The month of December has gotten off to a cold start across much of the eastern half of the nation and there will be multiple cold air outbreaks in coming days. Two signals that have foreshadowed a cold period include an unusually early season stratospheric warming event and the movement of a tropical disturbance into a position that favors colder-than-normal weather across much of the nation. In fact, there appears to be a second burst of stratospheric warming in the offing for later this month resulting in a “stretched” polar vortex, and the tropical disturbance will likely persist in much of the same “cold” position” for awhile longer...both of these favor the idea of additional cold air outbreaks as we progress through the month.
The cold pattern has been quite active as well and multiple systems will have to be watched in coming days. On Friday, low pressure will develop over the Deep South and head in an northeasterly direction. This system is likely to produce some accumulating snow in the southern half of the Mid-Atlantic region and looks like a light-to-moderate snow event. Another low pressure system may pull out of the southeastern states by early next week and head in an northeasterly direction at the same time a “clipper” moves southeastward across the Great Lakes…we’ll monitor this activity as it could result in some accumulating snow for the northern Mid-Atlantic and Northeast US. Later next week, it appears a couple of other “clipper” systems will drop southeastward from southwestern Canada into the Great Lakes and ultimately, to the Northeast US. Finally, the significant change in recent days of an index value known as the “Southern Oscillation” is raising a red flag that the chance of an east coast storm will be on the rise somewhere down the road as the sub-tropical jet stream likely becomes activated.
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Chilly weather continues across the Tennessee Valley with today’s temperatures doing no better than the lower 40’s for afternoon highs. The night will be quite cold with mainly clear skies and there is the chance for some late night “freezing” fog which could cause some slick spots on roadways. Milder conditions are likely at mid-week with afternoon highs on Wednesday around the 50-degree mark.
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A strong cold front passed through the region late yesterday paving the way for a chilly Turkey Day and the chill remains into the upcoming weekend. Temperatures this afternoon will do no better than 50 degrees for afternoon highs and will likely drop to below freezing on Thursday night and Friday night as well. Looking ahead, low pressure may ride up along a frontal boundary zone early next week and it could potentially bring a heavy rain event to the area.
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The period between Thanksgiving and Christmas will begin with a major Great Lakes snow event from Thursday to Friday and an Great Lakes/Midwest snowstorm this weekend and it could end with a White Christmas in many parts of the country. Two of the factors that have been highlighted here, likely leading to a cold and active stretch of weather, include an unusual early season stratospheric warming event and the likely movement of a tropical disturbance into a location that favors colder-than-normal conditions across a large part of the nation. Both of these phenomena – stratospheric warming and tropical forcing – will likely lead to a “buckling” of the polar jet stream which can lead to the unleashing of multiple Arctic air masses from northern Canada into the US (with intense cold in the table), and an activation of the southern branch of the jet stream which will likely produce multiple snow/ice threats.
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A strong cold front will approach the area during the next couple of days producing some shower and thunderstorm activity in the region. Temperatures will take a tumble by tomorrow night following the passage of the cold front and this will set us up for a windy and cold Turkey Day and the wind and chill will stick around to close out the shortened work week.
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There are signals that continue to point to an upcoming cold weather pattern for the central and eastern states as the early part of the winter season gets underway. These signs come from such diverse places as the stratosphere over the North Pole (re: Stratospheric Warming), the stratosphere over the tropics (re: QBO), and the equatorial part of the Pacific Ocean (re: MJO).
To begin, it appears as though there will be a “Stratospheric Warming” event over the polar region of the Northern Hemisphere in coming days which is quite a rare occurrence for this early stage of the winter season. In fact, it appears there have been only two Stratospheric Warming events in recent history that took place during the month of November...2000 and 1968...and in both of those years the month of December was quite cold across the nation. One atmospheric phenomenon that supports the idea of one (or more) “Stratospheric Warming” event(s) this winter season is known as the Quasi-Biennial Oscillation (QBO) which is a changing wind anomaly in the tropical lower stratosphere. When an “easterly” or “negative” phase of the QBO is combined with La Nina conditions in the tropical Pacific Ocean – both of which represent the current situation - there is a strong tendency for an increase in “Stratospheric Warming” events and the disruption of the polar vortex. This particular teleconnection was one of the factors highlighted in the ”2025-2026 Winter Outlook” issued back in October.
Additionally, there is an oceanic-atmospheric phenomenon known as the Madden-Julian Oscillation (MJO) that affects the weather patterns across the globe. The MJO is an eastward moving disturbance of clouds and rain that traverses the planet in the tropics and - depending on its location and the time of the year - it can contribute to colder-than-normal weather patterns across the central and eastern US.
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The rest of the week and weekend look to be rather mild and unsettled with the chance of showers and thunderstorms from time-to-time. In terms of temperatures, they’ll likely reach the upper 70’s later today and on Friday and the low-to-mid 70’s each day this weekend.
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The remainder of the week looks to be rather mild and unsettled with the chance of showers and thunderstorms from time-to-time. In terms of temperatures, they’ll likely reach the upper 70’s later today and on Thursday and the middle 70’s on Friday afternoon.
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The week ahead looks to be rather mild and unsettled with the chance of showers from time-to-time. In terms of temperatures, they’ll likely hold in the 60’s later today for afternoon highs, but then should reach into the 70’s during the next few days.
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The comeback in temperatures from the early week Arctic invasion continues today with afternoon highs likely to be within a few degrees of the 70-degree mark. The warmer trend continues into the weekend with highs likely to be in the low-to-mid 70’s on both Saturday and Sunday and plenty of sunshine each day.
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