[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 031459
TCDAT1

HURRICANE ARTHUR DISCUSSION NUMBER  11
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL012014
1100 AM EDT THU JUL 03 2014

Data from Air Force Reserve and NOAA Hurricane Hunter aircraft show
that Arthur continues to strengthen this morning.  The Air Force
plane has reported peak 700 mb flight-level winds of 83 kt.  The
NOAA aircraft reported 91 kt from 8,000 ft, and both aircraft have
measured surface winds of around 80 kt from the SFMR. Based on these
data, the initial intensity is increased to 80 kt. Arthur is
forecast to remain in low shear and move over warm water during the
next 24 hours.  This should allow for some additional
intensification.  The updated NHC intensity forecast now calls for
Arthur to reach category two strength prior to its landfall or
closest approach to the coast, in agreement with tightly clustered
intensity guidance.  After that time, Arthur will be moving over
cooler waters north of the Gulf Stream, and the shear is forecast to
increase as Arthur interacts with a deep-layer trough that will be
moving off the east coast of the United States. Arthur is forecast
to become a strong extratropical cyclone in 48 hours and should
steadily weaken after that.

Aircraft and radar data indicate that Arthur is moving a little
faster and appears to have turned north-northeastward, although
the motion over the last hour or two was northward.  The hurricane
should turn northeastward later today and accelerate ahead of the
deep-layer trough nearing the U.S. east coast.  The models are in
good agreement in showing the center of Arthur grazing the North
Carolina coast during the next 24 hours, however only a slight
westward shift in the track would bring the strongest winds inland
over eastern North Carolina. After 24 hours, the spread in the
models increases some with the GFS and HWRF faster and along the
western side of the guidance.  The ECMWF is a bit slower and to the
right.  The NHC forecast leans toward the faster GFS solution, but
has been adjusted a little to the east at days three through five.
The forecast track brings the center of the cyclone near or over
portions of Nova Scotia and Newfoundland in two to three days.

Users are reminded to not focus of the exact forecast track since
the associated hazards extend well away from the center.

The new experimental potential storm surge flooding map is
available at: http://www.nhc.noaa.gov/graphics_at1.shtml?inundation


FORECAST POSITIONS AND MAX WINDS

INIT  03/1500Z 32.4N  78.5W   80 KT  90 MPH
 12H  04/0000Z 33.8N  77.3W   85 KT 100 MPH
 24H  04/1200Z 36.3N  74.4W   90 KT 105 MPH
 36H  05/0000Z 39.4N  70.2W   80 KT  90 MPH
 48H  05/1200Z 42.7N  66.0W   70 KT  80 MPH...POST-TROP/EXTRATROP
 72H  06/1200Z 48.5N  58.0W   50 KT  60 MPH...POST-TROP/EXTRATROP
 96H  07/1200Z 55.0N  50.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
120H  08/1200Z 60.0N  45.0W   35 KT  40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Brown



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