Historical and modeled monthly values for Lake Ontario for the 64 months prior to the forecast outlooks starting 03May2018 Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total Basin Runoff to Lake (mm) 2013 140.25 131.83 126.70 179.43 123.04 117.91 50.90 31.86 40.28 68.11 126.34 133.29 2014 157.46 121.57 153.80 243.88 186.39 72.51 50.53 64.82 36.25 54.93 84.22 107.29 2015 96.67 36.62 110.22 186.76 91.91 100.70 64.08 27.83 54.20 95.58 98.50 99.24 2016 135.12 146.84 203.60 210.56 183.09 64.45 30.03 27.46 22.34 116.08 126.70 136.22 2017 177.24 146.84 184.93 383.40 495.82 208.36 105.10 61.52 45.77 118.28 279.40 157.10 2018 202.87 168.81 154.17 244.61 - - - - - - - - Total Over-Lake Precipitation (mm) 2013 53.48 60.60 20.30 76.87 68.97 118.60 76.77 72.41 72.27 95.34 68.48 63.27 2014 47.74 51.16 50.44 101.23 91.29 91.52 97.96 82.71 51.64 77.24 54.96 44.02 2015 39.49 31.92 35.02 67.82 52.93 139.12 57.52 67.37 84.94 79.31 42.55 75.58 2016 61.84 109.01 79.00 48.84 43.65 50.15 46.86 95.46 56.53 112.48 50.05 95.34 2017 134.00 108.44 91.47 111.75 150.31 105.16 97.57 72.54 47.41 144.21 100.74 58.56 2018 114.91 86.11 77.08 140.81 - - - - - - - - Total Lake Evaporation (mm) 2013 103.70 80.87 45.67 23.37 18.00 16.29 51.10 57.06 86.77 80.35 116.46 113.52 2014 115.70 52.88 45.07 6.71 -2.72 -3.87 26.06 51.05 67.45 72.32 116.68 76.21 2015 117.06 74.47 31.43 5.53 -2.85 -3.78 13.39 53.30 64.89 103.75 58.47 51.82 2016 118.08 68.44 42.40 34.86 7.10 28.91 46.44 59.00 90.05 92.35 77.85 127.69 2017 85.71 62.97 61.68 5.81 12.45 23.58 41.67 73.13 62.03 83.51 104.75 133.65 2018 100.58 33.45 49.54 31.49 - - - - - - - - Total Net Basin Supply to Lake (mm) 2013 90.04 111.56 101.32 232.93 174.02 220.23 76.57 47.20 25.78 83.10 78.36 83.04 2014 89.50 119.86 159.17 338.41 280.39 167.89 122.44 96.48 20.44 59.85 22.50 75.10 2015 19.10 -5.93 113.81 249.04 147.70 243.60 108.22 41.90 74.25 71.14 82.58 123.00 2016 78.89 187.41 240.21 224.55 219.65 85.69 30.44 63.92 -11.18 136.21 98.90 103.88 2017 225.52 192.31 214.71 489.33 633.68 289.95 161.00 60.93 31.16 178.99 275.39 82.00 2018 217.20 221.47 181.70 353.93 - - - - - - - - Average Over-Land Air Temperature (C) 2013 -4.66 -5.64 -1.14 5.51 13.88 17.52 21.19 19.23 14.96 10.32 1.94 -4.18 2014 -8.20 -8.02 -4.24 6.54 14.24 19.08 19.37 18.90 15.64 10.44 1.74 -1.40 2015 -8.87 -12.95 -3.20 6.13 15.44 17.12 20.01 19.45 18.09 8.68 5.84 3.10 2016 -4.68 -3.82 1.59 4.27 13.30 18.01 21.64 22.23 17.30 10.20 4.88 -2.54 2017 -2.92 -1.47 -2.16 8.68 12.13 17.79 20.26 18.96 17.02 12.67 2.76 -5.83 2018 -6.81 -2.44 -1.35 2.82 - - - - - - - - Average Lake Surface Temperature (C) 2013 5.40 3.22 2.30 3.60 9.09 15.64 21.42 20.94 18.57 14.55 8.89 5.85 2014 2.56 0.00 0.00 1.48 3.25 9.01 17.81 19.96 18.20 13.32 8.35 5.57 2015 2.25 0.00 0.00 0.90 3.16 8.16 17.14 20.73 19.99 12.99 9.10 6.94 2016 5.13 