An Air Force Reserve reconnaissance aircraft that has been
investigating the tropical cyclone east of Florida has recently
found maximum 925-mb flight-level winds of 45-46 kt to the
southeast and east of the center, which equates to surface winds
of 34-35 kt, along with uncontaminated SFMR surface wind speeds of
33-36 kt. Based on these data, the depression has been upgraded to
Tropical Storm Arthur, the first named storm of the 2020 Atlantic
hurricane season.
FORECAST POSITIONS AND MAX WINDS
INIT 17/0900Z 30.0N 77.6W 35 KT 40 MPH
12H 17/1800Z 31.2N 77.2W 40 KT 45 MPH
24H 18/0600Z 33.2N 76.4W 45 KT 50 MPH
36H 18/1800Z 35.5N 74.7W 45 KT 50 MPH
48H 19/0600Z 36.9N 72.0W 50 KT 60 MPH
60H 19/1800Z 37.3N 69.4W 50 KT 60 MPH...POST-TROP/EXTRATROP
72H 20/0600Z 37.0N 67.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
96H 21/0600Z 36.0N 66.0W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 22/0600Z...DISSIPATED
$$
Forecaster Pasch
only slight strengthening is anticipated during the next
24-36 hours