000 AXNT20 KNHC 040510 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 110 AM EDT Wed Jul 4 2018 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...TROPICAL WAVES... A vigorous tropical wave is producing a concentrated area of showers and thunderstorms several hundred miles southwest of the Cabo Verde Islands. As of 0000 UTC, this tropical wave is relocated farther E, and now extends from 16N31W to 04N32W. A 1010 mb low pressure has developed along the wave's axis near 09N32W. Although satellite images show some signs of organization, the disturbance is moving west-northwestward toward an area unfavorable for tropical cyclone formation. Currently, the Tropical Weather Outlook gives this system a low change of development through 48 hours. A tropical wave has entered the Caribbean Sea. Its axis is along 62W, and is generating scattered showers and isolated tstms over the Windward Islands as well as over the eastern Caribbean mainly S of 15N E of 65W. A recent scatterometer pass clearly indicates the wind shift associated with the wave axis, with fresh to locally strong SE winds just E of the Windward Islands. Gusty winds to near 35 kt have been reported in the Windward Islands with the wave passage. Moisture associated with this wave will remain S of Puerto Rico and the VIrgin Islands. The wave will reach the central Caribbean late Wed into Thu, and the western Caribbean by Fri. Another tropical wave is over the western Caribbean, and has an axis extending along 82W. A large area of moderate to isolated strong convection is at the base of the wave and covers the waters from 12N-15N between 80W and the coast of Nicaragua. Abundant moisture associated with this wave will spread over parts of Nicaragua and Honduras, including also the Gulf of Honduras today, bringing scattered showers and tstms. The wave is forecast to move west of the area by Thu. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean from the coast of of Guinea-Bissau near 12N16W, then continues westward to a 1010 mb low pressure located near 09N32W to 05N40W. The ITCZ stretches from 05N40W to the coast of Guyana near 06N58W. Aside from the convection associated with the tropical waves, scattered moderate to isolated strong convection is seen from 01N-05N between 30W- 37W. Scattered moderate is from 06N-08N between 35W-42W. ...DISCUSSION... GULF OF MEXICO... A trough extends from a 1014 mb low centered in southern Louisiana near 30N92W to 28N89W to 25N90W. Widespread showers with embedded tstms are noted N of 26N and W of the trough to about 94W. Lightning density indicates frequent lightning with much of the observed convection, more concentrated now over the upper Texas coast. This convective low pressure system will continue to enhance showers and thunderstorms system across the northern Gulf states from southern Mississippi to SE Texas today. The remainder of the Gulf remains under the influence of a weak ridge extending W from the Atlantic. This system is producing mainly light to gentle anticyclonic flow and seas of 1-3 ft across much of the Gulf region. This pattern will change little over the next 48 hours. A surface trough will emerge off the Yucatan Peninsula each evening through Sat, enhancing nocturnal winds over the SW Gulf. CARIBBEAN SEA... Two tropical waves are moving across the Caribbean Sea. Please see the Tropical Waves section for details. A recent ASCAT pass provides observations of fresh to strong winds across the central Caribbean between 70W-75W. Fresh winds are noted over the eastern Caribbean, and gentle to moderate winds over the NW Caribbean, including the Yucatan Channel. Fresh to strong trades are expected across much of the area S of 18N and E of 83W through at least Fri. Winds will approach gale force near the coast of Colombia Thu night through Fri night. ATLANTIC OCEAN... As of 0300 UTC, a surface trough, reflection of an upper level cyclonic circulation, extends from 32N78W to 24N79W. Scattered showers and isolated tstms are observed ahead of the trough axis forecast to move west into Florida through tonight. An area of cloudiness and showers remains a few hundred miles southeast of Bermuda. Although this disturbance is currently disorganized, environmental conditions could become more conducive for a low pressure system to form by late this week in the area southwest of Bermuda. The system is then forecast to move generally northward over the weekend and begin interacting with a frontal system on Sunday, which would limit any additional development. Surface high pressure of 1032 mb located W of the Azores near 37N39W extends a ridge across the remainder of the central and eastern Atlantic forecast waters. Moderate to fresh trade winds are noted along the southern periphery of the ridge, which reaches the NE Caribbean. For additional information please visit http://www.hurricanes.gov/marine $$ GR