Put simply, conditions in Miami will be hot and humid.
The NWS is warning of a “hazardous heat threat”, with the chance of heat-related illnesses likely to increase.
While air temperatures are likely to sit about 33C (91F), once you add in the humidity, it will feel like about 41C (106F).
The NWS put a heat advisory in place for the area on Friday, and experts say it is likely one will be issued covering the weekend too.
There is a risk of thunderstorms, especially near the start of the match, and a possibility of showers – but otherwise sunny spells are expected.
Global sporting bodies such as Fifa use an index called Wet Bulb Globe Temperature (WBGT), which takes into account temperature, humidity, time and amount of sunshine.
In its guidelines for playing in heat, external, players’ union Fifpro says a WBGT above 28C should lead to the “delay or postponement of matches” until conditions are safer.
Calculations of the WBGT for Miami at about kick-off give the WBGT as 28-30C.
There is no suggestion the game will not take place.
