000 AXNT20 KNHC 121804 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 204 PM EDT Wed Jul 12 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 23W/25W from the Cabo Verde Islands near 15N southward. Convective precipitation: widely scattered moderate to isolated strong from 06N to 10N between 20W and 26W. An Atlantic Ocean tropical wave is along 16N47W 10N44W 05N42W. Convective precipitation: widely scattered moderate to isolated strong from 13N southward between 30W and 50W. An Atlantic Ocean tropical wave is along 58W from 20N southward, moving westward 10 to 15 knots. Convective precipitation: widely scattered moderate to isolated strong from 17N to 18N between 60W and 61W. A Caribbean Sea tropical wave is along 83W/84W from 20N southward, moving into eastern sections of Honduras and Nicaragua. Convective precipitation: widely scattered moderate to isolated strong from 10N to 17N between 80W and 85W, in parts of Honduras and Nicaragua, and in the coastal waters between 80W and Central America. A tropical wave is along 95W/97W, from 20N southward, moving through southern Mexico, just to the west of the Isthmus of Tehuantepec of southern Mexico. Convective precipitation: nothing significant at the moment. ...ITCZ/MONSOON TROUGH... The Monsoon Trough passes through southern Mauritania near 17N16W, to 08N23W, 07N32W, and 04N34W. The ITCZ continues from 04N34W to 03N37W and 03N50W. Convective precipitation: scattered moderate to isolated strong from 07N to 11N between 50W and 62W. Isolated moderate to locally strong elsewhere from 12N southward from 60W eastward. ...DISCUSSION... ...THE GULF OF MEXICO... Upper level anticyclonic wind flow covers Mexico and the coastal waters from 26N southward, between 96W and 102W. An upper level cyclonic circulation center is in the Big Bend of Texas. An upper level cyclonic circulation center is near 19N89W, in the Yucatan Peninsula of Mexico. Cyclonic wind flow covers the area from Guatemala to 25N between the Yucatan Channel and 94W. Upper level anticyclonic wind flow covers the rest of the Gulf of Mexico, to the north of the Yucatan Peninsula cyclonic center, from 93W/94W eastward. Convective precipitation: isolated moderate to locally strong, from 27N northward from 93W eastward, and from 22N northward from 95W westward along the coasts of Texas and Mexico. A surface ridge passes through the Florida Panhandle to 22N96W. ...CURRENT CONDITIONS AND WEATHER, FOR THE OFFSHORE OIL PLATFORM SITES, THAT ARE IN THE AREA WHOSE BOUNDARIES ARE FROM 27N NORTHWARD AND FROM 88W WESTWARD... LIFR: none. IFR: none. MVFR: KVQT. CURRENT CONDITIONS AND WEATHER, FOR THE COASTAL PLAINS OF THE U.S.A., FROM THE DEEP SOUTH OF TEXAS TO FLORIDA... TEXAS: rain and thunder still are possible in the Deep South, closer to the coast, and near drizzle in Laredo. rain and thunder are near Kingsville. light rain in Angleton/Lake Jackson. rain and thunder have ended for the moment in Galveston. rain and thunder are in Beaumont/Port Arthur. rain and thunder are active in parts of the Houston metropolitan area and surrounding smaller communities. LOUISIANA: rain and thunder in Slidell, along the NE corner of Lake Pontchartrain. light rain in Boothville. rain and thunder also are just to the north of the SW corner of the area, more inland. MISSISSIPPI: light rain in Pascagoula. MVFR in parts of the Hattiesburg metropolitan area. ALABAMA: light rain in parts of the Mobile metropolitan area. FLORIDA: rain and thunder have ended for the moment in Crestview. light rain in Destin. rain and thunder have ended for the moment in the Panama City metropolitan area. rain and thunder are active in Apalachicola. ...THE CARIBBEAN SEA... Upper level anticyclonic wind flow covers the Caribbean Sea from 20N southward between 67W and Honduras/Belize. An upper level cyclonic circulation center is near 19N89W, in the Yucatan Peninsula of Mexico. Cyclonic wind flow covers the area from Guatemala to 25N between the Yucatan Channel and 94W. The monsoon trough is along 08N/09N from 77W westward, beyond Panama, into the eastern Pacific Ocean. Convective precipitation: earlier numerous strong from 14N southward between 75W and 80W, has weakened and dissipated. Convective debris clouds, and possible lingering rainshowers, are from 14N southward between 75W and 80W. 24-hour rainfall totals in inches, for the period that ended at 12/1200 UTC, according to the PAN AMERICAN TEMPERATURE AND PRECIPITATION TABLES...MIATPTPAN/SXCA01 KNHC...are: 0.58 in St. Thomas in the Virgin Islands, 0.12 in Nassau in the Bahamas, 0.10 in Freeport in the Bahamas, 0.07 in San Juan in Puerto Rico, 0.02 in Teguciagalpa, and 0.01 in Guadeloupe. ...HISPANIOLA... Broad upper level cyclonic wind flow is associated with a NW-to- SE oriented trough. Some rainshowers have developed in the easternmost part of the island. SURFACE OBSERVATIONS...for Port-au-Prince in Haiti: VFR. for the DOMINICAN REPUBLIC: Barahona: VFR. few cumulonimbus clouds. Santo Domingo: VFR. few cumulonimbus clouds. La Romana: MVFR. ceiling 1800 feet. Punta Cana: VFR. few cumulonimbus clouds. Santiago: VFR. few cumulonimbus clouds. Puerto Plata: VFR. few cumulonimbus clouds. The GFS MODEL forecast for 250 mb shows that broad cyclonic wind flow will encompass the area during the next 48 hours. Either a broad trough or a cyclonic circulation center will be present across the island. The GFS MODEL forecast for 500 mb shows that an inverted trough will move across the area, spreading cyclonic wind flow to the island for the first 24 hours of the 48-hour forecast period. Anticyclonic wind flow will cover Hispaniola during day two. A ridge will spread westward, from Puerto Rico. The