I'm sorry no one has responded sooner. This could be a couple of problems - and will require some trials to determine the problem on your side.
The digital signals are very directional sensitive and attenuate more easily with obstructions - also, because of the higher frequencies the use (the majority of them). Wind blowing, can cause a tree (or trees) - that is not in the direct view of your location so when the wind blows, the tree limbs/leaves blow in the path of the signal (yes foliage will obstruct the new TV signals).
Another possibility, is the cable feed to your TV, check the connection to the antenna, and ensure it is firmly attached to the feed point - also, make sure the feed cable is not moving with the wind.
Even though it is "omni-directional" there are peaks and nulls in even omni-directional antennas.
This antenna is rated for 30 miles - UHF signals, that is border line for your reception, since the rating is for direct line-of-site, with no obstructions - anything in the path between you and the transmitter
can cause attenuation - when the wind blows.
Other than being in the US, I do not know your geographic location and the topology, if you provide your zip code, I can check the signal strength to your location and perhaps some more possibilities.