New Year’s Day snow potential


First thing’s first before we go any further, I would like to wish everyone a Happy New Year! I hope 2017 is a fun and prosperous year for you all!

This week the models have been hinting at the chance of some snow to open 2017. Well if you like snow, then I’m sorry to say that unfortunately for you the models have slowly backed away from this idea over the last 24 hours. Saying that, if you live at higher levels there is still quite a good chance that you may see some of the white stuff this afternoon.

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Rainfall chart for 10:45 on New Year’s morning. Blue indicates rain, green indicates sleet/wet snow (chart courtesy of Netweather).

From the rainfall chart above you can see that over higher ground, the rain band is beginning to turn wintry as it heads south-eastwards across the UK. However, I mostly expect this wintry potential to stay over high ground, as I explain below the two charts.

From the charts above (click to enlarge), we have one of the main parameters for forecasting UK snow in place – that is the -5°C isotherm at 850hpa (approximately 1.5km above the surface). This is in place from the Midlands northwards, so this would indicate that snow is likely for these areas. However the bad news is from the second chart – the dewpoints are above freezing for most places underneath the weather front. This would therefore make snow unlikely for lower ground.

All in all if you are above 200m, then there is a good chance that you will see some snow today. This may even be enough for a bit of a dusting. If you are above 120m, there is a chance that you may see some very transient wet snow falling during heavier bursts, due to evaporative cooling. This will not be enough to produce any accumulations however. Anywhere below 120m therefore is unlikely to see anything today.

A significant cold spell brewing for January?


December 2016 has been a predominantly mild and dry month. However for the last three days or so we have had an area of high pressure sat more or less on top of the UK. This has brought some chilly, sunny days with moderate overnight frosts, thus making the weather feel a bit more seasonable for the run-up to the New Year. However, this may only just be the beginning of something perhaps a little bit more wintry in nature…

The current outlook has the weather turning briefly milder for New Year’s Eve as our area of high pressure weakens and loses some of its influence. This will bring cloud and some rain for Scotland and northern parts of England. However as we move into New Year’s Day, an area of low pressure will move from the north of Scotland and down the North Sea, which will move the winds into the north/north-west. This will bring down some cooler air in the form of a cold front, which itself could be rather interesting (more on this below).

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00z run of the GFS for midday on New Year’s Day (chart courtesy Netweather).

As colder air catches up with the rain band it may begin to undercut, allowing some areas to potentially see some back edge snow on New Year’s Night and into the early hours of January 2. This of course will need watching as we get nearer the time and I will update you on this on New Year’s Day itself.

Beyond this little incursion of winter however, is where the models get a lot more interesting. The weather will remain fairly benign and chilly with overnight frost for the rest of the working week, but from January 5/6 onwards, both the GFS and the ECMWF have been hinting at the possibility of quite a significant wintry blast hitting the UK. This has become something of a trend over recent days and it now beginning to arouse some suspicion.

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00z GFS chart for midday on Saturday 7 January 2016 (chart courtesy of Netweather).

The models have the -10°C isotherm at 850 hpa and air of 516 dam or less, blasting down across the country for next weekend on this morning’s runs. This would bring hard overnight frosts, ice days and of course snow (assuming we have the necessary precipitation), therefore bringing the UK its first country-wide cold spell since March 2013. Of course, keep in mind that this spell is still just about in the unreliable time frame of the models, so things could change. Furthermore, the UKMO model is still not on board with this yet, but as it has been a significant trend recently it is worth pointing out as a possible upcoming weather event.

I will of course keep you updated over the coming days, firstly about the potential New Year’s Night snow, and secondly the possible cold spell.

Winter 2016-17 Forecast


This is a forecast for the meteorological winter of 2016-17, issued by Scott Richards on Sunday 27 November 2016. The purpose of this forecast is solely for fun and should not be relied upon in any level of seriousness.

 Overview

This year has seen quite an interesting pattern. April was a rather blocked and cold month, whilst September was a remarkably warm month. This has also played part for quite an interesting and seasonable autumn, but will this follow through to the winter? I will be considering many parameters in this forecast before giving my forecast for each of the three winter months, so I hope you stay with me.

