000 AXNT20 KNHC 031203 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 803 AM 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 0600 UTC surface analysis and satellite imagery through 1145 UTC. ...TROPICAL WAVES... A tropical wave has an axis extending from 16N33W to 04N34W 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 within the moister southern portion of the wave from 01N to 08N between 30W and 36W. A tropical wave extends from 19N52W to 05N53W. 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. This wave remains surrounded by Saharan dust which is limiting convection in the vicinity of this wave. Only a small cluster of moderate convection is noted E of the wave axis from 09N to 11N between 49W and 51W. Moisture associated with this wave will begin reaching the Windward Islands early this afternoon and bring a modest increase in chances for showers and thunderstorms for this area during the next day or so. A tropical wave has an axis extending from the eastern Cuba near 21N76W to the coast of Colombia 08N77W, moving westward at around 20 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 near 10N74W. The tropical wave is interacting with the trough to generate numerous moderate and isolated strong convection from 11N to 13N between 81W and 84W. Scattered moderate and isolated strong convection is found elsewhere within 120 nm of a line from 08N75W to 14N83W. Model guidance indicates that the abundant moisture associated with this wave will spread W from the SW Caribbean over Nicaragua and Honduras this afternoon and tonight. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic Ocean from the coast of Senegal near 14N17W, then extends SW to 04N37W. The ITCZ continues from 04N37W to 04N45W to the coast of French Guiana near 05N53W. Aside from the convection associated with the tropical waves, cloudiness and isolated moderate convection is observed within 150 nm of a line from 11N16W to 07N28W and within 120 nm of a line from 03N38W to 07N46W. ...DISCUSSION... GULF OF MEXICO... A trough curves SSW from a weak 1014 mb surface low centered near the mouth of the Mississippi to near 24N90W. Scattered moderate convection is noted from 28N to 30N between 87W and 92W. 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 ridging curving W over the basin from the Atlantic. The ridge is manifested over the western Gulf in the form of two weak 1017 mb high pressure centers located near 27N94W and near 23N97W. The area of high pressure 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 through mid week. A surface trough will emerge off the Yucatan Peninsula each evening through the end of the week and generate moderate to fresh nocturnal winds over the SW Gulf. CARIBBEAN SEA... Satellite-derived wind data from 02Z this morning indicates moderate to fresh trades in the central and eastern Caribbean Sea, while surface observations show winds are light in the western Caribbean Sea. Winds are forecast to increase across the central Caribbean Sea beginning tonight, as high pressure to the north builds. Forecast models suggest that the wind speeds will be in the 25-30 kt range in the south central Caribbean Sea, with seas building to 10 to 12 feet by early Wednesday morning. Convection continues to flare up over the SW Caribbean Sea mainly in the vicinity of the monsoon trough. This pattern will remain in place for the next several days, even after the tropical wave departs. The Cuba-to-Panama broad tropical wave will enter the western Caribbean Sea on Wednesday, and arrive across Central America and the Yucatan Peninsula on Thursday morning. The next tropical wave to affect the Caribbean is in the tropical Atlantic Ocean along 52W/53W. This wave will move across the tropical N Atlantic Ocean, and enter the eastern Caribbean Sea this afternoon, reaching the central Caribbean Sea on Thursday and into the western Caribbean Sea on Friday. Fresh winds in the central Caribbean Sea will become strong from Wednesday through Friday night. Near gale force NE winds are possible near the coast of Colombia on Thursday night and Friday night. ATLANTIC OCEAN... An upper level cyclonic circulation center is near 29N73W, about 270 nm to the NNE of the NW Bahamas. Upper level cyclonic wind flow that is moving around the 29N73W center covers the Atlantic Ocean and the Gulf of Mexico from 23N northward between 65W and 85W. A surface trough is along 31N69W, to a 1015 mb low pressure center that is near 27N71W, with the trough curving to Andros Island in the Bahamas. Precipitation: isolated moderate to locally strong rainshowers cover the Gulf of Mexico and the Atlantic Ocean from 20N to 32N between 65W and 86W. Widely scattered moderate to isolated strong rainshowers are in the Atlantic Ocean from 24N northward between 58W and 65W. The low pressure center that is near 27N71W has weakened the surface ridge that covers the western Atlantic Ocean. The low center will move SW toward the Bahamas today and tonight. The high will rebuild and strengthen from Wednesday through Saturday night, as the low weakens into a trough and tracks across the NW Bahamas and over Florida on Wednesday and Wednesday night. The wind speeds to the N of Hispaniola will pulse to strong each day during the afternoon and evening beginning on Wednesday. Generally tranquil marine conditions are expected in the remainder of the area through the period. For additional information please visit http://www.hurricanes.gov/marine $$ CAM/MT