000 AXNT20 KNHC 211037 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 636 AM EDT Fri Apr 21 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 0600 UTC surface analysis and satellite imagery through 1030 UTC. ...SPECIAL FEATURES... The center of T.S. Arlene is located 40.0N 48.0W and is moving west at 27 knots. The estimated minimum central pressure is 993 mb. The maximum sustained wind speeds is 45 knots with gusts to 55 knots. Scattered moderate convection is observed from 39N-42N between 33W-49W. Please refer to the public advisory under the WMO header WTNT31 KNHC and under the AWIPS header MIATCPAT1 for more details. A tight pressure gradient generated between a broad low pressure system centered southwest of T.S. Arlene and a high pressure to the west is supporting gale-force winds north of 30N between 49W- 54W. Seas in this area will range between 12 to 19 ft this afternoon. These conditions will continue through the evening hours. Please see the latest High Seas Forecast product under the WMO header FZNT02 KNHC and under the AWIPS header MIAHSFAT2 for further details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across the western Africa coast from 11N15W to 03N19W. The Intertropical Convergence Zone continues from 03N19W to the coast of Brazil near 03S41W. Scattered moderate convection prevails from 04N-10S and east of 30W. ...DISCUSSION... GULF OF MEXICO... A mid to upper-level low is centered northwest of the Yucatan Peninsula near 23N91W. A diffluent flow aloft prevails to the east of the low supporting scattered moderate convection from 20N-26N between 80W-90W. A surface trough accompanies this convection, extending from the western Caribbean across the Yucatan Channel to 24N85W. A surface ridge extends across the basin anchored by a 1021 mb high centered over the west Atlantic. A 1019 mb surface high is centered over the Florida Panhandle near 30N85W. Scatterometer data depicts gentle to moderate easterly winds across the northern half of the basin while moderate to fresh easterlies prevail south of 26N. Expect for the upper-level low to dissipate in 24 hours. The surface trough is forecast to become a center of low pressure this weekend over the southeast Gulf. The low will move over northeast Gulf waters where it will dissipate by Sunday. CARIBBEAN SEA... The main feature in the basin is a surface trough that extends from 24N84W to 16N87W. This elongated area of low pressure is located under a broad area of mid to upper-level diffluent flow that along with abundant moisture in the region supports scattered to numerous showers mainly north of 20N west of 79W. This shower activity will continue today as the trough moves slowly west towards the Yucatan Peninsula. Latest scatterometer data depicts fresh to locally strong easterly winds in the vicinity of the trough. An area of fresh trades extends across the central Caribbean north of 14N, including the Windward Passage. Moderate trades dominate elsewhere. ...HISPANIOLA... Broken to overcast skies persist across the island with possible isolated showers over the adjacent waters. These conditions are expected to continue during the next two days. ATLANTIC OCEAN... T.S. Arlene is over central Atlantic waters north of the area. Gale-force winds have developed south of a 990 mb surface low located southwest of Arlene. See the Special Features section above for further details. A surface ridge extends across the western Atlantic anchored by a 1021 mb high centered near 31N70W. To the east, a cold front enters the area from 31N41W to 25N45W to 22N54W. A surface trough, previously part of the front, extends from 22N62W to 26N75W. No convection is associated with these boundaries at this time. A surface ridge dominates the remainder of the area, anchored by a 1018 mb high centered near 27N23W. T.S. Arlene is forecast to dissipate in 24 hours. The area of gale- force winds will dissipate in 24 hours. For additional information please visit http://www.hurricanes.gov/marine $$ ERA