ENSO

Throughout the course of the autumn, we have generally seen ENSO neutral to very weak La Niña conditions prevail. These conditions are expected to continue into and throughout the winter, peaking traditionally in late December. Whilst the UK is almost on the opposite side of the globe, ENSO can potentially have some effects on British weather patterns. There is a potential slight correlation between weak La Niña conditions and an increased possibility of cooler and blocked conditions for the UK during the winter months. This for me, does hint at the prospect of a slightly colder than average winter, especially in the first half.

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NOAA sea surface temperature anomaly map indicating very weak La Niña conditions in the Equatorial Pacific on 24 November 2016.

Long range models

The long range models are the second parameter I will involve. The models have generally seen quite a lot of intra-run variation this autumn. For instance, the CFSv2 has been hinting at a cold early winter, but has now switched to predicting a generally mild and westerly winter. The long range UKMO however, has seen the opposite. The model was consistently hinting at a mild winter, but is now hinting at a cold winter. This indicates that there is no clear signal for the models to pick up so could potentially hint at the prospect of a very variable winter with quickly alternating mild and cold spells.

Quasi-biennial oscillation

The QBO is also an important contributor to a winter forecast, and this year it is by far the most complicated. At the end of last winter the QBO began its transition back into an easterly phase, however this was shunted very quickly and a westerly phase was soon reinstated. This phenomenon is entirely unique and has not been documented or recorded ever before, and thus makes forecasting much more complicated for this winter.

As of current, a westerly QBO is expected to be prevalent for the winter of 2016-17. This has the effect of enhancing the zonal westerlies across the northern hemisphere, therefore making the North Atlantic oscillation more positive. In effect, this therefore increases the probability of a milder than average winter for the UK.

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QBO index chart from the University of Berlin, indicating a westerly phase (grey) for the winter of 2016-17.

Solar activity

Solar activity is the fourth and final parameter that I will analyse before presenting my forecast. Currently solar activity is decreasing after solar cycle 24 reached its maximum in early 2014. Over the next few years, solar activity is and will continue to decrease until the next solar minimum in 2019. As of late November, solar activity is designated as “very low.”

Low solar activity is potentially an important forecasting parameter, as it is believed to increase the chances of blocking over the Arctic, and thus an increased possibility of colder conditions for the UK. As solar activity is currently very low, this bodes well for those hoping for a colder winter. One caveat however is during a period of decreasing solar activity, minor increases in activity can happen quite frequently. This can therefore affect the chances of blocking quite significantly.

Monthly break-down

Here, I will now present my forecast for the winter of 2016-17 on a month-by-month basis.

December

Out of all three winter months, I am forecasting December to hold the best chances of colder weather for the UK. It appears as though this month could actually be a very anticyclonic month, with an area of high pressure centred quite close to the UK. Of course at this time of year, this would produce cold conditions at the surface due to temperature inversions. This means that many parts of the country will see a fair amount of frost and fog this month. Furthermore, this means that I also predict the month to be rather dry.

It is also worth noting that there is a chance that this high pressure system could possibly move westwards out into the mid-Atlantic, on some occasions. This would have the effect of bringing a northerly wind down across the country, which could increase the chances of snow and harder frosts, even for southern areas of the country.

January

I am forecasting January to be somewhat of a transitional month, with colder conditions being more dominant in the first half, before more of a milder Atlantic flow increases in the second half. In terms of individual weather, this means that this month could actually be very varied. There is the potential for some cold and snowy weather early on, followed by an increased chance of more stormy weather later on. I expect temperatures to overall come out very near to average, with northern areas being more prone to colder conditions and more southern areas being milder. Rainfall, I predict to be very near average in eastern and southern areas, whilst northern and western areas will see the wettest conditions.

February

Obviously confidence does naturally fall away for later in the season, but as of current, I am expecting February to be the mildest of the three winter months. Here I expect any UK blocking to collapse into Europe and for a predominantly west-to south westerly flow to set up nationwide. In February I expect both temperatures and rainfall to be above average especially for northern and western areas, with south-eastern areas seeing the driest conditions, closer to the Euro high. I also wouldn’t rule out some northern areas seeing some potentially stormy weather at times.