2.86 2.39 3.24 7.99 15.84 21.12 23.10 20.60 14.83 9.73 6.72 2017 4.97 3.42 1.90 4.15 9.38 16.05 20.69 21.26 18.78 15.44 9.45 6.37 2018 3.05 1.00 2.46 3.10 - - - - - - - - Average Over-Lake Air Temperature (C) 2013 0.49 -1.39 1.06 4.75 10.95 16.37 21.56 20.76 17.60 13.32 5.47 0.08 2014 -3.90 -5.02 -2.88 3.72 7.23 12.48 18.49 19.88 17.61 12.59 5.32 2.32 2015 -3.83 -8.51 -1.45 3.53 7.70 11.42 18.36 20.56 19.74 11.53 8.01 5.77 2016 -0.03 -0.59 1.14 3.36 10.22 16.80 21.59 23.22 20.04 13.33 7.92 2.31 2017 1.21 0.98 -0.08 6.16 10.46 16.64 20.73 20.78 18.47 14.68 6.50 -0.30 2018 -2.47 -0.51 1.21 3.34 - - - - - - - - Average Over-Lake Vapor Pressure (mb) 2013 4.78 4.03 4.77 6.61 10.53 15.92 21.52 19.95 15.70 12.01 6.39 4.53 2014 3.49 3.11 3.55 6.20 8.58 12.87 17.68 19.12 16.23 11.56 6.33 5.45 2015 3.15 2.22 4.01 6.11 8.77 12.13 17.80 19.82 18.78 9.88 8.32 7.40 2016 4.33 4.44 4.98 5.49 10.16 14.61 20.04 22.69 17.82 11.99 8.17 5.15 2017 5.16 4.85 4.45 7.68 10.59 15.83 20.14 19.60 17.26 13.13 6.87 4.30 2018 3.95 4.67 4.58 5.84 - - - - - - - - Average Over-Lake Wind Speed (m/s) 2013 7.76 7.60 6.50 6.00 4.74 4.16 4.47 4.69 5.40 6.08 7.83 7.36 2014 8.81 7.22 6.73 5.06 4.28 3.90 4.26 4.78 5.22 6.41 7.96 7.05 2015 8.46 7.90 6.09 5.14 4.20 4.08 3.88 4.80 5.01 6.77 6.37 6.47 2016 8.25 7.47 6.22 5.79 4.23 4.47 4.56 4.73 5.37 6.19 6.44 8.70 2017 7.49 7.01 6.93 4.98 4.70 4.53 4.43 5.09 4.50 6.31 7.43 7.83 2018 7.82 6.40 6.57 6.30 - - - - - - - - Average Over-Lake Cloud Cover (%) 2013 83.26 83.71 79.35 71.93 53.10 61.47 56.45 49.16 51.13 63.39 73.33 83.90 2014 75.87 71.29 67.23 63.33 65.00 59.10 53.10 54.55 50.83 72.03 81.13 84.00 2015 70.39 74.61 65.77 63.33 56.87 65.20 47.29 53.97 49.97 64.39 62.77 82.65 2016 76.97 75.97 69.19 59.13 56.23 47.87 48.23 48.61 46.63 64.32 65.20 79.97 2017 79.81 75.07 73.06 66.00 71.97 58.67 57.58 49.71 44.00 60.10 74.97 75.74 2018 78.03 75.86 64.94 72.10 - - - - - - - - Average Lake Surface Incident SW Radiation (w/m2) 2013 48.79 72.22 111.46 156.84 224.83 218.48 219.40 206.37 162.29 105.10 61.82 42.41 2014 54.31 86.66 129.16 173.34 198.68 223.91 227.65 195.73 163.26 94.75 55.77 42.48 2015 58.21 83.63 132.07 174.06 216.38 209.40 240.41 197.17 165.85 103.48 70.61 43.18 2016 53.13 81.26 126.84 182.60 218.92 251.14 238.64 207.82 171.82 104.59 69.01 44.82 2017 50.64 82.60 120.19 168.93 182.96 225.15 217.12 205.11 174.26 109.00 60.33 47.52 2018 52.73 81.73 134.13 156.90 - - - - - - - - Average Lake Surface Reflection (w/m2) 2013 -4.88 -7.22 -11.15 -15.68 -22.48 -21.85 -21.94 -20.64 -16.23 -10.51 -6.18 -4.24 2014 -6.11 -14.59 -22.27 -18.55 -19.87 -22.39 -22.76 -19.57 -16.33 -9.48 -5.58 -4.25 2015 -6.01 -15.14 -26.36 -20.93 -21.64 -20.94 -24.04 -19.72 -16.59 -10.35 -7.06 -4.32 2016 -5.31 -8.13 -12.68 -18.26 -21.89 -25.11 -23.86 -20.78 -17.18 -10.46 -6.90 -4.48 2017 -5.06 -8.26 -12.02 -16.89 -18.30 -22.51 -21.71 -20.51 -17.43 -10.90 -6.03 -4.75 2018 -5.27 -8.17 -13.41 -15.69 - - - - - - - - Average Lake Surface Net Long Wave Radiation (w/m2) 2013 -74.75 -75.64 -60.23 -46.01 -39.96 -21.24 -10.52 -23.24 -40.48 -45.28 -69.15 -79.60 2014 -88.01 -83.76 -75.88 -46.94 -29.14 -18.95 -22.16 -21.02 -36.88 -38.21 -63.27 -64.48 2015 -91.45 -98.05 -69.35 -45.77 -30.78 -18.49 -23.38 -19.81 -27.54 -53.62 -56.91 -48.21 2016 -81.05 -72.17 -64.14 -62.88 -37.54 -35.52 -20.15 -13.44 -35.66 -46.76 -60.06 -73.91 2017 -69.47 -67.86 -67.46 -41.04 -31.30 -24.49 -14.24 -26.03 -37.74 -41.36 -64.63 -88.65 2018 -82.06 -62.34 -68.69 -53.42 - - - - - - - - Average Lake Surface Latent Heat Flux (w/m2) 2013 -96.33 -83.32 -42.56 -22.48 -16.65 -15.50 -46.74 -52.24 -82.23 -74.05 -111.45 -105.41 2014 -107.79 -54.99 -42.47 -6.48 2.53 3.70 -23.90 -46.77 -63.97 -66.67 -111.71 -70.79 2015 -109.01 -77.26 -29.86 -5.39 2.66 3.63 -12.29 -48.80 -61.45 -95.63 -55.95 -48.08 2016 -109.71 -68.12 -39.50 -33.54 -6.58 -27.49 -42.51 -53.90 -85.22 -85.08 -74.43 -118.48 2017 -79.65 -64.87 -57.50 -5.59 -11.54 -22.40 -38.15 -66.93 -58.79 -76.87 -100.17 -124.06 2018 -93.59 -34.56 -46.16 -30.30 - - - - - - - - Average Lake Surface Sensible Heat Flux (w/m2) 2013 -66.50 -64.40 -18.32 1.84 2.99 2.43 -1.81 -2.06 -10.32 -14.70 -48.69 -78.73 2014 -109.06 -51.05 -28.60 7.65 8.03 6.13 1.62 -1.92 -6.79 -10.08 -49.31 -39.22 2015 -96.76 -94.94 -12.38 9.29 8.00 6.62 3.40 -1.86 -5.06 -18.35 -13.34 -16.99 2016 -76.97 -51.69 -18.34 -10.39 5.15 3.11 1.81 -0.08 -6.17 -18.98 -25.29 -67.97 2017 -52.03 -38.14 -35.48 7.26 4.14 1.90 -0.39 -4.20 -6.43 -11.62 -37.17 -92.78 2018 -89.39 -21.92 -14.28 -5.24 - - - - - - - - Average Lake Surface Net Surface Flux (w/m2) 2013 -194.56 -158.86 -20.95 74.38 148.45 161.93 136.64 106.34 10.38 -41.19 -175.29 -226.62 2014 -257.15 -117.70 -40.05 109.00 160.25 192.45 159.68 104.86 37.31 -31.22 -175.66 -136.93 2015 -245.57 -201.73 -5.86 111.24 174.64 180.26 183.72 105.26 53.15 -76.69 -63.48 -74.98 2016 -220.88 -119.20 -7.98 57.36 157.97 165.40 152.39 117.50 24.61 -58.75 -98.89 -221.37 2017 -156.25 -96.94 -52.43 112.63 125.80 157.02 141.26 85.01 51.99 -33.73 -149.27 -264.04 2018 -218.17 -45.30 -8.61 52.11 - - - - - - - - Average Lake-Ice Surface Temperature (C) 2013 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2014 -2.27 -6.32 -4.07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2015 -1.28 -10.53 -2.30 -0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2016 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2017 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2018 0.00 -0.23 0.00 0.00 - - - - - - - - Average Lake Ice Cover (%) 2013 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2014 3.05 19.28 20.73 1.85 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2015 0.86 21.83 28.71 6.