673 AXNT20 KNHC 150006 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 806 PM EDT Sat Jul 14 2018 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... Subtropical storm Beryl is centered near 37.3N 65.2W as of 14/2100 UTC or about 345 mi north of Bermuda, moving NE at 12 kt. Estimated minimum central pressure is 1010 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Little change in strength is forecast through Sunday. After that, Beryl should weaken as it moves over colder water, and the cyclone is expected to degenerate into a remnant low pressure area by Monday. Scattered moderate convection is within 120 nm north and south of the center. Refer to the latest NHC Forecast/Advisory under AWIPS/WMO headers MIATCMAT2/WTNT22 KNHC and high seas forecasts issued by the National Weather Service under AWIPS header NFDHSFAT1 and WMO header FZNT01 for more information. SW Caribbean gale warning off the coast of Colombia: NE gale force winds are forecast to resume near 0600 UTC Sun and continue through Sun afternoon hours. The pressure gradient will tighten up again Sun evening, and gale force winds will resume once more into early Mon within the same area. Model guidance indicates that these winds will once again pulse to minimal gale force Tue night until early on Wed morning. Seas are expected to build to the range of about 10-14 ft with these wind conditions. Please read the High Seas Forecast, under the AWIPS/WMO headers HSFAT2/FZNT02 KNHC, for more details. ...TROPICAL WAVES... An E Atlantic tropical wave has its axis along 22W from 05N to 18N, moving westward at 10-15 kt. Scattered moderate convection is in the southern wave environment associated with the monsoon trough. This convection is from 06N-10N between 17W-31W. The remainder wave environment lacks convection as it continues under the influence of Saharan dry air and dust. A central Atlantic tropical wave has its axis extending from near 05N53W to 21N49W, moving W at 15-20 kt. The wave continues to move through a rather dry and stable environment, and is void of deep convection. A central Caribbean Sea tropical wave has its axis along 70W, moving W at 15 kt. The wave is supporting scattered moderate isolated strong convection in NW Haiti and isolated showers over the central Caribbean between 66W and 74W. The leading edge of the Saharan Air layer (SAL) as noted from Univ. of Wisconsin CIMSS and as observed in the GOES-16 RGB Geocolor and dust images has entered the far eastern Caribbean Sea in the wake of the wave. A central Caribbean Sea tropical wave has its axis along 78W, moving westward near 15 kt. Its northern extent reaches to eastern Cuba where it supports scattered showers. No convection is noted elsewhere. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coastal areas of Africa near 10N14W to 07N30W, where latest scatterometer data indicates that it transitions to the ITCZ to 08N40W to 08N58W. For information about convection see the tropical waves section. ...DISCUSSION... GULF OF MEXICO... High pressure ridging from a 1021 mb high center at 26N91W as of 18Z continues to dominate the basin allowing for generally light to gentle anticyclonic flow to prevail through most of next week. Seas will remain on the rather low side, generally under 5 ft. Gentle to moderate southeast to south winds will continue over the western part of the gulf through the next few days. Per latest GOES-16 RGB Geocolor imagery, African dust has reached the SE Gulf, including the Yucatan Channel. A surface trough will move westward off the Yucatan Peninsula each evening through Wednesday. It will enhance nocturnal winds in the SW corner of the Gulf. CARIBBEAN SEA... Two tropical waves will continue to move across the basin. Refer to the Tropical Waves section above for details. A gale warning is in effect for the waters near the coast of Colombia. Refer to the Special Features section above for more information on this event. The tropical wave along 78W will move across the remainder of the central through early this evening, then across the western Caribbean tonight through Mon night. The eastern Caribbean Sea tropical wave along 66W/67W will move through the rest of the eastern Caribbean Sea through Sun afternoon. Drier air and haze attributed to the Saharan Air Layer (SAL) will filter across the eastern and central Caribbean in the wake of the wave into Mon. The shower and thunderstorm activity may be further aided by an upper-level trough that extends from the Mona Passage to the far SW Caribbean. An extensive area of dry sinking air is evident on water vapor imagery to the west of the trough. This wave is forecast to move across the central Caribbean Sun night tonight through Mon night and the western Caribbean Tue. This wave is expected to lack deep convection as it moves across the central and western Caribbean as it will be moving through a very dry and stable environment. The gradient behind the waves will tighten enough to freshen trade winds across the central Caribbean Sea well into next week. ATLANTIC OCEAN... Newly formed subtropical storm Beryl is well north of the area. See Special Features section above for the latest information on this system. A surface trough extends from 32N68W 28N72W and to the northwestern Bahamas. Scattered to numerous showers and thunderstorms are noted southeast and south of the trough north of 27N between a line from 32N62W to 27N65W and 73W. The trough will move little through Sun night while weakening. The remainder of the Atlantic forecast area is under the influence of the Bermuda-Azores High, with a center of 1033 mb located WNW of the Azores near 37N41W. Its associated ridge extends southwestward to the northeastern Caribbean and the SE Bahamas. High pressure building westward from the central Atlantic through Tue will support fresh to strong trade winds south of 23N W of 65W. Winds will pulse to strong north of Hispaniola at night this weekend. High pressure building westward from the central Atlantic Ocean through Wed will support fresh to strong trade winds south of 23N. The winds will pulse to strong north of Hispaniola at night through early Mon. For additional information please visit http://www.hurricanes.gov/marine $$ JA/NR