AXNT20 KNHC 122327

Tropical Weather Discussion
NWS National Hurricane Center Miami FL
627 PM EST Tue Dec 12 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 1800 UTC surface analysis and satellite imagery through 2315 UTC.


The monsoon trough enters the Atlantic Ocean through Liberia, Africa and continues to near 06N13W. The Intertropical Convergence Zone extends from 06N13W to 07N20W to 04N35W to the coast of NE Brazil near 02N51W. Scattered moderate isolated strong convection is within about 180 nm north of ITCZ axis W of 30W.


GULF OF MEXICO... A reinforcing and dry cold front extends from northern Florida across the northern Gulf waters to south Texas. The front will move across the southeast Gulf by early Wed morning followed by moderate to fresh NW winds over the eastern Gulf, and gentle moderate northerly winds elsewhere. A 1033 mb high pressure located over Texas extends a ridge over the remainder of the Gulf region, and will continue to build eastward in the wake of the front. This will reinforce the cool and dry airmass over the State of Florida. Cold air stratocumulus clouds are noted ahead of the front moving quickly southward. Patches of low level clouds with embedded light showers are over the Bay of Campeche, where a surface trough is analyzed on the 1800 UTC surface map. The next cold front will move into the northern Gulf waters Thu, and reach from the Florida Big Bend area in the NE Gulf to near Tampico Mexico by early Fri.

CARIBBEAN SEA... A quasistationary frontal boundary persists across the basin and extends from eastern Cuba to the SW Caribbean near 10N82W. The most recent scatterometer pass showed fresh to strong northerly winds within about 240 nm to the W of the front and mainly south of 20N. A band of broken to overcast multi-layered clouds prevails to the W of the front affecting from eastern Cuba to western Panama and Costa Rica. Some convective activity is also noted along the frontal boundary just south of Jamaica. A swirl of low clouds is seen on visible satellite imagery near 15N71W related to a weak easterly perturbation. Light to gentle winds dominate the eastern Caribbean with seas generally below 5 ft based on altimeter data and buoy observations. The front is forecast to meander across the central Caribbean and gradually weaken through Thursday.

HISPANIOLA... Moisture is forecast to increase across the island on Wed as the frontal boundary currently located over eastern Cuba drifts eastward across the Windward Passage into Hispaniola. This will increase the likelihood of showers Wed and possibly Thu.

ATLANTIC OCEAN... A quasistationary frontal boundary enters the forecast area near 31N59W, then continues SW to the SE Bahamas and eastern Cuba into the Caribbean Sea. A band of multi-layered clouds with embedded showers is associated with the front forecast to dissipate by late Wed. A reinforcing cold front is just moving off NE Florida and it is forecast to reach from near Bermuda to NW Cuba early on Wed. Fresh to strong SW flow is noted ahead of this front mainly N of 30N. A weak and narrow surface ridge extends from the Gulf of Mexico NE across S Florida to near Bermuda ahead of this reinforcing front. A third cold front enters the Atlantic Ocean through Mauritania, west Africa and continues W, then NW to near 23N34W. The remainder of the Atlantic Ocean is under the influence of a 1033 mb high pressure located just south of the Azores. Fresh to locally strong anticylonic flow is seen S and SW of the ridge, and generally E of 53W, where a surface trough is found drifting W. The pressure gradient between this high and a low pressure system over west Africa is resulting in gale force winds from 28N-31N between the coast of Africa and 13W. Fresh to strong winds are spreading west and south between the coast of Africa and the Canary Islands.

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

$$ GR