Tuesday, July 17, 2012

Strong storms likely today

Humidex Advisory: Ontario and southern Quebec. Strong thunderstorms this afternoon.

A sultry air mass remains in place across most of Eastern Canada this morning with temperatures in the 20's and high humidity making it feel rather uncomfortable. A few thunderstorms dumped a decent amount of rain on L'Ile Perrot this morning with nearly 25mm (1 inch) since 6am this morning. The rain is most welcome and much needed but it will leave the atmosphere soaked with moisture and ripe for a strong outbreak of storms this afternoon. The NWS Storm Prediction Center in the US has placed northern New York and the St. Lawrence Valley as well as much of northern New England under a slight risk of severe storms this afternoon. A significant cold front and low pressure area moving into the warm and humid air will produce supercell thunderstorms with strong winds and hail, and even the risk of an isolated tornado. The storms this morning will move off to the southeast to be replaced by sunny breaks and hot temperatures near 30C (86F) in Montreal and into the 30's in Ontario. The cold front will begin advancing into the warm and humid air in Ontario during the afternoon and across southern Quebec, you guessed it, in time for Montreal rush hour.

Watches and Warnings are likely by noon across a large area of eastern Ontario from Kingston to Ottawa and east into Montreal and Quebec. I will tweet and update any warnings or watches all day long.

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