The Tech - Online EditionMIT's oldest and largest
newspaper & the first
newspaper published
on the web
Boston Weather: 57.0°F | Partly Cloudy and Windy

Weather

Spring’s Here Early

A warm front that moved through our area early this morning will bring unseasonably warm weather this weekend. Today will start out dreary, but the low pressure system that brought us yesterday’s clouds will quickly exit the region by tonight, making way for high pressure and clear weather Saturday. On Sunday and Monday, we’ll see some clouds and a chance for rain. High temperatures Friday will approach 60, and be in the mid 50’s the rest of the weekend. Lows will still be dipping into the upper 30’s at night, so you might want to keep that jacket or sweatshirt handy.

Why is a low pressure system always associated with clouds and rain, and a high pressure system with sunshine? High in the atmosphere, where there is little friction, the winds spin counterclockwise around a center of low pressure (in the northern hemisphere). But near the ground, the higher friction causes a small component of the wind to flow inwards. As the air converges on the center, the only direction it can flow is up. Rising air cools and then moisture condenses, producing clouds and rain. Conversely, winds spin clockwise around a center of high pressure, causing net outflow from the center. This corresponds to sinking air, which is dry; hence, we have fair weather.

Extended Forecast

Today: Cloudy, windy, and unseasonably warm. High 60 F (16 C)

Tonight: Becoming clear. Low 39 F (4 C)

Tomorrow: Sunny and warm. High 57 F (14 C)

Tomorrow Night: Partly cloudy. Low 39 F (4 C)

Sunday and Monday: Mostly cloudy with a chance of showers. High 54 F (12 C). Low 41 F (5 C)