Five things you need to know about Wednesday, July 23

Wednesday, July 23, 2014, 7:16 AM - Wondering what you missed overnight or what you can expect for the day ahead? 

Here's your weather briefing for Wednesday, July 23.

1. Extreme heat hangs on in the east

Tuesday was another record breaking day in the east, with parts of Newfoundland seeing temperatures close to 30°C.

A warm southwesterly flow will persist over Newfoundland today with increasing humidity levels expected.

"By this afternoon humidex values are expected to reach 35 to 38," says Environment Canada in a special weather statement issued early Wednesday. "Persons engaging in outdoor activities should drink plenty of liquids, especially water, before feeling thirsty, to decrease risk of dehydration. Consider scheduling outdoor activities during the cooler parts of the day."

In addition to the high heat and humidity, severe thunderstorms are possible in parts of New Brunswick today.

"Conditions are favourable for the development of severe thunderstorms that may be capable of producing strong winds gusts, large hail and heavy rain this afternoon and evening," warns Environment Canada in a severe thunderstorm watch issued for the province.

2. Cool down to follow thunderstorms in southern Ontario

Reaching for that extra cup of coffee this morning? You're not alone.

Thunderstorms rumbled through parts of southern Ontario late Tuesday night bringing loud thunder, frequent lightning and heavy rain.

EXTENDED ACTIVE WEATHER COVERAGE: Tune in to The Weather Network for live updates on the summer storms in your area. Our team of reporters and meteorologists in the field provide you with the most accurate and up-to-date coverage.

Some lingering showers are expected to persist through the morning hours before a cold front pushes through.

Beauty lightning strike in #Scarborough by @lyndseyshank: pic.twitter.com/VwBipDMi9c #onstorm

— The Weather Network (@weathernetwork) July 23, 2014

"There will still be some humidity in the air, but it will be noticeably fresher than it was on Tuesday," says Weather Network meteorologist Dayna Vettese.

By Thursday, temperatures in the Greater Toronto Area will be hovering around the low 20s with the normal for this time of year being 27°C.

3. Severe thunderstorm watch in effect for southern Quebec

"Conditions are favourable for the development of dangerous thunderstorms that may be capable of producing damaging wind gusts and torrential rain," that's the warning from Environment Canada this morning.

Drivers are being warned to prepare for fast moving water on roads as well as rapidly rising rivers that can "sweep away bridges, culverts, buildings, and people."

"Very strong wind gusts can also damage buildings, down trees and blow large vehicles off the road," EC says. "Remember, severe thunderstorms can produce tornadoes."

4. Severe thunderstorm threat for the Prairies

Unstable conditions throughout parts of the Prairies have resulted in a severe thunderstorm threat in southern Alberta and southwestern Saskatchewan.

"Hail, strong winds and heavy rain are possible with these storms, and of course we can't rule out the chance for a tornado," warns Vettese.

Environment Canada also issued a special weather statement for parts of northern Alberta warning of up to 50 mm of rain through Thursday.

"Rain with a few thunderstorms will develop in the Grande Cache, Grande Prairie and Peace River regions tonight and then spread eastward into the Whitecourt and Slave Lake regions on Thursday," EC says. "Heavy rain will continue through Thursday and taper off Friday morning as the low continues eastward into Saskatchewan."

5. Thunderstorms, heavy rain to hit B.C.

A low pressure system pushing into B.C. this afternoon will bring the potential for severe thunderstorms over most of the southeastern regions.

"The thunderstorms could generate extremely heavy rainfall with local amounts of 25 to 50 millimetres in a few hours or less," Environment Canada say.

While the moisture is good news for fire crews that have been struggling with wildfires, the drawback is the instability that could spark thunderstorms.

MUST READ: Believe it or not, some types of rain are not ideal for fighting fires

"Many of the large wildfires experienced so far this year have been caused by lightning strikes," says Vettese.

For more B.C.'s fire season so far, check out this detailed analysis from Dayna Vettese.