Snowy L

Agreed the one marginal event Liverpool always seems to do well in is one where the wind is southerly or southeasterly, usually from a front coming in from the west. Hopefully the South and East get a good frost tonight.

snow rain and hail here. I've noticed these events becoming more and more marginal through the years. I think Christmas 2004 would be rain/sleet here if it happened today.

Sleet here in South Liverpool.

Mixing between rain and sleet here.

That's not what I meant, most winter forecasts went for a mild first half to winter because the vortex was so strong in November. The impossible part is to forecast what happens after the first half of winter.

It was very easy to forecast a mild December and first half of January based on the strength of the vortex at all levels in November.

Looks like a respite in energy at the 7-10 day range. We've had the pulse of energy in the 3rd week of December which has currently had a small effect, though most of it has been deflected by the monster vortex. Then we are forecast another pulse in the day 10+ range if the NW Eurasian high hopefully verifies.

13c here, the same as an average July night. Unreal.

Latest Cohen https://www.aer.com/science-research/climate-weather/arctic-oscillation Still expects a significant weakening of the vortex in January.

Temperature still rising here. Currently double the December average at 14c, just 70 miles away in Leeds it's 1c. Crazy gradient.

Decent warming on the 12z warming the North Pole by around 10-15c and by the end of the run there are 3 distinct warming events. That first warming is making its way to the High Res too which is encouraging. http://modeles.meteociel.fr/modeles/gfs/runs/2015121012/gfsnh-10-384.png?12

And just as I said that a sleet/hail shower has started

Happy to not be in the firing line of the streamers, temperature is falling away here and I need it to as it's not favourable here on the coast for later tonight. Currently 3c dew point of -1.

Wind northwesterly now, dew point down to 1c, temp is still 7c though

Looks like it's GFS vs ECM again. GFS has won pretty much every time these last 2 winters, not getting my hopes up.

Good to see Cohen not discouraged by the unfortunate West QBO/very low solar flux combination. Thing is this is the only factor working against the possibility of an SSW this winter. Sea ice, SAI, El Nino/West QBO combination all in our favour.

2014/15 had a very high rate. I know we didn't get the SSW, but did we at least get a strong siberian high during that winter?

That's the thing with the El Nino this year. Other years, especially 2013/14 we had an Aleutian high pressure keeping the polar vortex stuck on our side of the North Pole in all levels of the stratosphere which meant a relentless low pressure conveyor belt in the North Atlantic.

With the Aleutian/Alaskan Low expected to be a semi-permanent fixture due to the strong El Nino, is there more potential for high pressure to build towards East Canada? I don't see any big potential for HL blocking with the strong vortex, but would this disrupt the East Canada/West Greenland conveyor belt for low pressure systems? Can see a winter of weak low pressure systems and regular mid latitude blocking to our west/south-west.

I thought a strong El Nino typically brings a mild first half of winter and cooler 2nd half. Interesting that the analogues are going for the opposite. So many mixed signals this year.

What is it with our current governments and their hate of free speech? http://metro.co.uk/2015/10/11/courts-could-make-it-illegal-to-question-climate-change-5433637/ http://lastresistance.com/14170/climate-change-lemmings-say-climate-change-denial-worse-than-holocaust-denial/ Personally I don't deny that the Earth is warming up and will continue to do so for the next few thousand years, but I have a big problem accepting that it has been caused by man. In the context of glacial/interglacials there is nothing unusual about this warming and as we are 13,000 years in to this current interglacial we should be approaching peak warming in the next couple of thousand years. In fact the only thing unusual about this interglacial is that it's relatively weak compared to the last 4 peaks. Thoughts? Should certain air vibrations that come out of our mouths be criminal offences?

Evidence that an E-QBO does not help in the weakening of the vortex when in an El Nino phase. No significant difference in vortex strength in W-QBO or E-QBO when we have an El Nino. http://www.eps.jhu.edu/~cig4/2008JD009920new.pdf "In addition to the affect of ENSO on the polar stratosphere, studies have noted that the vortex is less disturbed under a WQBO at 50hPa than during an EQBO. Recently it's been found in observational data, the vortex is weaker in EQBO as compared to WQBO under CENSO and neutral ENSO but not under WENSO." "A hint that this mechanism cannot fully resolve the question can be seen by comparing the polar cap temperature and geopotential height under WENSO/EQBO to WENSO/noQBO. Throughout the middle and upper stratosphere, the geopotential anomaly from 70°N and poleward is almost twice as large in WENSO/no QBO as in WENSO/EQBO. In the midstratosphere, the polar cap temperature anomaly in WENSO/noQBO approaches 6°C, more than twice the anomaly in WENSO/EQBO. The vortex is actually weaker, albeit not significantly, under WENSO/noQBO than WENSO/EQBO." "The reason that the polar vortex in WENSO/EQBO is not as weak as expected is because WENSO has had different teleconnection patterns during WQBO and neutral QBO than during EQBO. The dominant teleconnection pattern to WENSO under WQBO and neutral QBO is a strengthening of the Aleutian Low, and in particular through the PNA, WENSO/no QBO not shown), and the dominant teleconnection pattern under WENSO/EQBO is the WP and TNH. Barnston et al. [1991] reached similar conclusions on data from 1951 to 1989; they found that ENSO under WQBO tended to excite the PNA mode, whereas ENSO under EQBO tended to excite the TNH and WP modes." "Thus, the WENSO/EQBO vortex is only slightly weakened as its tropospheric teleconnections do not reinforce the climatological wave 1 in midlatitudes. In contrast, WENSO under WQBO does have tropospheric teleconnections (namely, the PNA) that increase wave 1. Because the midlatitude wave 1 height in the troposphere is greater in WQBO than EQBO under WENSO, the difference between the polar vortex in EQBO and WQBO under WENSO is small despite the QBO’s effect on the vortex." The W-QBO might not be the hindrance that we think it could be this winter.

Met Office says Northwest England should be a good spot for tonight. Large uncertainty remains regarding areas most at risk from storms, and many areas will miss these altogether, staying largely dry. However, where they do develop, disruption is possible. The most likely area for disruptionis considered to be Wales, parts ofthe Midlands and northern (especially northwest) England, but a lesser riskextends around the periphery of this region.

29c here, 4c higher than what the BBC was forecasting last night.

Sun broke through much earlier at half ten today. Feels a lot warmer too,official T shirt weather