🥶 HERE COMES WINTER: Cold weather and snow on the way for some areas of the US, but how will global weather patterns – like a La Niña or polar vortex – factor into an early winter? FOX Weather digs into what Americans can expect:
The weather this November has been nothing short of interesting.
Record colds in the East, lake-effect snow around the Great Lakes, unsettled weather across the West, the largest Supermoon of the year and a geomagnetic storm that brought the Northern Lights to the US have all made headlines in the first half of the month. What’s in store for the second half?
As we inch closer to winter, in the event the Polar Vortex weakens, it won’t be until the last week of November, which could bring cold, snowy conditions to the US just in time for Thanksgiving.
Across the Central and Eastern US, wetter-than-average conditions are expected while much of the East will see above-average temperatures.
HOW LA NIÑA, POLAR VORTEX WINDS COULD FUEL A FAST-START TO BRUTAL WINTER FOR PARTS OF THE US
The opposite is expected in the West, as California and the Northwest will likely face below-average temperatures through the end of the month. The FOX Forecast Center expects the rest of the month to be stormy in the East, with lots of rain and little snow.
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Both the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) are trending more negative toward the end of the month, which typically results in a more amplified jet stream across the Lower 48, meaning stormier weather and the potential for shots of cooler-than-average air.
This trend is reflected in the Climate Prediction Center’s (CPC) precipitation and temperature outlooks through Thanksgiving week.
WHAT ARE THE ARCTIC OSCILLATION, NORTH AMERICAN OSCILLATION AND MADDEN-JULIAN OSCILLATION?
These expectations also tie into the Western Pacific Oscillation (WPO), a pattern of atmospheric pressure anomalies over the western Pacific Ocean.
The WPO can fluctuate between positive and negative phases over days to weeks. It’s currently forecast to remain more positive, which historically corresponds to warmer and wetter conditions across the East and cooler conditions across the West, consistent with the CPC’s current outlook.
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As the Polar Vortex weakens, the chance of more arctic blasts and colder periods could bring winter-like weather to the Lower 48.
However, the outlook for the rest of November for the lower 48 remains consistent: an unsettled pattern, meaning there are more chances for unfriendly weather as the month progresses.
The FOX Forecast Center is closely monitoring the end-of-month setup and larger-scale atmospheric signals that could be hinting at a more active weather pattern to round out the month and kick off the holiday season.
HOW TO WATCH FOX WEATHER
Known as a transitional month in terms, November ushers us into the holiday season, and whether you like it or not, winter-weather conditions.
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Weather into December
Looking towards December as we enter meteorological winter, La Niña conditions developing in the eastern Pacific are expected to become more significant.
La Niña is a climate pattern defined by cooler-than-average sea surface temperatures in the central and eastern equatorial Pacific Ocean, which can directly impact U.S. weather patterns. Typical La Niña winters feature a more active Pacific jet stream that funnels moisture into the West and northern tier of the country.
WHAT ARE EL NIÑO AND LA NINA CLIMATE PATTERNS?
In December, the CPC highlights above-average precipitation across the West and northern tier and drier conditions across the Southeast, a potential shift from what we may see to close out November.
The FOX Forecast Center is monitoring the Polar Vortex, which is expected to weaken into December, allowing for increased chances of blasts of cold, arctic air to engulf the Lower 48.
