summer blizzard

Is this hail or is this snow because it looks and feels like snow.

Sun Chaser Sadly I think its easier this time of year. April 09 was a cloudy and humid month here. March 17 and 24 were both unexceptionable. All have very warm CET's such that people probably won't question them in a few decades. July 22 is another example, for Yorkshire and Manchester barely more than a 2 day wonder.

In our hunt for an anticyclone it's worth saying that the Euro0z had 1020mb+ over the whole UK from days 7-10.

Before anybody gets overly excited it's worth remembering that the AO values are normally close to neutral in summer and that +/-1 months are rare. The polar vortex is net easterly regardless of what happens until late August.

Summer8906 I would hesitate to put 2022 on that list. The others produced nationwide summers, while by the time your as far north as even Leeds and Manchester, July 2022 was mediocre outside a handful of days. The two week spell was restricted to the south unlike the others. August 2022 was worthy of course but an individual month.

May 2020 was delightful and the trees here in full leaf.

03APR2024: Nino3: 1.0, Nino3.4: 1.2, Nino4: 0.9

raz.org.rain Sub-surface anomalies are pretty nuts currently so as soon as they surface we are going to see a stonking fall. We are likely go beyond -0.5 between July and September based on pacing from 1954, 2007 and 2010 which are good matches overall (a little ahead generally). 1959, 1966, 1984, 1993, 1998, 2003, 2016 and 2020 finished Q2 neutral after Nino events finished. 1998, 2016 and 2020 did move to La Nina by the end of Q3.

I think that any comparisons with 2007 thus far are likely to be coincidental (and not really true in weather type). In 2007 the Nino collapsed after January and SST's were already negative by April. In Feb-April the low -AAM suggested by the collapsing SST's (strong trades and possible atmospheric coupling) actually does tend to produce a somewhat anticyclonic response (for reasons beyond me). Our Nino is still hanging on with a WWB progressing over the next week or two likely to mean that our first collapse attempt won't occur until at least May (although sub-surface SST's are -5).

B87 A lot of synoptics from April 21 would result in a different temperature profile. April was still early enough that a slight inversion was present. The 1st-4th would likely feature a high durinal range and temperatures close to average. The 5th-12th would be quite cool but potentially damp with a stronger sun to spark showers. The 13th-19th would feature a west-east split but generally products temperatures close to or above average. The 20th-26th would draw mostly south easterlies and be warm. The 27th-30th would be cool and damp or even wet. So the first 12 days may be on the cool side but the 13th-26th would be warmer than average securing a warm month.

I suppose the bigger question then is what percentage of April's have a second half cooler than the first. Much like March there's certainly nothing forecast in terms of anticyclonic weather that would make it worthy.

Excited though we are getting, years like 2007 and 2020 did go off the boil so I think we should avoid being too bullish.

damianslaw It may be a local bias however while growth was advanced, most trees appear to have stalled. It is the grass and flowers that are proceeding at pace.

One interesting observation this spring is that as a result of the depressed sunshine and to a lesser degree maxima, while they got a very early start in late Feb, the majority of trees are still barely budding. It's the grass and flowers that seem quite happy. I was looking through my photos and contrasted to this day in 2020 when i had a full park of blossom, it was quite stark.

20MAR2024: Nino3: 1.0, Nino3.4: 1.3, Nino4: 0.9 27MAR2024: Nino3: 0.9, Nino3.4: 1.0, Nino4: 0.8 March ONI fell to +1.2.