[Weather]First Tropical System of the year (3 Weeks Early)

http://www.weather.com/newscenter/tropical/?from=wxcenter_news

What began as a mid-latitude or extratropical low pressure system has transitioned to what is known as a subtropical storm.

The subtropical storm is forecast to linger off the coast on Wednesday with some slight westward movement toward the Georgia coast. The current forecast calls for the storm to gradually weaken just off the Georgia/South Carolina coast during the next two days. Details of this storm will be closely monitored.

The greatest impacts from this storm have likely peaked but tropical storm-force wind gusts are possible Tuesday night especially along the South Carolina coast. Although wave heights will decrease on Wednesday, they'll still be formidable especially along the North Carolina coast with breakers of 8 to 12 feet. Minor to moderate beach erosion is still possible and the high risk of rip currents will remain through at least Wednesday.

Coastal showers will move onshore from time to time especially along the South Carolina, Georgia, and northeastern Florida coast. Unfortunately for the arid Southeast, it will likely not be a soaking rainfall and will offer little help in battling the wildfires. By Thursday, impacts will lessen and conditions will slowly improve.

The storm began on Sunday afternoon as an area of low pressure developed a few hundred miles off the North Carolina coast. It quickly strengthened and, along with a bullish high pressure system located over northern New England, created a very tight pressure gradient.

The tight pressure gradient led to strong, persistent northerly and northeasterly winds along the Southeast coastline especially over eastern North Carolina. Peak winds yesterday ranged between 45 and 55 mph. Hatteras, for example, had a peak gust of 51 mph.

The winds have also led to strong and potentially deadly rip currents. A high risk of rip currents extends up and down the coastline from North Carolina southward along the Atlantic coast of Florida.

High waves have been the most visible aspect of the storm. A buoy stationed 150 nautical miles east of Cape Hatteras documented 42 foot waves on Monday afternoon. The waves at this buoy have since decreased to 10-15 foot waves.

Along the immediate coast, the largest breakers have been found along the North Carolina coast. Waves are forecast to break between the 8 to 12 foot range during Wednesday not only for N.C. but also for much of the South Carolina coastline. Wave heights will be lower, between 1 to 5 feet, from coastal Georgia southward along Florida's coast.

Along with the thunderous waves, minor to major beach erosion and coastal flooding has also been documented. Coastal overwash spilled on top of U.S. 12 in the Outer Banks and portions of the road were at one point impassable on Monday. Major beach erosion and coastal flooding was also reported in Jupiter, Florida. The National Weather Service out of Miami reported a life guard office and garage were nearly washed into the ocean and about 100 feet of coast has been eroded. The road leading to Jupiter Inlet has since been closed. The pier at Flagler Beach (20 miles north of Daytona Beach) was also closed.

During the overnight hours of Monday into Tuesday, the extratropical low evolved into a subtropical storm. A subtropical storm has a few characteristics of both an extratropical low and a tropical cyclone. First, it has convection, or thunderstorm activity, around a well-defined center of circulation. Second, it has become detached from its associated fronts (cold, warm, occluded). Finally, it has sustained gale/tropical storm force winds.

Unlike a tropical cyclone, this is a cold-core system and its strongest winds are found miles away from the center of circulation; not tightly wrapped around the center.