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It's that time of year again time never stands still; last summer seems a distant memory, forecasting this summer presents particular challenges. The teleconnections or signals atmospheric/oceanic which govern the weather we see, are not particularly strong and are conflicting with one another. In contrast to exceptional summer that was 2018 in which the blueprint for the summer began in May and continued well into August. As such all forecasts should be treated particularly cautiously, as possible scenarios, a lot can and does change in season after all this forecast is a breakdown and analysis of current state of play. Of systems which are fluid. This summer we are set to experience a weak Nino and neutral to positive PDO these parameters help support fine, warm weather nonetheless they are not particularly strong, which may weaken their positive influence. As such one should not expect a washout summer which is devoid of lovely weather like 2007 this does not present itself; however there is likely to be cooler and unsettled weather punctuated through summer. This will give rise to thundery outbreaks which 2018 disappointed in that department.


*Not a poor summer but not a great one either **


Summer 2019 forecast summary


Temperature: near average most likely to fall within 0.5 both -/+ of 1981-2010 average

Precipitation: normal to above 

'Middle loaded although extending into August'


June


June is rather likely to experience wetter than average conditions with persistent negative AO/NAO state (high pressure across pole, lower pressure in mid lats affecting UK and Ireland) probable pronounced by the current second lowest sea ice extent on record & low solar. Furthermore, the Atlantic SSTs are not particularly promising with it possibly reflecting in storm track perhaps being further south than usual and subsequently lows steered our way. The start of summer has seen suppressed convection in Pacific atypical and typical in La Niña state there are encouraging signs later in the month, we may see a reversal. Taking a more Nino signature which we should be seeing, this is good as 2007 and 2011 (washout summers) both featured strong La Niña which reinforced a very blocked pattern not conducive for longtime warmth. This expected uptick will have corresponding effect of ridges of HP being able to truly take a foothold so while I believe much of month will not be particularly warm or settled, there is a good chance of something much more along those lines late in month while also not being a fleeting affair.


Temperature: below average 

Precipitation: above average particularly in N/W


July


Confidence truly slips away at this period however if expected uptick in tropical forcing happens later in June there is broad expectation July will be largely anticyclonic and warm. Everywhere particularly in the south and east in which it may turn hot at times although nothing overly unusual in a typical summer. At least in the first half of the month widely, and I do believe it is more likely to be the warmest month of the summer. Overall through this month this warm weather may be punctuated by cooler Atlantic air, this will cause thundery outbreaks and rain, so indeed a better summer for those storm 'chasers' out there? It may be a month which has a pronounced E-W split with Atlantic trough backing west however perhaps not enough for Ireland in which I feel summer could be particularly wet and cool.


Temperature: warmer than average

Precipitation: near normal large regional variance



August


Confidence is very low and therefore not much detail can be provided however, it is probable warm summery weather will feature with a greater chance perhaps in first half. There is some signal for a more La Nina signature with a decline in +ve Nino state to neutral verging on La Nina later in the summer this would mean the summer is not likely to finish particularly well. There is also good expectation in conjunction sea ice may be in a truly disastrous state with lowest sea ice extent on record. This could give aid to give rise to return of extensive northern latitude blocking seen early summer, which is why we are currently locked in an unsettled pattern. With increased westerlies seen with seasonal change August could finish unsettled although much of month may be pleasant beforehand.


Temperature: above average generally

Precipitation: near normal


Thanks for reading I sense this summer will help alleviate drought fears a respectable summer it is looking.


Dan

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As the clocks have gone forward unironically the weather has sort of gone backwards; with polar air moving south across UK and Western Europe. Courtesy of stronger sun which is now comparable strength to late summer, we often see in spring, 'April showers' the surface heating from the sun, causes air close to surface to rise as less dense than cooler air this condenses into shower clouds Cumulonimbus. Often days with long sunny spells in Spring and Summer, can be interrupted into afternoon as heating of the day peaks and we see sharp and brief torrential showers. This will be the story over the next few days.

A rash of torrential showers with hail/thunder poss across S/SE England Wednesday PM

Distinctive towering Cumulonimbus



Overnight tonight there will be a widespread air frost across UK and Ireland a cold night for April however not unheard of.


Do watch out for icy patches first thing following showers of today.

Minimum temperature at 0600 Wednesday widely freezing temperatures

Into tomorrow we see low pressure offshore east coast of Scotland back west and very slowly move SSW down Britain this will bring organised precipitation with weather fronts to Scotland and Northern England with significant snow for hills as much as 20cm possible. Most of the country will see a continuation of sunny spells and showers, some lucky areas may avoid them altogether the greatest risk areas will be in the south and east.

Following a showery regime another cold night with icy stretches possible for central and northern areas a little less cold in the south and east. Into Thursday, again a rather similar picture with a continuation of sunshine and showers these are possible anywhere. With a rather gusty wind it will feel particularly cool on already cool temperatures.


From Friday we see the beginning of a change with temperatures recovering nearer to normal with rain limited to west although remaining blustery with a cool wind off continent.

Into weekend it is looking dry for many however a slight chill with easterly flow this could result in cloud bubbling up for areas in east England close to the North Sea; with brightest and warmest conditions in the west.

Into the new week a continental flow will continue as it is April it will not be as remotely cold as it would have been in winter months - we would have seen very cold conditions from this then. We may see lows come in from east off North Sea which may bring organised rainfall most sheltered areas being those further south and west, likely not nicest of weeks in east with Stratus cover possible a persistent feature with cool sea.


