News weather

Work week ends with warm weather

The temperature in Boston will reach the 70°F mark this afternoon for the third time in 2016, as an approaching frontal system drives offshore flow. The offshore wind (blowing from the land toward the ocean) will result in a temperature increase over previous days, as it brings warm air in from the southwest, and prevents the development of a sea breeze. Sea breezes are thermally direct onshore wind flows that occur when the ocean surface is significantly cooler than the adjacent land. This happens frequently in New England springtime, since the heat capacity of the ocean is much greater than that of the land, and so there is a time lag in the warming response of sea surface temperatures to the brighter sunshine of the spring season. The frequency of sea breezes is one major reason why Boston’s average high temperature for today is only 58°F (14°C).

Today’s warming trend will carry over to tomorrow, when temperatures will have a chance to reach the upper 70s (°F) before a cold front passes through tomorrow night, bringing with it a band of showers and thunderstorms. Sunshine will return for Saturday and Sunday, but so will the likelihood of afternoon sea breezes, meaning the temperature will top out near 60°F (16°C) at around midday.