We’ve seen coverings of snow and snow showers in the air even through the sunny afternoon hours of late. How unusual is this for mid April, a time when the sun is as strong as late August?

Sure it may be late in the season and your ready for summer warmth, especially when you can enjoy daylight till 10pm with daylight returning by 5am but sometimes the atmosphere is reluctant to switch modes.

There’s a striking similarity between April 2015 and April 2016.

This was Shropshire yesterday morning.

Snow showers at 3pm on April 28, 2015 in Lennoxtown.

Campsie Hills turned white for a time.

Yep, there was a stratospheric warming event and the NAO was negative. Almost a repeat of this year.

Last April

This April.

So can we still get winter in April but not August given the sun is at the same strength? It’s all about the lag and gradual easing of cold and it’s coverage throughout the polar region. At this time of year, there’s still plenty of snow and ice cover throughout the high latitudes helping maintain cold air, meanwhile there’s building warmth gradually lifting north from the equator with a northbound subtropical high.

The northward progression of warmth is slow some years like this year but can also be fast with the appearance of low 20s over the UK as early as March. All depends on global weather pattern and drivers at the time.

As for August, well the arctic has least amount of sea ice, reflective snow cover and therefore available cold air, so even when the pattern favours cold through the mid latitudes, it’s far away and weak, often with the jet stream at it’s weakest and furthest north position.

This April may feel cool, surprisingly cool, especially when you see snow on nearby hills or even waken to see the white stuff cover your car or lawn, however, winter isn’t particularly far away even at this time of year and with the right ingredients in place, cold shots with snow can still hit.

As already stated, this April chill is associated with a late sudden stratospheric warming event, likely delayed in response to this years record tying El Nino which I believe held back a major SSWE this past winter but because of it’s weakening, has allowed the release of major warming throughout the polar stratosphere at the end of March and we’re now seeing the response within the mid latitudes now.

Check out the cooling between January 14 and April 14, 2016.

We now have cooler than normal water appearing along the SA coast.

You only have to go back 2 years ago when the UK experienced it’s coldest March in 50 years and this unseasonably cold weather extended into April.

As you can see from the below article from the Met Office, April 1981 was particularly noteworthy for nasty winter conditions during meteorological spring’s 2nd of 3 months.

The thermometer has dipped to -13C in April and just last April it hit -8.6C in Northern Ireland’s cold hollow, Katesbridge, Co Down. Not NI’s coldest for April (-9C) but given the UK and NI all-time minimum occurred at the start of April and last years -8.6 was achieved at the end of the month, the -8.6C was likely Northern Ireland’s coldest temp so late in the season.

Below is an account of the particularly cold March/early April period of 2013. Written by the Met Office.

Snow and low temperatures late March 2013

A spell of severe winter weather brought significant snowfalls and unseasonably low temperatures to many parts of the UK from late March to early April 2013.

From around 10 March to 10 April the UK experienced a prolonged spell of below average temperatures with winds from the east or north, drawing bitterly cold air from northern Europe and Siberia. Persistent cloud cover resulted in cold, overcast days with a strong easterly wind often contributing to significant wind chill. The cold was often accompanied by snowfalls. For example, from 10 to 12 March southern coastal counties of England and the Channel Islands were affected by snowfalls and strong north-easterly winds causing significant disruption, and further snow and low temperatures affected parts of North East England and Eastern Scotland around mid-month.

The most severe wintry weather occurred from 22 to 24 March 2013 as frontal systems associated with an area of low pressure to the west of the UK moved north, with the associated rain turning to snow. In South West England, most of the precipitation fell as rain. However, there were prolonged and heavy snowfalls across North Wales, northern England, south-west Scotland and the east of Northern Ireland. 20 cm or more of snow fell quite widely, especially across the higher ground, with significant drifting in a strong easterly wind. As the low temperatures continued, much of this snow lay un-melted across the higher ground until early April.

