Extreme Weather Watch

[Boris Sprinkler]

Probably due to it being east coast and weather pressure systems rather than a beef.

 

[brogdale]

Why do hurricanes have an issue with land falling on Virginia and Maryland? Too many federal employees living there?

I suspect that it's related to Hurricanes making it that far North being driven Eastwards, away from the ConUS, by the prevailing westerlies (jet stream) in the mid-latitudes. More likely to end up over us in the UK.

e2a:

 

[Elpenor]

I suspect that it's related to Hurricanes making it that far North being driven Eastwards, away from the ConUS, by the prevailing westerlies (jet stream) in the mid-latitudes. More likely to end up over us in the UK.

Ok, how does it explain the landfalls over New York and New Jersey?

 

[brogdale]

Ok, how does it explain the landfalls over New York and New Jersey?

Well, exceptions to the general pattern, I suppose. Although there is obviously a generalised curve that N.Atlantic hurricanes tend to follow:




each, individual system will be driven by the synoptic pattern that it evolves in; being repelled by High pressure systems and drawn towards other Low pressure systems. So sometimes, because of an unusual synoptic pattern, Hurricanes can behave in unusual ways. Though, I'm aware that there are posters here who know far more about that I do.

 

[2hats]

Various factors (Coriolis/dominant upper level wind direction and thus steering, decreasing sea surface temperatures, increasing vertical wind shear towards higher latitudes and the state of major climate drivers) all work to reduce the probability of more northerly hurricane landfalls but don't entirely eliminate them.

The separation of the Gulf Stream from the US east coast continental shelf (the detail of which varies with the North Atlantic Oscillation) tends to keep the warm water 'fuel' further off shore as one heads north (hence the apparent paucity of landfalls in the Mid-Atlantic coastal region).

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However, amplification of the polar jet, quite common as the Atlantic hurricane season progresses, can bring about setups that may steer suitably placed hurricanes further north towards the New England coast. For example, the Bermuda(/Azores) high is a big player here. The extent and positioning of that can strongly determine where a lot of hurricanes track (either into the Gulf of Mexico, or to the US SE coast, or to curve around to the NE and out into the Atlantic - sometimes towards Europe, or to bounce one back towards New England - especially where you get a low over the eastern US and a high over eastern Canada).

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e2a: Now with illustrative/explanatory eye candy.

 

[bcuster]

View attachment 455750

It expands out

 

[Dystopiary]

Scientists have confirmed that 2024 was the first year to exceed 1.5°C average above the pre-industrial baseline:

Hopes of keeping global warming below 1.5°C above pre-industrial levels have been all but extinguished after new data confirmed 2024 was the first calendar year to see average temperatures breach that critical threshold.

Last year was the hottest ever recorded in human history, the World Meteorological Organization (WMO) will declare later today, in the latest stark warning that humanity is pushing Earth’s climate into uncharted territory.

The WMO’s assessment is calculated using the average global temperature across six datasets, with the period of 1850 to 1900 used to provide a pre-industrial baseline. Temperature datasets collected by various agencies and institutions around the world vary slightly, mainly due to differences in how ocean temperatures have been measured and analysed over the decades. Some of those datasets will come in just below the 1.5°C mark, New Scientist understands, but others are well above.

The UK’s Met Office weather service puts 2024’s average temperature at 1.53°C above pre-industrial levels, with a margin of error of 0.08°C. That is 0.07°C above 2023, the previous warmest year on record. Meanwhile, the European Union’s climate change service Copernicus has 2024 temperatures at 1.6°C above pre-industrial levels, 0.12°C above 2023’s record.

2024 confirmed as first year to breach 1.5°C warming limit

 

[brogdale]

GFS model predicting a brute of a polar plunge across much of ConUS later this week:



If that run verified more extreme US weather headlines would result.

 

[2hats]

Quite likely (if verified) that will drive a change away from the predominant blocking high of the next 10-14 days, towards a more westerly flow trying to assert itself. The long range UKMO forecasts are already suggesting a move towards mixed/unsettled in ~10+ days time, and the GFS itself suggests more low pressure regions trying to rock up during the week after next, as that temperature difference over CONUS pushes a signal into the downstream jet. One deep depression can be seen (the weekend after next) to the W/NW of the UK at the extreme range of the current GFS operational run (but clearly that's to be taken with a large pinch of salt at this stage). The European model currently seems to view that potential event mostly as a brief hiccup in a longer period of more stable, high-dominated weather (well into February).

 

[brogdale]

Quite likely (if verified) that will drive a change away from the predominant blocking high of the next 10-14 days, towards a more westerly flow trying to assert itself. The long range UKMO forecasts are already suggesting a move towards mixed/unsettled in ~10+ days time, and the GFS itself suggests more low pressure regions trying to rock up during the week after next, as that temperature difference over CONUS pushes a signal into the downstream jet. One deep depression can be seen (the weekend after next) to the W/NW of the UK at the extreme range of the current GFS operational run (but clearly that's to be taken with a large pinch of salt at this stage). The European model currently seems to view that potential event mostly as a brief hiccup in a longer period of more stable, high-dominated weather (well into February).

Good overview; my basic understanding is that a big polar plunge like that into the ConUS would tend to see the downstream Jet stream push to the North of UK dragging in the milder Westerlies?

 

[2hats]

Good overview; my basic understanding is that a big polar plunge like that into the ConUS would tend to see the downstream Jet stream push to the North of UK dragging in the milder Westerlies?

It tends to perturb the downstream jet, so one would expect greater chances of a change from the (up to that point in time) prevailing state. The detail depends on the current regional state of the jet, air masses and pressure systems at that time, plus strengths of any relevant main climate drivers/teleconnections.

 

[2hats]

Quite likely (if verified) that will drive a change away from the predominant blocking high of the next 10-14 days, towards a more westerly flow trying to assert itself. The long range UKMO forecasts are already suggesting a move towards mixed/unsettled in ~10+ days time, and the GFS itself suggests more low pressure regions trying to rock up during the week after next, as that temperature difference over CONUS pushes a signal into the downstream jet. One deep depression can be seen (the weekend after next) to the W/NW of the UK at the extreme range of the current GFS operational run (but clearly that's to be taken with a large pinch of salt at this stage). The European model currently seems to view that potential event mostly as a brief hiccup in a longer period of more stable, high-dominated weather (well into February).

And lo[w], it may yet come to pass. Not bad for 12 days out if it verifies.

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