Video is live 35 miles off the coast of Cape Fear, NC. Courtesy of Explore.org

From the NWS-NHC
ropical Storm Arthur Discussion Number 5
NWS National Hurricane Center Miami FL AL012020
500 PM EDT Sun May 17 2020

Arthur’s satellite presentation has not changed much since the
previous advisory. There are still some fragmented convective
bands over the eastern portions of the circulation, but convective
activity remains limited over the western half of the storm. A
late-arriving ASCAT overpass from around the time of the previous
advisory revealed somewhat lower wind speeds than reported by
this morning’s reconnaissance aircraft. This could be the result
of the convection becoming more fragmented after the aircraft
sampled that portion of the storm or related to the low bias of
the ASCAT instrument. Regardless, the initial intensity remains a
possibly generous 40 kt for now. Another reconnaissance aircraft
is scheduled to investigate Arthur this evening.

Arthur is forecast to remain within a low wind shear environment
and over marginally warm sea surface temperatures through early
Monday. These conditions favor some strengthening, however the
sprawling structure of the cyclone and nearby dry mid-level air are
likely to temper any increase in wind speed. After 36-48 hours,
baroclinic forcing is expected to help the post-tropical cyclone
maintain its intensity. Later in the period, the frontal
gradients decrease which should cause weakening.

Recent satellite fixes show that the Arthur is still moving
north-northeastward at about 8 kt. The tropical storm should begin
to accelerate northeastward overnight as a mid-level trough moves
into the eastern United States. By Tuesday night, the steering
flow is expected to become westerly which should cause Arthur to
turn eastward, then southeastward later in the forecast period.
The lastest dynamical track guidance has come into a little better
agreement through 36-48 hours with the GFS and ECMWF converging on
the previous NHC track. As a result, little change was needed to
the first couple of days of the earlier NHC track forecast. After
that time, most of the guidance has trended toward a faster
eastward and east-southeastward motion, and the NHC forecast has
been adjusted accordingly in that direction as well.

Key Messages:

1. A Tropical Storm Warning is in effect for a portion of the
North Carolina coast. Tropical-storm-force winds and heavy rains
are expected there on Monday.

2. Dangerous coastal surf conditions and rip currents are expected
to spread northward along the southeast U.S. coast to the
mid-Atlantic states during the next couple of days. See products
from your local National Weather Service Forecast Office for more
details.

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