000 AXNT20 KNHC 232236 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 636 PM EDT Fri Jun 23 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 1800 UTC surface analysis and satellite imagery through 2145 UTC. ...TROPICAL WAVES... Tropical wave extends from 08N27W to 20N24W moving W at 15-20 kt. The wave coincides with a relatively sharp 700 mb trough between 21W-30W and an area of maximum 850 mb relative vorticity along the axis from 11N-20N. With the Saharan dust in place over much of the eastern Atlc waters E of 45W...only isolated moderate convection is occurring in the vicinity of 10N27W embedded within the ITCZ and near 24N21W at the northern extent of the wave. Tropical wave extends from 04N48W to 13N48W moving W at 15-20 kt. Broad and low-amplitude 700 mb troughing is noted between 45W-52W with 850 mb relative vorticity maximized along the wave axis near 10N. Widely scattered moderate convection is from 04N-13N between 46W-52W. Tropical wave extends from 04N66W to 15N64W moving W at 15 kt. The wave is moving within the southwestern periphery of 700 mb troughing over the eastern Caribbean Sea and an area to the NE of the Lesser Antilles to near 22N55W. This broad troughing aloft has allowed wave energy to fracture to the NE of the axis and thus is analyzed as a weak surface trough from 16N63W to 20N57W. Scattered moderate convection remains mostly contained S of 12N between 61W-67W across eastern Venezuela and Trinidad this evening...however isolated showers are also possible from 13N-20N between 56W-67W across Caribbean and Atlc waters. Tropical wave extends from 11N91W to 19N89W moving W at 15-20 kt. The wave coincides with subtle 700 mb troughing between 86W-92W as it approaches a developing area of low pressure centered S-SW of the Gulf of Tehuantepec in the East Pacific waters near 13N96W. As the energy of the wave becomes absorbed into the low pressure area during the next 24 to 36 hours...it will likely continue to provide a focus for scattered showers and tstms across portions of Central America and southern Mexico. In addition...an upper level low is centered 20N91W that is providing ample lifting dynamics across the area to support continued convection. Widely scattered moderate convection is from 12N-23N between 81W-92W. ...MONSOON TROUGH/ITCZ... The Monsoon Trough extends from 13N17W to 09N24W. The Intertropical Convergence Zone axis extends from 09N24W to 03N39W to 05N48W to 06N54W. Aside from convection associated with the tropical waves...scattered moderate convection is from 01N-06N between 40W-45W...and S of 07N between 53W-57W across interior portions of French Guiana and Suriname. ...DISCUSSION... GULF OF MEXICO... Surface ridging extends from the SW North Atlc anchored by a 1021 mb high centered near 30N68W W-SW to near Brownsville Texas this evening. The ridge supports moderate to fresh S-SE winds across the basin that are forecast to shift E-SE on Saturday as the ridge retreats E Saturday night into Sunday. While the ridge is providing overall fair conditions for the northern Gulf...an upper level low is centered over the SW Gulf waters near 20N91W. Middle to upper level lifting dynamics are generating isolated showers and tstms across the SE and S-central Gulf this evening S of 25N between 82W-90W. By Saturday night into Sunday...a weak frontal boundary is expected to impact the northern waters as it stalls along 30N and dissipates by Sunday night. CARIBBEAN SEA... An upper level low is centered over the SW Gulf of Mexico near 20N91W supporting widely scattered showers and tstms across portions of Central America and the NW Caribbean waters generally N of 12N W of 81W. The presence of a tropical wave across the Yucatan peninsula and Guatemala is providing additional focus for this convective activity. Farther east...another tropical wave is analyzed across the SE Caribbean generating scattered showers and isolated tstms S of 12N between 61W-65W. Energy from the wave continues to fracture to the NE of the axis as a weak surface trough extends from 16N63W to 21N57W. Both the northern extent of the wave and the surface trough are generating isolated showers occurring across much of the eastern Caribbean waters...Puerto Rico...the US/UK Virgin Islands...and Lesser Antilles. Otherwise...moderate to fresh trades are expected to persist overnight and gradually strengthen into fresh to strong breeze levels Saturday across the central waters. Little change is expected thereafter for the early portion of next week. ...HISPANIOLA... Mostly clear skies prevail currently across the island this evening as surface ridging to the N across the SW North Atlc remains in place providing mostly fair weather conditions. In addition...an upper level anticyclone centered N of the island is continuing to provide NE flow aloft and an environment of overall subsidence. ATLANTIC OCEAN... An upper level anticyclonic circulation is centered offshore of NE Florida near 29N78W that continues to support a 1021 mb high centered SW of Bermuda near 30N68W. Most cloudiness and isolated showers and tstms remain N of 30N between 63W-71W...with generally gentle to moderate winds prevailing within the southern periphery of the ridging. Otherwise...the remainder of the central and eastern Atlc is under the influence of surface ridging anchored by a 1023 mb high centered near 34N47W and a 1029 mb high centered N of the Azores near 40N26W. Water vapor imagery indicates a middle to upper level low is centered near 26N53W and is inducing a weak surface trough extending from 24N49W to 27N46W. Isolated showers and possible tstms are occurring from 24N-29N between 46W-52W. For additional information please visit http://www.hurricanes.gov/marine $$ HUFFMAN