Jack Wales

I’m surprised to see such a downgrade in the upcoming northerly at such close range. This looks to be the result of the highly amplified polar vortex and short wave toughing to the west of the UK. Consequently the -10C (850hpa) isotherm only reaches mainland Scotland for around 24 hours before being quickly toppled by the Atlantic. As for looking further ahead, the strength of the polar vertex and the fact it’s anchored around Greenland reduce the opportunities for cold across the UK. Especially when you look at the atmospheric thermal gradient off eastern Canada and the Atlantic (-20C to +15C at 850hpa), which will ensure a highly amplified jet stream. Just look at the sub 960mb lows forming off the Canadian seaboard. If you couple these factors with a blocking Euro high, then the result is a very warm fetch southerly across the UK and western Europe. Don’t be surprised to see temps hitting the 60’s (F) next week in some parts of the UK. On a different note, good luck to those living in Shetland who should have a wintry next three days ïŠ

Cool at times to start but gradually getting milder from mid month... 3.9°C

very mild... 8.9c

Still can't stop laughing!! Classic quotes from that vid... "6ft of snow on high ground" "-28C" "there is going to be a low pressure looking to be around Christmas time" "That's because the tilt of the earth is going to be more forward than last year" "The jet stream is not keeping up with the motion of the earth" "The jet stream fights off low pressure coming in from the west" "i just call 'em bubbles becasue I don't actually know the names for them" Typical, he has to be welsh as well!

very mild start, average finish... 11.5C

late again... 14.0c

oops one day late.... my punt... 17.0C

16.5

Warm dry start with a more unsettled finish to the month however night time minima should ensure a warm cet.... 16.1 C

Hi BFTV, Yes, the CPC have been forecasting ENSO neutral for a while now, however I can't help but feel they're underestimating the potential for La Nina. A visual observation of the Pacific is clearly indicitave of a developing La Nina, which is backed up by increased negative anomalies across the ENSO Zone... ENSO 1&2: -1.6C ENSO 2 -0.5C ENSO 3 -0.1C ENSO 4 no anomaly As I say, the longer the low level easterlies remain in place, the more scope there will be for the negative anomalies to propagate to the key 3.4 region. However MJO activity is on the rise and tropical convection is projected to emerge in a pattern consistent with MJO phase 8. This (to me) suggests a greater possibility for scrubbing of the low level easterlies by the end of the month as the atmpspheric pattern is not (yet anyway) consistent with La Nina. It's definately on a knife edge at the moment with some conflicting signals but I believe there is more reason to be hopeful for more 'summery' spells this summer. I'll try and spend some time on this over the weekend and hopefully post something more substantial.

Just thought I’d post some quick thoughts in here with summer now very much on the horizon… Following on from my recent post in the ‘Summer’ thread, the northern hemispheric pattern appears to be reflecting the recent ENSO neutral and positive AAM pattern; this combined with increased MJO activity and the recently favourable Atlantic SST profile should teleconnect with a northerly displaced Azores high with heights / ridging towards Scandinavia. This type of pattern now falls into the modelling timeframe and with the PV finally diminishing; this type of pattern is being picked up from around T+204. This chart at GFS T+324 shows the kind of synoptics which should set the scene for late May and into early June with heights ridging up from the Azores… http://cdn.nwstatic.co.uk/gfsimages/gfs.20130516/00/336/airpressure.png This is also reinforced up by the surface heights ensembles with the mean levels forecast at around 1020 mb from around T+240 onwards…. Going forward into late June and the rest of summer, I have some concerns in that the ENSO pattern is trending to more negative tendencies (La Nina) which would be less conducive for settled conditions over NW Europe. Here are the latest SST’s where you can clearly observe the negative anomalies propagating westward towards Nina 3.4… http://weather.unisys.com/archive/sst/sst_anom-130512.gif The eagle eyed may also notice that the Atlantic SST profile is not looking quite as favourable as it was just a couple of weeks ago. There are no signs yet that the atmosphere is starting to re-embrace La Nina, e.g. one of the firsts indications would be for Total Angular Momentum to plummet to negative values, whereas at present the latest AAM data is still positive... http://www.esrl.noaa.gov/psd/map/images/reanalysis/aam_total/gltotaam.sig.90day.gif If the upper level westerlies can filter down and scrub the lower level easterlies currently prevalent over the equatorial pacific (and assisting the ENSO- trend), this could halt La Nina in its tracks. An amplified MJO could also help facilitate this, so in my opinion the next couple of weeks could be crucial in terms of what the building blocks for this summer will be.

