I fall under the category of Chronic Migraine Sufferer, although my migraine is the lovely kind that started a few years ago and hasn't stopped yet. Regardless of your type of migraine, it's quite common to have weather changes as one of your triggers. Maybe you've found that usually when it rains or a storm system blows in your migraine appears, or maybe you've been able to pin the trigger down to changes in barometric pressure. Personally I find that when the barometeric pressure drops below 30 inches, my migraine gets worse. I've been on the lookout for a source to forecast the pressure, this combined with historical data helps me better identify what triggered the changes in my current migraine. This helps me gather better data for my headache calendar by avoid false positives and unknown triggers.
I've found a couple of useful tools when it ccomes to tracking and predicting the barometric pressure. Both come from Weather Underground. The first is the forcast, which can be found on the graph of the 10-day forecast for your area.
The black line in the second graph in the image is the forecasted barometric pressure for the next 10 days. In this particular case it's looking like a rough week for me, nearly all under 30".
The second useful tool from Weather Underground is their historical weather data. This too includes barometric pressure. One downside about the way they present the historical data, you will have to select the desired data every time you visit the page. There is no way to create a link to "today" or "yesterday." Here's an image of the history for a morning in Chicago. There's not much data on the graph yet because I was looking at the current date, in the morning, when I grabbed the image. The quickest way to get to "today's" graph is probably to start with the current forecast and then click on the History tab.
As you can see in the first graph, the pressure has been steadily falling all morning. As was forecasted, I'm in for a less-than-optimal day. Oh well.
So there you have it, the two tools that I use to help predict and track the weather's influence on my migraine. Credit where credit is due, my Dad found both of these and pointed them out to me, I thought I would pass them on :)