My facebook and twitter readers will already know that I’m in the USA doing a spot of storm chasing. The last few days have been a bit of a practice, chasing storms, jumping out of the car and getting the camera set up quickly (I’m shooting in 4K raw with the PMW-F5). I already have some really nice footage, but nothing spectacular yet, just some pretty scenic shots, some thunderstorms and a little bit of lightning. Today however looks to be a very interesting day. The Storm Prediction Center has issued a public advisory for severe weather including damaging winds, large hail and tornadoes. I’m right in the best place to catch some of the action and all set to go. However a tornado may only be 100m/100 yards across and the area where there is a 15% chance of tornadoes with 25 miles of a given point (a very high tornado probability) covers an area of about 50,000 square miles, that’s an area almost the size of the UK. So for the next couple of hours I will be looking at weather forecasting data and computer models trying to figure out exactly where to go.
There is a very serious risk of large and very violent tornadoes today across much of Oklahoma. The storms and tornadoes will be moving North East at about 25-35mph and possibly passing through some very heavily populated areas. In addition hail stones the size of tennis balls are expected along with straight line winds of up to 100 mph around some of the stronger storms. What’s going to cause all of this mayhem? Well the North of the US is currently sitting under some very cold winter air, it’s snowing about 300 miles north of here. Just to the south of me it’s hot, very hot and humid. High above strong jet stream winds are set to increase in strength today and dig down towards the south. As the jet stream digs south it will push that cold northern air south driving a cold front that will crash into the warm southern air. This cold front will push the warm air upwards and aided by the jet stream winds this creates atmospheric instability and lift that causes violent storms to break out along the front. The final ingredient is wind shear. Winds near the ground will be coming from the south towards the front while winds high above in the jet stream will be coming from the west. This will cause the stronger thunderstorms to start to spin and rotate which helps them to become much stronger turning them into “Supercells”. Supercell storms are responsible for almost all violent tornadoes.
So, wish me luck. Today will be a frantic and hectic day. Hopefully I’ll get some interesting 4K footage to share with you all very soon.