Meteorology Not Modelology™

Winter Forecast For 2024/25 PUBLIC VERSION

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London, GB
1:38 pm, Feb 9, 2025
weather icon 41°C | °F
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overcast clouds
Humidity 88 %
Pressure 1028 hPa
Wind 7 mph NE
Wind Gust Wind Gust: 0 mph
Precipitation Precipitation: 0 inch
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Visibility Visibility: 6 mi
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Sunrise Sunrise: 7:25 am
Sunset Sunset: 5:04 pm
Icicles and Snowstorm
Icicles and Snowstorm

This year’s winter weather pattern will be under the influence of a slowly developing La Nina, a strengthening Polar Vortex via the positive QBO, and very warm waters in the Tropical Atlantic.  How these factors interact will produce themes this winter that will mark the likely storm tracks and the potential of snow, ice, and rain events throughout the United States.  This forecast is focused on the Mid-Atlantic, eastern Great Lakes, and New England regions of the United States.

The winter forecast, like most seasonal forecasts, has significant volatility and low confidence attached to it.  The goal of the forecast is not to be 100% accurate as that is nearly impossible, but to provide guidelines on what to expect overall for this winter.  As a result, outliers may develop throughout the winter, creating unique winter weather events, which I will attempt to highlight so we can look out for them.

The first section will feature the PUBLIC Forecast with the overall theme of the winter, and the second section will feature a PREMIUM detailed analysis along with the timing of the best potential for winter weather events.

PUBLIC FORECAST

The climatological themes for the winter of 2024/2025 will fall under a La Nina season with some periods of high-latitude blocking.  At times, a strong Pacific jet stream will help to flood the United States with a Pacific air mass, creating mild conditions.  However, the Polar jet stream will be more amplified than not, supporting a high threat of storms over the eastern two-thirds of the nation.  The details on these factors can be found in the Premium Section.  Given these factors, here are the expected storm tracks for this winter.

STORM TRACK ONE: This is your traditional Alberta Clippers.  Most clippers are fast-moving low-pressure systems that transport Polar and Arctic air masses into the region.  They are most likely to be a threat from mid-November through early February.  Most of these low-pressure systems produce light precipitation, for example, a 1″ to 4″ snowfall, depending on snow ratios. However, a few rare low-pressure systems can slow down and produce a 6″+ snowfall over the Mid-Atlantic and southern New England.

STORM TRACK TWO: This storm track begins in the Desert Southwest or southern Plains and moves through The mid-Mississippi River Valley into the central or eastern Great Lakes.  This storm track typically produces significant rainfall along the coast and the I-95 corridor while interior locations in the Mid-Atlantic and much of interior New England end up with a mix of snow and ice before possibly changing over to rain.

STORM TRACK THREE: Storm track three starts off in either the Texas or Oklahoma Panhandles and tracks towards the Tennessee River Valley.  This low-pressure system is usually the result of a stalling Polar or Arctic cold front boundary.  Once in the Tennessee River Valley, the storm track can take two distinct tracks.

THREE A: With a positive NAO pattern, the storm lifts through central Pennsylvania into western New England. On the coast and I-95 corridor, it will be a wintry mix to rain, and over the interior of the Mid-Atlantic and New England, it will be a snow-to-wintry mix, with some significant snowfall possible.

THREE B: With a negative NAO pattern, the storm is forced to track or redevelop towards the DELMARVA Peninsula and through the coastal waters of the northern Mid-Atlantic and New England.  This storm track produces significant snowfall for the interior of the northern Mid-Atlantic and New England, while a snow-to-wintery mix is likely on the coastal plain with some potential for moderate to significant snow accumulation.  This storm track is called a Miller-B storm track.

STORM TRACK FOUR: In this situation, a stationary front develops from the lower Mississippi River Valley to the Mid-Atlantic coast with waves of low-pressure driving moisture into a Polar or Arctic air mass.  While the low-pressure systems are typically weak, the wintery precipitation can be prolonged, producing significant snow, ice, and rain depending on the position of air masses along the frontal boundary.

I created four forecast zones that will follow the overall expectations for November 2024 through March 2025.  This winter will be influenced by a weak central-east-based La Nina with a strong but disrupted or stretched Polar Vortex.  The result of this type of weather pattern will support an amplified Polar jet stream that will feature a robust upper-level ridge in the Gulf of Alaska that will drive Pacific and Polar/Arctic air masses into the eastern two-thirds of the United States.  The Subtropical jet stream will be active but weaker than the Polar jet stream and feature a persistent ridge between the Southeastern coast of the United States and the Bahamas.  This will feature an aggressive start to winter, possibly in late November, and continue through mid-February.  There is a good chance for an early start to Spring in late February and March.

