Memorial Day in the Northeast US brings pleasant air temperatures, but dangerously cold water remains in lakes and rivers. The National Weather Service (NWS) warns that water temperatures in the 40s and 50s can cause hypothermia within minutes of submersion. Swift currents from snowmelt and rainfall add to the risk, potentially overturning small boats.
In Paraná, Brazil, a cold front followed by a polar air mass is expected to cause a significant temperature drop. The Paraná State Environmental Technology and Monitoring System (Simepar) forecasts temperatures near 5°C in the northern half of the state and potentially below freezing in the south. Strong winds and the possibility of isolated showers and thunderstorms are also anticipated. Frost is expected, with a high risk in the south-central region.