Synoptic situation 00 UTC Friday 22 March 2013 showing frontal systems pushing north across the UK

The following photographs provide an indication of the snow depth on Hope Mountain, near Mold, Flintshire on 26 March 2013 (courtesy Tim Graham, Met Office Hadley Centre)

The following photograph shows lying snow at Tarn Hows (English Lake District) on 31 March 2013. This snow would have fallen a week earlier. Note the snow covered fells in the background (courtesy Roger Saunders, Met Office)

Impacts

The heavy rainfall resulted in localised flooding problems across parts of South Devon and Cornwall, with Newlyn, Penzance, Mevagissey, St Ives and Plymstock worst affected. Most problems related to surface water flooding but a number of properties were inundated.

The persistent heavy snowfalls, accompanied by freezing temperatures and drifting, caused numerous impacts across North Wales, northern England, south-west Scotland and the east of Northern Ireland. In Northern Ireland, ice, snow and strong winds brought down power lines with over 100,000 homes and businesses without power, and power cuts also affected parts of Arran and Kintyre. More than 1,000 schools were closed across the UK and there was severe disruption to transport networks. In the worst affected parts of the UK people in cut-off areas had emergency supplies flown in by helicopter.

The unseasonably late severe winter weather had an adverse impact on the farming community – particularly affecting hill farmers during the lambing season. With deep drifting snow, low temperatures and easterly winds adding to the wind chill, several thousand sheep and lambs died. In parts of Wales laws were relaxed concerning the burial of dead livestock.

The following links from BBC News describe some of the impacts.

BBC news – flooding in Devon and Cornwall

BBC news – thousands of homes in Kintyre, Arran and Wigtownshire without power

BBC news – hundreds still struggling with effects of snow storm

BBC news – electricity still out at thousands of homes

BBC news – snowbound family stranded near Wrexham

The Met Office is not responsible for the content of external internet sites.

Weather Data

The frontal systems brought heavy rain to parts of South West England. More than 50 mm of rain fell widely across Cornwall and South Devon in the 48 hours to 0900 UTC on 23 March, with 98.0 mm at Liskeard, Cornwall and 115.8 mm at Holne, Devon in this period. Over 50 mm also fell across parts of South Wales.

UK rain radar 00 UTC 21 March to 00 UTC 24 March 2013 showing frontal systems bringing heavy rain to South West England and significant snowfalls further north

Scale: mm per hour

Further north, the rain turned to snow across North Wales, northern England, south-west Scotland and the east of Northern Ireland. The snow was accompanied by strong winds, gusting at around 30 kt (35 mph). Recorded snow depths at 0900 UTC on 24 March included 41 cm at Middleton, Derbyshire, 27 cm at Bingley, West Yorkshire, 35 cm at Darwen, Lancashire and 75 cm at Llamarnon Dyffryn Ceiriog, Wrexham.

The snow was accompanied by unseasonably low temperatures. On Saturday 23 March, daily maximum temperatures were widely only 1-2 °C, lower across high ground. In places these temperatures were as much as 10 °C below normal for this time of year.

Daily maximum temperatures Saturday 23 March 2013

The cold spell persisted into early April with lying snow remaining un-melted across high ground for up to two weeks. As a result of the prolonged low temperatures, for the UK it was the coldest March since 1962. March was also the coldest month of the ‘extended winter’, the first time this has happened since 1975.

For more information, refer to the March 2013 UK summary.

Snow depths at selected stations (Bingley, West Yorkshire; Middleton, Derbyshire; Llanarmon Dyffryn Ceiriog, Wrexham; Shawbury, Shropshire; Copley, County Durham; Lllangunllo, Powys) show a steady build-up of accumulations from 22 to 23 March 2013, with a subsequent gradual decline (but in many cases a significant depth still remaining) by early April.

