Unusual Rain Interference

I have an outdoor antenna on a 22’ pole. On most days reception is great, however when it rains I lose the signal on Fox and CBS, which is my closest tower. In an effort to track down the problem I used a small 10" flat square antenna in my house (during the same rain) , laid it on a cabinet and ran a coax to the TV, Fox and CBS were crystal clear. I believe this isolated the problem to my setup and not the TV station. But I’m not sure where to go from here, I’d appreciate any suggestions anyone would offer. Thanks -

I think that water is getting in the wires and shorting the signal somewhers outside.