summer blizzard

It's always interesting to think there are now people here who don't remember 07-12 and can only reference statistics (for those of us here back then, it sticks in the memory like 09-10-13 does for summer. But yeah, 07 and 12 were basically a dream for those of us who dislike summer and we're truly horrific for the majority on here. Akin to winter 2014. Summer 2008 was horrifically dull and generally wet and cool. Summer 2011 while dry ish was the coolest in about 25 years and basically devoid of heat after the opening days of June. Summer 2009 is remembered by those who only look at statistics as being okay but in actuality it was what we can call a plume fail summer. Basically in June and August it tended to be humid but outside the south east it was barely memorable as the heat would always plume to our east. Summer 2010 is the one people forget most and glorify but in reality June was about as average nationally as you can get and from about the 10th July, summer was basically done north of Yorkshire, August was pretty cool and wet and I recall Scotland recording some abnormally cool temperatures. It gets glorified a little because from mid June to mid July the south east did get a great 25C period but here In Yorkshire the frontal boundary basically just sat north of us so it was a cloudy, humid month and north of us completely forgettable. Essentially a summer of 2 halves but with the first half at maybe 6/10 only nationally. So basically very poor summers generally with perhaps only summer 2009 trying (and failing) to produce something consistently warm.

It was very much a southern thing was 2022 before August. Somebody who lives in Manchester and London on here was illustrating earlier last year how the maxima in London were indicative of a proper 2 week 25+ hotspell basically making it a summer of two halves however in Manchester (and it fits with my own memory here), we basically had 2 hot days and 3 or 4 warm days scattered in tht two weeks. August 2022 was more national, probably because it was UK/Scandi High based.

Small changes from the Euro that May have been missed. So firstly the low on the 19th has a bit more negative tilt delaying the breakdown an extra day to the 21st. The low is also weaker. Then the second low instead of zipping north east, moves south east. The crux is that while we end up with a +AO, there’s enough amplification that high pressure keeps everything north of most of England/Wales. So as I said yesterday, don’t be shocked if the outcome is much more high pressure influenced than zonal.

Speaking for here they were not comparable. 2018 was spectacular from May through mid-August. It was dry, it was hot, it was sunny and only in mid-July to mid-August did we see humidity become an issue. It even had spectacular storms here in late May and July. 2022 here was meh until 2 hot days in July. We then finally got a hot first half to August and warm afterwards until about mid-September. In terms of duration we probably only have 2003 that compares to 2018 albeit 06 and 95 had stonking 60 day or so periods that were perhaps better. Would probably put May-June 18 just behind June-July 06 myself but I was too young to remember much from 95 and 97 (don't think 03 was comparable). For me I'd actually say that July-August 22 ranks behind July-August 13.

While not good it’s worth saying that the GEM and GFS keep some vortex separation which may suggest a better chance of a pressure build outcome even if a Euro/Sceuro High.

I prefer my summer to be May-July as per 2018 or 2006 so last year was quite good on the heat front albeit the low pressure spell afterwards was much too humid unlike recent summers with a poor back end.

27DEC2023: Nino3: 2.1 , Nino3.4: 2.0, Nino4: 1.4 03JAN2024: Nino3: 2.0 , Nino3.4: 1.9, Nino4: 1.4

GFS and GEM basically have two much interaction with the tropospheric lobes near Greenland. Euro keeps these seperate throughout. In theory, modelling tends to weaken lows closer to the time which suggests less interaction but that is not guaranteed.

Yeah, coldest two week period since Dec 10 i think.

Coolest first half since 2018 appears likely. More difficult to say what the end total will be but we have two large landing zones. 3.3-4.6C is the coldest Jan since 2021. 1.6-3.2C is the coldest Jan since 2010.

The eruption theoretically produced more water vapour which can fall as snow in winter. One of the ice age cycles is basically the northern hemisphere getting more solar radiation, becoming warmer and generated more snow. Theoretically the impacts can last a few years but it's one of those things you need to measure each to establish the decay rate.

