000 AXNT20 KNHC 060004 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Mon Mar 06 2023 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 31N. 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... Atlantic Significant Swell Event: Long-period NW swell is currently propagating through the central and eastern waters generating seas in the range of 12-18 ft north of 26N and between 35W-65W with a period of 14-16 seconds. This batch of swell will shift east-northeast through Mon while it subsides. Just as this happens, yet another set of long-period NW swell will begin to propagate through the far northern part of the central waters this afternoon through Mon night, and through a portion of the eastern part of the area Tue through early on Wed. The western part of the swell set is forecast to hang up over the north-central waters Tue night and Wed building seas to a range of 12-20 ft north of 27N between 47W-65W. By the Thu, the swell set will be reinforced by a rather massive set of NW to N swell, with a period of 10-13 seconds that will send seas of 12 ft and greater south to near 21N and E of the Bahamas to roughly a line from near 31N34W to 21N48W. Mariners navigating across these waters will encounter hazardous marine conditions. Please read the latest High Seas Forecast at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details on these swell events. ...MONSOON TROUGH/ITCZ... The monsoon trough is mainly confined to the African continent, reaching the coast of Liberia near 06N10W. It continues southwestward to 05N12W, where latest scatterometer data indicates that it transitions to the ITCZ and continues to 02N20W to along the Equator to near 49W. Scattered moderate convection is seen within 180 nm north of the ITCZ between 12W-17W, also within 180 nm south of the ITCZ between 15W-19W, within 180 nm north of the ITCZ between 27W-34W, within 120 nm south of the ITCZ between 19W-25W and within 120 nm north of the ITCZ between 34W-41W. ...GULF OF MEXICO... What was previously a stationary front is now analyzed as a trough from near 27N86W to 26N93W to 24N94W and to the central Bay of Campeche near 19N94W. An ASCAT data pass shows gentle to moderate northeast winds west of the trough to near 95W, shifting to southeast to south in direction east of the trough to near 87W. Some scattered to broken low clouds with possible isolated showers are seen on satellite imagery from 24N to 29N and between 87W-94W. Otherwise, the remainder of the Gulf is dominated by generally weak high pressure that is allowing for light to gentle winds. Seas in the range of 2-4 ft continue over the basin, except for lower seas of 1-3 ft in the central Bay of Campeche and SW Gulf. For the forecast, weak high pressure centered northeast of the area will dominate early this week, before shifting away, allowing for a weak cold front to enter the NE Gulf on Wed. ...CARIBBEAN SEA... The gradient associated to the subtropical ridge between Puerto Rico and Bermuda continues to support fresh to strong easterly trade winds across the central and eastern Caribbean Sea. The strongest winds are noted over the south-central Caribbean and off NW Colombia. Latest partial ASCAT data received indicates that gentle to moderate east to southeast winds in the northwestern part of the Caribbean. Seas of 5-7 ft are over the waters from 15N to 18N between 68W-85W. Seas of 4-6 ft are north of 15N between 64W-68W. Seas of 3-5 ft are north of 18N from the Windward Passage area west to 80W and north of 18N west of 85W. The highest seas over the basin are in the 7-10 ft range and are over south-central Caribbean. The lowest seas over the basin are found north of 18N between 80W-85W. Satellite imagery shows patches of scattered to occasionally broken low-level clouds moving westward with possible isolated showers over the eastern Caribbean from 14N to 17N and east of 68W. Low-level cloud streamers, containing possible isolated showers, are seen emanating westward off the Lesser Antilles in the trade wind flow. For the forecast, the pressure gradient between high pressure southeast of Bermuda and the Colombian diurnal low will support strong trades across the south-central Caribbean tonight. Moderate NE swell will gradually fade across the Tropical Atlantic waters and northeastern Caribbean passages tonight. Winds will gradually diminish to below normal basin-wide Tue through Thu as an Atlantic cold front sinks southward toward the northeastern Caribbean Sea. ...ATLANTIC OCEAN... Please read the Special Features section for details on an ongoing significant swell event. Additional swell events will continue to impact the Atlantic forecast waters next week. A weak cold front extends from near 31N59W to 29N68W and to 28N74W, where it becomes a stationary front to near 29N80W. Latest visible satellite imagery clearly shows a rope-type cloud marking the leading edge of the front. Overcast to broken low and mid-level clouds extend about 60 nm to the north of the rope cloud. Scattered showers are possible with these clouds, mainly east of 73W. A recent partial ASCAT data pass indicates fresh to strong southwest to west winds within about 60 to 120 nm southeast of the from east of 65W. Fresh to strong west to northwest winds are north of the front. Seas in the range of 8-11 ft are southeast and south of the front to near 28N and west to 65W. A broad subtropical ridge dominates the remainder of the forecast waters west of about 39W. High centers of 1019 mb are located near 23N62W and 22N41W. The associated gradient is generally supporting light to moderate anticyclonic winds along with moderate seas. In the far eastern Atlantic, a cold front enters that part of the region near 31N30W and continues southwestward to 26N38W, where it transitions to a weakening stationary front to near 26N45W. A trough out ahead of the front extends from 31N25W to 23N35W. No deep convection is occurring with both of these boundaries. Scattered to broken low-level clouds with possible isolated showers are along and near the front and trough. Long- period NW swell behind the cold front is producing seas of 8-12 ft west to 35W. A significant swell event is underway west of 35W as described above. Moderate or weaker winds and moderate seas remain elsewhere. For the forecast west of 55W, surface ridging extends from the central Atlantic westward along 24N to the Bahamas. A cold front that currently extends from Bermuda to Florida will move SE through Mon, bringing fresh to strong SW winds ahead of it north of 28N. The ridge will weaken and reform to the northeast of the Bahamas into Tue as the front dissipates along 25N. Large NW swell will impact the northeast waters behind the front tonight through Tue night, then large N to NE swell will move south of 31N and spread across all Atlantic waters into Thu night with the next frontal system approaching from the north. Gale conditions are expected by Tue night across the northeast portion or the area. Seas will peak to 20 ft near and north of 30N57W on Wed. $$ Aguirre