Is San Fernando Valley’s roaring economy slowing down? That appears to be the case, judging from a drop in the number of building permits in late fall. But a closer look at the numbers shows otherwise. The number of building permits issued by the Van Nuys branch of the L.A. Department of Building and Safety last November, the latest period available, dropped to 1,262, down from 1,978 the previous month and 1,393 a year ago. Given the seasonal nature of construction, the month-to-month dip from October to November doesn’t come as a surprise. Generally, the number of permits issued declines starting in October and begins to rise in March. That also explains the 53.4 percent decline in the value of building permits from October to November. But it doesn’t explain the fall in the value of permits issued from last November compared to a year ago. Building permits were valued at an estimated $29.6 million last November, down from an estimated $44.0 million in November 1996, or a 32.7 percent drop. That fall seems to portend a decline in construction. Looking at year-to-date values for the first 11 months of 1997, though, gives a different picture. Values for 1997, estimated at $601 million, were slightly higher compared to the same period for 1996, which were estimated at $587 million. And that shows that the economy is still on an upward trend. As for the drop in November 1997 permits from the previous year, blame El Ni & #324;o. Anticipating the onslaught of bad weather, builders rushed to get permits and complete construction before the winter began, according to Senior Management Analyst John Chavez at the Department of Building and Safety. “I am optimistic about the Valley,” Chavez said, adding that it “will enjoy continued growth.”