GFS MODEL forecast for 700 mb shows that an inverted trough will spread cyclonic wind flow across the area for much of the next 48 hours. Expect some SE wind flow during the last 6 hours to 12 hours also. ...THE ATLANTIC OCEAN... A surface trough is along 45W/47W from 20N to 26N. Convective precipitation: scattered moderate to isolated strong from 24N to 25N between 46W and 47W. rainshowers are possible elsewhere from 17N to 27N between 44W and 50W. A surface trough is along 69W from 21N to 26N. Convective precipitation: isolated moderate from 18N to 25N between 60W and 71W. An upper level cyclonic circulation center is 27N60W, about 520 nm to the ENE of the remnant of T.D. FOUR. Convective precipitation: isolated moderate from 22N northward between 52W and 62W. A second surface trough is along 77W/78W from Cuba to 30N. Convective precipitation: isolated moderate to locally strong from 23N northward between 70W and 80W. For additional information please visit http://www.hurricanes.gov/marine $$ MT ...TROPICAL WAVES... A tropical wave is in the E Atlc with axis extending from 15N20W to 05N21W, moving W at 5 kt within the last 24 hours. The wave is in a region of favorable wind shear, however extensive intrusion of Saharan dry air and dust are hindering deep convection. Shallow moisture and middle to upper level diffluence support scattered to isolated showers from 06N to 11N E of 22W. A tropical wave is in the central Atlc with axis extending from 14N45W to 04N41W, moving W at 20 kt within the last 24 hours. The wave is in a region of neutral to favorable wind shear, however extensive intrusion of Saharan dry air and dust are hindering deep convection. Shallow moisture support isolated showers from 08N to 12N between 40W and 46W. A tropical wave is just E of the Lesser Antilles with axis extending from 20N59W to 09N60W, moving W at 15 kt within the last 24 hours. The wave is in a region of favorable wind shear, however deep layer dry air hinder deep convection at the time. A tropical wave is over the central Caribbean Sea with axis extending from 20N79W to 10N79W, moving W at 15-20 kt within the last 24 hours. The wave is in a region of mainly unfavorable wind shear, and CIRA LPW imagery show large patches of dry air in its environment, which limit the convection to scattered showers from 15N to 18N between 74W and 85W. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the coast of W Africa near 16N16W to 08N22W to 05N39W. The ITCZ begins near 05N42W and continues to 06N57W. Aside from the convection associated with the tropical waves, scattered heavy showers and tstms are from 03N to 08N between 27W and 37W and from 07N to 12N between 50W and 58W. ...DISCUSSION... ...THE GULF OF MEXICO... A weak surface ridge continues to dominate the Gulf waters producing mainly gentle to moderate E-SE winds. This ridge and wind pattern will persist through Thursday morning. In the NE Gulf, remnants of a former surface trough, shallow moisture in the region and middle level diffluence support isolated showers N of 26N E of 89W. Similar convection is in the W Bay of Campeche being supported by a tropical wave that moves across southern Mexico and adjacent EPAC waters. Looking ahead, a surface trough, associated with the remnants of T.D Four, currently located over the southern Bahamas, will move across south Florida on Thursday, and across the E Gulf Thursday night into Friday, reaching the central Gulf later on Friday. This trough is expected to increase the likelihood of showers with embedded thunderstorms. ...THE CARIBBEAN SEA... The main feature in the basin is a tropical wave moving across the W Caribbean waters, which is supporting scattered to isolated showers. Another tropical wave is just E of the Lesser Antilles and is expected to enter the basin later this morning with possible isolated showers. See the waves section above for further details. The latest scatterometer pass continue to provide observations of fresh to strong winds over the south-central Caribbean S of 14N between 70W and 74W, including the Gulf of Venezuela. The area of strong trade winds is shrinking slightly as high pressure north of the region weakens. Heavy showers and thunderstorms continue over the eastern half of Panama and SW Caribbean waters between Panama and Colombia S of 11N. This convection is mainly being supported by the EPAC monsoon trough. Looking ahead, a stronger tropical wave is forecast to approach the Windward Islands late Thursday and enter the eastern Caribbean early on Friday. ...HISPANIOLA... Available moisture will combined with the local effects to produce scattered showers and isolated and thunderstorms during the afternoon and early evening hours today Wednesday and Thursday. An upper-level low will support these showers, which is forecast to dissipate afterwards while moving west towards E Cuba. ...THE ATLANTIC OCEAN... The remnants of T.D. Four continue situated in the SW N Atlc waters while it further weakens. A 1015 mb low pressure is associated with it, which is located near 22N71W along with a surface trough that extends from 25N71W to the low to 20N71W. Scattered showers and isolated thunderstorms area within 150 nm of the low center. Model guidance continue to suggest that a trough associated with the remnants of T.D. Four will move across the Bahamas through Wednesday night, reaching south Florida on Thursday. A surface trough extends from 29N73W to 23N79W. Scattered showers and tstms are from 23N to 28N between 74W and 80W. Otherwise, the Bermuda-Azores high extends a ridge across the remainder of the forecast region. For additional information please visit http://www.hurricanes.gov/marine $$ MT