1. M ETEOROLOGICAL C ONDITIONS A SSOCIATED WITH THE 2008 MIDWEST FLOOD Ray Wolf NOAA / National Weather Service Davenport, Iowa University of Iowa – Learning from the Flood, October 6, 2008

2. Outline o About the NWS o The NWS role in the flood event o The weather behind the flood o Event perspective

3. National Weather Service - an agency of the Federal government US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service

4. NWS Mission  The National Weather Service (NWS) provides weather, hydrologic, and climate data, forecasts and warnings for the US, for the protection of life and property and the enhancement of the national economy.

5. NWS Operations  ~4500 people  174 offices

6. NWS Operations  Collect data – surface, upper air, radar,  satellite, solar  Forecasts and Warnings  Public – severe and winter weather  Aviation  Rivers  Fire Weather  Marine  Tropical  Climate  Space

7. NWS Davenport

8. NWS Partnerships NWS EMUSGSMediaUSACE Research Community FEMA

9. And now the weather…  Heavy winter snow  + Significant flooding in April (high river levels)  + Extremely moist soils  + Heavy June rains  --------------------------------------  = Historic flooding

10. River Basins Extended period of heavy snow then heavy rain from November through June in the red shaded area

11. Winter Snow – mid February

12. Winter Snow Water Equivalent

13. Winter Snowfall Totals (inches)

14. April Precipitation

15. April Soil Moisture

16. April River Levels

17. June Rainfall

19. Precipitation Summary

20. Cedar Rapids, Iowa - 2008

21. June Soil Moisture

22. Hydrograph – Cedar Rapids

23. Hydrograph – Iowa City

24. Satellite View – Polar Orbiter

25. Cedar Rapids

26. Iowa City

27. Jet Stream level   << Mean from Jan – Jun  Anomaly >> 6 miles up

28. 500 mb Height Anomaly chart 3 miles up

29. 850 mb moisture 1 mile up

30. La Nina?  La Nina – cold event  Normal – neutral  El Nino – warm event

31. La Nina? – likely not a key factor La Nina precipitation composite brown = drier than normal green = wetter than normal

32. Global climate change? o No single event can be attributed to climate change o Regional climate is trending wetter o There are indications that heavy precipitation events are becoming more common

33. Perspective

37. o 1 in a 100 year = 1% chance each year o 1 in a 500 year = 0.2% chance each year o Climate is becoming wetter – fact o Climate change suggests higher probabilities of such events o Land use changes, i.e., urbanization increases rate of runoff

38. ?? Questions ??  ray.wolf@noaa.gov