Hydroclimate Review for the water year 2008 Kingtse

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. 1

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

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

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

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

Drought: local phenomenon June 2008 AMJ 2008 1. Heavy flooding over Iowa, Mo, & Illinois in June 2. Dryness over the Southeast & Texas and California 3. This pattern persisted from April-July Kansas : western Kansas : D 3 drought Eastern Kansas: Flood 6

Uncertainties of SM percentiles : Jun 2008 EMC/NCEP 3 model ensemble; Univ. of Washington ensemble: 6 model ensemble; CPC unified P analysis; P from NCDC stations Base: 1979 -2006 1920 -2003 7

6 -month SPI (SPI 6) 8

Ensemble sm percentiles (EMC) 9

Stream flow anomalies (USGS) Jan Apr Jul Oct 10

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

P SM Drought: §California §Southern Texas §Southeast SPI 6 SRI 6 Floods: §Mississippi River Basin §Northern Plains 12

California Drought Climatology P Below normal P for winter SM dry SM Month Strong seasonal cycle Rain: Nov-March Path to drought ØOND 2007 –JFM 2008: Below normal rainfall due to cold ENSO ØSM below normal ØNo rainfall after March ØSM depreciated even more Cold ENSO below normal rainfall SM: ensemble NLDAS (EMC) 13

SPI 6 Composites P Impact of cold ENSO: Dry Southern Texas Southeast, California Texas, Southern Plains: Cold ENSO drought Southeast: Cold ENSO Drought in winter Relieve in summer Mo and Schemm 2008 14

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

June 2008 Mississippi Flood Strong GPLLJ IASLLJ 16

Path to floods Byerle and Paegle 2003 (JGR) Interaction bwt U 200 and mountains GPLLJ S 200 a Colored U 200 a Contoured Box: (30 -50 N, 100 -120 W) 17

A Possible path to floods n n n 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 h. Pa Vorticity source (S 200 a) supported U 200 extended to the West Coast Jet interacts with the mountains strong GPLLJ more moisture more rainfall 18

Summary n n 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. 19

2008 hydroclimate conditions n n 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 20

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 21

Southeast drought 22

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