1919.] Pemberton.—Weather Forecasting in New Zealand. 173 
a loop or sinuosity in one of the isobars, or maybe a further centre. 
With “ secondaries 55 there is nearly always a gentler baric gradient, 
and consequently the wind-force is slighter, but they have often been 
known to produce more rainfall than the “ primary.” They are also 
apt to cause thunderstorms, and the one shown in fig. 10 was account¬ 
able for some severe thunderstorms in the northern portions of New 
Zealand. 
Judging from the apparent direction of its path, as shown in the chart, 
this one may possibly have been an offshoot of a tropical “ low ” of which 
there was evidence on the preceding day. 
Of all the atmospheric disturbances the “secondary” is undoubtedly 
the most difficult one for the forecaster to deal with. Its development may 
take place practically within local limits, in which case its effects would be 
felt before the forecaster became acquainted of its presence. There have 
Dec 16 TUESDAY 17 WEDNESDAY 
Fig. 13.—Barographic curve during passage of cyclone, 
Wellington, 16th-17th December, 1913. 
been cases where heavy local rains have occurred which have ^utterly 
falsified the forecast issued, at least for particular districts. When this 
happens people, especially those lacking a knowledge of weather science, 
are often apt to blame the forecaster, when neither the forecaster nor the 
system is really at fault. 
Cyclone originating in Tasman Sea. 
Cyclones sometimes develop on the Tasman Sea between New Zealand 
and Australia, and figs. 11 and 12 show one of this nature, the centre of 
which passed through Cook Strait between 6 and 8 o’clock on the night 
of the 16th December, 1913. The winds and the weather proved more 
intense on the northern side of the centre. The shaded portion of fig. 11 
shows where rain was falling at 9 a.m. on the 16th. It is noticeable how cer¬ 
tain portions of New Zealand had no rain falling, particularly the east coast 
of the North Island, although near the storm-centre. This may be taken 
as a further illustration of how a forecast of rain may fail, and how impossible 
