Cloudiness and thunderstorms associated with a broad area of low pressure over the southwestern Gulf of Mexico have become a little better organized today. This system is expected to move generally northward, and a tropical or subtropical depression is likely to form over the west-central Gulf of Mexico tonight or early Friday. Heavy rainfall will continue over portions of Central America and southern Mexico during the next couple of days. Heavy rains will also begin to affect portions of the northern Gulf Coast on Friday. Please consult products from your local meteorological service for more information. Please refer to the latest Tropical Weather Outlook issued by the NWS National Hurricane Center at www.hurricanes.gov for more details on this area.
A newly analyzed Atlantic tropical wave axis is along 23W from the Cabo Verde islands near 18N southward, and is moving west at 10 to 15 kt. Scattered moderate convection is seen from 01N to 07N between 16W and 31W.
Another Atlantic tropical wave axis is along 42W from 18N southward, moving west at 15 to 20 kt. Scattered showers are noted from 10N to 13N between 39W and 43W.
A Caribbean Sea tropical wave axis is over the Lesser Antilles and Windward Islands near 62W from 20N southward into Venezuela, and is moving W at around 15 to 20 kt. Scattered moderate convection is present from 06N to 17N between 57W and 68W. Stronger thunderstorms might produce fresh gusty winds across the Lesser Antilles and Windward Islands. Additional scattered moderate convection is noted inland over eastern Venezuela.
Another Caribbean Sea tropical wave axis in the western Caribbean is analyzed along 82W from 18N southward over western Panama, and is moving west at 5 to 10 kt. Scattered moderate to locally strong convection is evident from the coast of Panama north to 11N between 75W and 83W.
The monsoon trough passes through the coast of Africa near 11N15W to 04N26W. Segments of the ITCZ then continue westward from 04N26W to 06N39W and 05N43W to the coast of French Guiana at 05N53W. Scattered moderate convection is found near French Guiana and Suriname from 04N to 06N between 46W and 57W.
Gulf Of Mexico
Refer to the Special Features section above for details on a broad low pressure area over southwestern Gulf of Mexico.
A surface trough curves southeastward from near the Texas-Mexico border at 25N97W to the low pressure center near 20N93W. A band of scattered thunderstorms is found along the coast of Mexico within 50 nm of the trough axis. A second surface trough extends northeastward from the low to the north central Gulf near 28N88W. Near both troughs, fresh to locally strong winds were detected by the latest scatterometer passes. Aided by upper-level divergent flow, scattered moderate to isolated strong convection is occurring from the Yucatan Channel north to 27N between the Florida Gulf coast and 92W. This convection is also impacting portions of the NW Caribbean.
A stationary front stretches eastward from near New Orleans at 29N89W across the northeastern Gulf to northern Florida at 30N84W. No convection is noted with the front at this time. Gentle to moderate E winds are noted in the northern Gulf north of 26N, moderate to locally fresh E-SE winds are noted south of 26N and east of 94W, with moderate to fresh NE-N winds west of 94W. Finally, in the eastern Bay of Campeche, winds shift cyclonically to S around the broad low pressure. Seas are mainly in the 3-5 ft range, except 4-6 ft in the south central Gulf, southeast Gulf, and Straits of Florida.
For the forecast, the broad area of low pressure over the SW Gulf of Mexico is producing widespread but disorganized cloudiness, showers, and thunderstorms. This system is expected to move northward, and a tropical or subtropical depression is likely to form over the west-central Gulf of Mexico tonight or early Friday. Regardless of development, heavy rainfall will continue to affect most of the basin through Fri night, and the N and NE basin offshore the remainder weekend. High pressure is forecast to build in across the basin in the wake of the low Sat night into early next week.
A tropical wave is moving across the western Caribbean and another wave is near the Lesser Antilles. Refer to the Tropical Waves section above for details.
The eastern Pacific Ocean monsoon trough extends across Panama to NW Colombia near 10N75W. In the NW Caribbean, scattered moderate to isolated strong convection is noted north of 18N and west of 84W, including inland over the Yucatan Peninsula. This convection extends north into the Gulf of Mexico.
Fresh to strong tradewinds were detected by the latest scatterometer pass in the south central Caribbean. The strongest winds extend from the coast of Colombia north to 13N between 71W and 77W. Mainly moderate to fresh trades prevail elsewhere in the basin, except gentle to moderate in the SW Caribbean south of 11N. Seas of 4-8 ft throughout the basin, except 6-9 ft in the area of strong winds off in the south central Caribbean.
For the forecast, a ridge of high pressure north of the basin combined with lower pressure over Venezuela and Colombia will support pulsing fresh to strong trades over the S central Caribbean and Gulf of Honduras during the weekend and into Tue. Fresh to strong trades will expand in areal coverage and reach Hispaniola adjacent waters over the weekend. Elsewhere, moderate to fresh trades will prevail, except light to gentle variable winds over Panama and Costa Rica adjacent waters.
A pair of tropical waves are moving across the basin. Refer to the Tropical Waves section above for details.
Diffluent flow aloft continues to support scattered moderate convection over the Florida Peninsula and western Atlantic mainly north of 25N and west of 70W. To the east, a surface ridge dominates the entire Atlantic forecast area anchored by the Bermuda-Azores High located north of the area. Fresh to locally strong SW winds are occurring in the W Atlantic north of 30N between 68W and 71W. Moderate to fresh trades dominate south of 22N west of 50W. Gentle to moderate trades prevail elsewhere, except from 18N to 24N between the west coast of Africa and 24W where fresh N-NE winds persist due to a locally tight pressure gradient. Seas are 7 to 10 ft in this area of fresh winds. In the Bahamas, seas are 2-4 ft. Outside of these areas, seas of 5 to 8 ft prevail across the waters south of 22N, with mainly 4 to 7 ft seas north of 22N.
For the forecast west of 65W, a ridge of high pressure across the area will retreat eastward today enabling a trough to move through the northern forecast waters through Fri. High pressure will then return to the area this weekend into early next week. Fresh to strong winds are expected to pulse at night over Hispaniola adjacent waters during the forecast period and over Puerto Rico adjacent waters tonight.
Posted 4 hours ago by NHC Forecaster Mahoney/Chan