Persistent southwest flow and a strong high-pressure ridge over the eastern U.S. are sustaining a heat wave, keeping overnight lows in the mid- to upper 70s°F for New York City on July 15. National Weather Service guidance shows Tuesday night and Wednesday night minima near 76–79°F under mostly clear skies and light winds, limiting radiational cooling. Recent model runs from NOAA exhibit tight consensus around these values, with only modest spread tied to boundary-layer moisture and urban heat-island effects. Historical July climatology places average lows near 71°F, so current conditions represent a notable positive anomaly that traders have priced into the tightly bunched 78–83°F outcomes. Updated NWS and NDFD forecasts expected later today remain the key near-term catalyst for any probability shifts.