GODSON.W. L., 1951: Synoptic Properties of Frontal
Surfaces, Q.J . Roy. Met. SOC.,77 pp. 633-653.
The radiosonde station Liverpool (03322) gives the wind 200' 129 knots at 3 0 0 mb at a height of 29,200 feet. Station Larkhdl (03743) gives 200' 1 1 5 knots and the height 29,700 feet. Isotach analyses by many authors (e.g. NEWTONP,HILLIPCSA,RSON, and BRADBUR1Y9,51) give as a rule the jet centre quasi-parallel to the isohypses, in cases withod strong accelerations. Thus, in this case, the centre of the strong winds must pass to the west of the indicated turbulent area. In any case, I consider it impossible to get cyclonic shear through this area.
The most serious objection, however, to the discussed figure is the time difference between the chart and the observation of clear air turbulancc. As I pointed out in my paper the chart time is 0300 GCT, while the observation was made a t 1300 GCT. Studying the change of the wind from 0300 to 1500 GCT one gets the following interesting values. At 3 5 0 mb the Liverpool wind changed from 200' 122 knots to 230' 78 knots, while the corresponding values for Larkhill were 200' 1 1 1 knots and 200° 102 knots, respectively. The Downham Market (03476) sounding gave at 1500 GCT 210' 109 knots (unfortunately the 0300 GCT sounding did not reach the 3 5 0 mb level).
I cannot quite understand the reason to publish a 0300 GCT chart to illustrate the conditions at 1300 GCT, when there are soundings made at 1500GCT. I know that the 3 0 0 mb charts for that time were not published in the Upper Air Section, but that is not a sustainable explanation for the choice.