Jet Stream Intensity Proxy, ADS-B Passive Wind Sensing, Helena MT (Jan–May 2026)

115-day passive jet stream intensity proxy derived from ADS-B aircraft telemetry at 46.603°N 112.015°W, Helena, Montana. Eastbound vs westbound cruise-altitude (FL280–FL450) groundspeed differential used as a continuous wind proxy. Covers January 17 – May 14, 2026. Includes daily delta values, strength classification (Strong/Moderate/Weak), and distribution statistics. No weather instruments — derived entirely from RTL-SDR Blog V4 + readsb. Companion code: https://github.com/HelenaValleyObservatory/helena-valley-observatory