Suffolk's Weather in 2013
Suffolk's Weather in 2013 Edward
Jackson
W e a t h e r conditions locally, regionally and across t h e n o r t h e r n h e m i s p h e r e play a significant part in t h e w i n t e r survival of resident species and t h e arrival and d e p a r t u r e t i m e s of regular s u m m e r visitors. T e m p e r a t u r e and rainfall in p a r t i c u l a r affect b r e e d i n g success, w h i l e w i n d strength and direction o f t e n d e t e r m i n e t h e appearance and source areas of scarcities and rarities - t h e drift migrants t h a t can set pulses racing! This s h o r t review draws o n i n f o r m a t i o n f r o m a n u m b e r of w e a t h e r websites, including M e t Office data f o r East Anglia, t o give a feel for t h e w e a t h e r patterns experienced by Suffolk's birds in 2013. It f o l l o w s t h e M e t Office f o r m a t classifying December, January and February as ' w i n t e r ' ; March, April and May as 'spring'; June, July and August as ' s u m m e r ' and September, October and November as 'autumn'. M o n t h l y temperatures refer here t o the mean of all t h e daytime m a x i m u m readings. Comparisons w i t h 'average' t e m p e r a t u r e s and rainfall refer t h r o u g h o u t t o t h e 30-year long-term average. Winter: January and February January began fairly m i l d and settled, b u t it t u r n e d colder f r o m a r o u n d 11th, a situation t h a t c o n t i n u e d t o t h e end of t h e m o n t h . W a r m A t l a n t i c air masses c a m e up against m u c h colder easterly w i n d s f l o w i n g o u t of Scandinavia. This led t o several episodes of snowfall, leaving s n o w lying up t o 10cm d e e p in places. The m e a n m a x i m u m t e m p e r a t u r e across East Anglia was 5.7°C, 1.4°C b e l o w t h e l o n g - t e r m average. Rainfall of 4 7 m m , also across East Anglia, was a b o u t 10% b e l o w average. February continued the cold and unsettled theme. Snow falling on 11th and 12th was followed by a week of cold north-easterly winds m i d - m o n t h and then a final week that was grey, overcast and cold: just 20 hours of sunshine was recorded all m o n t h at Wattisham. The mean m a x i m u m temperature of 5.5°C was 1.9°C below the long-term average. Rainfall of 3 1 m m was 16% below average. A relatively the breeding
harsh start to the year, making
it challenging
for birds to gain condition
in time
for
season.
Spring: March, April and M a y March was as cold as t h e previous t w o months, creating an unusual 'extended winter'. For m u c h of t h e m o n t h , Suffolk's w e a t h e r was again d o m i n a t e d by easterly w i n d s blocking milder Atlantic air. It was t h e coldest M a r c h since 1962 and t h e second coldest in t h e past 100 years: t h e m e a n m a x i m u m t e m p e r a t u r e was 5.7°C (the same as January!) and a chilly 4.6 °C b e l o w average. However, rainfall of 5 3 m m was 22% above average. April s t a r t e d in m u c h t h e same w a y as M a r c h and it was n o t u n t i l 1 5 t h t h a t t e m p e r a t u r e s generally rose above 20.0°C, j u s t in t i m e for t h e main arrival of s u m m e r migrants. However, drier and cooler conditions t o o k over in t h e last w e e k of t h e m o n t h . The mean daily m a x i m u m o f 12.6°C was slightly above t h e l o n g - t e r m average; rainfall of 24 m m was half t h e average. M a y continued t h e run of challenging w e a t h e r for b o t h resident and migrant species w h i c h w e r e n o w well into their breeding cycle - it was t h e coldest May since 1996. After a calm start, t h e second w e e k saw s t r o n g w i n d s and rain r e t u r n ( c o n t r i b u t i n g t o a m o n t h l y t o t a l of 9 9 m m r e c o r d e d at Bredfield near Woodbridge). M o r e settled conditions w e r e re-established t o w a r d s t h e end of t h e m o n t h . The mean daily m a x i m u m climbed t o 15.5°C, but was still b e l o w t h e l o n g - t e r m average. A record-breaking
cold spring, which significantly affected the timing and success of breeding
attempts.
Summer: June, July and August June c o n d i t i o n s w e r e generally u n s e t t l e d f o r m u c h of t h e m o n t h , i n t e r s p e r s e d w i t h s h o r t periods of w a r m e r w e a t h e r u n t i l t e m p e r a t u r e s reached t h e high 20's in t h e last week. The m e a n