000 AXNT20 KNHC 311712 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Tue Aug 31 2021 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 1200 UTC surface analysis and satellite imagery through 1750 UTC. ...SPECIAL FEATURES... The center of Tropical Storm Ida, at 27/0600 UTC, is near 19.4N 80.9W. This position also is about 27 nm/50 km to the ENE of Grand Cayman, and about 270 nm/500 km to the ESE of the NW tip of Cuba. IDA is moving NW, or 320 degrees, 10 knots. The estimated minimum central pressure is 1006 mb. The maximum sustained wind speeds are 35 knots with gusts to 45 knots. The maximum sea heights are reaching 10 feet. Precipitation: scattered to numerous strong are within 260 nm of the center in the E semicircle. Hurricane watches have been announced for parts of the U.S.A. coast in the northern Gulf of Mexico. Please, read the latest WPC Public Advisory at: https://www.wpc.ncep.noaa.gov/tropical/tropical_advisories.php?storm=IDA, and the Storm Summary Message at: https://www.wpc.ncep.noaa.gov/discussions/nfdscc4.html, for more details. The center of Tropical Depression Kate, at 31/1500 UTC, is near 23.5N 50.8W, or about 900 nm to the ESE of Bermuda. Kate is moving N, or 010 degrees, 04 knots. The estimated minimum central pressure is 1007 mb. The maximum sustained wind speeds are 30 knots with gusts to 40 knots. A surface trough, the remnant of a cold front, is along 31N47W 28N59W 31N70W. Precipitation: isolated moderate to locally strong is within 400 nm of the center in the NE quadrant, and within 300 nm of the center everywhere else except for the west quadrant. Please read the latest NHC Public Advisory at: https://www.nhc.noaa.gov/text/MIATCPAT5.shtml, and the Forecast/Advisory at: https://www.nhc.noaa.gov/text/MIATCMAT5.shtml, for more details. An Atlantic Ocean tropical wave is along 18W/19W, from 19N southward, moving westward 10 to 15 knots. A 1006 mb low pressure center is along the tropical wave near 10.5N. Precipitation: scattered strong is within 250 nm of the center in the NW quadrant. Isolated moderate to locally strong is elsewhere within 600 nm of the center in the W quadrant. Widely scattered moderate to isolated strong is from 09N to 11N between 14W and 16W. The precipitation pattern continues to show signs of organization. The environmental conditions are conducive for additional development of this system. A tropical depression is likely to form during the next day or so, while the low pressure center moves westward to west-northwestward 10 to 15 mph. The formation chance through 48 hours is high. A broad area of low pressure is forecast to develop over the southwestern Caribbean Sea during the next couple of days. Some slow development of this system is possible by the end of the week, if the system remains over water. This system is expected to move gradually west-northwestward or northwestward at 5 to 10 mph toward Central America. * Formation chance through 48 hours...low...near 0 percent. * Formation chance through 5 days...low...20 percent. Refer to the latest Tropical Weather Outlook at: www.hurricanes.gov for more details. ...TROPICAL WAVES... An Atlantic Ocean tropical wave is along 23W/24W, from 18N southward, moving westward 10 knots. Precipitation: isolated moderate to locally strong is from 05N to 10N between Africa and 33W. A Caribbean Sea tropical wave is along 61W/62W, from 19N southward, moving westward 10 to 15 knots. Precipitation: isolated moderate is within 150 nm on either side of the tropical wave. A Caribbean Sea tropical wave is along 82W/83W, from 15N southward, moving W 5 to 10 knots. Precipitation: scattered moderate to isolated strong is within 135 nm to the west of the tropical wave, from 08N to 10N, in Panama and in Costa Rica, and in the coastal waters. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Senegal near 14N17W, to 09N23W, to 14N30W, 14N35W, through the 1008 mb low pressure center that is along the 43W/44W tropical wave, to 06N49W. The ITCZ continues from 06N49W to the coast of French Guiana along 53W/54W. Precipitation: isolated moderate is elsewhere to the south of the line that runs from 20N16W to 20N50W to 13N60W to 10N62W. GULF OF MEXICO... Upper level anticyclonic outflow, that is curving away from the NW Caribbean Sea Tropical Storm IDA, is reaching Florida near 29N, and curving toward 29N70W in the Atlantic Ocean. Upper level cyclonic wind flow covers the rest of the Gulf of Mexico that is away from the T.S. IDA outflow, from 90W eastward. A surface trough is along 18N86W in the NW Caribbean Sea, through the Yucatan Channel, to 25N87W and 30N87W at the Florida Panhandle. Precipitation: widely scattered moderate to isolated strong is within 100 nm on either side of the trough in the Gulf of Mexico. Isolated moderate to locally strong is within 150 nm on either side of the trough, from the Yucatan Peninsula and the Yucatan Channel southward, into the NE Caribbean Sea. Upper level anticyclonic wind flow covers the Gulf of Mexico from 22N northward from 90W westward. Precipitation: isolated moderate covers the area of upper level anticyclonic wind flow. Fresh to strong south to southwest winds in the north central Gulf of Mexico will shift to the NE Gulf, from tonight through Wednesday night, and to northeast of the Gulf on Thursday, in advance of a frontal boundary. A ridge will dominate the Gulf of Mexico, producing mainly gentle to moderate southerly winds through Friday. Pulsing fresh winds are expected to the northwest of the Yucatan Peninsula, at night through Saturday night. CARIBBEAN SEA... The eastern extension of the eastern Pacific Ocean monsoon trough is along 10N/11N from 74W in Colombia, beyond Costa Rica, and into the eastern Pacific Ocean. Precipitation: numerous strong is within 120 nm to the south of the monsoon trough between 73W and 77W. Widely scattered moderate to isolated strong is within 120 nm to the north of the monsoon trough between 73W and 77W. The pressure gradient, between a ridge east of Florida and lower pressure in northern Colombia, will support moderate to fresh trade winds in the south central Caribbean Sea. Similar wind speeds are expected in the Gulf of Honduras at night. A broad area of low pressure is forecast to develop in the southwestern Caribbean Sea in a couple of days. Some slow development of this system is possible by the end of the week, if the system remains over water. This system is expected to move gradually west- northwestward or northwestward toward Central America. This will bring some increase in winds and seas, first in the southwestern Caribbean Sea, and then in the northwestern Caribbean Sea, from Wednesday through Friday. ATLANTIC OCEAN... Upper level anticyclonic outflow, that is curving away from the NW Caribbean Sea Tropical Storm IDA, is reaching Florida near 29N, and curving toward 29N70W in the Atlantic Ocean. A surface trough is along 29N64W, 25N66W, 22N69W. Precipitation: isolated moderate to locally strong is within 275 nm to the west and northwest of the surface trough, and within 210 nm to the east of the surface trough from 27N northward. A surface trough passes through 31N22W, to 30N25W 29N29W 27N30W 23N32W. Precipitation: rainshowers are possible within 210 nm to the north and northwest of the trough from 30W eastward, and from 20N northward between 30W and 44W. A weak pressure gradient will prevail through tonight with mainly light to gentle winds. Fresh to strong southwest winds are expected just off northeastern Florida on Wednesday, in advance of a frontal boundary that is forecast to clip the northwestern waters, from late Thursday into Friday. $$ mt/ja/mtorres