Table 3: Morphology


900mb winds above 25m/s are indicated in Red

IOP Frontal Fracture? 700mb vertical velocity Thunderstorms or Strong Convection? Cloud Head? Dry Intrusion(s) in WV imagery? Max wind at 900mb (ms-1)*
>5cms-1? Maximum Value (cms-1) Dimensions (major x minor axes) of 10cms-1 contour (deg lat)*
1 Possibly Yes 16 6 x 2 No Sferics available Yes Yes (excellent) 25
2 No Yes 9 - Sferics west of MSA Yes Yes 29
4 NoYes 7 - Yes (Sferics present) YesYes 20
5 Yes Yes 10 0.1 x 0.1 No Yes Yes 16
6 No Yes 10 1 x 0.5 No Sferics or imagery available No imagery available No imagery available 28
7 NoNo 3 - No Sferics (Up to 0.2mm/hour convective rainfall in model) NoNo (Maybe around 30W on G-IV flight) 13
9 No (possibly beyond domain, to the west) Yes 16 (28@55W) 3.5x1.5 (7x4@55W) Yes (FUS only) Yes Yes (limited) 32 (38@45W)
10 No Yes 6 - Imagery missing, narrow squall line observed by P3 No Yes 22
11 No Yes 10 2 x 1 No No No 36
11a Possibly Yes 10 2.5 x 1 Yes (12-24 hrs before G-IV flight Yes. Possibly multiple In classical location as low develops 38
12 No Yes 16 6 x 2 Yes (very active) Yes Yes 33
15 Yes Yes 24 6 x 3 Yes Yes No 30
16 Yes Yes 13 6 x 2 No Yes Yes 40
17 Yes Yes 30 6 x 2 Yes (Sferics on and behind cold front) Yes Yes 42
18 No Yes 19 10 x 2 Yes (on & behind primary cold front) No Yes (fragmented, develops south of low) 34
19 No Yes 8 - Yes No No 34
IOP Frontal Fracture? 700mb vertical velocity Thunderstorms or Strong Convection? Cloud Head? Dry Intrusion(s) in WV imagery? Max wind at 900mb (ms-1)*
> 5cms-1? Maximum Value (cms-1) Dimensions (major x minor axes) of 10cms-1 contour (deg lat)*

* Max Values given for MSA period but max value during whole life cycle may be added in brackets.


Humphrey W Lean | hwlean@meto.gov.uk