000 AXNT20 KNHC 262349 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 749 PM EDT Sat Aug 26 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 2330 UTC. ...SPECIAL FEATURES... Tropical Storm Harvey is centered near 29.1N 97.6W at 26/2100 UTC or about 40 nm WNW of Victoria Texas and about 50 nm ESE of San Antonio Texas. The system is stationary. Estimated minimum central pressure is 990 mb. Maximum sustained wind speed is 55 kt with gusts to 65 kt. Numerous moderate and isolated strong convection is occurring within 60 nm of the center. Scattered moderate and strong convection is seen elsewhere in the E semicircle within 240 nm of the center. See the latest Intermediate Public Advisory under AWIPS/WMO headers MIATCPAT4/WTNT34 KNHC and the full Forecast/Advisory under AWIPS/WMO headers MIATCMAT4/WTNT24 KNHC for more details. An elongated area of low pressure is stretching across north- central Florida continues to produce a large area of disorganized cloudiness and thunderstorms extending from the southwest coast of Florida northeastward into the western Atlantic. Although upper- level winds are not particularly conducive, this system has the potential to become a tropical or subtropical depression early next week after it moves off the northeast coast of Florida on Sunday. Regardless of tropical cyclone development, the low is expected to cause heavy rain and increasing winds and rough surf along the coasts of Georgia and the Carolinas through early next week. This system has a a medium chance of tropical formation within the next 48 hours. ...TROPICAL WAVES... A tropical wave extends its axis from 25N24W to 14N27W, moving slowly west at around 5-10 kt. The wave coincides with amplified 700 mb troughing in initial model field wind data. Infrared satellite imagery shows a large area of Saharan dust to the north of the wave to about 30N and west of the wave to about 40W. No deep convection is associated with this feature at this time. A tropical wave extends its axis from 22N51W to 12N50W, moving west at around 10 kt. A broad cyclonic circulation is observed along the wave's axis but not a defined low center has been found. Initial global model guidance indicates weak 700 mb troughing in conjunction with this wave. Scattered moderate convection is present from 16N-20N between 47W-55W. The northern extension of a tropical wave reaches the southern portion of the Bay of Campeche south of 20N and along 95W. Global model guidance shows modest 700 mb troughing in conjunction with this wave. The convection related to this wave prevails inland over southern Mexico and over the EPAC waters. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 15N17W to 14N35W to 13N51W. The ITCZ continues from 13N51W to 10N61W. Scattered moderate convection is from 04N to 18N and east of 20W. ...DISCUSSION... GULF OF MEXICO... The primary concern for the northwestern Gulf of Mexico is T.S. Harvey, currently stationary over southern Texas. The southeastern portion of the system is expected to remain over water and allow Harvey to continue generating winds and heavy rains along the Texas and Louisiana Coasts. To the east, a 1012 mb low is centered over west-central Florida near 28N82W. A surface trough extends from the low to 29N87W. This low was described in the section above. Scatterometer data depicts variable gentle to moderate winds across the basin except near T.S. Harvey. As Harvey impacts the northwest Gulf waters and coastal Texas for the next several days, the troughing and low pressure across the eastern Gulf waters and Florida peninsula are expected to maintain unsettled conditions across the region as this system moves northeast into the western Atlantic on Sunday night or Monday. CARIBBEAN SEA... The only area with scattered moderate convection over the basin remains in the proximity of the monsoon trough that extends along 10N. To the east, a surface trough extends from 19N64W to 11N65W. Scatterometer data depicts gentle to moderate trades across most of the basin except over the waters north of Colombia and over the Gulf of Honduras. In these areas moderate to fresh easterlies prevail. This overall synoptic pattern is expected to persist through Monday. ...HISPANIOLA... An upper-level low centered northwest of the island could trigger isolated afternoon showers and thunderstorms this weekend during the time of maximum daytime heating and instability, along with local sea breeze effects. Otherwise, a relatively dry weather pattern is expected during the next few days. ATLANTIC OCEAN... Tow tropical waves are moving across the basin. Refer to the section above for details. Upper-level ridging and an overall divergent upper-level pattern prevails over the western Atlantic generating scattered showers and thunderstorms mainly west of 70W. To the east, an upper-level low is centered near 30N48W and has induced a weak surface trough that extends from 30N51W to 28N54W. The remainder of the central and eastern Atlantic remains under the influence of a surface ridge anchored by a broad 1028 mb high centered near 40N36W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA