The heat building into this week has my full attention — NWS Buffalo is flagging dangerous heat indices Tuesday, potentially topping 100°, driven by a massive high-pressure dome centered over the upper Mississippi Valley strengthening to levels that rank in the 99th percentile for mid-July. Tonight is still comfortable, with clear skies and readings in the low 70s from Ithaca to Corning.
Monday is a transition day: highs climbing into the upper 80s to near 90° in Geneva and Canandaigua, with humidity still manageable and heat indices mostly in the low 90s. Tuesday is where things get serious — 850mb temperatures trending warmer in the latest guidance, pushing surface readings into the low-to-mid 90s regionwide. When humidity spikes alongside that, heat index values from the mid-90s to near 105° become realistic, especially across the lake plains. Wednesday eases slightly, with indices back to the low-to-mid 90s. Thursday and Friday stay warm, with the first hint of a pattern change arriving late in the week as light drizzle chances return by Saturday.
Weather Center forecast for the Finger Lakes region. Sourced from NWS, Open-Meteo, NWS Area Forecast Discussion, and USGS stream-flow data. Updated 6 AM, noon, and 6 PM ET.