Decoding Meteorological Time

Weather doesn’t recognize geographic or political borders. In a rare example of international cooperation, the majority of countries with a national weather forecasting agency readily share their observations and forecasts. In order to coordinate the timing of observations and forecasts, meteorologists adhere to a standard timekeeping system.

The original standard timekeeping system was Greenwich Mean Time (GMT), a 24-hour clock system based on the local time on the prime meridian in Greenwich, England. Since the local time in Greenwich is the same at GMT, 1:00 am is 0100 GMT, noon is 1200 GMT, and 6:00 pm is 18 GMT. Continue reading

Weather Forecast Model 101 — Forecasting A High Wind Event

Several weeks ago, I published a summary of storm-force sustained winds, hurricane-force gusts, and a drop in water level approaching six feet across Lake Erie’s western basin, all courtesy of the passage of a deep low pressure system on November 27, 2019 (click here to read the summary). This article examines how the weather forecast models performed during the event. Continue reading

Weather 101 – Thunderstorm Resources

Seasoned boaters know first-hand that weather conditions on the Great Lakes can change from pleasant to terrifying very quickly. From dangerous lightning to high winds, thunderstorms can ruin an outing in many ways. However, reading the marine forecast before leaving the dock and regularly checking weather radar along the way will dramatically increase your chances of avoiding uncomfortable or dangerous conditions. Continue reading

Hurricane Force Winds on Lake Erie

Wednesday, November 27, 2019 was a wild day on Lake Erie thanks to the passage of a deep low pressure system and its accompanying cold front. The surface forecasts issued by the Weather Prediction Center (WPC) suggested the powerful and fast-moving low and its cold front would reach Lake Erie’s western basin around sunrise on the 27th (Figure 1) and the eastern end of Lake Ontario by early evening (click here for forecast graphic). Continue reading

Lake Breeze Enhanced Thunderstorms

Even when the atmosphere is supportive of thunderstorms, a source of lift is necessary to provide the upward motion required by a fledgling storm’s updraft. A reliable source of lift is often found near a cold, warm, or stationary front accompanying an approaching low pressure system (figure 1). Terrain or the leading edge of a downdraft from an existing thunderstorm (outflow boundary) can also provide a storm with this all-important ingredient. Continue reading

Chaff on Radar?

On the afternoon on December 10, 2018, an area of what initially appeared to be precipitation (Figure 1) was detected northwest of Evansville, Indiana by the National Weather Service (NWS) Doppler Weather Radar station at Paducah, Kentucky (KPAH). When first detected, the blob was 100 nm northeast of KPAH at an elevation of approximately 12,000 feet. A check of surface weather stations near the blob and visible satellite imagery (Figure 2) indicated that no precipitation was occurring and that skies were clear in the area.

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