3. July 25, 2001 presents “Past, Present, and Future” Ed Kieser

6. Total Precipitation in Inches March through May 2001 Total Precipitation in Inches March through May 2001 Midwestern Regional Climate Center Illinois State Water Survey Champaign, IL

7. Total Rainfall in Inches June 2001 Total Rainfall in Inches June 2001 Midwestern Regional Climate Center Illinois State Water Survey Champaign, IL

8. Total Rainfall Departure in inches June 2001 Total Rainfall Departure in inches June 2001 Midwestern Regional Climate Center Illinois State Water Survey Champaign, IL

9. Total Rainfall in Inches July 1-24, 2001 Total Rainfall in Inches July 1-24, 2001 Midwestern Regional Climate Center Illinois State Water Survey Champaign, IL

10. Total Rainfall Percent of Mean July 1-24, 2001 Total Rainfall Percent of Mean July 1-24, 2001 Midwestern Regional Climate Center Illinois State Water Survey Champaign, IL

11. Total Rainfall in Inches July 18-24, 2001 Total Rainfall in Inches July 18-24, 2001 Midwestern Regional Climate Center Illinois State Water Survey Champaign, IL

12. Total Rainfall Departure in Inches July 18-24, 2001 Total Rainfall Departure in Inches July 18-24, 2001 Midwestern Regional Climate Center Illinois State Water Survey Champaign, IL

14. Dry

25. Palmer Drought Severity Index

26. Crop Moisture Index

27. Current Drought Assessment

28. National Weather Service Prediction

42. Temperature Outlook July 31-August 4, 2001 Temperature Outlook July 31-August 4, 2001

43. Precipitation Outlook July 31-August 4, 2001 Precipitation Outlook July 31-August 4, 2001

44. Temperature Outlook August 2-8, 2001 Temperature Outlook August 2-8, 2001

45. Precipitation Outlook August 2-8, 2001 Precipitation Outlook August 2-8, 2001

46. Long-Lead Outlooks CL – Climatology – Chances are 1/3 A, 1/3 N, 1/3 B. CL – Climatology – Chances are 1/3 A, 1/3 N, 1/3 B. A – Above Average. A – Above Average. N – Near Average. N – Near Average. B – Below Average. B – Below Average. How to read them:

47. Long-Lead Outlooks Chance for “Above Average” increases from climatology by 10%. Chance for “Above Average” increases from climatology by 10%. A – Odds for Above Average: 43 1/3%. A – Odds for Above Average: 43 1/3%. N – Odds for Near Average: 33 1/3%. N – Odds for Near Average: 33 1/3%. B – Odds for Below Average: 23 1/3%. B – Odds for Below Average: 23 1/3%. Example: “10” around “A”:

48. Temperature Outlook August 2001 Temperature Outlook August 2001

49. Precipitation Outlook August 2001 Precipitation Outlook August 2001

50. Climate Outlook August-October 2001 Temperature Climate Outlook August-October 2001 Temperature

51. Climate Outlook August-October Precipitation Climate Outlook August-October Precipitation

52. Climate Outlooks Temperature Climate Outlooks Temperature

53. Climate Outlooks Precipitation Climate Outlooks Precipitation

55. El Niño/La Niña ENSO: El Niño/Southern Oscillation. ENSO: El Niño/Southern Oscillation. El Niño: unusually warm water in the eastern Pacific Ocean near the Equator. El Niño: unusually warm water in the eastern Pacific Ocean near the Equator. La Niña: unusually cool water in the eastern Pacific Ocean near the Equator. La Niña: unusually cool water in the eastern Pacific Ocean near the Equator. Some terms:

56. La Niña Easterly trade winds strengthen, causing more upwelling of cold water in the eastern Pacific Ocean. Easterly trade winds strengthen, causing more upwelling of cold water in the eastern Pacific Ocean. The reasons for the strengthening of the trade winds are still not fully known. El Niño and La Niña are extreme phases of a naturally occurring climate cycle. The reasons for the strengthening of the trade winds are still not fully known. El Niño and La Niña are extreme phases of a naturally occurring climate cycle. Why does it occur?