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2016 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2017 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2018 0.00 0.00 0.00 0.00 - - - - - - - - End-of-Month Lake Heat Storage (cal/10e17) 2013 77.28 59.89 57.37 66.10 84.09 103.09 119.66 132.55 133.74 128.72 108.15 80.66 2014 52.93 43.42 35.52 43.91 63.34 85.93 105.30 118.00 122.34 118.54 97.91 81.31 2015 52.69 42.52 36.15 40.90 62.08 83.24 105.52 118.26 124.48 115.15 107.69 98.60 2016 71.81 58.29 57.33 64.06 83.22 102.62 121.10 135.34 138.18 131.04 119.42 92.57 2017 73.62 63.01 56.65 69.87 85.13 103.56 120.67 130.92 137.01 132.91 115.37 83.35 2018 56.91 51.96 50.92 57.04 - - - - - - - - End-of-Month Basin Soil Moisture (cm) 2013 2.41 2.62 1.85 4.54 1.60 0.23 0.11 0.29 0.52 2.56 2.59 2.58 2014 2.91 3.16 4.95 4.47 0.55 0.22 0.55 0.19 0.22 1.38 2.53 2.27 2015 1.49 0.92 2.13 3.75 1.26 0.90 0.08 0.07 1.08 2.51 1.91 2.72 2016 2.22 2.72 4.25 7.48 1.87 0.14 0.09 0.25 0.24 1.96 2.50 2.91 2017 2.48 3.75 4.04 15.06 8.73 2.50 0.17 0.21 0.58 2.76 4.46 2.97 2018 3.35 3.61 2.90 8.38 - - - - - - - - End-of-Month Basin Groundwater Moisture (cm) 2013 0.89 0.91 0.93 1.27 1.23 1.03 0.75 0.57 0.50 0.56 0.84 0.91 2014 1.14 1.17 1.38 1.78 1.59 1.20 0.90 0.69 0.56 0.54 0.68 0.77 2015 0.73 0.58 0.77 1.12 0.99 0.83 0.62 0.48 0.41 0.50 0.61 0.72 2016 0.89 0.98 1.14 1.58 1.98 1.58 1.19 0.93 0.73 0.76 0.73 1.02 2017 1.27 1.31 1.41 2.39 3.94 3.63 2.79 2.12 1.64 1.42 1.68 1.71 2018 1.88 1.89 1.70 1.97 - - - - - - - - End-of-Month Basin Surface Moisture (cm) 2013 2.09 2.14 1.03 1.32 0.85 0.92 0.42 0.20 0.32 0.96 1.09 1.36 2014 1.01 1.52 2.20 2.23 1.10 0.57 0.85 0.57 0.24 0.61 0.92 1.05 2015 0.59 0.26 1.36 1.29 0.79 1.32 0.37 0.20 1.33 1.51 0.63 1.48 2016 1.05 2.61 1.92 1.12 0.52 0.27 0.12 0.22 0.19 2.42 1.03 1.36 2017 1.61 1.98 2.36 2.10 1.72 0.85 0.77 0.25 0.26 3.46 1.79 0.94 2018 1.79 1.94 1.77 2.07 - - - - - - - - End-of-Month Basin Snow Pack (cm) 2013 2.28 4.12 3.73 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.78 2.50 2014 2.33 3.08 0.56 0.00 0.00 0.00 0.00 0.00 0.00 0.06 0.00 0.61 2015 3.00 6.19 3.60 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.11 1.50 2016 4.24 8.22 7.40 1.15 0.00 0.00 0.00 0.00 0.00 0.01 0.22 4.29 2017 12.03 16.09 18.18 1.66 0.00 0.00 0.00 0.00 0.00 0.00 0.21 3.49 2018 7.50 10.14 13.98 13.24 - - - - - - - - End-of-Month Basin Total Moisture (cm) 2013 7.67 9.79 7.54 7.13 3.68 2.18 1.28 1.06 1.34 4.08 5.30 7.35 2014 7.39 8.93 9.09 8.48 3.24 1.99 2.30 1.45 1.02 2.59 4.13 4.70 2015 5.81 7.95 7.86 6.16 3.04 3.05 1.07 0.75 2.82 4.53 3.26 6.42 2016 8.40 14.53 14.71 11.33 4.37 1.99 1.40 1.40 1.16 5.15 4.48 9.58 2017 17.39 23.13 25.99 21.21 14.39 6.98 3.73 2.58 2.48 7.64 8.14 9.11 2018 14.52 17.58 20.35 25.66 - 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