Table 2: Development


IOP
LOCATION LOW LEVEL DEVELOPMENT

observed between 50W and 30W

UPPER LEVEL CONNECTION

observed up to 20 deg west of surface feature

RATE OF DEVELOPMENT

Surface deepening rate

Location of low centre when 4mb interval closed isobar first appears Is the Low developing on a frontal zone? If so, was this front trailing from a parent cyclone? Length of 900mb relative vorticity zone > 1.5x10-4s-1 in the along front direction (deg. lat) Max 900mb relative vorticity in the low (x10-4s-1) Max 900mb PV in the low (PVU) Is there a trough axis in the 315K PV distribution? If so, how far west of the surface feature is the trough axis? (deg long) What is the approx meridional extent of the trough (deg lat) WEST (50W-30W)

mb/day equivalent

EAST (30W-10W)

mb/day equivalent

1 54N, 20W Yes No - 1.2 0.4 Yes 23 25 0 0
2 - Yes No - - - - - - - -
4 48N, 22.5WNo- -1.4 0.6 Yes 2 8 0 0
5 48N 18W Yes Yes 4 1.7 0.8 Yes 1 8 - Open wave
6 - - - - 2.0 1.0 Yes 5 25 - -
7 -YesNo (in col region) -0.8 0.7 Yes (2) 5 30 - 0
9 Beyond domain (to the SW) Yes (probably) No (probably) ? 2.4 2.4 No (probably) - - 7 21
10 - Yes Yes - 0.3 0.5 Yes 5 2 - -
11 - No No 8 2.4 1.1 Yes 9 12 28 13
11a 54N, 20W Yes Yes - 1 0.7 Yes 5 18 4 11
12 57N, 27W Yes Yes 3 2.2 1.1 Yes 20 5 - 28
15 Beyond domain (to the SW) Yes No 7 2.9 (just) 1.6 Yes 0 20 16 0
16 -Yes Yes -1.5x10-4 (just) 1.3 Yes but very broad 8 8 - 18
17 Beyond domain (to the SW) Yes No 12 3.9 (just) 1.6 Yes 6 13 30 40
18 57N, 46W No - - 0.9 0.4 No (jet instead) - - 18 44
19 - Maybe Yes 6 2.2 1.1 Yes 10 12 - -
IOP
Location of low centre when 4mb interval closed isobar first appears Is the Low developing on a frontal zone? If so, was this front trailing from a parent cyclone? Length of 900mb relative vorticity zone > 1.5x10-4s-1 in the along front direction (deg. lat) Max 900mb relative vorticity in the low (x10-4s-1) Max 900mb PV in the low (PVU) Is there a trough axis in the 315K PV distribution? If so, how far west of the surface feature is the trough axis? (deg long) What is the approx meridional extent of the trough (deg lat) WEST (50W-30W)

mb/day equivalent

EAST (30W-10W)

mb/day equivalent

LOCATION LOW LEVEL DEVELOPMENT

observed between 50W and 30W

UPPER LEVEL CONNECTION

observed up to 20 deg west of surface feature

RATE OF DEVELOPMENT

Surface deepening rate


Humphrey W Lean | | hwlean@meto.gov.uk