000 AXNT20 KNHC 182345 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 745 PM EDT SAT JUN 18 2016 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 2345 UTC. ...SPECIAL FEATURE... A surface low pressure has formed along the northwestern coast of the Yucatan peninsula near 20N91W. Scattered to numerous showers and thunderstorms is S of 22N between 90W-94W. This low is forecast to move slowly to the west-northwestward during the next couple of days across the southwestern Gulf of Mexico. This system has a medium chance of developing into a tropical cyclone during the next 48 hours. Please refer to the Atlantic Tropical Weather Outlook under AWIPS/WMO headers TWOAT/ABNT20 KNHC for more details. ...TROPICAL WAVES... A tropical wave is in the E tropical Atlantic with axis from 10N22W to 03N24W, moving W at 15 kt during the last 24 hours. The wave coincides with broad 700 mb troughing between 16W and 28W according to the GFS model. No significant convection is related to this wave at this time. A tropical wave is over the W tropical Atlantic with axis from 13N52W to 05N54W, moving W at 15 kt during the last 24 hours. The wave coincides with broad 700 mb troughing between 50W and 60W according to the GFS model and visible satellite imagery depicts the classic inverted V pattern. Isolated convection is observed within the wave between 50W-57W. A tropical wave is crossing the Windward Islands with axis from 16N59W to 09N61W, moving W at 15 kt during the last 24 hours. The wave coincides with 700 mb troughing between 58W-66W according to the GFS model. Isolated convection prevails within this wave between 60W-65W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 12N16W to 07N22W, then resumes W of a tropical wave from 06N24W to 05N31W. The ITCZ axis continues from 05N31W to 04N51W. Aside from the convection associated with the tropical waves, scattered moderate convection is located from 03N-06N between 27W-32W. ...DISCUSSION... GULF OF MEXICO... A surface low has formed along the western coast of the Yucatan Peninsula. Please see the special features section for details. To the E, a 1018 mb surface high is centered near 25N85W. A pre-frontal trough extends across the northeastern Gulf waters from 29N91W to 28N86W to 29N84W. A cold front extends across northern Florida enhancing convection across the peninsula. Scatterometer data depicts a gentle to moderate easterly flow across the western Gulf while a gentle to moderate westerly flow prevails east of 90W. Expect a similar weather pattern to prevail during the next 24 hours, with convection prevailing over the southwest and northeast portions of the basin. CARIBBEAN SEA... The surface low pressure along the W coast of the Yucatan Peninsula is supporting scattered moderate convection across the W Caribbean W of 82W. The only feature of interest at this time is the tropical wave that is currently moving across the Lesser Antilles. Please refer to the section above for details. Scatterometer data depicts moderate to fresh trades across the basin. Expect for the tropical wave to continue moving west across the area during the next 24 hours. Another wave will approach the E Caribbean with convection. ...HISPANIOLA... Low-level moisture transported by the trades is moving across the island generating isolated showers and thunderstorms. This activity will dissipate in the evening hours. Afternoon convection is expected once again on Sunday. ATLANTIC OCEAN... A cold front extends across the W Atlantic from 30N81W to 1011 mb low near 31N71W. Scattered to numerous showers and thunderstorms are observed along and S of the frontal boundary affecting the Atlantic waters W of 68W. Three tropical waves were analyzed across the basin. PLease refer to the section above for details. The remainder of the basin is under a surface ridge anchored by a 1034 mb high near 40N20W. Expect for the cold front to continue enhancing convection across the W Atlantic during the next 24 hours. Surface ridging will prevail elsewhere. For additional information please visit http://www.hurricanes.gov/marine $$ ERA