000 AXNT20 KNHC 261127 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 627 AM EST Sun Feb 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 0600 UTC surface analysis and satellite imagery through 1115 UTC. ...SPECIAL FEATURE... ...Caribbean Gale Warning... Winds are forecast to increase across the central Caribbean tonight through Monday as a high pressure builds over the southwest Atlantic. Strong nocturnal flow is expected along the northwest coast of Colombia, with gale conditions possible during the overnight and early morning hours from Monday through Thursday. Seas are forecast to build to 13-14 ft near the coast of Colombia with the gale-force winds. See the latest High Seas Forecast product under AWIPS/WHO headers HSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough passes through the coast of Africa near 10N15W to 03N20W. The ITCZ continues from 03N20W to 02S42W. Scattered showers prevail within 100 nm on either side of the ITCZ between 27W-42W. ...DISCUSSION... GULF OF MEXICO... A cold front extends across the basin from 27N83W to 25N90W. Scatterometer data depicts gentle to moderate northerly winds north of the front while light to gentle southerly winds prevail south of the front. A surface trough extends over the Bay of Campeche from 22N92W to 20N93W. A surface ridge is building in the wake of the cold front across the northern half of the basin. The cold front is expected to continue moving southeast during the next 24 hours while weakening. Return southeasterly flow begins over the Gulf W of 90W this afternoon and spreads over most of the Gulf through early Monday. CARIBBEAN SEA... A sharp mid-to-upper level trough passes through the Windward Passage and into the southwest corner of the basin. At the surface, a trough was analyzed from 20N82W to 17N86W with isolated showers. Another trough extends across the western half of Hispaniola from 21N73W to 18N72W with isolated convection. Very strong subsidence was noted in the wake of the trough and elsewhere over the basin east of 80W. A weak surface ridge extended from 20N60W through the northern Leeward Islands to 15N75W. This ridge maintained sub-normal trade winds over the basin, generally around 10 kt. The trade winds should begin to increase today as high pressure builds north of the area, with strong winds likely within 90 nm of the coast of Colombia on Sunday night into Monday. Gale-force winds are expected to develop across the south-central Caribbean. Please refer to the section above for details. ...HISPANIOLA... Water vapor imagery indicated very dry air/strong subsidence over the entire island. A surface trough extends over Haiti with isolated showers. Little change in the overall conditions is anticipated through the remainder of the weekend. ATLANTIC OCEAN... A cold front has entered the west Atlantic extending from 29N81W to 31N77W. A deep-layer trough extends through 32N66W to the southeast Bahamas, through the Windward Passage, then into the southwest corner of the Caribbean Sea. This trough is providing limited support a surface trough that extends from 31N64W to 26N69W. Another surface trough extends from 24N73W to 20N73W. A dissipating stationary front has transitioned into a surface trough that extends from 31N41W to 27N50W to 24N54W. No significant convection is observed at this time with this trough. The remainder of the basin is under the influence of a surface ridge anchored by a 1030 mb surface high centered near 37N39W. Expect for the troughs to continue weakening through the next 24 hours. The cold front over the west Atlantic will continue moving east enhancing winds/seas. For additional information please visit http://www.hurricanes.gov/marine $$ ERA