82 
PACIFIC SCIENCE, Vol, II, April, 1948 
in trade wind is accompanied by an increase in 
the onshore flow. 
The trade-wind decrease is commonly asso¬ 
ciated with the passage of a front or pressure 
trough. In such instances, the wind direction 
over the ocean tends to change to south or 
southwest preceding the pressure trough, and 
veering to westerly in the area behind the 
trough. The tendency for reversal in wind 
direction from the northeasterly trades accounts 
for an inflow of warmer air from lower latitudes. 
It can be seen, therefore, that "kona” weather 
cannot be interpreted as "south-wind weather” 
except in particular localities, and it follows 
that "leeward” is a more correct interpretation 
of the term. 
Frontal storms are those related to pressure 
troughs in the westerly winds aloft. This west¬ 
erly circulation is strongest in winter. In sum¬ 
mer the trade winds reach higher levels as the 
Fig. 1. Map of Oahu showing location of stations and day and night wind directions. 
