000 AXNT20 KNHC 131717 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1217 PM EST Sat Jan 13 2018 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. ...THE MONSOON TROUGH/THE ITCZ... The monsoon trough extends from the coast of Africa near 05N03W to 03N23W. The ITCZ continues from 03N23W to 02N40W to the Equator at 51W. Scattered moderate convection is from 00N-03N between 35W- 43W. ...DISCUSSION... GULF OF MEXICO... Strong high pressure of 1046 mb centered over the northern Plains of U.S. extends a ridge southward across the central and southern Plains into the Gulf region. This system is producing moderate to fresh northerly winds, and seas of up to 9-10 ft based on recent altimeter passes and buoy observations. Abundant cold air stratocumulus clouds are noted mainly over the eastern half of the Gulf due to the advection of cold air over relatively warm waters. Reinforcing cold air will move through the eastern Gulf today behind a secondary front currently crossing north-central Florida. This front is forecast to reach south Florida later today into this evening bringing another round of cold temperatures. High pres will continue to prevail over the area through early Mon, then begin to slide eastward on Tue nigh as the next cold front moves over the NW gulf waters. Fresh northerly winds will persit across the eastern Gulf tonight and Sunday, with gentle to moderate NE-E winds elsewhere. CARIBBEAN SEA... As of 1500 UTC, a cold front extends from central Cuba to the Gulf of Honduras followed by fresh to locally strong northerly winds. Patches of low level clouds with embedded showers are noted along the frontal boundary. The front will move slowly southeastward and become stationary from eastern Cuba to Costa Rica tonight. Fresh to locally strong notherly winds are expected behind the front through tonight, increasing to near gale force along the coast of Nicaragua on Sun. A surface trough is analyzed over the central Caribbean, and extends from the westernmost tip of Jamaica to near 11N78W. Scattered showers and isolated tstms are noted over the central and SW Caribbean in association with this trough. The most recent scatterometer pass showed mainly fresh winds near the coast of Colombia, but strong winds are expected to pulse in this area each night through the period. Fresh to locally strong trades are over the eastern Caribbean. Large long-period NE swell will affect the waters E of the Lesser Antilles through Tue. ...HISPANIOLA... Isolated to scattered passing showers are expected across the island today under the influence of a ridge. Moisture will continue to be limited on Sunday. ATLANTIC OCEAN... As of 1500 UTC, a cold front extends from 31N74W across the central Bahamas and central Cuba. Scattered showers and isolated tstms are along the frontal boundary. Fresh to locally strong southerly winds are noted N of 29N, and ahead of the front to about 71W. A secondary front stretches from 31N78W to north-central Florida. Fresh to strong SW-W winds are blowing between fronts. The main front will become stationary from 31N73W to the central Bahamas and to eastern Cuba on Sun while the secondary front will merge with the main front tonight. A large area of cloudiness with embedded showers and tstms is over the central Atlantic, and covers mainly the waters from 19N-23N between 48W-57W. This convective activity is related to an upper-level low. A recent ASCAT pass indicates that a surface trough has developed in association with this low, and roughly extends from 24N50W to 19N52W. This trough coincides with a concentrated area of showers and tstms. The pressure gradient between this trough and strong high pressure to the N is producing strong to near gale force easterly winds from 23N-28N between 46W-52W. As previously mentioned, a strong high pressure of 1041 mb located N of the area near 37.5N47W dominates the central and eastern Atlantic Ocean. This system will shift eastward over the next 24 hours. Another cold front is just south of the Canary Islands. For additional information please visit http://www.hurricanes.gov/marine $$ GR