Atlantic Tropical Weather Discussion (Text)

AXNT20 KNHC 190519 CCA

Tropical Weather Discussion...Corrected
NWS National Hurricane Center Miami FL
705 PM EST Sun Feb 18 2018

Corrected Monsoon Trough/ITCZ 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 1800 UTC surface analysis and satellite imagery through 
2345 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 South 
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
06N10W southwestward to 03N14W 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 convection is within 30 nm N of the 
axis between 18W-19W.



A surface ridge extends westward from a 1026 mb high centered 
over the Atlantic near 28N64W to 1023 mb high centered over 
central Florida, and continues westward to the NW Gulf. The 
earlier frontal boundary that was along the coastal plains has N 
of the as a warm front, and is over eastern Texas and the southern
portions of Louisiana, Mississippi and Alabama. A rather weak 
surface trough is over the NE Gulf from 30N86W to 27N88W. Earlier 
related shower activity has dissipated. Another surface trough 
has recently emerged off the west coast of the Yucatan Peninsula 
to over the far eastern Bay of Campeche. Isolated showers are S 
of 21N and E of 94W. Areas of fog are expected over portions of 
the northern and central gulf during the overnight hours and 
into Mon morning. Both buoy observations and latest 
scatterometer data reveal 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 by early next week as high pressure 
strengthens in the western Atlantic Ocean. The thermal trough 
will develop again over the western Yucatan Peninsula each 
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 quick passing 
isolated showers, except over the far western Caribbean from 
14N-18N W of 83W, including the Gulf of Honduras, where patches 
of overcast low clouds contain scattered showers. 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 system on Mon. This stronger system will bring increasing 
winds and building seas across the eastern and central Caribbean, 
and the Tropical N Atlantic waters possibly into the middle of 
next week.


Broad area of high pressure prevails across the basin, centered by
a 1026 mb high center near 28N64W and a 1024 mb high center near 
31N34W. A weakness in the ridge was analyzed as a surface trough,
extending from 28N44W to 19N45W. The tail end of a stationary
front is along 32N from 44W-51W, while a cold front is just along 
32N W of 72W. The cold front will drop southward over the NW
waters tonight and dissipate on Mon. The ridge will be reinforced
by a stronger high pressure system through Tuesday.

For additional information please visit 


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Page last modified: Monday, 19-Feb-2018 05:19:15 UTC