Sorry pjl, I was being sarcastic (which I realise is the lowest form of wit!). Pws / Vantage are imo produced directly for the media however this forecast is unusually benign. I bet the daily express are furious! The fact that they never provide any detail behind their forecasts also gives the impression they've been plucked from the air!

I'm sorry to hear GP has left. I'll miss his posts and he will be a loss to NW. Good luck to him though in his new role. Ha ha lol, just when I thought all was lost, I'm now cautiously optimistic for summer... dust off the the bbq!!

This summer is going to be very difficult to predict due to conflicting signals. Whilst there is the ongoing sign for northern blocking (and subsequent southerly tracking jet = cool & wet for UK), there are also tentative signs of something more settled. I don’t buy into the recent debate that the summer season is a write off if early June starts badly. As I recall the first week of June 2003 was very unsettled and windy, the rest of that summer speaks for itself. June 2006 started cool and northerly with ground frost but that led on to an even better summer than 2003 (here in the west anyway!). Although we are currently enduring an unsettled spell, predominantly due to the still active polar vortex over Greenland, the models are indicating that the stratosphere will finally disperse the vortex towards the end of the month. Historically this kind of pattern (spring monsoon) has tentative links to a weaker summer jet stream and a more settled summer pattern over NW Europe. Another factor is that although we are currently in a northern blocked pattern, the overall signal for northern hemispheric base state is (as I see it) less aligned to La Nina than some recent summers. There have also been indications recently for slightly stronger heights over the Azores with a (albeit weak) tendency to ridge towards the UK. SST’s imo aren’t looking great but are not disastrous either. The current ENSO pattern across the Pacific is neutral. Therefore other factors such as MJO activity and Angular Momentum could play a more significant role in the summer weather pattern. The one fly in the ointment is the potential for La Nina development. Cold anomalies can clearly be observed in the east pacific (ENSO regions 1, 2 and 3 which are starting to propagate westwards). Crucially the anomalies have not reached the ‘key’ ENSO area 3.4 yet and with a positive QBO phase developing, this should help build more ‘westerlyness’ into the upper atmosphere and inhibit any further development of La Nina. I’m less inclined to rely on Atlantic SST’s so much as they often change quickly but the current set up (with a warm over cold anomaly in the mid Atlantic around 45 deg north) is indicative of a northerly displaced Azores high and NAO neutral conditions. Although this would seem to indicate the jet toppling over the hp cell and towards the UK, the long range models are also forecasting heights over Scandinavia. Therefore, as there is a potential for a weaker jet stream, there is more scope for ridging between the Atlantic and Scandi highs, thus providing greater opportunities for more settled conditions over the UK this summer. I’m not saying it’s going to be a scorcher by any means but at least there should be some dry settled spells. I’m going to stick my neck out and say that June and July will be the best months. I'd welcome an opinion from one of the 'experts' on here to see what their thinking is as I could be way of the mark!!

A cool but fairly dry month. Northern blocking will be prevalent. Best of the sun in the north perhaps. My estimate: 10.9C

8.1C please

Mild to win through.... 6.1C

Cool at times but no sustained cold, my bid... 4.0°C

The first showers appear to have hit the Llantwit area although these appear to be of rain. The front should widen as it hits the colder air thus increasing the temp inversion. Most of se wales should get some ppn out of this, I think it's going to be marginal but above 100m you stand a chance of lying snow.

A good six inches here, still snowing and blowing heavily!

my last post before bed... Temps dropping like a stone here in Tonyrefail now down to 0C, here is a selection of others... Cardiff 3C Cwmbran 2C Ebbw Vale 0C Llanelli 3C Swansea 2C Usk 0C Goodnight all zzzzzzz

Everything turning white now, snow starting to stick, air temp down to 0.9C........

Blizzard in full swing, temp down to 1.4C DP now down to 1C, what a sudden drop. All we need is for the snow to start sticking, need that dp to get down more!!

Latest air temps from around South Wales Swansea 3C Tonyrefail 2C Cardiff 4C Saundersfoot 2C Cwmbran 2C Ebbw Vale 0C Nantymoel 1C General trend is temps dropping away, is it just evaporative cooling or has the undercutting started?

What a difference 10 minutes makes, temp dropped 0.4C and wait for it.... BLIZZARD conditions outside!