The National Oceanic and Atmospheric Administration is planning a $12 million network of 30 experimental radar stations that would track winds up to an altitude of 10 miles over nine states in the central part of the nation.

The network, which is expected to improve the reliability of weather forecasting in an area unusually vulnerable to tornados and other fast-forming storms, could eventually be extended to the entire country.

Winds not only are weather in themselves; they propel other forms of weather, such as rain clouds, warm fronts and hurricanes. Because of this, the most important winds are not necessarily those that blow near the ground where they are easiest to measure.

For many years meteorologists have released helium-filled balloons with wind sensors, called radiosondes, whose data were radioed to the ground as the balloon rose into the upper atmosphere. Typically, these single-use balloons are released every 12 hours.

But that's not good enough, said Vernon E. Derr, director of NOAA's Environmental Research Laboratories in Boulder, Colo.

"Significant changes in the atmosphere, preceding severe storms and other hazardous weather, can occur within a matter of only a few hours," Derr said. "Meteorologists trying to forecast short-term local weather today lack information often critical to public safety."

The new system, for which construction bids are being solicited, will provide a complete profile of wind patterns from the ground up to about 10 miles every half hour, 24 times as often as the radiosonde system. The network will rely on ground-based radars, called profilers, which bounce radio waves off the surfaces of subtle variations in air density. The different densities are caused by turbulence and variations in temperature and humidity.

The beams aim straight up, then to the north and then to the east to sense motion in each direction. Computers process the separate readings into a form that can be displayed in several ways, including a video animation that looks like an aerial view of moving arrows.

David Small, head of the Profiler Project Office, said the profilers would be spaced about 120 miles apart in a grid between Iowa and Nebraska in the north and Texas and Louisiana in the south. Each automated station, occupying no more than an acre of land, would radio its data to NOAA's research center in Boulder.

Small said the 30-station network and the Boulder hub would cost about $12 million and are expected to go into operation in 1989. Data on wind patterns will be relayed to forecasters at the National Weather Service, a division of NOAA. In the first three years, operation, evaluation and research costs would add $28 million to the total.

If the system proves useful in the first few years, Small said, the network could be enlarged to cover the whole country.

UNDERWATER VENTS . . . Meanwhile, in NOAA's wetter realm, the agency's oceanographers have discovered the first known hydrothermal vents in the Atlantic, about 1,800 miles east of Miami. Similar vents -- submarine geysers of hot, mineral-rich water -- were discovered a few years ago in the Pacific, near the Oregon-Washington coast and near the Galapagos Islands off Ecuador.

The Atlantic vents, according to Peter Rona of NOAA's Atlantic Oceanographic and Meteorological Laboratories, are situated on the Mid-Atlantic Ridge, the line along which the Atlantic floor is spreading, pushing North and South America away from Europe and Africa.

The ridge is, in effect, a continuously erupting volcano stretching thousands of miles and roughly paralleling the coastlines, which once fit together as a single continent. Along with the magma that wells up and spreads to each side, billows of mineral-blackened water emerge and mix into the colder surrounding water.

Rona said the dissolved minerals were mostly sulfides of copper, iron and zinc.

Another vent research team, led by Herbert Curl of NOAA's Pacific Marine Environmental Laboratory in Seattle, has found high concentrations of dissolved metals as far as 60 miles from the Pacific hydrothermal vents.

HAPPY BIRTHDAY . . . NOAA marks its 15th anniversary this week. On Oct. 3, 1970, it was created by the merger of the Commerce Department's Environmental Science Services Administration and the Interior Department's Bureau of Commercial Fisheries, Marine Sport Fisheries Program and Marine Minerals Technology Center, as well as parts of the National Science Foundation, the Army, the Navy and the Transportation Department. The agency has 12,000 employes. -- Boyce Rensberger