Winds will be north-east to south-easterly 20 to 25 km/h tending north-west to south-westerly 15 to 20 km/h in the late afternoon then tending north-easterly 20 to 25 km/h in the evening.​

Temperatures across the south-west will be into the high 30s and 40s.

Warrnambool is expecting a top temperature of 39 degrees, Hamilton 41, Colac 37, Casterton 43, Mortlake 41, Heywood 40, Portland 38 and Port Fairy 39.

A high pressure system east of Tasmania will merge with an existing high pressure system over the Tasman Sea later today. 

Meanwhile, a low pressure trough will cross the Bight today and will approach the western Victorian border tonight. 

The trough will cross most of the the State on Friday, but will weaken as it moves over north-east Victoria on Saturday. 

The trough will linger near northeastern Victoria on Sunday while a high pressure ridge will lie over southern Victoria.  

On Friday Warrnambool is expecting a top temperature of 26, Saturday 21, Sunday  21 and Monday 23.

Heat warnings have been issued for Victoria by the emergency management commissioner.

Temperatures will be at or above heat health thresholds across the state on Thursday.

Protect your health: 

Heat can make anyone sick. 

People over 65, the very young and those with a pre-existing medical condition are most at risk. 

Heat related illness can range from mild conditions, such as a rash or cramps, to heat stroke - which is life threatening.

It is vital to monitor your health and the health of those around you. Act early. 

To find out more information visit: www.betterhealth.vic.gov.au/health/healthyliving/heat-stress-and-heat-related-illness.

You should be aware of the risk of heat related illness and take actions early to keep yourself and others safe.

What you should do:

Drink plenty of water. Always take a bottle of water with you.

Hot cars kill. Never leave kids, adults or pets in cars. The temperature inside a parked car can double within minutes.

Keep cool. Seek out air-conditioned buildings, use a fan, take cool showers and dress in light, loose clothing made from natural fabrics.

Plan ahead. Schedule activities in the coolest part of the day and avoid exercising in the heat. If you must go out, wear a hat and sunscreen and take a bottle of water with you.

Help others. Look after those most at risk in the heat - your friends and family or your neighbour living alone, the elderly, the young, people with a medical condition and don't forget your pets. 

Back to back days of extreme heat coupled with high overnight temperatures can interfere with your body’s natural ability to cool down and can cause heat illness. This includes cramps and heat exhaustion, which if left untreated, can lead to heatstroke which is a life-threatening illness. 

If you're seeking respite from the heat at beaches, rivers or inland waterways take care:

- Learn about rip current safety.

- Swim at patrolled beach locations between the red and yellow flags.

- Monitor weather reports for changing conditions.

- Wear a lifejacket when boating.

- Read safety signs at waterways.

- Consider your own safety when attempting a rescue.

- Respect the river by looking for hidden dangers, such as submerged objects. Supervise children at all times around water (under five years within arm’s reach and in line of sight for ten and under).

- Find a patrolled location at beachsafe.org.au.

Symptoms of heatstroke include turning pale, a rapid or irregular heart beat, dizziness, nausea and fainting. You may also stop sweating.

In a medical emergency and you should call 000 immediately. 

Provide cool, clean water and shade for your pets and animals.

Impacts in your area:

- Public transport may be impacted by the heat. You should check www.ptv.vic.gov.au/live-travel-updates for updates.

- Power outages are more likely during hot weather due to equipment failures, high demand and the impact of bushfires. 

- NBN connected phone and internet services will not work during a power outage. You may not be able to call Triple Zero (000) using your home phone.