Special Features

Tropical Storm Gabrielle is centered near 27. 7N 61. 0W at 21/1500 UTC or 340 nm southeast of Bermuda, and moving NW at 10 kt. Estimated minimum central pressure is 995 mb. Maximum sustained winds are 55 kt with gusts to 65 kt. Seas are peaking at 22 to 24 ft near and just northeast of the center. Scattered moderate to isolated strong convection is seen near and up to 105 nm northwest of the center. A northwestward motion is expected through tonight, before turning toward the north on Monday and then a faster northeastward or east-northeastward motion on Tue. Gabrielle is expected to pass east of Bermuda on Monday. Gabrielle will likely become a hurricane later today with rapid intensification possible through Monday.

Swells generated by Gabrielle will continue to affect Bermuda during the next few days. These swells are expected to reach the east coast of the United States from North Carolina northward, as well as Atlantic Canada, starting today and continuing through early this week. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

Please read the latest HIGH SEAS and OFFSHORE WATERS FORECASTS issued by the National Hurricane Center at websites - https: //www. nhc. noaa. gov/text/MIAHSFAT2. shtml and https: //www. nhc. noaa. gov/marine/offshores. php for more information. For the latest Gabrielle NHC Forecast/Advisory and Public Advisory, please visit www. hurricanes. gov for more details.

Tropical Waves

A far eastern Atlantic tropical wave is near 35W from 21N southward, and moving west at 10 to 15 kt. A 1011 mb low is along the wave axis near 13N33W. Widely scattered moderate convection is noted from 08N to 15N between 30W and 36W.

A central Atlantic tropical wave is near 49W from 20N southward, and moving west at 15 to 20 kt. Scattered moderate to isolated strong convection is present from 14N to 16N between 49W and 51W. Scattered moderate convection is seen farther south from 06N to 08N between 43W and 51W, and also farther northeast from 16N to 20N between 45W and 49W.

A western Caribbean tropical wave is near 82W from the Cayman Islands southward from the Cayman Islands to western Panama. It is moving west around 10 kt. Scattered showers and isolated thunderstorms are occurring near the the Cayman Islands and western Jamaica.

Monsoon Trough Itcz

A monsoon trough enters the Atlantic along the coast of Mauritania near Nouakchott, then curves southwestward through 11N30W to 11N40W. An ITCZ continues westward from 11N40W to 11N47W, then resumes west of a tropical wave near 11N50W to 09N59W. Numerous scattered to isolated strong convection is flaring up south of the trough from 04N to 10N between the Guinea- Bissau/Sierra Leon coast and 29W. No significant convection found near the ITCZ.

The eastern end of the East Pacific monsoon trough is triggering numerous heavy showers and isolated strong thunderstorms across the Caribbean waters near Panama and northwestern Colombia.

Gulf Of America

An upper-level trough over the central Gulf is generating scattered moderate convection at the south-central Gulf, north and northwest of the Yucatan Peninsula. Isolated thunderstorms are evident near the Yucatan Channel and at the north-central Gulf. A persistent surface trough near the central Mexico coast is creating widely scattered showers and isolated thunderstorms at the Bay of Campeche. A modest 1018 mb high just east of New Orleans is supporting gentle to moderate ENE to SE winds and seas of 2 to 4 ft for the entire Gulf, except the western Bay of Campeche and Yucatan Channel where light to gentle winds and 1 to 2 ft seas prevail.

For the forecast, the aforementioned high will control the general weather pattern today before shifting northeastward and weakening. With Tropical Cyclone Gabrielle over the Atlantic lifting northward through Mon night, Atlantic ridging will then build westward along the northern Gulf, becoming centered over the northeastern Gulf by midweek. Mainly gentle to moderate winds and slight seas will prevail across the Gulf. Winds may pulse and become moderate to fresh near the Yucatan Peninsula at night with locally moderate seas.

Caribbean Sea

Island heating is producing widely scattered showers and isolated thunderstorms over and near Hispaniola and Puerto Rico. Refer to the Monsoon Trough/ITCZ and Tropical Waves sections for additional convection in the Caribbean Sea. The presence of Tropical Storm Gabrielle at the western Atlantic has created a weak gradient environment across the Caribbean Sea. Moderate with locally fresh NE to ESE winds and seas of 3 to 5 ft are noted at the south- central basin. Gentle to moderate E to SE winds and 2 to 4 ft seas dominate the north-central and eastern basin. Light to gentle winds and seas at 1 to 2 ft prevail for the rest of the Caribbean Sea.

For the forecast, sporadic showers and thunderstorms are expected near the Gulf of Honduras later today and at the western basin through tonight as a tropical wave moves through. Gentle to moderate trades along with moderate seas are expected today with locally fresh in the south-central basin. Winds will increase slightly thereafter basinwide as the pressure gradient tightens in the wake of Tropical Cyclone Gabrielle lifting northward into the north-central Atlantic. Fresh to strong winds may pulse in the south-central basin Mon night and Tue night.

Atlantic Ocean

Refer to the Special Features section at the very beginning for details on Tropical Storm Gabrielle.

A frontal trough extends southwestward from the tail end of a stationary front off the Georgia/South Carolina coast across 31N74W and the northwest Bahamas to central Cuba. Enhanced by modest southwesterly wind shear aloft, scattered heavy showers and isolated strong thunderstorms are present from the Great Bahama Bank, northeastward across the northwest and central Bahamas to southwest of Bermuda near 70W. Farther east, convergent southerly winds feeding toward Tropical Storm Gabrielle are producing numerous moderate to scattered strong convection from 24N to 27N between 59W and 63W. Refer to the Monsoon Trough/ITCZ and Tropical Waves sections for additional convection in the Atlantic Basin.

Outside the direct impact of Tropical Storm Gabrielle, fresh to strong SE to S winds and seas of 10 to 14 ft are present north of 24N between 54W and 59W, fresh to strong SW to NW winds and 8 to 12 ft seas are found north of 26N between 62W and 65W. Otherwise, gentle to moderate ENE to SE winds and seas at 4 to 6 ft exist north of 15N between 35W and 59W. To the west, gentle NE to SE winds and 4 to 6 ft in mixed moderate swells are evident north of 20N and west of 65W. Farther southeast from 15N to 20N and west of 59W, gentle to moderate NE to E winds and seas of 5 to 6 ft persist. Gentle with locally moderate and 3 to 5 ft seas in mixed light to moderate swells prevail elsewhere in the Atlantic west of 35W.

For the forecast west of 55W, Tropical Storm Gabrielle will strengthen to a hurricane near 28. 8N 61. 8W this evening, then move to 30. 3N 62. 0W Mon morning. Afterward, it will move north of the area to 31. 9N 61. 3W Mon evening, 33. 3N 59. 2W Tue morning, 34. 8N 55. 5W Tue evening, and then 35. 6N 50. 5W Wed morning. Gabrielle will change little in intensity as it moves well away from the area to 36. 9N 38. 4W early Thu. A surface trough will persist off the southeast U. S. coast to the northern Bahamas through at least Mon, enhancing convection in the vicinity. Otherwise, in the wake of Gabrielle, central Atlantic high pressure will build westward providing for light to gentle winds over the central and western portions of the area, and for gentle to moderate winds over the eastern portion into midweek. Seas associated with Gabrielle will gradually subside by midweek.

Chan Posted 27 minutes ago by NHC Forecaster