I got some good questions from my last post that I'll try to answer.
The first question was about the lag between the longest day of the year, and the hottest time of year.
The reason we don't see the hottest temperatures on the longest day of the year, has to do with the Earth's energy balance. Over the whole planet, incoming radiation is in balance with the outgoing radiation. This is why the earth maintains a stable temperature, and doesn't heat up uncontrollably. On a local scale however, this is not true. In the months around the Solstice, incoming radiation and outgoing radiation are not in balance. In late spring and through the summer we see more radiation hitting the land and ocean than is released. When there is a surplus of solar radiation the ocean and atmosphere warm causing higher temperatures. The opposite is true in the winter. The atmosphere and ocean have stored that excess energy all summer and only slowly release it back to space. The energy deficit continues until spring when the the energy equation becomes balanced again.
Another question related to the difference in temperatures on the East and West Coasts. If there is record heat in the East does that mean there will be record cold in the West?
In terms of records, this could be true, but more than likely not. What is usually, but not always true, is that when temperatures are well above normal on one coast, they will be below normal on the other coast. This is a result of the "Long Wave Pattern" of the jet stream. Warm weather is typical of a ridge (crest) in the jet stream, while cool weather is typical of a trough. The wavelength of the waves in the jet stream is on the same order of magnitude as the width of the country, so usually one coast will be under a ridge while the other coast will be under a trough.
The last question was California specific, why is this summer so cold and foggy, and will that mean we are going to have a late "Indian Summer" that will have dire implications for fire season.
The first part of that question was sort of answered above, the East has been hot, we had a relatively stationary pattern, so the West has been cool. This has a little to do with La Nina too. High pressure has remained off the coast of California keeping the north winds going and causing upwelling.
As far as an Indian Summer, the lack of hot weather in the summer isn't a good indication of what will come, but La Nina is. La Nina traditionally brings cooler and drier air to the West Coast for the fall and winter months.
What does that mean for fires?
Hard to say, on one hand dry is good for fire season lasting late into the year, but cool means fewer days where the fire danger is critical.
