000 AXNT20 KNHC 181802 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 202 PM EDT Mon Jun 18 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. ...TROPICAL WAVES... A tropical wave came off the coast of Africa last night. It axis extends from 05N19W to 13N18W, moving W at 10 kt. The wave is in a low or favorable deep layer wind shear environment. However, the GOES-16 Dust RGB and Split window imagery show the wave is being affected by dry air and dust, especially in the northern wave environment. No deep convection is associated with the wave. Isolated showers are from 05N-13N between 13W-22W. A tropical wave is in the central Atlc with axis extending from 03N31W to 12N29W, moving W at 20 kt. Similar to the wave in the E Atlc, this wave is in a low or favorable deep layer wind shear environment. However, is being affected by dry air and dust, especially in the northern wave environment. No deep convection is associated with the wave at the time. A tropical wave is over the central Atlc with axis extending from 04N48W to 14N45W, moving W at 15-20 kt. GOES-16 RGB imagery show dry air and dust intrusion in the wave environment, which along with strong deep layer wind shear inhibit deep convection at the time. Shallow moisture and middle to upper level diffluence support isolated showers from 07N-12N between 45W-50W. A tropical wave is within 120 nm SE of the Windward Islands with axis extending from 06N60W to 14N58W, moving W at 15 kt. This wave is within a very moist environment and under middle to upper level diffluent flow, which is supporting scattered moderate convection from 07N to 16N between 57W and 63W. A tropical wave is in the central Caribbean with axis extending from 09N76W to 19N74W, moving W at 10 kt. The wave is in a strong or unfavorable deep layer wind shear environment and GOES-16 middle and lower level water vapor imagery show very dry air in the central Caribbean. These two factor are hindering the development of deep convection at the time. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa near 09N13W to 05N20W to 04N28W. The ITCZ begins near 03N34W and continues to 05N46W. In addition to the convection associated with the tropical waves, scattered showers are from 01N to 07N between 20W and 29W and from 05N to 11N between 50W and 56W. ...DISCUSSION... GULF OF MEXICO... Scattered to numerous heavy showers and thunderstorms are over the NW Gulf of Mexico associated with a middle to upper level low interacting with a surface trough located along the Texas coast. Development of this system is not anticipated. However, heavy rainfall and flash flooding across portions of southern and southeastern Texas are likely to continue during the next few days. The pressure gradient between this area of low pressure and a ridge anchored in the SE CONUS extending into the NE Gulf support fresh to strong SE to S winds N of 22N between 91W and 95W. The ridge is forecast to weaken by Tue evening and the winds will diminish to less than 20 kt. Light to fresh return flow will dominate across the basin thereafter through Wed night, with the strongest winds being in the western half of the basin. CARIBBEAN SEA... Strong trades across the S central Caribbean will gradually decrease in areal coverage through Tue morning as high pressure in the SW N Atlc shift east. Fresh to strong winds will pulse at night in the Gulf of Honduras through early Wed morning. Otherwise, a tropical wave moves across the central Caribbean between Jamaica and Haiti, however no convection is associated with it. See the tropical waves section for further information on this wave. A new tropical wave currently within 120 nm SE of the Windward Islands is forecast to enter the E Caribbean tonight along with showers. The wave is forecast to move S of Puerto Rico Tue morning and into the central Caribbean on Wed. ATLANTIC OCEAN... Weak surface ridging extends from the NW Atlc SSW to just N of the Bahamas into the SE CONUS and support light to gentle winds along with fair weather. Lingering moisture associated with the passage of a cold front support isolated showers across the northern and central Bahamas as well as the Florida Straits and the SE Florida seaboard. To the east, a middle to upper level trough continue to support a frontal system analyzed as a stationary front from a 1018 mb low near 29N57W SW to 26N73W. Satellite enhanced imagery along with lighting density data show scattered showers and tstms within 135 nm ahead of the front. Latest scatterometer data show fresh winds nearby the low center. Otherwise, the remainder Atlc continue under the influence of the Azores subtropical ridge being anchored by a 1030 mb high NE of the Azores Islands. The front is forecast to weaken and dissipate by Tue night. Surface ridging will dominate thereafter. For additional information please visit http://www.hurricanes.gov/marine $$ NR/AW