000 AXNT20 KNHC 172349 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 749 PM EDT Tue Oct 17 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 2345 UTC. ...SPECIAL FEATURES... A frontal boundary extends from central Florida to the Bay of Campeche in the SW Gulf. Strong high pressure west of the front supports gale-force northerly winds south of 21N west of 95W. The front is expected to gradually weaken through Wednesday night with winds decreasing below gale-force tonight. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/KNHC for more details. ...TROPICAL WAVES... A tropical wave extends its axis from 14N56W to 07N57W, moving west at 10-15 kt. The wave coincides with troughing at 700 mb troughing and a maximum in 850 mb relative vorticity. Scattered moderate convection is from 07N-13N between 54W-60W. A tropical wave is moving across the eastern Caribbean extending its axis from 16N64W to 07N64W, moving west at 10-15 kt. The wave coincides with troughing at 700 mb troughing and a maximum in 850 mb relative vorticity. At this time, no significant convection is related to this feature. A tropical wave is over the western Caribbean with axis from 16N81W to 04N81W, moving west at 10-15 kt. The wave coincides with broad 700 mb troughing west of 80W. Scattered moderate to strong convection is south of 15N and west of 80W. ...ITCZ/MONSOON TROUGH... The African monsoon trough extends from 09N14W to 08N25W. The ITCZ continues from 08N25W to 07N52W. Scattered moderate convection is from 06N-10N between 37W-50W. ...DISCUSSION... GULF OF MEXICO... The frontal boundary mentioned in the section above is supported aloft by an upper-level trough pushing into the north-central Gulf. Scattered showers are occurring along and southeast of the front. As of 1800 UTC, the front was analyzed as a cold front over the eastern Gulf along 26N to 85W, then stationary from that point to 24N92W to 18N94W. The front will gradually become diffuse through Wednesday night. Fresh to strong northerly winds will prevail behind the front through early Wednesday and then weaken through Thursday. Surface ridging is expected to remain in place across the basin through the rest of the week. CARIBBEAN SEA... Two low amplitude tropical waves are moving across the basin See the section above for details. The eastern extension of the Pacific monsoon trough is analyzed from 10N83W to 09N76W. An upper-level anticyclone centered over the west Caribbean near 16N81W supports mostly dry air aloft across the region. Scatterometer data shows fresh easterly winds in the eastern Caribbean, and gentle to moderate easterly winds west of 75W. ...HISPANIOLA... A line of showers is slowly moving over the southwestern portion of the island. This activity will dissipate overnight. A tropical wave will move south of the island by Wednesday and Thursday, increasing the potential for convection. ATLANTIC OCEAN... A cold front extends across the western Atlantic from 32N70W to central Florida. Scattered showers are occurring within 180 nm to the north of the front. To the east, a surface trough extends from a low near 33N67W to 24N72W. This feature is the reflection of an upper-level trough. Scattered showers are within 240 nm of the trough. Another surface trough extends from 31N42W to 22N46W. A broad ridge anchored by 1030 mb high pressure centered near 33N38W dominates the remainder of the basin. For additional information please visit http://www.hurricanes.gov/marine $$ ERA