENSO event, convection was still suppressed. • Enhanced convection (rainfall) was located over the eastern Pacific and southern Mexico • The downward branch of the Hadley cell was located in the Southeast less P consistent with anticyclone • Anomalous 200 hPa Vorticity source (S200a) supported U200 extended to the West Coast • Jet interacts with the mountains  strong GPLLJ more moisture  more rainfall

19. Summary • RR and ensemble NLDAS were used to monitor drought/floods over the United States. • Drought briefing is given monthly to support drought monitor and outlook • While all NLDAS systems are able to point to areas under drought, spread is too large to determine the drought classification. • We are looking for the results from this meeting to give us guidance.

20. 2008 hydroclimate conditions • While the SSTAs show drought ended in JAS, the convection pattern still showed suppressed convection over the central Pacific and enhanced convection over the eastern Pacific & southern Mexico. • California drought: strong seasonal cycle , lack of rain in winter 2007 and depreciated soil moisture • Southeast: Drought intensified in winter, but had some relieve in summer due to hurricanes. • Southern Texas: Cold ENSO drought

21. Evolution of SSTAs Cold ENSO lasted from OND 2007 through JFM 2008 and then diminished. In JAS, the cold event ended and the ENSO neutral conditions were observed in the tropical Pacific. The North Atlantic SSTAs are still in the decadal positive phase of the AMO

22. Southeast drought