W0X0F is an old National Weather Service symbol which indicated the weather at the airport was down to "zero, zero". It went into disuse in the mid 1990's when the United States adopted the weather format in use by the European Union.
W stood for "Indefinite Ceiling"
0 stood for the feet in height of the ceiling
X stood for "Obscured"
0 stood for the miles of horizontal visibility
F stood for "Fog"
A more typical string would have been 50OVC10R which reads "Five thousand overcast with ten miles in rain"
My son came up with the idea of a cartoon strip called W0X0F.
This was inspired by my telling him of hitting a bug while descending into Chicago. The bug hit right in the center of my windshield while we were coming down through 11,800 feet. It is still a mystery to me, the thought of a bug flying at 11,800 feet.