Climate Outlook Jayantha Obeysekera (’Obey’), Ph.D.,P.E.,D.WRE Department Director Hydrologic & Environmental Systems Modeling

Case Study: Lake Okeechobee Operation of Lake Okeechobee requires a balance between multiple objectives. Climate outlook has been incorporated into operations. Climate based operations are designed to balance current release decisions with future potential shortages and/or surpluses. Position Analysis is a tool for projecting probabilities associated with future lake levels. It is a valuable tool for Lake Okeechobee operations.

Lake Okeechobee Management Objectives Protect the integrity of the Dike Protect Estuaries Meet Agricultural/Urban Water Supply needs Maintain a healthy Littoral Zone Provide water to Everglades Maintain Navigation

Balancing the Objectives Key Management Objective Lake Level HighLow Protect the integrity of the Dike Protect Estuaries Meet Water Supply needs Maintain a healthy Littoral ZoneNeed lake to be between 12.5' -15.5' Provide water to Everglades Maintain Navigation undesirabledesirable

Flood Control Water Shortage Lake Okeechobee Management Zones

& Meteorological Forecast Seasonal Climate Outlook Tributary Hydrologic Conditions Multi- Seasonal Climate Outlook No Discharge to Tidewater Up to Maximum Pulse Release to the Estuaries No Discharge to Tidewater Up to Maximum Discharge Capacity To Tidewater WSE Operational Guidelines Decision Tree Part 2: Define Lake Okeechobee Discharges to Tidewater (Estuaries) Apply Tributary Condition Criteria Weekly Apply Tributary Condition Criteria Weekly Apply Meteorological Forecasts on a Weekly Basis; apply Seasonal and Multi-Seasonal Climate Outlooks on a Monthly Basis Apply Meteorological Forecasts on a Weekly Basis; apply Seasonal and Multi-Seasonal Climate Outlooks on a Monthly Basis Check Special Lake Criteria daily as needed for Zones B & D Check Special Lake Criteria daily as needed for Zones B & D START Lake Okeechobee Water Level ZONE A DRY VERY WET ZONE B ZONE C ZONE D Tributary Hydrologic Conditions Tributary Hydrologic Conditions Lake Stage within 0.5 feet of Zone C Lake Stage within 0.5 feet of Zone C Seasonal Climate Outlook Seasonal Climate Outlook Multi- Seasonal Climate Outlook Zone C Steady Flow S-80 Up to 2500cfs S-77 Up to 4500cfs Up to Maximum Pulse Release to the Estuaries Zone B Steady Flow S-80 Up to 3500cfs S-77 Up to 6500cfs Up to 30 day Meteorological Forecast Lake Less than 17.5’ & it’s the Dry Season Up to 30 day Meteorological Forecast Up to Zone B S-80 Up to 3500cfs S-77 Up to 6500cfs Up to Zone C S-80 Up to 2500cfs S-77 Up to 4500cfs Up to Maximum Pulse Release to the Estuaries Seasonal Climate Outlook Up to 30 day Meteorological Forecast WET TO VERY WET NORMAL EXTREMELY WET TRUE FALSE TRUE OTHERWISE WET TO VERY WET NORMAL TO DRY VERY WET OTHERWISE NORMAL TO DRY WET TO VERY WET EXTREMELY WET WET TO VERY WET NORMAL TO DRY EITHER FORECAST INDICATES WET TO VERY WET BOTH FORECASTS INDICATE NORMAL TO DRY NORMAL TO VERY WET DRY EXTREMELY WET NORMAL TO VERY WET DRY TRUE FALSE NORMAL TO VERY WET DRY WET TO VERY WET NORMAL TO DRY

WSE Regulation Schedule Operational Elements Lake Okeechobee Water Level Tributary Hydrologic Condition  30 Day Net Rainfall  Average Kissimmee River (Tributary watershed) inflow Lake Okeechobee Net Inflow Outlook  Seasonal Outlook (6 month)  Multi-seasonal Outlook (7 to 12 months)

Climate Outlook Indicators El Niño/La Nina ( Roller Coaster )

warm cold warm cold Decadal to multi-decadal scale fluctuations in the sea surface temperature (only about 1º F) in the North Atlantic Ocean  Cold Phase (~ , )  Warm Phase ( , 1995-???) Climate Outlook Indicators: Atlantic Multidecadal Oscillation (AMO)

Summary of What We Know (These are tendencies and not absolutes!) RainfallAtlantic Hurricanes Wet SeasonDry Season El Ni ñ o No clear pattern WetterLess activity La Ni ñ a No clear pattern DrierMore activity AMO Warm Phase Wetter decades; drought still possible Greater # of major storms AMO Cold Phase Drier decades; wet years still possible Lesser # of major storms

& Meteorological Forecast Seasonal Climate Outlook Tributary Hydrologic Conditions Multi- Seasonal Climate Outlook No Discharge to Tidewater Up to Maximum Pulse Release to the Estuaries No Discharge to Tidewater Up to Maximum Discharge Capacity To Tidewater WSE Operational Guidelines Decision Tree Part 2: Define Lake Okeechobee Discharges to Tidewater (Estuaries) Apply Tributary Condition Criteria Weekly Apply Tributary Condition Criteria Weekly Apply Meteorological Forecasts on a Weekly Basis; apply Seasonal and Multi-Seasonal Climate Outlooks on a Monthly Basis Apply Meteorological Forecasts on a Weekly Basis; apply Seasonal and Multi-Seasonal Climate Outlooks on a Monthly Basis Check Special Lake Criteria daily as needed for Zones B & D Check Special Lake Criteria daily as needed for Zones B & D START Lake Okeechobee Water Level ZONE A DRY VERY WET ZONE B ZONE C ZONE D Tributary Hydrologic Conditions Tributary Hydrologic Conditions Lake Stage within 0.5 feet of Zone C Lake Stage within 0.5 feet of Zone C Seasonal Climate Outlook Seasonal Climate Outlook Multi- Seasonal Climate Outlook Zone C Steady Flow S-80 Up to 2500cfs S-77 Up to 4500cfs Up to Maximum Pulse Release to the Estuaries Zone B Steady Flow S-80 Up to 3500cfs S-77 Up to 6500cfs Up to 30 day Meteorological Forecast Lake Less than 17.5’ & it’s the Dry Season Up to 30 day Meteorological Forecast Up to Zone B S-80 Up to 3500cfs S-77 Up to 6500cfs Up to Zone C S-80 Up to 2500cfs S-77 Up to 4500cfs Up to Maximum Pulse Release to the Estuaries Seasonal Climate Outlook Up to 30 day Meteorological Forecast WET TO VERY WET NORMAL EXTREMELY WET TRUE FALSE TRUE OTHERWISE WET TO VERY WET NORMAL TO DRY VERY WET OTHERWISE NORMAL TO DRY WET TO VERY WET EXTREMELY WET WET TO VERY WET NORMAL TO DRY EITHER FORECAST INDICATES WET TO VERY WET BOTH FORECASTS INDICATE NORMAL TO DRY NORMAL TO VERY WET DRY EXTREMELY WET NORMAL TO VERY WET DRY TRUE FALSE NORMAL TO VERY WET DRY WET TO VERY WET NORMAL TO DRY 16.5 (Zone C) DRY

Lake Okeechobee November 15, 2007 Position Analysis Middle 50%

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