Summary

  • A winter of two halves – colder in the first half, milder in the second half.
  • Chance of a widespread cold spell in December.
  • Wettest in the north and west, whilst driest in the south and east.
  • Quite mild weather in February.

Cooler for now but warmer by weekend


August so far has been a rather mixed month, with a spell of warm weather this past weekend in the south and a rather notable late summer gale in the north, and it looks like remaining this way. At the moment winds have turned more north-westerly behind last night’s system which is bringing in cooler air off of the North Atlantic. This will only be temporary though, as the Azores High will be making another move this weekend…

The rest of today will generally see cooler than average conditions, with a scattering of showers. Temperatures will range from between 16-18°C in the north, to between 19-21°C in the south. Overnight tonight, skies will mostly clear allowing temperatures to fall quite readily. The major towns and cities may just about hold up into double figures, but northern rural areas may get down into the mid-single figures.

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After a cool start, tomorrow will then be rather similar to today with some sunshine, but still a scattering of some showers. Temperatures again will be rather cool for the time of the year, ranging from between 16-18°C in the north, to between 19-21°C in the south.

Into Wednesday and we will bring a slight feature in from the Atlantic. This will gradually make its way south-eastwards across the UK during the morning and afternoon, bringing some cloud and light rain. Maximum temperatures are again expected to be rather restricted for the time of year, especially under the weather front, ranging from 15-18°C in the north, to 18-21°C in the south.

Finally by Thursday however, we should start to introduce some warmer air from the south-west. Initially this will bring a fair amount of cloud across the country, but it should feel noticeably warmer and more humid by this point. Temperatures on this day are expected to range between 17-19°C in the north, to 19-22°C in the south and east.

Friday again is then expected to a better day still. Sunshine should be a bit more abundant on this day too, so overall many areas are expected to get away with a fairly decent late summer’s day. In the any sunshine is should feel rather pleasant and temperatures should be slightly higher still, ranging from 18-21°C in the north, to 21-24°C in the south and east.

Looking beyond the working week, there is a possibility for us to potentially see another intense Spanish plume (similar to the one in mid-July)  setting up early next week. There is a possibility for quite a hot spell of weather, and of course with that comes thunderstorms too. I will just leave you with the following…

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Scorchio, then bang!


The weather over the past few days has been gradually ramping up to this day. Each day has seen heat that has intensified slightly bit by bit, with temperatures getting into the low 30s Celsius yesterday. Well today we are reaching the climax of this spell of weather, as exceptionally high temperatures are expected across most of the UK today!

Over the course of this morning, any mist and low cloud pockets will very quickly clear away, and then it’s game on for the sunshine. In the remarkably hot air mass that we have in place across the UK at the moment, temperatures will respond very, very quickly.

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Don’t be fooled by the models. They have a serious habit of undercooking very high temperatures in the summer.

In the strong sunshine, a large part of England and Wales will see temperatures getting up into the low-to possibly even mid-thirties Celsius this afternoon. In fact, this Spanish plume extends very far north, so even places like Manchester and Leeds could potentially see 32°C (90°F) later. This is coming very close to record-breaking heat for these areas, and actually I wouldn’t be surprised if some northern towns and cities do see some records falling this afternoon! Even parts of Scotland and Northern Ireland have a chance of seeing 30°C too. The highest temperatures of course will be across South East England, where 35°C (95°F) is very plausible.

Then over the course of this evening, slightly more humid air will begin to pump up from the south, and this will fuel a recipe for some large and potentially severe thunderstorms over the course of the early hours of Wednesday. These storms will be most likely across western parts of Wales and into Northern Ireland and parts of western Scotland. Do be advised of flash flooding and severe lightning, as these elements could be a feature in these thunderstorms.

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Across the rest of England and Wales however, tonight will be an exceptionally warm night. If you thought last night was too warm, then this one will be even warmer. In fact, the highest night-time minimum ever to be recorded in the UK is 23.9°C at Brighton on 4 August 1990, and there is a very good chance that this record could go tonight. Parts of the South East may not see temperatures below 24°C tonight. Even much further north, minima will be very high, again sticking in the low twenties.

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Very high CAPE across the UK tomorrow. This chart is for 10:00 on Wednesday morning.

