April 2013. Cold first 12 days, then somewhat warmer till the 25th; generally dry and sunny
Version of Record online: 23 MAY 2013
Copyright © 2013 Crown Copyright, Met Office
Volume 68, Issue 6, pages i–iv, June 2013
How to Cite
Eden, P. (2013), April 2013. Cold first 12 days, then somewhat warmer till the 25th; generally dry and sunny. Weather, 68: i–iv. doi: 10.1002/wea.2016
- Issue online: 23 MAY 2013
- Version of Record online: 23 MAY 2013
With two contrasting weather types during the month, mean pressure was not far from normal during April. Averaged over the entire month a gentle southwesterly flow covered the UK, while the anomalous flow was weakly south to southwesterly; the pressure anomaly ranged from –3mbar in Shetland and the Western Isles to +1mbar in East Anglia and Kent.
The cold easterly flow so prominent in late March continued during the first eleven days of April over the greater part of the UK. Snow flurries occurred in eastern Scotland and northeast England during the first three days, and there was slight but persistent snow in East Anglia and southern England on the 4th and at first on the 5th. There were some very low maxima, including 0.5°C on the 1st at Lake Vyrnwy (Montgomeryshire) and 1.2°C on the 4th at Wych Cross (Sussex), while the overnight low hit −11.2°C at Braemar (Aberdeenshire) early on the 2nd. The easterly relaxed for one day – the 7th – under the influence of a ridge of high pressure, but some heavy snow showers were observed in northern Scotland on this day with a high of just 1.3°C at Loch Glascarnoch (Wester Ross). The second week of April was slightly less cold, though much of England and Wales was cloudier with outbreaks of rain (and some hill snow) in southern districts, while there were wintry showers in eastern Scotland. Remains of old snow-drifts persisted until the 12th as far south as the Chilterns and Cotswolds. However, western Scotland was very sunny, with 109.3h of bright sunshine during the first ten days at Tiree (Argyllshire).
A disturbed south to southwesterly airstream prevailed between the 13th and 17th bringing much higher temperatures; amounts of rain were small in East Anglia and the southeast, but there was much wind and rain in northern and western parts. On the 14th the temperature reached 22.0°C at Gravesend/Broadness (Kent) and 21.9°C at Santon Downham (Norfolk). Cluanie Inn (Wester Ross) logged 58mm of rain on the 14th and Lusa (Skye) had 64mm on the 17th; over the five-day period from the 13th to the 18th Cluanie Inn collected 209mm. There was a notable sandstorm during the 15th–16th in northeast Scotland between Forres and Nairn, especially along the A96 road close to Culbin Sands where visibility dropped below 50m at times; the strongest winds, though, were recorded on the 18th with gusts to 73kn at Aberdaron (Caernarfon). It became briefly colder in eastern England on the 19th, but the 20th was a sunny day after widespread early frost. The next two days were rather changeable, but with only small amounts of rain in eastern, central and southern England.
Warm weather resumed over much of England and Wales (except near the south coast) between the 23rd and 25th with highs exceeding 20°C locally, though the weather remained changeable in Scotland and Northern Ireland; the highest temperature was 23.0°C at St James's Park (London) on the 25th. The wind swung into the northwest on the 26th, and the remainder of the month was rather cold, and quite windy in northern districts, and there were sharp showers of rain, hail and sleet, with hill snow. The lowest maximum during this period was 5.6°C at Altnahinch (Co Antrim) on the 26th and slight to moderate frost occurred on several nights. On the 30th 14.2h of bright sunshine was measured at Morecambe (Lancs).
Mean temperature during April was between 0.5 and 1.5 degC below the 1981–2010 normal in all regions; as measured by the CET the month was fractionally warmer than April last year, but in scattered locations it was the coldest April since 1989. There have been 19 colder Aprils in the last 100 years. Except in western and northern Scotland it was a dry month – remarkably so in northeast England, Yorkshire and Lincolnshire, where Bramham (West Yorks) recorded just 5mm of rain. Sunshine duration was above normal except in southwest England and south Wales; an aggregate of 238 hours was measured at Tiree (Argyllshire).
All the charts on these pages are © Crown Copyright, Met Office. Charts on this page are based on NCEP Re-analysis data provided by the NOAA-CIRES Climate Diagnostics Center, Boulder, Colorado, USA.
Data supplied by the Met Office: www.metoffice.gov.uk
§ All averages are for the period 1981–2010, except for stations marked with an asterisk, for which averages are for the period 1961–1990.
The assistance of the Met Office in producing the maps and tables is gratefully acknowledged.