57. Normal Conditions Convective Loop Equator 120ºE 80ºW

58. La Niña Every 2-7 years. The interval between events is irregular. Every 2-7 years. The interval between events is irregular. Maximum cooling of the Pacific waters is generally observed between December and February, the same time period as the maximum warming during El Niño. Maximum cooling of the Pacific waters is generally observed between December and February, the same time period as the maximum warming during El Niño. When does it occur?

59. 0 180 O 150 O W 120 O W 090 O W 0O0O0O0O 5OS5OS5OS5OS 10 O S NIÑO - 4 NIÑO - 3 160 O E NIÑO - 2 NIÑO - 1 Sea Surface Temperature Anomalies Niño 3

60. 0 180 O 150 O W 120 O W 090 O W 0O0O0O0O 5OS5OS5OS5OS 10 O S NIÑO - 4 NIÑO - 3 160 O E NIÑO - 2 NIÑO - 1 Sea Surface Temperature Anomalies Niño 3 El Niño

61. 0 180 O 150 O W 120 O W 090 O W 0O0O0O0O 5OS5OS5OS5OS 10 O S NIÑO - 4 NIÑO - 3 160 O E NIÑO - 2 NIÑO - 1 Sea Surface Temperature Anomalies Niño 3 El Niño La Niña

62. Slightly drier-than-average conditions in eastern Argentina and southern Brazil from November through March. Slightly drier-than-average conditions in eastern Argentina and southern Brazil from November through March. Often drier than average during the winter for northeast Mexico and for the southwest U.S and southeast U.S. Often drier than average during the winter for northeast Mexico and for the southwest U.S and southeast U.S. Often wetter than average in southern Africa, Indonesia, Philippines, and northern Australia. Often wetter than average in southern Africa, Indonesia, Philippines, and northern Australia. There is NO SIGNIFICANT CORRELATION between La Niña and summer temperature or rainfall in the U.S. Corn Belt and Great Plains. There is NO SIGNIFICANT CORRELATION between La Niña and summer temperature or rainfall in the U.S. Corn Belt and Great Plains. What impact does it typically have on climate and weather?

64. La Niña Conditions in Winter Equator

65. La Niña Conditions in Winter Equator

66. La Niña The Southwest is drier than average from late summer through the following winter. The Southwest is drier than average from late summer through the following winter. The Central Plains are typically drier in fall and the Southeast is drier in winter. The Central Plains are typically drier in fall and the Southeast is drier in winter. The Pacific Northwest is wetter in late fall and early winter. The Pacific Northwest is wetter in late fall and early winter. La Niña winters are typically warmer than average in the Southeast and cooler than average in the Northwest. La Niña winters are typically warmer than average in the Southeast and cooler than average in the Northwest. Impacts on the U.S.:

67. La Niña Impacts Bottom Line: There is little correlation between La Niña and weather in Illinois, especially in summer. Bottom Line: There is little correlation between La Niña and weather in Illinois, especially in summer. There is a slight tilt in the odds toward a wetter than average spring (April through June). There is a slight tilt in the odds toward a wetter than average spring (April through June). There is a slight tilt in the odds toward a cooler than average spring. There is a slight tilt in the odds toward a cooler than average spring. Illinois:

68. El Niño Impacts Bottom Line: There is little correlation between El Niño and weather in Illinois, especially in summer. Bottom Line: There is little correlation between El Niño and weather in Illinois, especially in summer. Winters are often milder than average during a strong El Niño. Winters are often milder than average during a strong El Niño. There is a good chance of less snowfall than average during a strong El Niño. There is a good chance of less snowfall than average during a strong El Niño. Illinois:

69. Pacific Decadal Oscillation Know as the “PDO.” It’s a long-term ocean fluctuation of the Pacific Ocean, with a cycle of about 20 to 30 years. Know as the “PDO.” It’s a long-term ocean fluctuation of the Pacific Ocean, with a cycle of about 20 to 30 years. What is it?

70. Pacific Decadal Oscillation Evidence suggests that the PDO switched to the “cool” or “negative” phase in the eastern Pacific Ocean in 1999. Evidence suggests that the PDO switched to the “cool” or “negative” phase in the eastern Pacific Ocean in 1999. It appears that this will act to steer the jet stream farther north over the western U.S. It appears that this will act to steer the jet stream farther north over the western U.S. The “warm” or “positive” phase appears to have lasted from 1977-1998. The “warm” or “positive” phase appears to have lasted from 1977-1998. What is happening?

