000 AXNT20 KNHC 101734 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1234 PM EST Fri Mar 10 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. ...SPECIAL FEATURES... A low pressure of 1012 mb is located near 26N28W. A cold front extends from the low center to 20N29W to 15N39W where it begins to dissipate. The pressure gradient between this low and a high pressure of 1029 mb located near 29N48W will likely support near gale to gale force winds within about 90 nm west semicircle of the low center this afternoon and tonight. Increasing rough or very rough seas are expected with this system forecast to move eastward to a position near 27N22W over the next 24 hours. Scattered showers and isolated thunderstorms are related to this feature, particularly in the NE quadrant. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends from the African coast near 06N11W to 03N21W. The Intertropical Convergence Zone axis extends from 03N21W to 02N30W to the Equator at 36W, and then to the coast of Brazil near 2S45W. Isolated moderate convection is S of 04N between 18W and 26W. Scattered moderate convection is S of 02N west of 36W. ...DISCUSSION... GULF OF MEXICO... While upper level ridging prevails over much of the Gulf, mid- level energy embedded within a weak shortwave trough is supporting an area of scattered showers and tstms over the NW Gulf. Mosaic Doppler Radar from the SE of United States confirmed the presence of this convective activity. At 1500 UTC, a surface trough is analyzed near the coast of Texas in association with this weather conditions. A thermal trough will develop during the evening hours over the Yucatan Peninsula before pushing offshore into the SW Gulf each night. A surge of fresh to occasionally strong northeast to east winds will accompany this trough through Sunday night. Otherwise, the remainder of the Gulf is under the influence of a surface ridge anchored by a 1023 mb high centered in the NE Gulf near 28N85W. Mostly moderate E-SE winds are expected across the basin the rest of today with the next weak frontal boundary forecast to clip the north-central and NE Gulf waters tonight. Moderate to fresh N-NE winds are briefly expected behind the front over the NE Gulf through Saturday morning. A second and stronger cold front is forecast to enter the Gulf region on Sunday. A weak low is expected to form along the frontal boundary dragging a cold front across the remainder of the Gulf through early next week. Model guidance suggests fresh to strong NE winds behind the front, and across the NW and N-central waters on Sunday, with seas building to 6-7 ft. CARIBBEAN SEA... Winds have dimimished below gale force near the coast of Colombia. The latest ASCAT pass provided observations of 20-25 kt NE-E winds over the south-central Caribbean, with a few wind barbs of 30 kt. As a result, the Gale Warning has been discontinued. Fresh to locally strong trade winds are noted across the remainder of the east and central Caribbean. These winds are forecast to diminish tonight into Saturday across the basin as high pressure located north of the area continues to shift farther eastward. A patch of moisture is noted over the eastern Caribbean and just south of Dominican Republic embedded in the trade wind flow. This cloudiness was previously associated with a shear line, but currently scatterometer data indicate the presence of a weak trough across this area. This patch of moisture is forecast to move across Hispaniola on Saturday. Aloft, a ridge dominates most of the basin, producing moderate to strong upper level subsidence and implied dry airmass. ...HISPANIOLA... Moisture is forecast to increase across the island on Saturday increasing the likelihood of showers and isolated thunderstorms, mainly in the afternoon and early evening hours due to local effects. ATLANTIC OCEAN... High pressure of 1029 mb located near 29N48W extends a ridge westward across much of the forecast area west of 30W, including the Bahamas and Florida. A low pressure of 1012 mb is located near 26N28W. Near gale to gale force conditions are expected in association with this low. Please, see Special Features section for details. Scatterometer data show fresh to strong trade winds across the southern periphery of the aforementioned high. Broken stratocumulus clouds are over the central Atlantic in the wake of the cold front and a dissipating cold front extending to near Barbados in the Lesser Antilles. A cold front will enter the discussion area this evening, reaching from 31N65W to the NW Bahamas by early Saturday morning, and from 31N58W to south Florida by Saturday night. Fresh to strong southwesterly winds are expected ahead of the front, particularly N of 30N this evening. Fresh to strong northerly winds will briefly follow the front through late Saturday morning. For additional information please visit http://www.hurricanes.gov/marine $$ GR