000 AXNT20 KNHC 180601 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 201 AM EDT Tue Jul 18 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 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...SPECIAL FEATURES... Tropical Storm Don is east of the Windward Islands. On 18/0300 UTC, the location of the storm center is near 11.3N54.6W or about 308 nm ESE of Barbados, and has a minimum central pressure of 1009 mb. Don is moving westward at 16 kt. Maximum sustained winds are 40 kt with gusts to 50 kt. The center of Don will move through the Windward Islands late Tuesday and Tuesday night. Don is expected to produce total rain accumulations of 2 to 4 inches across the Windward Islands through Wednesday morning. Please refer to the latest NHC forecast/advisory under AWIPS/WMO headers MIATCPAT5/WTNT35 KNHC for more details. ...TROPICAL WAVES... A tropical wave is in the central Atlc with axis extending from 18N37W to a 1013 mb low near 10N38W to 05N37W, moving west at 20 kt. A 18/0011 UTC scatterometer pass depicted the low center well. The SSMI total precipitable water imagery shows a very moist area S of 15N. The wave is in a region of neutral to unfavorable wind shear and dry air intrusion to its environment well NW of the low center. Scattered moderate to isolated strong convection is from 10N-12N between 37W-40W. Some gradual development of this system is possible over the next few days while it moves slowly W over the open Atlantic Ocean. A tropical wave is just east of the Lesser Antilles with axis extending from 20N58W to 08N59W, moving west at 20 kt. The wave is mainly in a region of neutral to unfavorable wind shear, and Saharan dry air and dust is noted W of 62W. Scattered showers are within 90 nm of the wave axis. A tropical wave is in the west Caribbean with axis extending from 21N86W to 12N89W, moving west at 5 to 10 kt. SSMI total precipitable water imagery shows a very moist area over Central America. Numerous strong convection is presently from 11N-17N between 87W-91W, especially over El Salvador. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from 12N16W to 10N22W to 12N30W to 08N43W to 08N50W. Aside from the convection associated with the tropical waves, isolated moderate convection is off the coast of W Africa from 08N-10N between 14W-19W. Similar convection is off the coast of South America from 03N-09N between 43W-50W. ...DISCUSSION... GULF OF MEXICO... A surface trough is over the Bay of Campeche from 22N90W to 17N93W. Scattered moderate convection is within 60 nm of the trough axis. The remainder of the Gulf of Mexico has weak surface ridging 5-10 kt southerly flow. Radar imagery shows scattered showers over S Florida and the Straits of Florida. Similar showers extend from SE Louisiana to the Florida Panhandle. Lightning detection system shows isolated thunderstorms over the W Gulf between 90W-96W. In the upper levels, an upper level low is centered over Tampico Mexico near 21N97W. Upper level diffluence E of the center is enhancing convection over the Yucatan Peninsula. Expect little change over the next 24 hours. CARIBBEAN SEA... A tropical wave is moving through the western Caribbean and Central America, with convection. See above. Further south, scattered moderate to isolated strong convection is along the coast of Nicaragua from 11N-13N between 80W-85W. Of note in the upper levels, a small upper level low is centered S of Cuba near 19N80W. Expect tropical storm Don to move through the Windward Islands starting late Tuesday. See above. ...HISPANIOLA... Presently scattered showers remain over Hispaniola. Upper level diffluence is enhancing these showers. Expect conditions to improve Tuesday. ATLANTIC OCEAN... Scattered showers are over the N Bahamas and the W Atlantic, N of 25N and W of 76W. A large 1032 mb high is centered over the central Atlantic near 34N42W producing fair weather. As typical for this time of year, tropical waves are moving through the tropical Atlantic waters. See above. Of note in the upper levels, an upper level low is centered over the W Atlantic near 32N68W enhancing showers. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa