000 AXNT20 KNHC 091804 RRA TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 105 PM EST Thu Mar 9 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 1745 UTC. ...SPECIAL FEATURES... ...Caribbean Gale Warning... The strong pressure gradient generated between 1030 mb high centered near 31N54W and lower pressure analyzed across northwestern South America will support near-gale to gale-force northeast to east winds again tonight along the over a portion of the south-central and southwest Caribbean Sea that covers the area from 11N to 13N between 73W and 76W. These winds will diminish to strong winds during Friday. See the latest NWS High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough axis extends from the African coast near 11N16W to 04N21W. The Intertropical Convergence Zone extends from 04N21W to near 01N39W. Scattered moderate/isolated strong within 120 nm within 120 nm south of the axis between 23W-29W. Scattered moderate convection within 90 nm south of the axis between 29W-39W. ...DISCUSSION... GULF OF MEXICO... A dissipating stationary front extends from just north north of Tampa Bay Florida to 28N89W northwest to near 28N94W where it transitions to a warm frontal boundary to central Texas near Corpus Christi. High pressure is present elsewhere across the basin with the associated gradient providing for generally gentle to moderate east to southeast winds. The exception is in the southwest portion of the basin where the gradeint between a surface trough located from 23N91W southeast to 21N93 and 18N93W and high pressure over east-central Mexico is allowing for moderate northerly winds between the trough and the coast of Mexico. Satellite imagery is showing multilayer clouds over the southwest gulf south of 25N and west of 94W. Scattered showers are within this area of clouds, with lightning density data suggesting thunderstorm activity from 20N to 21N between 94W and 95W, and within 30 nm of a line from 25N97W to 22.5N97W. Elsewhere, scattered to locally broken low clouds with isolated showers are moving westward south of 26N east of 91W, and moving west-northwest west of 91W. The warm front will begin to dissipate this afternoon as a large area of high pressure builds southward over much of the basin through Saturday. A cold front may move into the northwest gulf area on Sunday. CARIBBEAN SEA... Near-gale to gale-force winds will pulse again tonight over a portion of the south-central and southwest Caribbean Sea. See the Special Features section above for additional details. A shear-line feature extends into the Caribbean from just southwest of Guadeloupe to 16N65W and to near 14N72W. Scattered showers in strong northeast trade winds are within 60-90 nm of the shearline. The shear line is forecast to gradually dissipate through Friday, however a tight pressure gradient over the basin will continue to support fresh to strong northeast to east trades over much of the central and eastern portions of the sea through Friday before diminishing to mainly fresh winds. Satellite imagery shows low-topped isolated showers moving rather quickly westward southwest of Haiti and Jamaica. Similar activity also moving quickly westward is seen south of Puerto Rico to near 16N. Little change is expected with this activity during the next 48 hours. ...HISPANIOLA... Abundant low-level moisture advecting westward in fresh to strong trade wind flow will continue to produce isolated showers over much of the interior of the island and waters adjacent to the east and south coasts of the island through the next 48 hours. The combination of daytime heating and the low-level moisture should allow for increasing instability. This could promote showers to become scattered over the interior of the island later this afternoon and again on Friday afternoon. ATLANTIC OCEAN... A cold front has entered the far northwest portion of the area, and is along a position from near 32N75W southwest to 29N80W, where it becomes a diffusing stationary front across central Florida. A pre-frontal trough extends from just south of the front near 78W southwest to West Palm Beach. Scattered showers and isolated thunderstorms are present within along and within about 60 nm east and southeast of the front. Similar activity is southeast of the trough to near 27N. A 1030 mb high center is analyzed near 32N51W. Farther to the east, a cold front extends from near 32N30W to 22N38W and to 19N42W, where it transitions to a dissipating cold front to 18N47W. It then becomes a dissipating stationary front from 18N47W to Guadeloupe. A well depicted upper trough is within about 500 nm to the northwest of the front as observed in water vapor imagery. Scattered showers and isolated thunderstorms are present north of 25N between 31W and 33.5W. Scattered showers are along and east of the front north of 24N, and also east of the front to near 27N. Strong high pressure is west of the cold front to near 74W. The cold front over the northwest portion of the area will reach from near Bermuda to near the northwest Bahamas this evening, then stall and dissipate through early Friday. The second cold front over the central and eastern Atlantic will continue moving east while weakening through Saturday. For additional information please visit http://www.hurricanes.gov/marine $$ AGUIRRE