About a week or so, I got an e-mail from Matty, MD0MAN drawing my attention to some propagation forecasting websites. One that I hadn't come across before, though somewhere at the back of my mind, I think I've heard it mentioned, is William Hepburn's Tropospheric Ducting Forecast site.
The site allows you to select the area of the globe that you're in - so in my case, I selected the North West Europe page but if you're in North America, this is your map
But how well does it work? After Matty's e-mail, I looked at the maps for the UK and NW Europe last weekend and could see that there would be a chance of some tropo to the South West towards the end of this week, from Thursday onwards.
Driving to the station this morning, with one VFO going on 145.650, there was another repeater just breaking the squelch - something not normally audible. Purely a guess, but I'll bet it was the GB3TR repeater, to the South West of me, in Torbay.
An interesting site - I'm looking forward to keeping an eye on it. Thanks to William for some fascinating data and to Matty, MD0MAN for the tip-off.