intvl = 60

m = Basemap(llcrnrlon=west, urcrnrlon=east, llcrnrlat=south, urcrnrlat=north)

for lon, lat in zip(lons, lats):
    for lo, la in zip(lon, lat):
        m.plot(np.r_[lo[::intvl],lo[-1]], np.r_[la[::intvl],la[-1]], linewidth=0.4, color='k')

plt.show()
plt.close()