West Palm Beach, FLA. (WPEC) — The system we’ve been watching northwest of the Azores has officially transitioned into Subtropical Storm Karen, according to the National Hurricane Center. While Karen is now a named storm, it’s expected to be a short-lived one.
Karen formed from a frontal low—a low-pressure system originally attached to cold and warm fronts—that became occluded (meaning the fronts wrapped around the center and lost their distinct boundaries) early on October 8. Since then, it’s been shedding those frontal features and developing more organized thunderstorms near its center.
Based on all this data, Karen was upgraded to a subtropical storm with winds of 40 knots (about 46 mph). Subtropical storms are hybrid systems that get energy from both warm ocean water and upper-level atmospheric features, like troughs and cold air aloft.
Karen is currently moving northeastward at about 8 knots (roughly 9 mph) and is already embedded in the mid-latitude westerlies—the prevailing winds that blow from west to east in the middle latitudes. It’s expected to accelerate over the next day or so as it gets picked up by another mid-latitude trough (a dip in the jet stream that can steer weather systems).
Despite its current organization, Karen’s time is limited. It’s heading into colder sea-surface temperatures, which will cut off its energy supply. Most forecast models agree that Karen will weaken and lose its tropical characteristics within 48 hours, possibly becoming post-tropical (a system that no longer has the structure of a tropical cyclone) or even dissipating entirely.
