When Bay Staters turn want to know the weather, they turn to the National Weather Service’s Taunton office. The service is known for its accurate forecasters and timely advisories when the weather turns nasty, be it unseemly heat or surprise Nor’easters.

And now it’s going away.

At least for a few days.

The Taunton office’s radar will be down this week as crews install the first of four much-needed upgrades to the system.

The work is part of a national plan to upgrade more than 150 radar stations across the country over the next five years with more up-to-date technology, said Michael Esip, an electronic system analyst with the National Weather Service.

“What you have to understand is that these radar sites are more than 20 years old in some cases. This is really going to be a life-extending upgrade,’’ said Esip.

Crews this week are scheduled to replace a signal processor, which is expected to increase processing speeds, support IT security, and add general functionality, Esip said.

The other upgrades, called Service Life Extension Projects, are scheduled to replace the radar’s transmitter, the pedestal, and the equipment shelters, he said.

“These projects are really just to keep the equipment going. They’re designed to catch up with modern technology, but they aren’t the cutting edge. There isn’t going to be a drastic increase in radar range or anything like that,’’ Esip said.

Still, when completed, the radar should be better able to detect meteorological events such as tornados forming or hail spikes, as well as non-meteorological occurrences such as migrating birds or traffic on major highways, said Esip.

The work began Tuesday morning and could last for as many as four days, Esip said.

“Four days is pretty much the worst case scenario, but when you’re doing big work like this, it pays to take the unexpected into consideration,’’ he said.

Esip added that, while the Taunton radar site will be down while the work is being completed, there should be no disruption in regular weather updates.

“There should be no impact at all. We have three alternate sites to draw data from in New York and Maine,’’ Esip said.

The upgrades are part of a $150 million national plan paid for in large part by the National Weather Service, the United States Air Force, and the Federal Aviation Administration.

“We hope these upgrades will allow us to keep up with the times and continue to provide accurate information to the people we serve,’’ Esip said.

Andrew Grant can be reached at andrew.grant@globe.com.