000 AXNT20 KNHC 201002 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 602 AM EDT THU OCT 20 2016 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...SPECIAL FEATURES... An elongated non-tropical 1005 mb surface low is centered northeast of the central Bahamas near 26N73W. Scattered moderate convection and isolated tstms are from 20N to 30N between 56W and 76W. Showers associated with this low are also affecting Hispaniola and Puerto Rico. Although the associated shower and thunderstorm activity remains disorganized, environmental conditions could become a little more conducive for the low to acquire some tropical characteristics during the next day or so, and this system could still become a subtropical or tropical cyclone before it merges with a cold front over the western Atlantic late Friday. Regardless of development, locally heavy rainfall is possible over Hispaniola, Puerto Rico, and portions of the northern Leeward Islands through today. Please see the Tropical Weather Outlook under AWIPS/WMO headers MIATWOAT/ABNT20 KNHC for more details. Gale force winds are expected to develop in the Gulf of Mexico Friday night associated with a cold front that will enter the NW waters of the Gulf early Friday morning. NW to N gale force winds are forecast for the area S of 25N W of the front with seas to 10 ft. Please see the High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...TROPICAL WAVES... Tropical wave is in the central Atlantic extending from 06N to 15N with axis near 39W, moving W at 15 kt over the past 24 hours. The wave continues in a region of unfavorable deep layer wind shear. However, CIRA LPW imagery from surface to 850 mb show the wave is in an abundant moist environment that along with divergent upper level wind flow support scattered moderate convection from 01N to 15N between 31W and 45W. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends across Africa into the east Tropical Atlantic near 14N17W to 09N25W to 09N41W. The ITCZ begins near 09N41W and continues to 07N50W to 07N57W. Aside from the convection related to the tropical wave, scattered moderate convection is from 02N to 08N between 20W and 31W. ...DISCUSSION... ...GULF OF MEXICO... Surface ridging across the SE CONUS extends SW into the Gulf, thus providing E-SE gentle to moderate flow basin-wide, except for the Bay of Campeche where winds are from the NE. Middle to upper level ridging and strong dry air subsidence persist across the basin supporting stable and fair weather conditions. The current wind regime will persist through this afternoon, then NE wind flow will dominate ahead of a cold front forecast to enter the NW Gulf waters early Friday morning. The front is expected to reach S Florida Saturday near sunrise. Gale force winds are expected to develop W of the front S of 25N Friday night. See special features section for further details. ...CARIBBEAN SEA... An elongated area of low pressure in the SW N Atlantic waters centered northeast of the central Bahamas, and upper divergence generated by the upper trough that support the low and a ridge to the east over the central Atlantic continue to support scattered showers and tstms across Hispaniola and adjacent waters. Isolated showers are across Puerto Rico. In the central basin, surface observations indicate the presence of a surface trough that extends from 18N74W to Panama near 09N78W with scattered showers within 120 nm either side of its axis. The low in the special features section continue to support gentle to moderate SE wind E of 71W and NE flow of the same magnitude W of 77W. Showers will cease for Puerto Rico Friday and will continue across Hispaniola through the weekend. A center of low pressure is forecast to develop in the central basin today and will persist through Saturday. A cold front will reach the NW basin Saturday night. ...HISPANIOLA... An elongated area of low pressure centered northeast of the central Bahamas and upper divergence continue to support scattered showers across Hispaniola and adjacent waters. Showers associated with this low will continue across Hispaniola through the weekend. ...ATLANTIC OCEAN... The main feature of interest in the basin is an area of low pressure centered northeast of the central Bahamas, which is generating scattered moderate convection and isolated tstms from 20N to 30N between 56W and 76W. There is a medium chance for this area of low pressure to become a cyclone. See special features for further details. Fresh to near gale force winds are in the SW N Atlantic waters associated with this low. Please see the High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. The other feature of interest is a tropical wave in the central Atlantic. See the tropical waves section for further details. Also in the central Atlantic, the remnants of a stationary front are analyzed as a surface trough extending from 31N36W to 24N48W. Scattered showers are within 120 nm either side of the trough axis N of 25N. The remainder basin is under the influence of a surface ridge. The area of low pressure NE of the Bahamas will move NW today and will weaken into a surface trough Friday ahead of a cold front that will come off the NE Florida Peninsula Friday night. For additional information please visit http://www.hurricanes.gov/marine $$ RAMOS