UK daily mean temperatures for spring 2013 (March to May)

Observed snow depths at selected stations 20 March to 5 April 2013

Hill farmers were particularly badly affected by the severe wintry weather. In mid-Wales, the air temperature at Lake Vyrnwy, Powys (303 m above sea level) remained continuously below freezing for 6 consecutive days from 22 to 28 March inclusive, with minima around -3 °C. The 1981-2010 mean daily maximum temperature for March at this station is 8.0 °C. With an easterly wind gusting at 25 Kt (around 30 mph) and deep drifts of snow the conditions were exceptionally severe for livestock.

Air temperature at Lake Vyrnwy, Powys 15 March to 5 April 2013

Historical context

The snow and low temperatures were unusual because they occurred so late in the year – in late March – and this was the most significant spell of snow and low temperatures at this time of year since 1979. There are a number of examples of snow in late March or April in the UK’s historical record; dates include: 4 April 2012, 6 April 2008, 23 March 2008, 21-22 March 2001, 28 March 1995, 19 March 1987, 25 April 1981, 17-24 March 1979, 16 March 1964. However, for many of these events the snow was less extensive, less deep or less long-lasting.

One of the most significant examples of snowfall in late March was from 17 to 24 March 1979. 10 to 20 cm of snow fell across the Midlands and North West England, with 10 to 30 cm across the Pennines and North Wales, with the snow lying un-melted for at least a week. This event was similarly accompanied by strong north-easterly winds causing significant drifting, for example snow drifts up to 5 metres deep were observed in the northern Pennines. For more information, see the March 1979 Monthly Weather Report.

There was also a very significant snow event on 25 April 1981 (one month later in the calendar year). Observed depths included 26 cm at Buxton, Derbyshire and 29 cm at Sheffield, with over 30 cm across the high ground of the Pennines. The photograph below provides an indication of snow depths in Sheffield in late April.

Snow in Crookes, a suburb of Sheffield, 27 April 1981 (courtesy David Parker, Met Office Hadley Centre)

Last updated: 21 September 2015

Here are some interesting thoughts on past April cold spells from Netweather, written by MP-R

As we know, March can be as wintry if not more so than December, resulting in some fantastic wintry conditions at times. However, proper cold spells are that bit harder to achieve come April, at least in longevity, with emphasis normally no snowfall (particularly overnight), fast melting in the day’s light. I’d be interested to hear from people of their memories of snow in April. Living in the south, mine are fairly limited but almost stand out more for that reason.

06th-07th April 2008

 

This event brought a dusting of snow overnight, which quickly melted throughout the morning of the 06th. In fact, it was the only time snow lay here at 09:00 in the whole extended 2007/2008 period. Although snow fell and temporarily settled on January 11th, it didn’t hang around for long. There was ample snow on the Mendips however when I went walking around midday. It was great to caught in a heavy snow shower too. I woke to snow falling again on the 07th though none settled and showers turned increasingly to rain/hail as the day wore on.

10th April 2003

I think this spell is often forgotten about as it wasn’t particularly disruptive, but I remember snow falling on the morning of the 10th with the lightest of accumulations on the grass. It had been nice and dry with low dewpoints on the days preceding it. The following days however were cold and rather damp. Incredibly, the following Thursday at temperatures around 24-25C, agai from an easterly wind.

04th April 2000

@jethro will remember this event well. This brought heaps of snow to the Mendips but little lying where I live. I do remember, however, snow falling heavily for a while on this day.

14th April 1999

This is my favourite memory of snow in April. We got loads of the stuff overnight into the 14th as what appeared to be a polar low within the northerly flow moved southwards with a wedge of -8C uppers. A good 12cm+ fell imby and at least half was still lying by the end of the day. A frigid night followed into a sparkling day on the 15th. I remember, being quite young at the time, being amazed at how so much snow could fall so late in the year. Haven’t seen snow so late in the season since.

Unfortunately I was no in the country for a lot of April 1998 so do not remember a snow from then.

Something to note – not all of these spells required high pressure in the Atlantic.