Vone: You can get a pretty accurate weather forecast for ballooning from Met office which will give wind velocity : This then indicates best launch site to avoid flying into CAS in the first place.
Yes they do have VHF comms with a dedicated balloon frequency: tho' it's mainly used to talk to ground crew.
And No they don't show up on radar.
As you know, wind direction veers as you ascend and backs as you descend so a certain amount of directional control can be achieved.
Last week it was pretty still as we launched so first job was to climb to 3000ft to pick up a light northerly to take us away from the town. Once clear we descended for photos etc to about 500-800ft.
Still only covered 5 miles in an hour.
Higher than acceptable winds prevent ballooning but my mate has also scrubbed a flight because of absolute flat calm as he couldn't guarantee getting clear of the town in still air in the time allotted (remember most flights are evening and VFR only, so as the evenings get shorter the time available between punters getting from work to
launch site and SS +30 minutes gets less.)
And we did get a visit by two local microlights as we hung there. More than 500ft away of course.
Great experience: everyone should do it at least once............
Cusco