000 AXNT20 KNHC 131011 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sun Dec 13 2020 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... Gulf of Mexico Gale Warning: A strong cold front will move into the NW Gulf tonight. Behind the front, northerly gale force winds are expected to develop over sections of the western and SW Gulf Mon through Mon evening, with strong north winds elsewhere over the western Gulf. Seas are forecast to reach 12 ft in the SW Gulf. Winds and seas will decrease Tue as high pressure moves over the area. Please read the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough axis extends from the coast of Sierra Leone near 08N13W to 06N21W. The ITCZ stretches from 06N21W to 04N38W to 03N51W. Scattered moderate to strong convection is within 150 nm S of the trough east of 21W, and from 02N-09N between 28W-41W. Scattered moderate isolated strong convection is noted from 05.5N- 11N between 42W-58W. GULF OF MEXICO... A cold front extends from the entrance to Mobile Bay to the mouth of the Mississippi River, then become a warm front to southeast Texas. A pre-frontal trough extends from Pensacola Florida to 27N92W. Widely scattered light to moderate showers are along and within 90 nm south and east of the front east of 93W. The front will lift northward and inland later this morning. A surface trough is over the Yucatan Channel along 86W and south of 24N, with isolated showers to the east of it over the SE Gulf of Mexico. High pressure ridging stretches from the north central Atlantic to northern Florida and weakly into the NE Gulf. Gentle SE to S winds are over the Gulf east of 90W while, moderate to fresh SE to S winds prevail west of 90W. A significant cold front will move into the NW Gulf early tonight, then cross much of the basin Mon into Tue. Strong N winds will spill behind the front, and gales will develop over parts of the W and SW Gulf Mon into Mon evening. Please see the Special Features section above for details on the Gale Warning in the western Gulf. Winds and seas will decrease Tue as high pressures builds in. The next front will move into the western Gulf Tue night. CARIBBEAN SEA... Upper-level ridging covers the western Caribbean and Central America. An upper-level trough axis extends from near 30N60W to the eastern Caribbean Sea. At the surface, a trough is over the Yucatan Channel, with isolated to scattered light to moderate showers extending east of the surface trough from western Cuba to the Cayman Islands. Isolated light trade wind showers are over the eastern Caribbean. Dry air is over the central and SW portion of the basin. Overnight ASCAT data showed fresh trades over the south-central Caribbean from 10.5N-16N between 70W-78W. Within that area, there are strong trades near the coast of Colombia from 11N-14N between 71W-75W. Moderate tradewind cover the remainder of the Caribbean. Strong NE winds will pulse nightly into Mon along the Colombian coast. High pressure will weaken across the western Atlc early Mon through Wed and yield a weakened wind flow across the entire basin. A weakening cold front is forecast to move slowly SE across the Yucatan Channel and western Cuba late Thu through Fri. ATLANTIC OCEAN... A cold front enters the area through 32N33W and extends to 28N42W, where it transitions to a stationary front to 27N49W, where it then becomes a shearline to 23N62W. Overnight ASCAT data showed strong northeast to east winds north of the front and shearline to 30N, between 42W-60W, where seas were 10-12 ft. Scattered moderate to strong convection is seen from 20N-25N between 50W-61W. This convection is being enhanced by an upper- level trough axis that stretches from near 30N60W to the eastern Caribbean. Eslewhere across the eastern waters, moderate to large NW swell dominates the area N of 20N and E of 66W, where seas are 8-12 ft. In the western Atlantic, a surface trough is just east of northern Florida, and another surface trough extends N from the SE Bahamas to 27N. Isolated showers are north of 26N and west of 70W. West of 73W, SE winds are moderate. Fresh E winds are between 63W-73W. A 1032 mb high is north of the front near 35N53W and extends a ridge southwest to north Florida. The fresh E winds between 63W-73W will diminish early this morning as the high pressure building into the area weakens and slides east. Ahead of the next cold front, strong SW winds will develop Mon offshore the N Florida coast. This front will move into the NW waters Mon afternoon and stretch from Bermuda to south-central Florida along 27.5N Tue morning before stalling. $$ Stripling