145 AXNT20 KNHC 112353 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 753 PM EDT Wed Jul 11 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... The center of Hurricane Chris is located near 37.8N 65.7W at 11/2100Z, or about 503 nm ENE of Cape Hatteras in North Carolina. Chris is moving toward the NE, or 50 degrees, at 19 knots. On the forecast track, the center of Chris will pass near southeastern Newfoundland on Thursday. The estimated minimum central pressure is 976 mb. The maximum sustained wind speed is 80 knots with gusts to 100 knots. Little change in strength is expected during the day tonight, with some weakening forecast on Thursday. Chris will likely also become a strong post-tropical cyclone on Thursday. Numerous moderate convection is observed from 35N-37N between 67W- 69W. Please read the latest NHC forecast/advisory under AWIPS/WMO headers MIATCMAT3/WTNT23 KNHC for more details. ...TROPICAL WAVES... A tropical wave is along 22W from 05N-17N. Scattered moderate convection is near the wave's axis, particularly from 05N-10N between 20W-25W. This wave coincides with a good surge of moisture based on the TPW product, and Model diagnostic guidance also confirms the presence of the wave. A tropical wave has its axis along 41W from 06N-19N, moving W at 15 to 20 knots. Saharan dust follows the wave inhibiting convection at this time. Visible satellite imagery indicates some inverted-V pattern in the cloud field associated with this wave. A low amplitude tropical wave extends its axis along 62W from 04N- 15N, moving W 10 to 15 knots. The wave is now moving across the Windward Islands where light showers have been reported. Saharan dust surrounds the wave. GFS computer model suggests an increase in moisture in association with this wave as it reaches the central Caribbean by Fri. Another tropical wave is moving across the western Caribbean. Its axis along 81.5W from 10N-21N, moving W at 10 knots. A well defined inverted-V pattern is noted in the cloud field associated with the wave. GOES-16 RGB Geocolor shows African dust behind the wave'axis covering the basin all the way to the Lesser Antilles. Areas of dust and mostly drier air will prevail across Puerto Rico and the UK/US Virgin Islands through Friday. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal sections of Senegal near 15N17W to 09N40W. The ITCZ extends from 09N42W to 08N54W to 10N61W. Scattered moderate convection prevails within about 150 nm N of the ITCZ axis between 50W and 58W. ...DISCUSSION... GULF OF MEXICO... A surface trough is analyzed over the eastern Gulf and extends from 24N84W to 29N85W. Another trough is over the central Bay of Campeche. Elsewhere, broad surface anticyclonic flow covers the basin, with surface ridge anchored by a 1020 mb high pressure centered over the NW Gulf near 26N95W. Scattered showers with embedded tstms are noted near the Mouth of Mississippi River. Similar convection is also noted near 26N87W, and over the central Bay of Campeche. High pressure is forecast to prevail across the northern Gulf waters through the upcoming weekend. A surface trough will move westward off the Yucatan Peninsula each evening through Sun, and enhance nocturnal winds over the SW Gulf, producing moderate to fresh NE-E winds and seas of 3-4 ft. Winds and seas will slightly increase in association with this trough by Sat night. CARIBBEAN SEA... Two tropical waves are moving across the basin. Refer to the Tropical Waves section above for details. Recent scatterometer data provide observations of fresh to locally strong trade winds over the central Caribbean while moderate to fresh winds are blowing across the eastern Caribbean. Gentle to moderate winds are over the NW part of the basin. The Atlantic high pressure will build across the region behind the tropical wave with axis along 81W to freshen tradewinds across the central Caribbean waters. Winds will pulse to near or just below gale force each night off Colombia beginning Thu night through at least Sun night. Convection continues to flare-up over the SW Caribbean, mainly S of 11N due to the presence of the monsoon trough. This convective activity is affecting parts of Panama and Costa Rica. Plenty of moisture is expected to remain in place across this area which will foster scattered showers and tstms the remainder of the work- week. ATLANTIC OCEAN... As of 2100 UTC, Hurricane Chris is centered north of the forecast area near 37.8N 65.7W. Swells generated by Hurricane Chris are expected to affect portions of the coasts of North Carolina and the mid-Atlantic states during the next few days. These swells could cause life-threatening surf and rip current conditions. A large area of cloudiness and disorganized showers and thunderstorms associated with the remnants of Beryl is located over much of the Bahamas and extends northwestward over the western Atlantic for a few hundred miles. A surface trough is analyzed in this area and extends 27N75W across the central Bahamas to near 23N78W. Little or no tropical cyclone development is expected today, but conditions could become a little more favorable later in the week and over the weekend while the disturbance moves slowly northward and northeastward over the western Atlantic. The latest Tropical Weather Outlook gives this system a low chance of tropical cyclone formation during the next 48 hours. A recent scatterometer pass clearly indicates the wind shift associated with the aforementioned surface trough. Wind and seas could be higher near tstms. Lightning density indicates frequent lightning with the observed convection. Surface ridge prevails across the remainder of the Atlantic forecast area, anchored by a 1036 mb high pressure centered near NW of the Azores near 43N33W. The ridge extends into the NE Caribbean. The Saharan Air Layer (SAL) from CIMSS shows a new surge of African dust over the eastern Atlantic, and behind the tropical wave along 40W. For additional information please visit http://www.hurricanes.gov/marine $$ GR/ERA