Marine Observation Platforms NOAA 3-meter discus buoy Anemometer height: 5 m/16.4 feet above site elevation

Marine Observation Platforms Gravelly Shoals Light Anemometer height: 24.7 m/81 feet above site elevation

Marine Observation Platforms Lake St Clair C-MAN Coastal-Marine Automated Network (C-MAN) Anemometer height: 14.4 m/47.2 feet above site elevation

Marine Observation Platforms St Clair Shores GLOS Weather Station Great Lakes Observing System Anemometer height: 10.0 m/32.8 feet above site elevation

Marine Observation Platforms Ship Observations Mesabi Miner: built in ft. long Anemometer height: approximately 100 feet above water surface. Voluntary Observing Ship (VOS) Program

NOAA Marine Observations Infrastructure Other marine weather observations…  US Coast Guard  NOAA Great Lakes Environmental Research Lab  NOAA National Ocean Service  NOAA Voluntary Observing Ship Program  NOAA POES Quickscat winds

Marine Meteorology Lake Breeze Coastal wind that blows from the lake to the land (lake breeze) Caused by temperature difference between land and lake Can occur for lake/air temperature difference of as little as 1C. However...no lake breeze likely if offshore winds at 2000 feet are greater than 17 knots, regardless of air/lake temperature difference.

Marine Meteorology Lake Breeze Wikipedia

Marine Meteorology Lake Breeze Wikipedia

Marine Meteorology Lake Breeze NWS, Southern Region Roberto Giudici

Marine Meteorology Waterspouts

Marine Meteorology Rip Currents Substantial onshore wind, near 25 knots. Large waves and higher water level. Beach water piles up on the shoreline and squirts strongly back offshore.

Marine Meteorology Rip Currents

Keep your feet in heavy surf rather than tread water. Keep your feet in heavy surf rather than tread water. Swim parallel to the shoreline to escape the offshore current. Swim parallel to the shoreline to escape the offshore current.

Marine Meteorology Hazardous Weather Elements and Safety Reminders Lightning behavior on the water. –“When lightning strikes the ocean or other large water bodies, it spreads out over the conducting surface. It also penetrates down and can kill fish in the nearby region”, says Don MacGorman, physicist at the National Severe Storms Laboratory (NSSL). –"Lightning strikes have killed or injured people on the surface more than 30 yards away," says David Schultz of the NSSL.

Marine Meteorology Hazardous Weather Elements and Safety Reminders

Marine Meteorology Hazardous Weather Elements and Safety Reminders Be aware of any thunderstorm threat before you begin your trip – Check the forecast! Keep abreast of weather information while on the water – NOAA Weather Radio, Marine Radio, Internet if available – Pay particular attention to any Special Marine Warnings Keep an eye on the sky for threatening weather – Listen for pulses of static on an AM radio station

Marine Meteorology Hazardous Weather Elements and Safety Reminders If a Special Marine Warning is issued for your location, or if threatening weather approaches If a Special Marine Warning is issued for your location, or if threatening weather approaches – Head to a harbor of refuge if at all possible Then get out of the boat and away from the water Then get out of the boat and away from the water Find shelter immediately Find shelter immediately – If you are caught afloat and cannot reach harbor... Make sure you are wearing a flotation device Make sure you are wearing a flotation device Stay below deck Stay below deck Avoid ungrounded metal objects Avoid ungrounded metal objects Do not touch multiple grounded objects at the same time Do not touch multiple grounded objects at the same time

Insert fog image Jim Wenzloff

Marine Meteorology Fog Three types of Fog... – Advection - occurs when warm, moist air crosses a cool surface The most hazardous for mariners. Tends to form in spring and early summer when lakes are cool. Can form any time of the day. Can be widespread and very dense. – Radiation Tends to form on clear, calm nights, mainly over land. Most common when humidity is high. For marine interests, is a problem only near the shore. –Steam – occurs when cold air moves across warm water Most common in fall and winter with light winds and high pressure. Can occur any time of the day or night. Thickest near the lake surface.

Marine Meteorology Fog Slow and safe speed. Vessel lighting and horns. Navigation aids/GPS.

Marine Meteorology Waterspouts Two types... –Warm Season –Cool Season Warm Season –tornadoes over water. Cool Season –Cool air over warm water. –Lots of instability. Roberto Giudici

Marine Meteorology Waterspouts Cool season waterspout develops from light showers, or even non-precipitating clouds. – Waterspout wind speeds in the range of 30 to 80 knots. – Occur when winds are light with surface high pressure over the Great Lakes, and when the air is much cooler than the water. – Most common in the late summer and autumn. – Most common in the morning. – Can occur in groups.

Marine Meteorology Wind

Forecasting Tools Computer Simulations This is an example of a forecast from a simulation from our office. –Winds are in purple –Waves are represented by the shading, and also by the blue-green lines We can zoom in for more detail...

Forecasting Tools Computer Simulations We have the ability to generate very detailed forecasts. But are they correct forecasts? As best we can tell, the simulation does a good job. But our ability to evaluate is limited, due to limited observations.

Forecasting Tools Computer Simulations Conditions at North Buoy as of (11:00 am EDT) 1500 GMT on 09/24/2001: Wind Direction (WDIR): N ( 10 deg ) Wind Speed (WSPD): 27.2 kts Wind Gust (GST): 33.0 kts Wave Height (WVHT): 8.9 ft Air Temperature (ATMP): 49.3 °F Water Temperature (WTMP): 58.6 °F Conditions at South Buoy as of (11:00 am EDT) 1500 GMT on 09/24/2001: Wind Direction (WDIR): N ( 360 deg ) Wind Speed (WSPD): 25.3 kts Wind Gust (GST): 31.1 kts Wave Height (WVHT): 10.5 ft Air Temperature (ATMP): 50.0 °F Water Temperature (WTMP): 61.0 °F