000 AXNT20 KNHC 150004 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 805 PM Thu May 14 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... An increasing area of cloudiness along with numerous showers and thunderstorms is over the Straits of Florida and western Atlantic waters south of 27N and west of 70W, including the Bahamas and vicinity waters. In addition, a very tight pressure gradient between strong high pressure ridging centered off the eastern U.S. seaboard and a surface trough that extends from central Bahamas westward to the Straits of Florida is producing strong northeast to east winds with frequent gusts to gale force over these waters as is presently being noted in both buoy and ship observations. These winds are forecast to continue into Fri afternoon. As a result, a gale warning for frequent gusts is in effect for the waters south of 27N and west of 74W. Please read the latest High Seas Forecast https://www.nhc.noaa.gov/text/ MIAHSFAT2.shtml for more details. Environmental conditions are expected to become conducive for development for the aforementioned area of cloudiness and shower and thunderstorm activity. This system is likely to become a tropical or subtropical storm by late Fri or Sat when it is located near the northwestern Bahamas. The system is then forecast to move generally northeastward over the western Atlantic early next week. Regardless of development, the disturbance has the potential to bring heavy rainfall to portions of the Florida Keys, southeast Florida, and the Bahamas through Saturday. Tropical-storm-force wind gusts are also possible in the Florida Keys, southeast Florida, and the Bahamas during the next day or two. Hazardous marine conditions are also expected along the Florida east coast and in the Bahamas where Gale Warnings are in effect. The system now has a high chance of becoming a tropical or subtropical storm during the next 48 hours. Please refer to the latest NHC Tropical Weather Outlook at www.hurricanes.gov for more details and also see products from your local weather office. ...MONSOON TROUGH/ITCZ... The monsoon trough axis passes through the coastal sections of Guinea-Bissau near 12N16W to 08N20W, where afternoon scatterometer data indicates that it transitions to the ITCZ and continues to 04N30W to 02N40W and to 00N49W. Scattered moderate convection is within 120 nm north of the ITCZ between 34W-38W and between 40W-46W. Similar activity is within 60 nm south of the ITCZ between 39W-42W. GULF OF MEXICO... Broad upper level westerly wind flow is present across the Gulf. Within this flow pattern, a pair of embedded shortwave troughs advancing eastward are noted. One is over the north- central Gulf, the other is over the southeastern Gulf. At the surface, a trough is oriented east to west across the Straits of Florida, while high pressure ridging extends from the western Atlantic across the basin. Scattered showers and isolated thunderstorms are over the north-central Gulf waters north of 29N and between 90W-94W, while isolated showers occurring in the outer western fringes of the Special Features system are over the far southeastern Gulf. Mainly moderate to fresh east to southeast winds are over the Gulf, except for stronger winds of fresh to strong speeds, over the southeastern Gulf waters south of 27N and east of 84W based the latest Ascat data pass and buoy data. Wave heights are in the range of 4-7 ft, except for higher heights of up to 8 ft over the waters south of 27N and east of 84W. As for the forecast, the trough over the Straits of Florida will change little tonight then begin to lift northward Fri. The gradient between the high pressure ridge and trough will maintain little change to winds over the eastern and central Gulf through most of Fri. Little change with winds is expected elsewhere through the upcoming weekend. Low pressure may develop near Louisiana on Sun and pull a weak cold front across the northern Gulf early next week. CARIBBEAN SEA... A trough is over the northwestern Caribbean along a position from 22N82W to 18N87W. No significant weather is associated to this trough. Scattered showers and thunderstorms are over the interior of Cuba and moving in a general northeastward direction. Similar activity is over the interior of northern Haiti and the western part of the Dominican Republic. Isolated showers and thunderstorms are seen over the southwestern Caribbean south of 13N and west of 80W. Brief passing isolated showers are possible mainly north of 14N, where low-level cloud streamers are present. Moderate to fresh trade winds are over sea, with the exception of the south-central section where fresh to strong trade winds are present. Wave heights are in the range of about 3-6 ft, except in the south-central section of the sea where higher wave heights of up to 8 ft are due to the persistence of the fresh to strong trade winds there. As for the forecast, high pressure will remain north of the region tonight, then shift eastward and weaken Fri into this weekend. Fresh to strong trades will prevail in the south-central Caribbean into early next week. ATLANTIC OCEAN... Please refer above to the Special Features section for details about a system that has potential to become a tropical or subtropical storm by late Fri or Sat. A cold front extends from near 32N50W southwestward to 29N56W, where it transitions to a stationary front to 26N62W and to 25N70W, where it becomes a trough across the central Bahamas and to the Straits of Florida. The tight gradient between the strong high pressure over the western Atlantic and the trough has induced strong northeast to east winds with frequent gusts to gale force over a good portion of the western half of the area. For details refer above under the Special Features section. Areas of rain along with numerous showers and scattered thunderstorms are increasing in coverage south of 28N and west of 70W. To the southeast of the stationary front, a weak 1018 mb low is analyzed near 26N57W, with a trough extending northeastward to 28N55W and southwestward to near 22N59W. No significant convection is associated with this feature. Scattered showers are seen from 25N to 28N and between 53W and the low and trough. High pressure dominates the remainder of the Atlantic anchored by a 1027 mb high center analyzed just north of the discussion area at 33N31W. As for the forecast, the trough over the central Bahamas and Straits of Florida will lift northward through Fri. See Special Features section for tropical or subtropical potential of a system near the NW Bahamas late Fri or Sat. This system is likely to significantly impact winds and wave heights over the western half of the area into early next week. $$ Aguirre