####018006291#### FZUS81 KCLE 210053 ICEGL GREAT LAKES FREEZE-UP OUTLOOK NATIONAL WEATHER SERVICE CLEVELAND OH 753 PM EST Mon Nov 20 2023 ...Great Lakes Ice Season for 2023-2024 Expected to Be Average to Slightly Below-Average Ice Cover... An El Nino Advisory continues with equatorial sea surface temperatures above normal over the central and eastern Pacific. El Nino is expected to continue through the Spring of 2024. During El Nino, the subtropical jet stream strengthens over the southern tier of the United States, with less stormy and milder conditions over the US-Canadian border into the Great Lakes, as the upper level flows remain more west to east with transient weather systems through the region. It is important to note that no two El Nino events are the same, and outliers are possible. El Nino also influences the other teleconnections (Arctic Oscillation, North Atlantic Oscillation, Pacific-North American Oscillation) which are typically more directly influential in the regional weather patterns across the Great Lakes. As the month of October came to an end and November began, temperatures over the Great Lakes region were colder than normal during that period due to a strong upper level low pressure system that dominated much of that two week period. However, this transitioned to near normal temperatures for the northern Great Lakes and slightly above normal overall for the southern Great Lakes for the first half of November, largely devoid of any unseasonably cold airmasses. The result has been only minimal heat loss out of the Great Lakes since the last outlook. Lake Superior remains in the low to mid 40s across the open waters. The northern halves of Lake Michigan and Lake Huron are in the upper 40s, while the southern half of each lake is in the lower 50s. Perhaps the greatest change has been seen in the shallow western basin of Lake Erie that has dropped into the upper 40s, while the central and eastern basins remain near 50F. Some of the coastal areas are beginning to run a bit cooler than their open water counterparts as the shallower areas are experiencing a bit more efficient heat loss. The long range operational models and ensembles are indicating a colder period for the Great Lakes for the last week of November. This is also supported by the Arctic Oscillation and North Atlantic Oscillations which are trending negative over the next two week period, also indicative of a colder period as well. The progressive pattern with low pressure systems pushing through the region will bring windy conditions at times, and expect some upwelling/downwelling as a result. This will limit the lake surface temperature drops due to the replacement of the surface water in these situations. After the forecast late November period of seasonally cold air, there are strong signals for a return to warmer than normal conditions for the first half of December. From the Climate Prediction Center, the updated 3-4 week and 1 month outlooks are showing relatively high confidence for this warming trend along the US-Canadian border into the Great Lakes. The longer ranges of the ensembles are consistent with the CPC predictions, and this supports the forecast for slower than normal ice formation heading through the end of fall time frame. The three month outlooks continue to support warmer than normal conditions. Ice formation is determined by two factors: The amount of heat stored in the water from the summer and how fast that heat can be removed by Arctic outbreaks of polar air and high winds. Long range outlooks do not consider the storminess factor which can significantly alter the lakes thermal structure over short periods of time. Freezing degree days are running near normal for this time of year across the entirety of the Great Lakes. FREEZING DEGREE DAY ACCUMULATIONS AT SELECTED STATIONS COMPARED TO NORMAL CALCULATED ON Thu Nov 16: LOCATION DATE NORMAL CURRENT ---------------------------------------- DULUTH, MN NOV 15 5 0 MARQUETTE, MI NOV 15 2 0 SAU_S_MAR, MI NOV 15 0 0 GREENBAY, WI NOV 15 0 0 MILWAUKEE, WI NOV 15 0 0 CHIGAGO, IL NOV 15 0 0 MUSKEGON, MI NOV 15 0 0 ALPENA, MI NOV 15 0 0 DETROIT, MI NOV 15 0 0 TOLEDO, OH NOV 15 0 0 CLEVELAND, OH NOV 15 0 0 BUFFALO, NY NOV 15 0 0 THE LATEST HARBOR WATER TEMPERATURES COMPARED TO PREVIOUS YEARS: 2023 2022 2021 2020 2019 2018 2017 2016 2015 NORMAL DULUTH 47 46 44 40 40 42 44 48 53 44 SAULT STE MARIE 47 49 48 48 46 42 44 50 53 46 CHICAGO 49 52 52 47 44 46 44 52 55 48 ALPENA 47 49 49 47 42 42 46 50 53 50 DETROIT 47 47 47 52 44 43 42 50 53 49 CLEVELAND 49 54 53 53 51 48 50 55 58 53 BUFFALO 49 54 53 50 52 49 46 50 54 52 WATER TEMPERATURES FROM THE MID-LAKE BUOYS OR NEARBY SHIPS COMPARED TO PREVIOUS YEARS: LAKE SUPERIOR WEST MM 43 MM MM 40 41 41 44 43 43 CENTRAL MM 42 MM MM 40 41 41 48 45 42 EAST MM 42 MM MM 42 40 43 47 45 42 LAKE MICHIGAN NORTH 46 47 MM 48 48 47 48 50 51 47 SOUTH 51 49 52 44 46 44 49 55 54 46 LAKE HURON NORTH 47 51 MM 46 45 41 46 49 53 48 SOUTH 51 53 52 55 45 49 45 50 54 49 LAKE ERIE WEST 50 47 50 MM 46 43 45 53 51 51 CENTRAL MM 55 52 51 49 47 50 55 58 53 EAST MM 55 52 51 47 47 54 53 56 52 THE NEXT FREEZE-UP OUTLOOK WILL BE ISSUED IN APPROXIMATELY TWO WEEKS. $$ Marsalek