The Lyall Singularities

This list of annual trends and singularities are based on changes in circulation frequencies through the year- the circulation types being those proposed by H H Lamb (British Isles Weather Types and a Register of the Daily Sequence of Circulation Patterns in Met.O.Geophys.Mem.,116,H.M.S.O.,1972) . The Lyall Singularities are based on an article published in the Journal of Meteorology,8,pp311-317,1983

DATE SINGULARITY

Jan 26-30 Mild & unsettled
Feb 10-19 Cold and after 15th becoming more settled
Feb 20-Mar 1 Settled, and turning milder
Mar 12-16 Mild and dry
Mar 17-21 Colder
April 6-10 Cold; often with late snowfalls
April 16-20 Settled
April 26-30 Becoming colder
May 6-10 Marked warming
May 16-20 Cold- often late frosts (the European 'Ice Saints')
June 5-9 Settled
June 15-19 Cooler, less settled (the 'Return of the Westerlies')
July 14-18 Fine and warm (one of the Buchan 'warm spells')
July 19-23 Becoming more unsettled
July 29-Aug 11 Unsettled - often thundery
Aug 14-18 Settled (another Buchan 'warm spell')
Sept 3-7 Warm and settled
Sept 18-27 First Autumn storms
Oct 3-7 Dry and warm
Oct 23-27 Dry and warm
Nov 12-16 Colder
Dec 22-26 Mild
Dec 27-Jan 6 Cold, unsettled

N.B. These are only types which often occur at a particular time of the year- they are NOT forecasts.

Ian Lyall accepts no responsibility for anyone planning holidays or other activities based on these singularities