FORECAST ZONE ONE: In this zone, the combination of storm tracks would support several snow events, strong lake effect storms, and longer periods of below-freezing days.  Temperatures will average near to slightly below normal, and precipitation will average above normal.  Snowfall accumulation will be above normal for the season.

FORECAST ZONE TWO: This region will be closer to the mean storm track but on the cold side of most of the storms.  Many storms will feature snow mixing with sleet and freezing rain.  Temperatures will average near normal and precipitation near normal.  Snowfall accumulation will be near to slightly above normal for the season.

FORECAST ZONE THREE: This region will be closer to the mean storm track but on the warm side of most storms.  Many storms will feature snow mixing over to sleet and rain.  Temperatures will average near to slightly above normal, and precipitation near normal.  Snowfall accumulation will be near to slightly below normal for the season.  However, if a more sustained negative NAO pattern is established, the region could be much more like Zone Two.

FORECAST ZONE FOUR:  This region will feature most storm tracks aside from storm track four (see above) to the north of this region, with most precipitation events starting briefly with snow or all rain.  In the rare case of a storm track four event, these locations may have the best potential for significant accumulating snowfall and feature most of the season’s snowfall.  If a sustained negative NAO pattern develops, this region may exceed the forecasted expectations.  Temperatures will average above normal and precipitation near normal.  Snowfall accumulations will be below normal for the season.

STORM THEME EXPECTATIONS: This year’s bulk of the winter storms will feature precipitation events with multiple precipitation types and changeover timing challenges.  Many storms will feature precipitation that will start off as snowfall and then change over to sleet or rain.  The best potential for heavy snowfall will be found over the interior.

The key phrase of the winter is that an easterly wind kills a snowfall.

WHAT COULD GO WRONG

In many years, the forecast would feature a what could go wrong section.  I think this helps you prepare for some wild cards that winter can feature.

  1. La Nina ends up stronger: In this case, the whole forecast would be adjusted to warmer and drier, with most storms lifting into the central Great Lakes and very mild conditions taking hold by mid-January.  This outcome is not likely.
  2. La Nina fails to form: In this case, both the Polar and Subtropical jet streams are equally amplified, and a colder storm track focused along the coast or over the coastal waters is far more likely to develop.  This would produce colder solutions than expected.  This outcome is possible but not expected.
  3. The NAO goes negative more often than not: If an environment of a positive QBO and a Polar Vortex near North America, a negative NAO forms and breaks down repeatedly, producing several Miller-B storms (Storm Track Three B) for the region with more snow and ice for the region.  This outcome is possible.
  4. The NAO goes positive more often than not: If an environment of a positive QBO and a Polar Vortex near Asia, a positive NAO forms frequently supporting frequent storm tracks one and three A that will produce warm and wet conditions and a significant reduction of snowfall for the whole forecast area.  This outcome is possible.

For technical details on this forecast, please consider subscribing to NY NJ PA Weather Consulting Membership!

COMBINING FORCING FACTORS AND FORECAST EXPECTATIONS

Some may dream of a white Christmas or just any precipitation at this point; I just wish I had one easy seasonal forecast. There are other factors I could have added to this forecast that I have already accounted for, like climate change factors. I should note that because of our warmer climate, I no longer reference other winters because our baseline has changed so much compared to the 1990s, let alone the mid-20th century.

This winter will feature a period of cold and stormy conditions; the question is simply how frequently these conditions will develop and whether those conditions will align to produce winter storms or a lot of frustrating close calls.  Much like last year, you could develop a favorable pattern, but one or two features are poorly timed, and thus, a storm track ends up suppressed.  With that said, I don’t expect any major Miller A Nor’Easters this year, and Miller B storms are more likely to impact New England rather than the northern Mid-Atlantic unless the timing is perfect.

Our warm and cold signals throughout the winter will start and end in the Gulf of Alaska.  When an upper-level low develops in the Gulf of Alaska or over Alaska, the Polar jet stream will drive Pacific air masses throughout Canada and the United States, producing mild conditions.  Such a pattern will develop to start November, which will feature below normal heights over the Rockies and a broad ridge over the eastern two-thirds of the United States.  However, when the trough retrogrades towards the Aleutian Islands and a ridge builds throughout the Gulf of Alaska and Alaska, the Polar jet stream will support a broad trough from the eastern Rockies to the East Coast that will allow Polar and Arctic air masses to invade the United States.  This pattern would make blocking in the Northern Atlantic more favorable at times.  When the NAO is negative, widespread winter storms will be possible, with the best potential for this type of pattern from mid-December through early February.  However, I don’t think this type of weather pattern can sustain itself and most of the factors will need to be near perfect and then repeat themselves.  As a result, I am expecting a winter that will average slightly above average for temperatures, near average for precipitation, and near to slightly below average for snowfall for most of the region.

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