The El Nino phase is fully in place and in fact has strengthened slightly over the past month. Sea-surface temperatures are running 1 to 3 degrees warmer than average throughout the central and eastern Equatorial Pacific Ocean. The latest long-range climate models continue to indicate that the current El Nino will persist through at least the upcoming winter season and may last into next spring as well.
As for the October temperature outlook, slightly above normal readings are forecast across much of the Pacific Northwest, north-central Rockies, Intermountain West, and Great Basin. A monthly deficit of early season heating degree days of between 30 and 60 is projected across these regions of the country during October.
Parts of the Northeast and Southeast may also see temperatures average a little above normal in October, possibly due to a positive NAO (North Atlantic Oscillation) that may develop. The Northeast will likely see fewer early season heating degree days while parts of the Southeast could see a bit of a surplus of late season cooling degree days. Much of the Midwest, Great Lakes, Ohio Valley, and Tennessee Valley are expected to see temperatures on a whole average closer to normal in October.
