000 AXNT20 KNHC 280519 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 119 AM EDT Wed Jun 28 2017 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 tropical wave has its axis just off the coast of Africa along 18W from 12N to 20N, moving westward at around 10 kt. Low-level moisture is limited within this wave, therefore, no convection is associated with this feature at this time. A tropical wave has its axis from 11N32W to 01N34W, moving westward at 10-15 kt. Last visible satellite imagery and TPW data reveals that the wave remains embedded within a very moist environment, except for over its eastern region where Saharan dry air and dust is present. Isolated moderate convection is noted north of 07N between 34W-37W. A broad tropical wave has its axis tilted from 15N55W to 06N59W, moving westward 15-20 kt. This wave continues to be easily identifiable on satellite imagery as having the typical configuration of waves observed later during the season. It is detected in the model fields, and is further supported by the latest diagnostic model analysis. Scattered moderate convection is observed from 07N-15N between 53W-64W. The wave is forecast to continue moving west affecting the eastern and central Caribbean waters through Thursday. A tropical wave is moving into the western Caribbean Sea with its axis along 81W from 08N to 21N, moving westward at 10-15 kt. This wave is also evident in satellite imagery, and continues to mark the leading surge of very deep atmospheric moisture as seen in TPW data. Isolated moderate convection is observed in the vicinity of this wave between 77W-83W. The wave will move across the remainder of the western Caribbean Sea through Wednesday, and inland Central America Wednesday night. A tropical wave is just west of the Yucatan Peninsula near 91W and south of 22N, and extends southward to inland southeastern Mexico, moving westward around 10 kt. The wave has contributed to the typical diurnal convection that occurs over the Yucatan peninsula. Increasing clusters of scattered strong convection are noted over much of the interior of the Yucatan peninsula as well as the northern portion of Guatemala. This activity is beginning to spread into the far eastern section of Mexico. This wave will most likely become ill-defined over the SW Gulf on Wednesday, however the southern extent of the wave is expected to continue on westward over the eastern Pacific Ocean. ...MONSOON TROUGH/ITCZ... The Monsoon Trough extends from the coast of Africa near 19N16W, and continues southwest to 08N29W. The Intertropical Convergence Zone then extends from 06N35W to 10N53W. Isolated moderate convection is within 200 nm on either side of the ITCZ axis. ...DISCUSSION... GULF OF MEXICO... A mid to upper level trough axis is over the far northwest Gulf, while a surface trough is along the Texas coast. The combination of these features along with the presence of diffluent flow aloft east of the mid-upper level trough continues to support isolated showers and thunderstorms mainly north of 24N and west of 89W. A stationary front is analyzed from NE Florida southwest to near Cross City, Florida and to 29N86W where it becomes diffuse from there to just east of southeastern Louisiana. The shower and thunderstorm activity over the western Gulf is forecast to remain active through today, then shift northeast by tonight and Thursday as the mid/upper level trough slides eastward. The stationary frontal boundary is forecast to gradually become diffuse through the morning hours, with the remnants lifting back to the north through tonight. A tropical wave is over the eastern Bay of Campeche. Associated convection is described in the section above. CARIBBEAN SEA... The main feature presently in the basin is a tropical wave currently over the western Caribbean, and the near-future arrival of another tropical wave which is approaching the Lesser Antilles at this time. These features are discussed in the section above. Aside from the convection related to the tropical waves, fair weather prevails elsewhere. Scatterometer data depicts moderate to fresh trades across the basin. The pressure gradient is forecast to tighten over portions of the far south-central Caribbean beginning tonight and continuing through Thursday night inducing strong to near-gale force east winds over this area, with the near-gale force winds expected across and near the Gulf of Venezuela. ...HISPANIOLA... Fair weather prevails across the island at this time. Little change is expected in the present weather pattern through the next 24 hours. Convection is expected once again by the end of the week as a tropical wave approaches. ATLANTIC OCEAN... Three tropical waves are moving across the tropical Atlantic. Refer to the section above for details. A broad mid to upper trough extends southwestward from along the eastern seaboard to the far northwest portion of the basin. It supports a stationary front that extends through 32N75W to 30N81W. Scattered showers and thunderstorms are noted north of the Bahamas and west of about 75W. This activity will continue through much of today and tonight as the surface boundary weakens, and the mid to upper trough slides eastward while it broadens out further. A surface trough extends from 30N56W to 26N57W with scattered showers. This trough is a reflection of an upper-level low centered in the same area. A broad high pressure prevails across the remainder of the basin, anchored by a 1028 mb surface high centered near 36N40W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA