A spring nor’easter will dump heavy rain on the area this week

As April days go, Monday will be one of the best. And as April days go, Tuesday and Wednesday will be two of the nastiest.

Spring weather is highly variable, and dramatic shifts in conditions often occur in just a few hours. We’ve had relatively dry springs the past few years, and we are finally starting to make up for some of those deficits.

In the big picture, a spring nor’easter is headed up the eastern seaboard. The moisture from this storm is already gathering along the East Coast. Notice two areas of white, corresponding with moisture around the Carolinas. The area off the coast has a tropical connection and is part of the reason for the heavy downpours in the forecast.

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Rain will break out across the area Tuesday, but it won’t be heavy. The morning commute may be dry, or we may get some light showers. As the day progresses, I expect the rain to become heavier and more widespread, lasting through both the evening commute on Tuesday and the morning commute on Wednesday. The rain will taper late Wednesday afternoon or early that evening.

Temperatures will be very chilly on Tuesday ahead of the storm. Highs probably won’t reach the 50s in Boston, and will only reach the lower 50s in the interior.

The areas of yellow and red in this forecast loop represent heavy downpours and possible thunderstorms.

Tides are astronomically high this week. This will bring some minor coastal flooding during high tide on Tuesday evening and Wednesday morning. Winds won’t be excessively strong, but they will be noticeable, mainly along the coastline. I expect to see some beach erosion, but nothing too major.

How much rain are we talking about? Generally think about this storm as bringing one to two inches of rainfall in a two-day period. This is enough to create some minor flooding on small streams and in poor drainage areas, inundating some people’s basements. It isn’t enough rain to create major problems.

Clouds will likely dominate on Thursday, despite some sunny breaks. Friday is also a rather cloudy day. Temperatures will be much warmer at the end of the week, reaching and exceeding 70 degrees.

The upcoming weekend appears dry and seasonable, but the pattern is active now, and that could change.