As the sun rises on Wednesday, the main focus of the weather will shift from intense heat over to severe thunderstorms, as humidity continues to rise and the atmosphere becomes more unstable. We could see some big thunderstorms kicking off quite widely across western areas – Wales, West Midlands, North West England and into southern Scotland will all be the main risk areas. Again, do be advised that some of these storms could be particularly intense, with flash flooding and severe lightning continuing to be a concern. After lunch time however, this thunderstorm risk should gradually begin to diminish as fresher air from the Atlantic starts to make an inroads.

Away from the thunderstorms in the west, eastern areas will again have another very hot and fine day on Wednesday, with temperatures possibly hitting 32°C again tomorrow afternoon. Across western areas it will be much cooler than today (still very warm, mind you) with temperatures in the mid-twenties. However, the high humidity of tomorrow will make it feel much warmer than it is. By the end of the afternoon though, temperatures may gradually start to fall further for these areas as cooler Atlantic air moves in.

So if you enjoy high heat and thunderstorms then I hope you enjoy the next 24-48 hours or so, as there will be some very interesting and exciting weather for you. Of course, please do take care in weather like this. Make sure you drink lots of water today and seek shade if you are susceptible to heat. Also watch out for lightning tomorrow if you are out chasing storms, and don’t risk your life just for a photo! 🙂

Spanish plume next week!


If you’ve been following the weather quite closely, then I’m sure you’ve heard about an upcoming pattern known as a “Spanish plume”. Well, one of these is coming our way this week so you can expect to see some hot and sunny weather, with the added risk of some thunderstorms too. It will only be a temporary feature though, so the heat will be limited for a short time, before cooler air moves in from the Atlantic again later on.

Today we will have quite a bit of sunshine around, though the north is currently being plagued by some low cloud off of the Irish Sea. I expect this to gradually clear through the morning, leaving most areas with a fine and pleasant day. Highs today will range from between 19-22°C in the north, to a very warm 24-27°C in the south.

Into Monday and we will start to see signs of the Spanish plume, as warmer and more humid air starts to be introduced from the south. Cloud amounts are expected to be rather variable, but where the sun comes out temperatures will rise fairly sharply. I expect highs in the north to range from 21-25°C in the north, to 26-29°C in the south, with some places potentially hitting 30°C (86°F) during th afternoon.

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Tuesday will then see a splendid summer’s day, as the Spanish plume reaches it’s peak. This day will feature lots of hot sunshine for pretty much all areas in a light south-to south easterly wind. Locally it will feel hot or even very hot with temperatures in South East getting up to 32°C (90°F), perhaps even a touch higher in some places! Even further north in cities like Manchester and Leeds, temperatures still have a very good chance of hitting the magic 30°C.

However as we move into Tuesday night and the early hours of Wednesday, the humidity will start to rise quite sharply, allowing some thunderstorms to kick off in southern and central areas. These storms are expected to gradually track northwards, intensifying as they do so. Temperatures will also remain fairly high too, perhaps not really getting below 19-20°C for most areas of England and Wales, so it could be quite an unpleasant night for sleeping for some.

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Wednesday will then see some big and widespread thunderstorms kicking off, mostly in the morning and afternoon. I expect these storms to develop around Wales and North West England during the morning, gradually moving northwards, before shifting to eastern areas in the afternoon, again gradually tracking northwards. Temperatures will also be lower on Wednesday, though given the high humidity, it will still feel very warm or even hot in the sunshine. Highs are expected to range from between 22-25°C in the north, to 27-30°C in the south.

Then as we move through Wednesday night and into Thursday, cooler air will start to move back in off of the Atlantic, so it will feel markedly fresher for most by this time (though the South East may just about hang on to the warmer air). Cloud amounts will be variable and some showers may develop through the day. Highs will be much lower, ranging from 18-21°C in the north, to 22-26°C in the south and east.

Looking at Friday and beyond, and the weather is actually looking fairly pleasant for a change. The models are hinting at the Azores High attempting to build through the country as we move into next weekend, potentially allowing us to enjoy some warm and dry weather during this time too. Of course, confidence cannot be nailed at this point, but I will keep you updated. Finally, I will leave you with this:

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