HAARP does this, and there is no sign of HAARP use at this time. The warming mentioned in this article has not occurred. The polar vortex, currently freezing Siberia and Japan, has maintained the pattern it has followed since it began in the late fall of last year, and it's current position may be related to the el nina in the Pacific ocean. The last time I observed them using HAARP to break a polar vortex in half was in 2017 at the inauguration of President Trump. That polar vortex had been dominating the Great Lakes region with -40C temperatures in the lower Great Lakes. Winter had started early in 2016, with snow on the ground in Toronto before Halloween, and very cold temps right up through Christmas. The use of HAARP to heat the atmosphere and break the vortex could be clearly scene by satellite, and the operation was highly successful, not only leading to the splitting of the vortex in January, but that in turn also brought an early and mild spring. HAARP has been with us for decades now. When they do use it, it cannot be hidden. Normally very few people are looking for it however. Also, it is not frequently used.