Atlantic Discussion

  • NHC Atlantic Tropical Weather Discussion
    by nhcwebmaster@noaa.gov (nhcwebmaster) on November 24, 2020 at 10:11 AM

    000 AXNT20 KNHC 241011 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue Nov 24 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 1000 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning...The gradient of pressure has tightened between a broad area of low pressure located about 450 nm east of Bahamas and a strong ridge over the central Atlantic. This is resulting in gale force SE winds within 90 nm east of the trough axis that extends from 31N66W to a 1008 mb low near 28N67W to 22N70W. These conditions are expected to dissipate tonight. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of West Africa near 09N13W to 09N18W. The ITCZ continues from 09N18W to 07N31W, then resumes near 05N36W and continues to 02N51W. A 1009 mb low is analyzed near 06N33W. Scattered moderate convection is noted from 03N to 15N between 20W and 40W. GULF OF MEXICO... Strong high pressure over the southeastern United States extends southward into the Gulf waters, supporting moderate to locally fresh E to SE winds. Deep layer dry air dominates the region and continue to support fair weather. Fresh southerly return flow will prevail over the western Gulf through tonight ahead of the next cold front forecast to reach the northern Gulf late on Wed, then stall and lift northward Thu. Looking ahead, the next cold front is expected to move across the Gulf waters over the weekend. CARIBBEAN SEA... High pressure over both the Gulf of Mexico and the central Atlantic continue to support moderate to locally fresh winds across the basin. Scattered showers are observed in a swath from Hispaniola, the Windward Passage to the Gulf of Honduras to Nicaragua adjacent waters. This activity is supported by shallow moisture and divergent flow between two middle level anticyclones. Surface ridge over the Gulf of Mexico will shift eastward to the region of the Bahamas today and will result in a stronger pressure gradient in the Caribbean. This in turn will increase the winds in the south-central Caribbean through Thu and support fresh to strong NE winds across the Windward passage. ATLANTIC OCEAN... Refer to the section above for details on the Gale Warning currently in effect over the west-central Atlantic. A cold front extends across the west Atlantic from 31N69W to 23N80W. Moderate to fresh northerly winds prevail behind the front, with seas to 7 ft. Ahead of the front is the low and trough related to the Gale Warning described above. Scattered showers are noted east of these features between 56W-64W. To the east, a surface trough extends from 31N32W to 25N33W. Surface ridging prevails across the remainder of the basin. The gale low/trough is expected to move northeastward, and there is a slight chance that it could acquire some subtropical characteristics before it merges with the cold front today. Elsewhere, surface high pressure will dominate the remainder central Atlantic waters along with moderate to fresh easterlies and seas to 8 ft. $$ ERA

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