000 AXNT20 KNHC 040003 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 803 PM EDT Tue Jul 3 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...TROPICAL WAVES... A tropical wave has an axis extending from 16N35W to 02N36W and is moving W around 10 kt. The wave coincides with a surge of moisture as noted in the TPW product, but African dust surrounds the northern side of the wave and is inhibiting convection there. Scattered moderate convection is seen where the wave meets the monsoon trough from 01N to 10N between 30W and 38W. A tropical wave is along 60W from 05N-19N. This feature is moving W around 10 kt. The low level cloud field associated with this wave exhibits an inverted-V signature. This wave shows up well in the TPW animation where a pronounced bulge of moisture is observed. Scattered moderate convection is noted along the wave's axis S of 15N. Th wave will move across the Windward Islands this evening, entering the eastern Caribbean tonight. Expect scattered showers and isolated tstms with the wave passage. A tropical wave has an axis extending along 80W from central Cuba to the coast of Panama, moving westward at around 15 knots. The wave is well depicted in the moisture product. The monsoon trough extends E over the SW Caribbean from Costa Rica to northern Colombia. Clusters of scattered moderate to isolated strong convection are noted ahead of the wave's axis. This convective activity is affecting parts of Nicaragua and Honduras. The wave will 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 extends SW to 05N37W. The ITCZ continues from 05N37W to 06N55W. Aside from the convection associated with the tropical waves, scattered moderate convection is near 10N26W, and near 08N51W. ...DISCUSSION... GULF OF MEXICO... A trough extends SW from a weak 1014 mb surface low centered near the mouth of the Mississippi to near 28N94W. Scattered to numerous showers and tstms are noted near the low/trough and over Louisiana. Lightning density indicates frequent lightning with much of the observed convection. This system is forecast to weaken and slowly move W toward NE Texas through Wed. 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 waters. This pattern will change little over the next 24-48 hours. A surface trough will emerge off the Yucatan Peninsula each evening through Thu, enhancing nocturnal winds over the SW Gulf. CARIBBEAN SEA... A tropical wave is moving across the central Caribbean. Please see the Tropical Waves section for details. A recent ASCAT pass provides observations of fresh trades over the south-central Caribbean, with moderate to locally fresh winds elsewhere S of 18N E of 80W. Light to gentle winds are noted over the NW Caribbean. Winds are forecast to increase across the central Caribbean tonight. Marine guidance suggests winds in the 25-30 kt range over the south-central Caribbean, with building seas to 10-12 ft by early Wed morning. Near gale force NE winds are possible near the coast of Colombia Wed night and Thu night. ATLANTIC OCEAN... A surface trough, reflection of an upper level cyclonic circulation, extends from 32N71W to the central Bahamas near 24N77W. Scattered showers and isolated tstms are seen ahead of the trough forecast to move across the NW Bahamas and over Florida Wed and Wed night. A second trough will develop near Bermuda and extending SW into the forecast waters. This trough will shift NW of the area by the end of the week. High pressure will build in its wake. Winds N of Hispaniola will pulse to strong speed each day during the afternoon and evening beginning on Wed. Surface high pressure of 1032 mb located W of the Azores 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. For additional information please visit http://www.hurricanes.gov/marine $$ GR