 Temperature advection is just the dot product of the velocity vector and the temperature gradient vector at that point. Let's choose this point in Pennsylvania. We've already calculated the gradient for this point. Let's look at the wind vector. So the station weather plot has a wind bar that's northwesternly and five knots. And so we can estimate, since this is x direction and since this is north, we can estimate that this is about 300 degrees in terms of mirology angle. So to find the math angle, which is what we need for the calculation here, we take 270 degrees and we subtract 300 degrees from that and we get alpha equals minus 30, which is 330 degrees. If we start from the x-axis and we go counterclockwise all the way around to this direction like this. We've already figured out that the gradient has an angle that's 301 degrees and that's from the x-axis going all the way around. So that's something like this and therefore the difference between the two is 29 degrees and that's beta. We know that the magnitude of the temperature gradient is 0.12 degrees Fahrenheit so when we multiply the magnitude of the velocity times the magnitude of the temperature gradient times cosine of 29 degrees, we end up getting a value of 0.52 and the minus sign, degrees Fahrenheit per hour. So the minus sign is here because this is positive, positive and positive and so the advection is minus 0.52 degrees Fahrenheit per hour. This is cold air advection or cold advection.