A. J. and I e-mailed back & forth awhile back about this time in 2008, while Tropical Storm Fay was coming in, about the odd conditions one can experience while dialing around the bands. Just a couple of excerpts from our discussions:
"One thing to do while storms are happening, such as T.S. Fay is doing right now, coming across the Gulf Coast, or when warm or cold fronts are traveling, is to manually scan the broadcast bands. Like today (8/23/08), I twiddled the "Tune" knob on the radio in my wife's Jimmy while I was waiting for her to complete a 5-minute task at a neighbor's home...I tuned into Yes' "Roundabout" on 690 AM. I'd not encountered a station on 690 in the Mobile area before, but instantly realized it was a DX (distant) station, due to it's fluttery signal. When we got underway, I lost the signal in the myriad of power line noises while we drove. I tried for 10 minutes, but never could get an identification before we reached our destination.
I got on line and searched for "690 AM" and found several stations that it could be...one was in New Orleans, WIST...another was Birmingham, WJOX...another was Jacksonville, FL, WOKV. Unfortunately, these were either talk of sports stations, but, in this day of automation, anything could have gone down and music could be playing, due to the storm.
...(try to) monitor during odd weather patterns and events. Even FM stations can travel hundreds of miles along a cold front late in the year over a path called an "inversion layer". I have heard not only broadcast signals traveling on this "pipeline", but seen VHF and UHF TV and heard VHF Ham radio stations travel it, too! ...sometimes AM stations can be heard for many miles during the day along odd weather patterns. You may hear a station not normally heard in your area!
One note of caution: listening to AM radio during thunderstorms can be irritating, from all the static crashes, if not downright dangerous, if you're using an outside antenna. At the very least, a near-strike can damage or blow out the "front-end" of a receiver (normally damage a high gain transistor, rendering the radio useless until repaired.) T.S. Fay today has virtually no lightening, at least that I can hear...just rain, rain and more rain. The curtain of rain coming east-to-west can act as a reflector, bouncing a signal back to your area, hence, fluttery or "picket-fence" propagation. It's...interesting phenomena well worth tuning around while it's happening!"
Somewhere, I had A. J.'s response about the station I had on 690 AM, but I've lost it in my myriad of e-mails...and if I find it, I'll edit this post to include it.
Ron H., also being a Ham radio operator like myself, has probably heard the same phenomenon I have. I sat up one night and, as a big cold front came down from the northwest, I could hear radio stations, both Ham and broadcast, fading in ahead of the front, then fading away as this fast-moving front passed through the respective areas. I was able to somewhat track things on a weather radar and correlate where the stations were with the front's passing. It made for a long, but exciting night!
Now that we're smack-dab in the middle of hurricane season (and thank God there's none out there!), we could have some unusual opportunities to listen out for some AM or FM stations that we don't normally hear. This week alone, we've had two cold fronts (not really cold at all) that have brought loads of rain- and, as mentioned before, these signals could be reflected back TO the listener from whence they come.
Bud S. (firstname.lastname@example.org)