Special Features

Newly formed Tropical Storm Arthur is centered near 28. 6N 95. 8W at 17/1500 UTC or 27 nm ENE of Port Oconnor Texas, moving NE at 8 kt. Estimated minimum central pressure is 1001 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Numerous moderate to scattered strong thunderstorms are active around 150 nm to the southeast of Arthur, and scattered showers and thunderstorms are active elsewhere within 90 nm to 270 nm in the southeast semicircle of Arthur. Rough seas are noted within 180 nm in the southeast quadrant of Arthur, with maximum seas to 11 ft. The strongest winds and rougher seas are expected to remain offshore to the southeast of Arthur as it moves along the Texas coast through the afternoon. Winds and seas will diminish over the northwest Gulf starting this evening as the center of Arthur move inland near the Sabine Pass. However, strong onshore flow and poor marine conditions will persist off southwest Louisiana into the overnight hours.

Please read the latest High Seas Forecast issued by the National Hurricane Center at website- https: //www. nhc. noaa. gov/text/MIAHSFAT2. shtml and the latest Arthur NHC Forecast/Advisory and Public Advisory at www. hurricanes. gov for more details.

Tropical Waves

A new tropical wave is along the west coast of Africa, along 16W, south of 17N, moving west around 10 kt. Scattered moderate to strong convection is noted from 05N to 08N between 14W and 18W.

An eastern Atlantic tropical wave is along 35W, south of 17N, moving westward at 15 kt. No significant convection is evident near this tropical wave at this time.

An Atlantic tropical wave is along 58W, south of 17N, moving westward at 15-20 kt. No significant convection is evident near this tropical wave at this time.

A central Caribbean tropical wave is along 75W, south of 17N, moving westward at 15-20 kt. Scattered moderate convection is active from 15N to 17N between 75W and 78W.

Monsoon Trough Itcz

The monsoon trough remains over land at this time. Segments of the ITCZ extend from 06N19W to 07N33W, and from 06N37W to 03N51W. Scattered moderate convection is active from 03N to 06N between 20W and 30W, and from 05N to 07N between 37W and 42W.

Gulf Of America

Please refer to the Special Features section above for details on newly formed Tropical Storm Arthur along the middle Texas coast.

Outside of the conditions concerning Tropical Storm Arthur discussed above in the the Special Features section, the remainder of the Gulf is under the influence of the subtropical ridge that extends from the western Atlantic, across Florida into the central Gulf. This pattern is supporting fresh to strong SE to S winds across the central Gulf, where seas are estimated to be 5-7 ft. Gentle to moderate SE to S winds persist elsewhere with 2-4 ft seas.

For the forecast, Arthur will weaken to a tropical depression near 30. 0N 94. 2W this evening, become a remnant low and move to 31. 9N 91. 6W Thu morning, and dissipate Thu evening. Swells generated by Arthur are likely to cause life-threatening surf and rip current conditions along the northwestern Gulf Coast for the next couple of days. Otherwise, a tightening pressure gradient will develop over the basin and sustain fresh to strong southerly winds over the western and central Gulf late today through Thu night, and moderate to fresh winds over the eastern Gulf. Winds and seas will begin to diminish late Fri through the weekend as weak high pressure settles over the eastern Gulf.

Caribbean Sea

The broad subtropical ridge over the western Atlantic is maintaining fresh to strong easterly trade winds and moderate to rough seas in the central Caribbean. Fresh SE winds and 5-6 ft seas are noted over the Gulf of Honduras. Moderate E to SE winds and 4-5 ft seas are noted elsewhere. Trade wind convergence is supporting scattered showers and thunderstorms over the far southwest Caribbean, off Panama, Costa Rica, and southeast Nicaragua.

For the forecast, the western Atlantic ridge will remain in place north of the area along 27N-28N through early Sat before weakening Sat night through Mon, as a frontal system moves slowly offshore of the SE U. S. coast. The pressure gradient south of the ridge will sustain fresh to strong trade winds and moderate to rough seas in the south-central Caribbean through the forecast period, with highest winds and seas expected off the coast of Colombia. Pulsing winds at fresh to strong speeds and moderate to rough seas are expected in the Gulf of Honduras nightly through Sat, pulsing briefly to near gale-force tonight and Thu night. Moderate to fresh E to SE winds are expected elsewhere across the northwestern Caribbean through Sun. Active showers and thunderstorms are expected across SW portions Wed through Fri as an upper-level trough digs into the area.

Atlantic Ocean

The Bermuda-Azores subtropical ridge is the dominant feature of interest across the tropical Atlantic, and is interrupted only by a frontal trough extending into the region from the western Azores to 22N48W. This pattern is supporting moderate southern flow and 4-5 ft seas over west of 70W, gentle breezes and 3-4 ft seas north of 22N along the ridge axis, and moderate to fresh trade winds and 5-6 ft seas south of 22N.

For the forecast west of 55W, the Atlantic subtropical ridge will dominate the forecast area through Fri, then begin to weaken Fri night through the weekend as a weak cold front moves slowly offshore of the SE U. S coast. The related pressure gradient will maintain moderate to locally fresh trade winds south of 22N through Fri, diminishing slightly Fri night through Sat. Moderate to locally fresh SW winds offshore of northeast Florida to near 72W will expand eastward to near 65W through tonight, as a weak frontal system moves across the southeastern U. S. The front is expected to move slowly offshore early Sat and stall offshore northeast Florida by Sun. Expect fresh to strong winds each afternoon through late evening across Atlantic waters near Puerto Rico and Hispaniola.

Posted about 5 hours ago by NHC Forecaster Christensen