Special Features

Northwestern Gulf of America (Invest AL90): A trough of low pressure extending across coastal portions of NE Mexico, across the Texas/Mexico border and into south Texas, continues to produce a large area of strong showers and thunderstorms from NE Mexico to SW Louisiana. This system is expected to move north- northeastward during the next few days, and could re-emerge over the northwestern Gulf of America today through Wed. Environmental conditions there are expected to be marginally conducive for the formation of a short- lived tropical storm later today or on Wed. Regardless of tropical cyclone formation, interests across southern and eastern Texas, southern portions of Louisiana and Mississippi should prepare for periods of intense rainfall over the next several days, which could produce widespread, life- threatening flash, urban, and river flooding. Gusty winds and coastal flooding are also possible along portions of the northwestern Gulf Coast, and Tropical Storm Watches or Warnings could be required later today. Additional information on this system can be found in products issued by your local National Weather Service Forecast Office or the NHC Key Messages.

This area has a medium chance of tropical cyclone formation in the next 48 hours. Please refer to the latest Tropical Weather Outlook issued by the National Hurricane Center under AWIPS/WMO headers ABNT20 KNHC/TWOAT or at website https://www.nhc.noaa.gov/text/MIATWOAT.shtml for further details.

Tropical Waves

An eastern Atlantic tropical wave is along 25W, south of 17N, moving westward at around 10 kt. Scattered moderate isolated strong convection is observed from 04N to 12N between 20W and 32W.

A central Atlantic tropical wave is along 46W-47W, south of 17N, moving westward at around 20 kt. Scattered moderate convection is present from 04.5N to 09.5N and between 40W and 54W.

A Caribbean tropical wave is along 63W, south of 16N, moving westward at around 20 kt. Scattered moderate isolated strong convection is noted from 11N to 13.5N between 58W and 66W.

Another Caribbean tropical wave is along 78W, south of 19N, moving westward at 15-20 kt. Scattered moderate convection is found south of 14N and between 74W and 82W.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic through the coast of Senegal near 14.5N17W and continues southwestward to 05.5N34W. The ITCZ extends from 05.5N34W to 05.5N45W and then from 05.5N48W to 06N57W. Convection is described in the TROPICAL WAVES section.

Gulf Of America

Please refer to the Special Features section above for details on the potential for tropical cyclone formation in the NW Gulf of America.

Abundant low level moisture continues to stream northward across the western Gulf and is converging on the easter side of a trough of low pressure extending from eastern Mexico into south Texas. Favorable upper level conditions aloft continue to support numerous large clusters of strong convection across coastal sections and the near shore waters from NE Mexico to SW Louisiana. The remainder of the basin is under the western extent of the Atlantic subtropical ridge extending across south Florida and into the eastern Gulf. This pattern is supporting moderate to locally fresh SE winds and moderate seas to 6 ft, west of 90W and off northern Yucatan. Elsewhere, light to gentle winds and slight seas prevail.

For the forecast, the low pressure across NE Mexico and S Texas is expected to move slowly NE during the next couple of days, and along the Texas coast, and possibly re-emerge over the NW Gulf today or Wed. Environmental conditions are marginally conducive for the formation of a short- lived tropical storm as this occurs. Widespread showers and thunderstorms are expected over the NW Gulf Tue through Thu as this systems moves through the area. Otherwise, a tightening pressure gradient over the basin will sustain fresh to strong southerly winds over the western Gulf Tue night through late Thu night, and moderate to fresh winds over the eastern Gulf. Winds will begin to diminish Fri as high pressure settles in over the eastern Gulf.

Caribbean Sea

Scattered moderate convection continues early this morning across eastern Cuba, the Windward Passage and into western Haiti, while a few showers are across the Cayman Islands. The pressure gradient between the subtropical Atlantic ridge over the central Atlantic and lower pressures in northern South America is forcing fresh to strong easterly trade winds and rough seas in the central Caribbean, south of 17N. The strongest winds and highest seas are noted off Colombia. Moderate to fresh easterly trades and moderate seas are found in the eastern Caribbean and Gulf of Honduras. Elsewhere, moderate or lighter winds and slight to moderate seas are prevalent.

For the forecast, the Atlantic subtropical ridge will generally remain in place into this weekend. The pressure gradient across the region will sustain fresh to strong trade winds in the south- central basin through the forecast period, with highest winds and seas expected off the coast of Colombia. Pulsing winds at fresh to strong speeds are expected in the Gulf of Honduras nightly through Sat, pulsing to near gale-force Wed night and Thu night. Gentle to moderate winds elsewhere across the northwestern Caribbean will become SE at fresh to strong speeds Wed through Thu night, then will diminish through the weekend.

Atlantic Ocean

An expansive subtropical ridge dominates the tropical Atlantic, extending from 1022 mb high pressure southeast of the Azores, southwestward into the central Atlantic and then westward along 26N and across south Florida. This pattern is supporting fresh to locally strong easterly trade winds and seas of 5-8 ft south of 23N and between 65W and 75W. Moderate to fresh SW winds and moderate seas are occurring north of 28N and west of 67W. South of the ridge, moderate to locally fresh easterly winds and seas of 5-8 ft are found south of 20N and west of 35W. In the far east, moderate to fresh N-NE winds and seas of 5-8 ft are present north of 18N and east of 25W. Elsewhere, moderate or weaker winds and moderate seas are prevalent.

For the forecast west of 55W, the Atlantic ridge will change little through Fri, then begin to weaken Fri night. 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 fresh SW winds offshore of northeast Florida to near 67W are occurring ahead of a surface trough. These winds will expand eastward to near 65W through Wed, as a weak frontal system moves across the southeastern U.S. The front is expected to move offshore early Sat and stall offshore northeast Florida to Bermuda by Sun. Expect fresh to strong winds each afternoon through late evening across Atlantic waters near Puerto Rico and Hispaniola.

Posted 0 minutes ago by NHC Forecaster Stripling