Subtropical Storm Ana active in the Atlantic Ocean…located approximately 180 miles south-southeast of Myrtle Beach, South Carolina
A pre-season, subtropical storm has spun-up in the Atlantic, offshore from South Carolina…and is starting to shows signs of becoming a tropical storm
Ana is located about 180 miles south-southeast of Myrtle Beach, South Carolina, and is currently stationary
At the time of NHC advisory #3, sustained winds were estimated to be 40 mph…with gusts to near 50 mph.
According to the National Hurricane Center (NHC), satellite images show that Ana is starting to show signs of transforming into a tropical storm, with a more compact structure, and tighter convective cloud bands near the center. The storm still has less-intense convection than most tropical cyclones, thus is classified as subtropical.
Ana has been nearly stationary for the past several hours offshore from the U.S. southeast coast, although recently the storm has drifted eastward a bit. Computer model guidance brings Ana to the coast of the Carolinas in about two days. Thereafter, a strong trough of low pressure should cause Ana to move more quickly to the north and east late Sunday and into early next week. Extratropical transition is anticipated in about four days…in line with the global model guidance.
Some strengthening of Ana is possible since the storm is embedded within an environment of cold upper-level temperatures, leading to more thunderstorms than one would expect over the marginally warm waters. However, there’s quite a bit of dry air around the storm, which could help limit convection. Most of the guidance shows some intensification during the next day or so, and the official NHC forecast does the same. As Ana approaches land, some weakening seems probable due to the storm moving over cooler waters right along the coast.
The greatest limiting factor for this system, as it was yesterday, is the dry air coming into the circulation, due to strong winds aloft out of the west…forcing this air into the storm’s core. In addition, somewhat cool sea water temperatures, ranging between 77-79F degrees prevail in the path of Ana towards the coast. Tropical cyclones prefer water that is 80 upwards for optimum growth.
The NHC brings the sustained winds up to 50 mph, with higher gusts within 12 hours, and keeps these winds active through 36 hours. This is well below the hurricane wind levels.
The NHC is showing these Watches and Warnings:
A Tropical Storm Warning has been issued from South Santee River South Carolina to Surf City North Carolina.
A Tropical Storm Warning is in effect for…
* South Santee River to Surf City
A Tropical Storm Watch is in effect for…
* Edisto Beach South Carolina to South of South Santee River
* North of Surf City to Cape Lookout North Carolina
A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours.
A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, in this case also within 36 hours.
Interests elsewhere in eastern North Carolina should monitor the progress of Ana.
HAZARDS AFFECTING LAND
WIND: Tropical storm conditions are expected within the warning
area, and possible within the watch areas, by Saturday evening.
STORM SURGE: The combination of storm surge and the tide will cause
normally dry areas near the coast to be flooded by rising waters.
The water could reach 1 to 2 ft above ground at times of high tide
in coastal areas from Cape Hatteras, North Carolina southward
through South Carolina. For information specific to your area,
please see products issued by your local National Weather Service
RAINFALL: Ana is expected to produce rainfall accumulations of 2 to
4 inches, with isolated amounts of 6 inches, over eastern portions
of North Carolina and South Carolina through the weekend.
SURF: Swells generated by Ana are affecting portions of the
southeastern U.S. coast. These swells will likely cause life-
threatening surf and rip currents. Please see statements issued by
your local National Weather Service forecast office.
This NWS looping radar image from Charleston, South Carolina shows most of Ana’s showers over the offshore waters…while the NWS looping radar image from Wilmington, North Carolina shows the showers associated with this storm beginning to move inland. The bulk of the associated precipitation was too far offshore for the NWS radars to pick up yet.
As far as rainfall, 2-4 inches are expected as this system makes landfall.
Subtropical storm Ana
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