Jet stream analysis - is blocked, cold weather turning more likely?

Not really sure how this stuff really, works, but I'll have a look at AAM

The drop in AAM, at least for now, and it will likely remain weakly negative

cfsv2_aam_fcst_current.png

MR-latest-30days.png

The January weakening of AAM seems to have led to the polar jet stream largely weakening, while the subtropical jet stream has weakened and shifted south, while the stalling in the decrease in AAM may have led to the polar jet stream shifting north, into the high latitudes (70 to 90N)

aam_profile_current.png

aam_stdanom20260116_0000.png

My educated guess is that the weakening and shifting south of the subtropical jet stream will likely lead to less influence from the Azores high and southern Europe highs on our weather, so a lesser risk of them ruining the potential cold spell. Meanwhile, the polar jet stream, that's tends to be on the same latitude of us, weakens and is displaced north, causing a raise of pressure in the high latitudes.

My guess is that both the jet streams moving away from each other would increase the amplitude of Rossby waves and the jet stream, which supports blocked patterns that can cause anomalous warm, or cold (which is more relevant at the moment) weather. However, the weakening of AAM on both sides would make these patterns less anchored and resilient, so there's more of a signal for waxing and waning of blocking that fails to consistently take hold, but this can still be supportive of cold easterlies, but it is much more precarious

I urge this to be taken with a massive grain of salt, because these are just merely educated guesses

Comments

Post a Comment

Popular posts from this blog

The Impacts of an AMOC collapse on Europe

Image
The impacts of an AMOC collapse on Europe Introduction As the Earth has warmed, one section of the Atlantic Ocean has been cooling. This has been attributed to an ocean current, known as the Atlantic Meridional Overturning Circulation (AMOC) weakening. This ocean current regulates the climate worldwide by transporting waters at different temperatures, but this is expected to continue to weaken with climate change, bringing worrying consequences on the climate. However, a more extreme, but still a very plausible scenario of the current collapsing may occur as early as mid-century, where the climate may rapidly change within a few decades. In this summary, I'll focus on Europe. Source: High-resolution ‘fingerprint’ images reveal a weakening Atlantic Ocean circulation (AMOC) The AMOC brings warmer water from the Gulf of Mexico to Europe, contributing to keeping its climate mild in comparison to areas such as Canada. Under a collapse, a lot of the warmer water is shut off, shown by the...
Read more

Long range UK weather forecast: 8th February 2026

Image
First, let's look at the main factors at play. Current situation Lack of a clear tropospheric polar vortex Higher pressure over Greenland, but not strong enough to have a big influence aside from weakening the Atlantic storm track High pressure over Scandinavian snow cover, trapping cold air that forces the Atlantic storm track to weaken and shift south as it moves west, into the UK Active Atlantic storm track, albeit weaker on the eastern side as it passes over the UK As a result, you have a weak zonal flow dominating the UK, causing rain, as well as more settled weather between low pressure systems. The lack of jet stream amplification keeps temperatures close to average. Mid-range model output On Monday to Wednesday, pressure over Scandinavia is reduced, strengthening the storm track. It creates wetter and slightly milder conditions On the rest of the week, cold air in Scandinavia and Siberia mixes with the Atlantic storm track. In the north of the UK, there's more influence...
Read more

Cold spell inbound for the UK? Can we see more cold in early and mid Febuary?

Image
This weekend and into next week, high pressure over Scandinavia will draw in cold air into Europe, and also block and push the jet stream south, allowing this cold air to move over the UK, starting with the north. For the northeast of the UK, this easterly winds over the North Sea may stir up some snow showers under low temperatures. For the south, things look more uncertain, but temperatures will be below average, with risks of rain and snow Past this point, may we see further cold spells?  First of all, the EC46 suggests this, but at the same time, it does very often overestimate the risks of weather patterns that tend to bring cold weather to the UK. High pressure north of us blocks westerlies and forces the jet stream south, which can lead to cold air from the north, east or northeast filling in the gap Notice the high pressure to our north and low pressure to our south? That's a clear NAO- pattern here. Both the GEFS and CFS are on board with the NAO- being negative till mid-F...
Read more