71. Pacific Decadal Oscillation

72. Sea Surface Temperature Anomalies - January 8, 2000 Sea Surface Temperature Anomalies - January 8, 2000

73. Sea Surface Temperature Anomalies - January 8, 2000 Sea Surface Temperature Anomalies - January 8, 2000

74. Sea Surface Temperature Anomalies - January 8, 2000 Sea Surface Temperature Anomalies - January 8, 2000

75. Pacific Decadal Oscillation PDO Index:

76. Pacific Decadal Oscillation PDO Index: + --- +

77. Pacific Decadal Oscillation PDO Index: + --- + 42654962

78. Pacific Decadal Oscillation The average national summer temperature ranking tends to be lower than average. The average national summer temperature ranking tends to be lower than average. Annual precipitation tends to be less in the Midwest, Tennessee Valley, southern New England, and West. Annual precipitation tends to be less in the Midwest, Tennessee Valley, southern New England, and West. Trend toward more precipitation in the northern Rockies, Oklahoma, eastern Texas, and the Mid-Atlantic Coast. Trend toward more precipitation in the northern Rockies, Oklahoma, eastern Texas, and the Mid-Atlantic Coast. Impacts - Negative Phase:

79. No Simple Answers The atmosphere operates on many time and space scales. They all influence the weather. The atmosphere operates on many time and space scales. They all influence the weather. La Niña, El Niño, PDO, etc. do influence the jet stream (and the global scale), with the greatest impact on weather near the Pacific Ocean and in and near the tropics. The impact is much reduced here. La Niña, El Niño, PDO, etc. do influence the jet stream (and the global scale), with the greatest impact on weather near the Pacific Ocean and in and near the tropics. The impact is much reduced here. Beware!

80. Time and Space Scales Global Scale: More than a week. > 2000 miles. Longwaves in westerlies. Global Scale: More than a week. > 2000 miles. Longwaves in westerlies. Synoptic Scale: Days to more than a week. 200-2000 miles. Fronts, highs, lows. Synoptic Scale: Days to more than a week. 200-2000 miles. Fronts, highs, lows. Mesoscale: Minutes to hours. 2-200 miles. Thunderstorms, tornadoes, sea breezes. Mesoscale: Minutes to hours. 2-200 miles. Thunderstorms, tornadoes, sea breezes. Microscale: Seconds to minutes. < 2 miles. Small turbulent eddies. Microscale: Seconds to minutes. < 2 miles. Small turbulent eddies.

82. El Niño It appears that an El Niño is forming in the Pacific Ocean for this winter. Many will make forecasts accordingly. It appears that an El Niño is forming in the Pacific Ocean for this winter. Many will make forecasts accordingly. Remember, not all El Niños are strong. The last one was, so beware of hype! Remember, not all El Niños are strong. The last one was, so beware of hype! A weak El Niño usually has little direct impact on our weather. A weak El Niño usually has little direct impact on our weather. What to consider:

83. Final Thoughts All large-scale indicators heading into harvest season are neutral. Shorter-range and smaller-scale events will dominate. All large-scale indicators heading into harvest season are neutral. Shorter-range and smaller-scale events will dominate. The hit and miss nature of rainfall this season will lead to high variability in yields, even within counties. The hit and miss nature of rainfall this season will lead to high variability in yields, even within counties. Best decisions are still made by following shorter-term weather trends. There are surprises every year! Best decisions are still made by following shorter-term weather trends. There are surprises every year! Looking ahead:

84. And what does La Niña have to do with Pizza? And what does La Niña have to do with Pizza?

85. In-Depth Weather: 5:35, 6:35, 7:35, 8:35, 9:35 AM 5:35, 6:35, 7:35, 8:35, 9:35 AM and 12:35 PM Central Time and 12:35 PM Central Time Detailed Agricultural Weather: 8:51 AM & 2:32 PM Central Time 8:51 AM & 2:32 PM Central Time

86. www.will.uiuc.edu

87. Thank You!

88. Questions?