Northern lights possible Wednesday night for parts of New England.

A coronal mass ejection from the sun could strengthen to a G3 geomagnetic storm and make the northern lights visible farther south on Wednesday night; forecasters say clear to partly clear skies are expected in much of New England and the best viewing window is reported between 10 p.m. and 2 a.m.

An incoming coronal mass ejection (CME) from the sun could bring visible aurora to parts of New England on Wednesday night. Forecasters say the CME has the potential to escalate to a G3, strong, geomagnetic storm, which would move the viewing line farther south. Predicting the exact strength and timing is difficult until the CME reaches instruments about 1 million miles from Earth. The spring equinox is making Earth's orientation more favorable for magnetic interaction between the CME and Earth's field. What is known: - The CME carries plasma and a magnetic field; if it interacts strongly with Earth's magnetic field it can trigger a geomagnetic storm that produces the aurora borealis. - Officials note the storm could upgrade to a G3 event, which would extend aurora visibility farther south than typical. - Space weather forecasts become more certain once satellites about 1 million miles from Earth directly measure the incoming plasma, its magnetic orientation (Bz), field strength (Bt), and solar wind speed. - High pressure is expected to bring mostly sunny conditions and partly to mostly clear skies across much of New England on Wednesday, improving viewing prospects from a weather standpoint. - Experts report the prime viewing window is roughly 10 p.m. to 2 a.m., and cellphone cameras can sometimes record auroral light that is faint to the naked eye. Summary: If the CME strengthens as indicated, auroral displays may be visible farther south in New England than usual. Space weather forecasters will refine timing and intensity as satellite measurements arrive roughly 1 million miles out. Further updates from those forecasts will clarify where and when the lights are most likely to appear.