Table 1: Basic Information


IOP Number Cyclone? Subjective Classification MAX no. of 1mb interval closed isobars attained* Low centre position for MAX Date/time for MAX Diameter of largest closed isobar at MAX (km) System Speed ms-1/Direction (towards) deg** MSA flight start/end times***
IOP 1 Yes Wave cyclone 3 55N, 20W 09Z 10/1 500 22/ 040 01Z - 11Z 10/1
IOP 2 No Warm Sector Wave - - - - 30/ 040 11Z - 21Z 12/1
IOP 4 YesCold Air Comma Cloud 6 48N, 22W 15Z 17/1 700 7/ 060 G-IV 10Z - 14Z 17/1
IOP 5 No Col within high pressure region 2 47N, 18W 12Z 22/1 450 ?/070 (hard to define low centre) 06Z - 16Z 22/1
IOP 6 No Cold Front - - - - 22/090 G-IV: 16Z 23/1 - 00Z 24/1
IOP 7 MaybeFlat wave in deformation zone 0 - - - 23 /050 21Z 25/1 - 05Z 26/1
IOP 8 NoGreenland Lee Waves 0 - - - - -
IOP 9 Yes Mature low - two deepening phases 16 60N, 23W 00Z 3/2 1000 19/060 16Z - 23Z 2/2
IOP 10 No Flat Wave - - - - Inconsistent forecasts 06Z - 15Z 4/2
IOP 11 Yes Large developing cyclone 17 64N, 6W 15Z 6/2 900 31/ 045 19Z 5/2 - 06Z 6/2
IOP 11a Yes Developing Secondary Cold Front Wave 5 56N, 17W 15Z 8/2 400 23/040 G-IV 11Z - 12Z 8/2
IOP 12 Yes Explosive cyclogenesis 16 63N, 26W 06Z 10/2 900 9/040 14Z - 22Z 9/2
IOP 15 Yes Occluded system 32 53N, 24.5W 18Z 15/2 1600 12/060 08Z - 17Z 15/2
IOP 16 Yes Frontal Wave 0 61N, 8W 18Z 17/2 250 30/065 04Z - 13Z 17/2
IOP 17 Yes Explosively deepening col wave 20 62N, 8W 18Z 19/2 600 18/030 02Z - 12Z 19/2
IOP 18 Yes Explosively deepening cold air vortex 30 57N, 18W 21Z, 23/2 1200 7/080 11Z - 20Z 23/2
IOP 19 No Open Wave 0 - - - 41/ 045 02Z - 15Z 27/2
IOP Number Cyclone? Subjective Classification MAX no. of 1mb interval closed isobars attained* Low centre position for MAX Date/time for MAX Diameter of largest closed isobar at MAX (km) System Speed ms-1/Direction (towards) deg** MSA flight start/end times***

* at any time when the low centre was south of 65N

** during MSA flight(s), or if no MSA flight then when low centre crosses 30W

*** Times of entry of first MSA aircraft and leaving of last to nearest hour


Humphrey W Lean | hwlean@meto.gov.uk