summer blizzard

7.3C, 74mm. High pressure to the east, low to the west. Probably more potential for warmth than cold given that it's rare to have a March cooler than Feb and Feb was mild enough that to be warmer is actually quite warm in March. Not especially dry as we may see an undercut attempt or two.

B87 I'd keep March 12. I'd swap for April 07 (it felt a much more impressive month though I'm not sure if that's bourne out by maxima and sunshine). I'd keep March 20. I'd swap for June 18 or 06 (the final third of last June was horrifically humid). I'd swap for July 13. June 18 became humid in the second half. I'd keep August 22.

Better down welling as we head towards mid March on this one. https://twitter.com/MetRyan96/status/1761082180615221332?t=6IU6Ui2A0UAqr3Bc4XD5ZQ&s=19

raz.org.rain The theory goes that flip years are disproportionately bad because of tendancy but like El Nino flip years (including 76, 06, 18) it doesn't guarantee the outcome. The link is far from clear cut here. It may be worth splitting flip years by strength. Years that made it to weak or neutral cold by years end are 1954, 1964, 1992, 2005, 2016. Years which made it to moderate are 1970, 1973, 1983, 1988, 1995, 1998, 2007, 2010. Only applicable if the year started as El Nino and ended south of neutral. Pace may also play a factor. Years which saw a declared La Nina before July were 1954, 1964, 1973, 1988, 2007, 2010. Years which saw a declared La Nina after July were 1970, 1983, 1995, 2005, 2016. Would need to check the stats properly but it looks to me like pace may have more impact. The years which develop slower are the warmer summers from memory.

14FEB2024: Nino3: 1.5, Nino3.4: 1.5, Nino4: 1.1

LetItSnow!

Does anybody have the NASA link to see each winter at each atmospheric level.

SSW now looking much stronger.

In terms of my own Q2 thoughts; QBO - Likely to be easterly and weakening given that we have already passed -1.8 for January. Years with 2 Q2 months below -1 (and at least -1 in April) are 1982, 1984, 1987, 1992, 1994, 2001, 2010, 2012, 2018, 2022. PDO - Likely to remain peristently negative given that it has blown through this Nino untouched Years with all 3 Q2 months below -1 are 1991, 1999, 2001, 2002, 2008, 2012, 2021, 2022, 2023 ONI - Likely to weaken but remain positive given that we still hold moderate to strong raw ONI values. Years retaining positive Q2 MEI values are 1980, 1983, 1987, 1992, 2005, 2015, 2019 As you can see, since 1979 (limited for standardised QBO values), there's not really a Q2 ONI-PDO match. Since ONI is probably the most important of the three, i would put 1987 and 1992 as primary anaologues but 2001, 2012 and 2022 as good secondaries. April - CET range is 7.7 to 8.7 when excluding the warmest and coolest. Mean is classic Atlantic High, Scandi Trough May - CET range is 11.8 to 13.1 when excluding the warmest and coolest. Mean is Atlantic/UK High (perhaps suggesting that the April pattern relents as the month progresses). Warm second half? June - CET range is 13.5 to 14.9 when excluding the warmest and coolest. Mean is a Greenland High and southerly tracking Jet Stream. For interest and because it's a spring thread, i did apply these analogues to March. March - CET range is 5.2 to 8.0 when excluding the warmest and coolest. Mean is Atlantic Low, Scandi/Russian High.

. Editing

Rain All Night Standard Nino stereotype. Cool March, warm May.

Rain All Night 2016 saw the earliest final warning on record in mid February (also a strong Nino so It would be interesting to check dates). So in theory the initial impact should be similar to a normal SSW and the duration should increase the chance of downwelling (so possibly bad for those wanting a warm March) but by April it will essentially encourage a weaker tropospheric response (be that blocking or westerlies) and the kind of more stagnant patterns that we normally see in spring and summer (good or bad). So in short, you might not notice it all that much outside the initial impact but we probably see a less mobile pattern and one that for good or bad is increasingly stagnant, this just starts earlier than it would.

To answer my own earlier question regarding the SSW currently occuring, it looks like almost no impact here with another reflective structure but even less kind. We actually see the tropospheric vortex strengthen around months end. Euro still goes for what is likely an early warming afterwards.

For stable temperature your best idicator is probably to be close to the center of a high that breeds its own uppers over time albeit even then you risk at least one or two cool days as another high attempts to reinforce. The 1st-4th August 1990 is a good example although the first 12 days of June 2006 was also a good example.

Final warming anybody.

07FEB2024: Nino3: 1.6, Nino3.4: 1.7, Nino4: 1.3

Catbrainz I don't think we can solely blame the El Nino because MEI values suggest its actually not been terribly well coupled outside the tropics and indeed, we have seen a weaker than average stratosphere which normally corresponds to cooler and drier weather. We did see a pronounced +IOD event which typically produces cyclonic weather at our lattitude but that weakened so i don't we can blame it for this month. In truth i'm simply not sure. It may be as simple as water vapour from Hunga Tsonga and the solar maximum but there may be other things we are missing. It's certainly not what i expected.

I would not compare this month to Dec 15 albeit mild. I do wonder if any winter has recorded two 7C months before though.

Euro is solid around the 19th albeit its downwelling we need.

SqueakheartLW Do you have an updated U Wind anomoly chart so we can see how quickly the SSW is likely to downwell.

If there's an impact from the SSW quickly then it will be felt in the final third of Feb and first third of March. So yes, a good chance of a cooling month albeit we can't price in proper cold at this stage so well above average appears likely.

Yes, reasonable chance of a proper SSW in around ten days. Late Feb/early March most likely to feel the impact.

Snow has surprisingly survived. Tally for the winter so far is now 5 events, 8 days of lying snow. Maximum depth was this event at 7cm.

Can our Sheffield contingent tell us if it's rain or snow the second band early on.

Measured 7cm just now so an average just under 1cm per hour.