Further outlook: Very uncertain nonetheless the first half of April is very unlikely to bring anything warm with a southerly tracking jet stream deflected south by regions of blocking (high pressure) to north. I do sense it may be quite a struggle this month, however greater chance of drier and warmer conditions in the second half of April, perhaps it will not be May or late April until we truly see the weather settle down and lose its changeable nature.

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First of all I'd like to apologise for the lack of content that's life for you, but let's just get into it; this blog post will look at spring-like conditions this week and beyond with these conditions unlikely to hold, is winter finished with; or is there a sting to its tail? Read on to find answer. After a lacklustre winter promising so much background signals et al, although, I'm sure many in Southern Central England enjoyed witnessing biggest snowfall since 2010 despite no impressive cold and in situ and of NW origin. Attention increasingly draws to Spring; easter bunnies and all that shenanigans with gathering warmth of sun's rays for many comes as a relief as we move away, from often, dark and dreary season that is winter.


After a very unsettled period of weather in which we were bombarded by low pressure barrelling across Atlantic with only second named Storm Eric which brought widespread gales and drenching rains, although rather tame. In contrast winter 13/14 had over twelve major wind storms, notable has been clear absence of stormy weather courtesy of subtropical ridges from Azores extending unusually north. With polar jet shifted to north of UK and has derailed several easterly cold spells despite macro-pattern being good.

Storm Erik approaching the British Isles at 0600 UTC 07/02/18 imagery from Meteosat-SEVIRI

After a rather cool feeling Monday with a weak northerly airstream, we lose the chilly wind with Azores high poised to move in imminently, cutting of chilly flow with positive heights anchored over Central Europe this week. Bringing the first unseasonably mild conditions of 2019 to Europe most anomalous mild conditions to be seen in northern Europe on Friday GFS has 850hPa temps this is roughly 1500 meters up, 16C above norm in south of Finland.


This ridge of high pressure will introduce much 'warmer' airmass however will not remotely carry characteristics of a 'Spanish plume' with southerly winds prevailing this week. In summer time temperatures would have soared to low 30s in south of England alas it is far too early for that. However, there will be plenty of sunshine in which it will feel quite warm across England and Wales but do note early in day likely to be chilly with frost risk. Generally temperatures will range from 11-13C perhaps 14C in the capital. Areas further N and W Scotland, NI and Ireland will be more vulnerable to cloud and drizzly conditions with more of a moist southwesterly component. The foehn effect is likely to result in highest temperatures in mountainous regions of North Wales and North Scotland where a localised 16C is achievable. The peak of this mild spell countrywide is expected on Thursday.

Although do make the most of it this proper taste of spring is unfortunately expected to be fleeting, a breakdown from W will initiate on Saturday first across N/NW parts and by Sunday all areas will be subject to a more cyclonic westerly flow. With much more in way of cloud and temperatures nearer to seasonal norm although still quite mild perhaps it won't feel it.

The expectation into next week is for weather to start more unsettled with the spring-like conditions of this week a far cry although by no means is a wet period being signalled just less in the way of high pressure. Something which has grabbed my interest is current sea surface temperature anomalies (SSTs) through Atlantic basin; this winter, waters south of Greenland have been cold. This has recently reversed there are papers which show a greater correlation with -NAO with above average SSTs in this region, this means an area of blocking high pressure to north of UK which deters milder airflows and more often than not UK can see colder conditions, notably so in the case of 2018 infamous beast from the east. What's been notable this winter is clear lack of -NAO despite background signals/NWP suggesting otherwise. I would say there is great scope going into March for a wintry pattern -NAO pattern, although be aware of a lesser significance than mid winter. Furthermore what can be drawn, it seems going into spring a greater emphasis for a more southerly tracking storm track/ jet stream this is not good if you are after settled Spring.

I am of the opinion the weather will turn more settled mid week so a short period of wet and blustery weather for NW parts especially. With another blocking high likely to fill in vacuum but this may bring decidedly different weather at first it may be mild but it is conceivable we could see a cooling trend. A blocking high to north/northeast has been glanced at NWP and does reflect with pacific forcing which has an influence on our weather, MJO phase 8 this is a cold blocked phase for NW Europe the below chart is representative of what's possible.


Low risk for now but the possibility of drawing in much cooler east winds in final week of February into March. I do see a cold spell in next few weeks certainly not forecasting something exceptional, although with a chance of settling snow possibly anywhere. Atlantic intrusions may deliver more substantial snow to lower levels. I do not think winter is quite done with us even if it seems it never turned up.....

In recent years spring has testified winter weather can easily strike in this transitioning period from winter to spring. There are roughly 3 to 4 weeks remaining in which widespread swathes, can see a wintry pattern you may be fearful to know and indeed it is premature to say winter is over. Although a sizeable chunk of mild weather to get through first if so. We may have passed the point of temperatures remaining below freezing and continuous lying snow cover away from high ground. The arctic itself is its coldest early March its time of year where we see maximum arctic sea ice extent. Well into spring northerly airstreams can be potent exemplified in 2016 the capital had some flakes at end of April some of the latest snow I can remember, with the frequency of E/N/NE winds is greatest in spring it's not so surprising. And I wouldn't be so surprised if we winter has a final encore.


Cheers,


Dan

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