Model tweets

[CK1981]

2 minutes ago, knocker said:

Rather depends what you mean by cold but within my limited understanding I don't know of any direct correlation with pressure distribution in north west Europe. It does seem to be related to the pattern change in N.America but downstream still looks pretty unsettled with trough domination into the ext period according to tonight's EPS mean anomalies.

It seems a very finely balanced situation at the moment and certainly very different from our usual winter weather pattern. More surprises to come methinks!

[keithlucky]

Looks good for a easterly of sorts by the end of week

 

[northwestsnow]

12 minutes ago, keithlucky said:

Looks good for a easterly of sorts by the end of week

 

thats yesterays 12z EC- this mornings is nothing really like it..

[knocker]

 

[northwestsnow]

1 minute ago, ShortWaveHell said:

Gracious me ! Today’s output has made Hammond make another prediction ! 

That sounds VERY interesting!!

[knocker]

24 minutes ago, northwestsnow said:

That sounds VERY interesting!!

It's not a great surprise as both the METO and ecm have a front arriving from the west with quite possibly (emphasis at this range) a fair bit of snow in the north on the leading edge.

[Summer Sun]

 

[northwestsnow]

what does the tweet say Gavin im getting an error

[Mark wheeler]

10 minutes ago, northwestsnow said:

what does the tweet say Gavin im getting an error

Likewise 

[ArHu3]

1 hour ago, northwestsnow said:

what does the tweet say Gavin im getting an error

 

Quote posts with broken tweets and you can see those tweets 

https://mobile.twitter.com/fergieweather/status/950666872713773056?ref_src=twsrc^tfw

 

To me, "freezer" equates to eg N America lately or UK 2010-11 but yes, colder, windy Pm/Am cyclonic phase continues well-signalled with risk of snow at times. As for SSW, no reliable signals "soon", with stratospheric polar vortex f'cast stronger than avg rest of Jan in GloSea5.

 

@Mark wheeler

Edited January 9, 2018 by ArHu3

[Summer Sun]

 

[knocker]

 

[Interitus]

Might be a bit controversial for some, an interesting tweet from the just finished 2018 AMS meeting casting doubt on a teleconnection staple -

Presentation was based on these works (unfortunately abstracts only) -

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-17-0041.1

Quote

Snow–(N)AO Teleconnection and Its Modulation by the Quasi-Biennial Oscillation

This study explores the wintertime extratropical atmospheric response to Siberian snow anomalies in fall, using observations and two distinct atmospheric general circulation models. The role of the quasi-biennial oscillation (QBO) in modulating this response is discussed by differentiating easterly and westerly QBO years. The remote influence of Siberian snow anomalies is found to be weak in the models, especially in the stratosphere where the “Holton–Tan” effect of the QBO dominates the simulated snow influence on the polar vortex. At the surface, discrepancies between composite analyses from observations and model results question the causal relationship between snow and the atmospheric circulation, suggesting that the atmosphere might have driven snow anomalies rather than the other way around. When both forcings are combined, the simulations suggest destructive interference between the response to positive snow anomalies and easterly QBO (and vice versa), at odds with the hypothesis that the snow–North Atlantic Oscillation/Arctic Oscillation [(N)AO] teleconnection in recent decades has been promoted by the QBO. Although model limitations in capturing the relationship exist, altogether these results suggest that the snow–(N)AO teleconnection may be a stochastic artifact rather than a genuine atmospheric response to snow-cover variability. This study adds to a growing body of evidence suggesting that climate models do not capture a robust and stationary snow–(N)AO relationship. It also highlights the need for extending observations and/or improving models to progress on this matter.

http://onlinelibrary.wiley.com/doi/10.1002/2016GL071584/full

Quote

Snow-(N)AO relationship revisited over the whole twentieth century

Several studies suggest that the Siberian snow cover in fall is a source of predictability of the Arctic Oscillation (AO) in winter. Although a plausible dynamical mechanism was proposed, the robustness of this relationship was recently challenged. Here we use two atmospheric reanalyses to revisit the snow-AO relationship and its modulation across the whole twentieth century. While our results support a stratospheric pathway mechanism, they show that the snow-AO relationship has only emerged in the 1970s and should be rather analyzed as a contrasted multidecadal behavior of the North Atlantic Oscillation (NAO) and Pacific North America pattern. They confirm that the quasi-biennial oscillation is a plausible candidate for the modulation of the snow-(N)AO relationship across the twentieth century, but they further show that this modulation might be a purely stochastic effect. Therefore, they emphasize the limitations of any empirical prediction of the (N)AO only based on snow and/or sea ice predictors.

 

[Day 10]

 

[knocker]

 

[Summer Sun]

 

[Blessed Weather]

Latest thoughts from Matt Taylor about the track of next Thursday's runner:

 

[knocker]

 

[snowbunting]

50 minutes ago, knocker said:

 

Which then in turn has ramifications for the UK as it gets plunged again into the North side of atlantic jet

[Summer Sun]

 

[Blessed Weather]

Ventrice not impressed with ECMWF performance on this occasion....

 

[knocker]

 

[Summer Sun]

 

[knocker]

 

[knocker]