000 AXNT20 KNHC 261748 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 148 PM EDT Fri May 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 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...TROPICAL WAVES... Some of the tropical waves were re-located based on a long loop IR satellite imagery, the Hovmoller Diagram, the TPW animation, the 700 mb streamlines, visible satellite imagery, and 1200 UTC surface data. Currently, four tropical waves are between the west coast of Africa and the Lesser Antilles. A tropical wave has an axis extending from 12N20W to 02N21W. Scattered showers and isolated thunderstorms are within about 120 nm E of the wave axis from 07N-09N. Isolated moderate convection is near the southern end of the wave axis. TPW imagery shows the wave is situated in an area of deep layer moisture. A tropical wave is added to the 1200 UTC analysis/surface map along 34W/35W from 02N-10N. A cluster of moderate to isolated strong convection is associated with the wave and covers the waters from 03N-07N between 32W-36W. TPW animation shows the wave is situated in an area of deep layer moisture south of 10N. A tropical wave extends from 12N45W to 04N46W. The position of this wave is based on the above mentioned long loop IR satellite imagery. At the same time, visible satellite imagery indicates some cyclonic turning ahead of the wave axis near 09N51W. This is likely associated with the ITCZ. The TPW data indicate a decent surge of moisture in association with this wave. Another tropical wave is approaching the Lesser Antilles and extends from 16N57W to 08N58W. A weak cyclonic turning is also noted along the wave axis near 11N. Moisture associated with this wave is more concentrated on the east side of the wave axis. This moisture will spread across the Leeward Islands later today and tonight, and continue to affect the islands on Sunday. A tropical wave is moving across the SW Caribbean. The wave axis extends from 15N81W across Costa Rica into the EPAC waters near 05N82W. The wave, combined with the monsoon trough, is producing clusters of moderate to strong convection over parts of Panama, Costa Rica and the Atlantic coast of Nicaragua. The wave is well depicted in the moisture product with the TPW showing a bulge a moisture near the wave axis. Another tropical wave is exiting Guatemala and will move across SE Mexico. Please refer to the Tropical Weather Discussion for the eastern Pacific Ocean. ...ITCZ/MONSOON TROUGH... The Monsoon Trough enters the tropical Atlantic near 07N11W and continues to 05N14W. The ITCZ extends from 05N14W to 05N19W to 05N32W to 07N45W to 09N51W to 08N57W. Aside from the convection associated with the tropical waves, scattered moderate and isolated strong convection is present from 04N-08N between 10W- 18W. ...DISCUSSION... GULF OF MEXICO... The cold front that was affecting the Gulf of Mexico during the previous days is now over South Florida and the Florida Keys generating some shower activity. A 1018 mb high pressure follows the front and it is located near the Florida Big Bend. This system extends a ridge aross most of the Gulf region, producing mainly gentle to moderate winds over the eastern half of the Gulf, and moderate to fresh winds over the western half. A thermal trough will develop over the Yucatan Peninsula during the evenings, move west across the SW Gulf during the overnight hours and dissipate near 94W by late each morning. A surge of fresh to locally strong winds will follow the trough. Little change in this weather pattern is expected over the upcoming weekend. CARIBBEAN SEA... A tropical wave is over the SW Caribbean. See the Tropical wave section for more details on this system. Otherwise, high pressure over the central Atlantic extends a ridge SW across the eastern Caribbean Sea. The ridge supports fresh to strong easterly winds across the east and central Caribbean with strong to near gale force winds near the coast of Colombia. Moderate to fresh ESE winds are over the western part of the basin, except for S of 11N, where winds are lighter in the vicinity of the monsoon trough. The strong winds over the central Caribbean will diminish this weekend. Pulsing fresh to strong E to SE winds are expected over the Gulf of Honduras at night through Monday night. Moderate to locally fresh trades are expected elsewhere. Once again, visible satellite imagery and Saharan Air layer from UW-CIMSS reveal the presense of abundant saharan dust across much of the Caribbean producing dry and hazy conditions. ...HISPANIOLA... Mostly dry and hazy conditions will prevail across the island under the influence of a ridge. Model guidance continue to show limted moisture across this areaexpected today and tomorrow. However, patches of low level moisture, embedded in the trade wind flow, could bring some cloudinees and isolated showers, particulary late Saturday into Sunday. ...ATLANTIC OCEAN... A cold front enters the forecast area near 31N71W and continues SW to south Florida and the Florida Keys. A 120 nm wide band of showers with embedded thunderstorms is associated with the front, forecast to stall from Bermuda to the NW Bahamas on Saturday and gradually dissipate through Sunday. A recent scatterometer pass shows mainly light to gentle winds behind the front and gentle to moderate winds ahead of the front. A 1026 mb high pressure located near 31N52W currently dominates the remainder of the Atlantic Ocean. A weakening frontal boundary crosses between the Madeira and the Canary Islands, stretching from 31N16W to 23N30W. A narrow band of clouds with some showers is associated with the front forecast to dissipate in about 24 hours. Four tropical waves are located over the Atlantic between the west coast of Africa and the Lesser antilles. Please refer to the Tropical Waves section for more details. African dust is noted across much of the Atlantic Ocean ahead of the first cold front and mainly from 10N-30N. For additional information please visit http://www.hurricanes.gov/marine $$ GR