Computer Models Hint at Development
For more than a week prior to Sandy's development, numerical weather prediction models hinted that a tropical depression or storm may form in the western Caribbean, which is an area that we typically look for tropical development in late October.
In fact, one computer model, the so-called GFS model, hinted two weeks in advance that a tropical cyclone may be near the eastern coast of Florida around Halloween while a cold front was driving into the East.
Though the details of what transpired did not match this model depiction, in hindsight, the long-range forecast models suggested to forecasters that a tropical cyclone could form and potentially pose a threat to at least part of the U.S.
After days of monitoring the Caribbean, Sandy formed on October 22.