Hurricanes

Special Features

Global models continue to suggest a Central American Gyre (CAG) will form across the southwest Caribbean and Central America by Fri, and then gradually shift west to northwest across Central America through early next week. CAGs tends to enhance the strength of SW monsoon flow, and lift the monsoon trough well north of its typical position. This will increase convergent surface winds and advect abundant moisture northward, triggering widespread strong convection over Central America. Expect heavy rainfall commencing across Panama and Costa Rica today, then spreading to parts of Guatemala and Honduras. Extreme rainfall is possible across the Pacific coasts of these countries, and also over southern Honduras and northeast Nicaragua. This will increase the potential for flash flooding and mud landslides, especially near valleys in mountainous terrain. Please refer to products issued by your local weather service for more information.

Tropical Waves

An Atlantic tropical wave is along 38W, south of 11N, moving west at 15 to 20 kt. Scattered moderate to strong convection is seen near the southern portion of the wave from 03N to 06N between 35W and 40W.

A Caribbean tropical wave is along 82W, south of 17N, moving west-northwest near 10 kt. Enhanced by a mid-level trough to its NW, scattered moderate to strong convection is evident over the southwest Caribbean Sea from 09N to 12N between 74W and 79W.

Monsoon Trough/ITCZ

The monsoon trough exits the African coast of Guinea-Bissau near 11N15W and extends to 05N20W. The ITCZ continues from 05N20W to 05N35W. West of the tropical wave, the ITCZ continues from 02N40W to 00N50W near the mouth of the Amazon River. Scattered moderate convection is observed from 02N to 07N between 30W and 50W.

Gulf Of Mexico

A surface ridge extends from the western Atlantic to the central Gulf along 26N/27N. A trough is analyzed over the Yucatan Peninsula. A recent scatterometer satellite pass showed fresh NE winds off the western Yucatan Peninsula, and gentle to moderate SE winds elsewhere. Buoy observations indicate sea are 3 to 5 ft over the western Gulf. Light and variable breezes are noted over the eastern Gulf, where seas are 1 to 3 ft.

For the forecast, the high pressure over the northeast Gulf will shift eastward through Fri, as low pressure develops south of the area over Central America. This pattern will allow an area of moderate to fresh SE winds over the western Gulf to expand eastward across the Gulf by late Fri. Winds and seas will then diminish slightly across most of the basin Sun through early next week as the pressure gradient relaxes, leaving only pulses of fresh to occasionally strong winds at night off the northern and western Yucatan Peninsula.

Caribbean Sea

Please see the Special Features section for information on a potential heavy rainfall event.

Recent observations show moderate to fresh with locally strong easterly trades and 5-7 ft seas in the south-central basin south of 15N. Gentle to moderate easterly trades with 4-6 ft seas are observed across the eastern, north- central and southwest basin. Gentle to moderate SE trades and 1-3 ft seas prevail over the northwest Caribbean.

For the forecast, surface ridging over the western Atlantic are supporting moderate to fresh trade winds across the east and central Caribbean, with fresh to strong winds. Winds and seas across the basin will increase tonight into the weekend as the ridge strengthens and broad lower pressure forms over Central America. The strongest winds and highest seas are expected to be over parts of the northwest and south-central Caribbean during this period. Looking ahead, winds and seas will start to diminish over the eastern and central Caribbean early next week as the ridge to the north and the lower pressure over Central America weakens.

Atlantic Ocean

A weak surface ridge extends from 1021 mb high pressure centered near 27N41W along roughly 27N to the northern Bahamas. Recent observations show mainly gentle to moderate breezes and 3 to 5 ft seas north of 22N across the Atlantic, except for an area of moderate to fresh SW winds north of 28N between 50W and 55W, ahead of a frontal boundary north of the area extending from the north central Atlantic to near Bermuda. Moderate to fresh trade winds are noted south of 22N, with 5 to 8 ft seas.

For the forecast west of 55W, the surface ridge along 27N will lift north to 30N through Fri and strengthen. This pattern will support mainly gentle to moderate breezes across the region through early next week, except for moderate to fresh winds north of Hispaniola starting late Fri.

Posted 11 hours ago by NHC Forecaster Christensen