342 AXNT20 KNHC 141804 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 204 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 1200 UTC surface analysis and satellite imagery through 1745 UTC. ...SPECIAL FEATURES... What was earlier an area of low pressure associated with the remnants of Beryl has regenerated into subtropical storm Beryl centered near 36.4N 65.7W as of 14/1700 UTC or about 250 nm north of Bermuda, moving NE at 10 kt. Estimated minimum central pressure is 101 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Beryl is forecast to maintain intensity through Sun, then weaken to a depression afterwards as it continues on a northeastern track motion over cold water. Satellite imagery shows scattered moderate isolated strong convection within 180 nm north- northeast 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 coast of Colombia: NE gale-force winds that occurred within 90 nm off the coast of Colombia during the overnight hours have diminished to strong to near gale force. Resultant seas with the recent gale force winds are in the 10-13 ft range from 11N-14N between 74W and 75W. The pressure gradient will tighten up again tonight into early Sun, and from Sun night into early Mon to allow for a repeat pulsing of the NE gale force winds to once again develop 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... A far eastern Atlantic broad tropical wave has its axis along 22W from 07N to 19N, moving westward at 10-15 kt. Both satellite imagery and 700 mb model diagnostic guidance correlate very well with respect to the location of this wave. The satellite imagery shows scattered moderate convection within about 270 nm to the west of the southern segment of the wave's axis within 60 nm of the monsoon trough axis. Similar convection is behind the wave from 07N-11N east of 20W to the coast of Africa. A central Atlantic tropical wave has its axis extending from near 20N48W to 10N51W. This wave is observed as having a broad inverted-V shape cloud structure as seen in satellite imagery as it moves westward at 15-20 kt. The wave is moving through a rather dry and stable environment, and is void of deep convection. Isolated showers are possible from 10N-14N between 47W-51W. An eastern Caribbean Sea tropical wave has its axis along 66W/67W S of 19N, moving westward around 16 kt. The northern portion is passing just to the south of Puerto Rico. Expect increasing moisture with scattered showers and isolated to affect some areas of the eastern Caribbean into tonight. 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 76W/77W, moving westward at 15 kt. Its northern extent reaches to eastern Cuba. No significant deep convective precipitation is noted in latest satellite imagery, however isolated showers moving quickly westward are possible near the wave axis. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from through the coastal areas of Guinea Bissau near 11N15W to 10N20W and 09N29W, where latest scatterometer data indicates that it transitions to the ITCZ to 08N38W to 09N48W to 09N55W to 09N60W. Aside from convection associated with the tropical wave along 22W, only scattered moderate convection is seen within 150 nm south and 60 nm north of the ITCZ between 41W-43W. ...DISCUSSION... GULF OF MEXICO... High pressure ridging from a 1021 mb high center at 26N91W as of 15Z 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 76W/77W 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 the next few days. For additional information please visit http://www.hurricanes.gov/marine $$ Aguirre