Heat and Humidity

Widespread damage occurred yesterday in Chicago from hurricane force winds. (Photo Chicago Tribune)

High heat and humidity continues to engulf most of eastern North America. Temperatures are in the high 80's to 100F with heat index values from 100F in southern Quebec and Ontario up to as high as 115F across the Tennessee and Ohio Valley's and into the southern plains and Gulf Coast. Yesterday a fast moving line of very strong thunderstorms known as a derecho blasted the Midwest from Illinois southeast into the middle Atlantic. Chicago at the height of the storm reported nearly 870,000 customers without power, a new record for the city. The storm produced widespread damage as hurricane force winds were recorded. Vehicles were blown over, trees torn down and wires and poles snapped. The thunderstorm complex started in the pre-dawn hours and raced across Illinois and Michigan, brushing southwest Ontario and lasting until late afternoon when the system finally dissipated over northern Virginia.

Besides the heat today, close to 30C in Montreal, we can expect a 40% chance of more thunderstorms. I had expected drier air today, but the cold front remains to our northwest. Wednesday will be showery and muggy as well before a period off great summer weather into next weekend with sunshine, low humidity and warm temperatures. Stay tuned and be sure to check out my twitter link for updates during the day.