AXNT20 KNHC 190639 CCA

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
105 AM EST Mon Feb 19 2018

Corrected Gulf of Mexico section

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 0000 UTC surface analysis and satellite imagery through 0545 UTC.


Caribbean Sea Gale Warning: A tight surface pressure gradient continues between a surface high pressure in the western Atlantic and lower surface pressures in northern sections of S America. This pattern supports winds pulsing to minimal gale force near the coast of Colombia through early next week. Wave heights within the area of gale force winds will range between 12-17 ft. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details.


The monsoon trough axis extends from the coast of Africa near 07N12W southwestward to 03N15W and dips below the Equator at 19W where it transitions to the ITCZ axis to 02S29W and to the coast of S America at 03S39W. The ITCZ continues from that point to 03N39W. Scattered moderate isolated strong convection is within 120 nm S of the axis between 25W-29W, and within 60 nm N of the axis between 18W-20W. Scattered moderate convection is within 30 nm of the axis between 12W-14W.


GULF OF MEXICO...Corrected

A surface ridge extends westward from a 1027 mb high centered over the Atlantic near 28N64W to a 1023 mb high centered just west of the coast of Florida at 29N83W, and weakens as it continues to NW Gulf. The NW part of a surface trough extends off the NW coast of Cuba to near 23N85W. A surface trough is along the west coast of the Yucatan Peninsula. The earlier scattered moderate convection noted near this trough has dissipated. Isolated showers are S of 21N and E of 94W. Isolated showers are S of 22N between 91W-95W. Patches of fog lifting northward are seen over the NW Gulf early this morning. Expect these patches of fog to linger through the morning, with other patches of fog possible to form along and near the coastal sections of the N central and NE portions of the gulf. Both buoy observations and scatterometer data from last night indicate generally light to gentle east to southeast flow N of of 26N, and gentle to moderate east to southeast winds S of 26N, except for higher winds in the moderate to fresh range E of 88W and W of 94W. Expect increasing winds and building seas beginning today as high pressure strengthens in the western Atlantic Ocean. The thermal trough will develop over the western Yucatan Peninsula through Wed afternoon, drift westward across the eastern Bay of Campeche during the overnight hours, and then dissipate in the SW Gulf waters by the late morning hours.


Please refer to the SPECIAL FEATURES section for details regarding the Gale Warning near the coast of Colombia.

A tight pressure gradient across the basin created by the combination of high pressure over the central Atlantic and lower pressure over NW Colombia is producing strong east winds throughout. These winds continue to quickly advect patches of mainly broken low clouds westward along with passing isolated showers, except over the far western Caribbean from 14N-18N W of 81W, including the Gulf of Honduras, where patches of overcast to broken low clouds contain scattered showers. Overall shower activity across the basin has decreased during the past 24 to 48 hours as abundant dry sinking air aloft maintains is influence on the atmosphere. This same gradient will continue to support pulsing winds of minimal gale force near the coast of Colombia through early next week. Fresh to locally strong trade winds are expected elsewhere across the Caribbean Sea. The high pressure will be reinforced by a stronger one today. The pressure gradient associated with the stronger high system will bring increasing winds and building seas across the eastern and central Caribbean, and the Tropical N Atlantic waters through Wed.


Broad area of high pressure prevails across the basin, centered by a 1027 mb high center near 28N64W and a 1024 mb high center near 30N37W. A weakness in the ridge is noted as a surface trough that extends from 28N44W to 19N45W. A backdoor type cold front has nudged southward to roughly along 31N between 72W-80W, becoming a stationary front northwestward to inland Georgia at 32N81W. A pre-frontal trough is just ahead of the front between 72W-76W. Only scattered low clouds are seen along the trough, while very minimal cloudiness is near the front. The cold front will become stationary today and dissipate by early Tue. Current satellite imagery is depicting low clouds (stratus) and fog over the extreme far northwest waters along the NE Florida coast. These clouds and fog are slowly moving inland that coast. The existing area of high pressure is forecast to be fortified by stronger high pressure system through Wed.

Currently over the eastern portion of the Atlantic, extensive mid and upper level moisture in the form of overcast to broken mid and high level clouds is observed streaming northeastward from northeastern S America to within 360 nm either side of a line from 02N50W to 13N34W to 18N25W to the coast of Africa at 21N17W, where the moisture thins out. This area of moisture and clouds are driven by a rather strong jet stream branch that is along the southeastern sector of a broad and persistent central Atlantic upper level trough. Scattered moderate convection is within 60 nm of a line from 01N37W to the Equator at 43W. Isolated showers are possible elsewhere from the Equator to 11N to the west of 35W, and also from 14N-21N between 17W-30W.

For additional information please visit http://www.hurricanes.gov/marine

$$ Aguirre