Linda Lam
October may not feel like fall in much of the northern tier of the United States.
Temperatures will be the most above average from the northern High Plains through the Midwest into the Northeast in October, according to the latest outlook from The Weather Company, an IBM Business. Above-average temperatures will extend southward into parts of the Southern Plains and the Southeast.
Cooler than average conditions are expected for much of California and southern Arizona, while much of the Northwest, Southwest and portions of the Gulf Coast and Florida may trend near to slightly cooler than average in October.
One important factor in this temperature outlook is the development of La Niña, which looks likely to emerge this fall into the winter. La Niña is the periodic cooling of the equatorial Pacific Ocean waters, which depending on its strength, can influence weather patterns across the globe, including in the U.S.
Above-average temperatures are typically experienced across much of the Lower 48 in Octobers when La Niña has developed. This is especially true from the Rockies into the Midwest. But areas along the Gulf Coast and portions of the West Coast often experience cooler than average conditions in La Niña Octobers. This overall theme closely matches the current October outlook.
The typical October La Niña pattern also correlates well with what forecast models are showing for much of October.
Current models depict an upper-level ridge or northward bulge of the jet stream over a good chunk of the Lower 48, indicating warmer than average temperatures. A trough or southward dip in the jet stream is also likely over parts of the West at times, suggesting cooler than average temperatures.
"We've made further warmer adjustments to the October forecast to be more in line with our medium-range and subseasonal forecasts, which are in line with warmer historical La Niña aggregates," Todd Crawford, director of meteorology at Atmospheric G2 pointed out.
The agreement between recent computer model forecasts for October and what has typically been the case in La Niña Octobers gives higher confidence in the current October outlook, Crawford notes.
Typical October Temperatures
Crisp temperatures become more common across the northern tier of the U.S. in October, with average highs in the 50s and 60s. Warmer than average temperatures there suggest that a milder month may be in store.
Above-average temperatures in parts of the South indicate a warm October may make it feel less like fall.
However, in areas of the West where below-average temperatures are anticipated a chillier October may be ahead.
Many areas from the West into the Midwest into parts of the Northeast often experience the first freeze of the season by the end of October.
But warmer than average temperatures may mean milder mornings will last a bit longer for much of the Lower 48.
Chillier mornings than is typical for October could occur in parts of the West and near the Gulf Coast where a cooler than average trend is anticipated.
The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.
The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.
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