Recent averages have skewed the expectation of August. Historically what we have seen is a bit wetter than expected but closer to the historic norm for August. We also had a string of warm August's between 90 and 04. Last summer was actually quite thundery hear. Indeed, we've had a good run of thunder since 2017 here. Not sure if we had a notable event in 2022 but can recall every year aside from that. It may just be that this. I'm suprised you got nothing notable in 20/21 as i remember a string of storms from the SE to the NW. August 2016 was a pet hate month here. It was humid and dull much like July 10. Presumably, we were around the mean frontal boundary.

I'd basically prefer summer 11 to repeat. That was wonderful for the lack of heat and humidity. But If we must have a hot summer then it needs to avoid humidity. June 18, July 13 and I suppose August 22 would be acceptable.

Starting to get very excited for around the end of the month. The second SSW attempt whether it fails or not will have its peak impact in the final third of the month as weak zonal winds downwell into an already weak environment. Meanwhile, we have kept a much more robust tropical cycle and around the 25th will enter the traditionally better locations. The combination is such that as we end the month then both of these factors may well provide an exceptionally strong basis for a significant -AO period and subsequently, our best chance at a stonking cold spell atop an already likely cool January.

Yes, I was speaking from a heat point of view. I personally would love a 07/11/12 repeat.

Good to see the thread up. Just on this point though, it's important to note the difference between flip years and stable years. Years with La Nina to El Nino flips appear to produce good summers disproportionately, stable years do not. Years which start and end with positive ONI are.. 1953 1958 1969 1977 1987 1991 1994 2003 2004 2015 2019 Compare this to years which start negative and end positive with ONI. 1951 1957 1963 1965 1968 1972 1976 1986 2002 2006 2009 2014 2018 2023 You can see here that the rate of 17C+ months is about the same at ~40% of each summers producing at least one 'hot' month however you can also see that the infamous summers of legend are very much in the flip set (76, 06, 18). 2024 is either in the stable set or the Nino to Nina set and i don't think you need reminding that the later is not often good.

I'll admit that my hopes were raised last night by the Euro but I'll remind you all of two days ago when I said that arguably the biggest combined impact on any downwelling zonal wind weakness and progression of the tropical convection is likely to be around the 20th. What we are seeing now is more the lagged impact of MJO movement during December. Moral of the story, we may need two or three bites from a UK high cherry but the medium term signal is likely to get better rather than worse as the month progresses. To keep a bit more on topic, I think the Euro is a good shout.

An official SSW just means that the vortex is sufficiently displaced or split to generate mean easterlies. Essentially we are still getting the thump and enough of one to split the vortex, just not one that will knock the main vortex chunk away enough to count as an official SSW. So same thing, just technicalities.

Winter 2006 was cool and dry throughout after mid-November. Not sure April was snowy either. You may be thinking more of Winter 2008 which was zonal and then had a cool spring until May.

2015 and 2012 were the other cool ones (6.2).

7.4 5.5 2.4 - 2021 7.5 5.7 4.8 - 2018 5.2 5.1 6.2 6.2 4.7 - 2013 6.2 5.2 -0.2 - 2010 Took a look at the first halves to Jan given the cool outlook be that UK High or Scandi High. Not many cool first halves means it's not difficult to rank well although we are unlikely to surpass 2021.

Euro tonight has moved to mid-latitude ridging from day 6 onwards. Not entirely surprised and the vortex while weak, will take a while to push down the main thump from the attempted SSW even if it’s failed (tropospheric vortex is much less hostile to weakening than last year so I don’t think it matters that it’s failed - Euro indeed does split to 50hpa). The combination of downwelling weaker zonal winds and the location of tropical convection could produce an exciting second half. Moral of the story, we may need more than one bite of the cherry but I think we go from a U.K. high to something better rather than worse.

5.6, 91mm

See the post just above yours, yes. With 14 out of ~300 years of records it's about once every 25 years.

The Jan spell was almost definitely the SSW response. The timing is about right and you can see even on the European archive that there's a -AO which develops, just not near Greenland as much. We also saw a very blocked February around the UK which is again very common in weeks 3-7 for the UK after a SSW. The stratosphere was not especially weak during Feb/March which suggests it wasn't directly responsible albeit the tropospheric vortex may well have still been shredded from it. It's not a radical change in the overall forecast, comparing the charts it looks like we've simply lost the very deep SSW forecasts and so the mean has risen a little higher. We are also seeing the warming right now so it's perhaps a little weaker than expected.