000 AXNT20 KNHC 231033 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Tue May 23 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... Gulf of Mexico Ashfall Advisory: The Popocatepetl Volcano in Mexico continues in an active state of unrest. Ash from recent large eruptions has moved E-NE as far as the Yucatan Peninsula. Ash from more recent moderate eruptions is reaching as high as 30000 ft. Upper-level westerly winds are transporting the ash across the adjacent SW Gulf of Mexico, S of 20N and west of 93W, and is expected to reach 91W by morning. Mariners who encounter volcanic ash or floating volcanic debris are encouraged to report this observation to the National Hurricane Center, by calling +1-305-229-4424. ...TROPICAL WAVES... An eastern Atlantic tropical wave has its axis along 26W, south of 12N. It is moving west at 10 kt. Scattered moderate to strong convection is observed from 05N to 09N and between 21W and 28W. Another eastern Atlantic tropical wave has its axis along 42W, south of 10N. It is moving westward at 10 kt. Scattered moderate to strong convection is present from 04N to 09.5N between 39W and 46W. ...MONSOON TROUGH/ITCZ... The monsoon trough reaches the Atlantic through the coast of Guinea-Bissau near 11N15W and continues to 08N20W. The ITCZ extends from 08N20W to 07.5N25W, then resumes from 07N27W to 06N40W, and then resumes again from 06N43W to the coast of Guyana at 07.5N59W. Scattered moderate isolated strong convection is seen from 01.5N to 07N between 07W and 17W. Outside of convection described with the tropical waves, scattered moderate to strong convection is noted within 120 nm N and 60 nm S of the ITCZ between 28W and 47W. GULF OF MEXICO... Please read the Special Features section for information on the Ashfall Advisory for the SW Gulf of Mexico. An outflow boundary has moved west-southwestward across much of the NE Gulf overnight, and has recently reached from Lake Pontchartrain to just north of Tampa Bay. The passage of this boundary has triggered scattered moderate convection that lingers from 27N to 29N between 85W and 89W. The rest of the basin is dominated by a weak high pressure system centered over the NW Gulf. Surface observations and a recent scatterometer satellite pass show light to gentle anticyclonic winds prevailing over most of the Gulf, except for localized fresh winds off the Big Bend region of Florida, behind the outflow boundary, and in the eastern Bay of Campeche. Seas are 1-3 ft across the Gulf waters. For the forecast, weak high pressure will generally dominate the basin through the week, yielding light to gentle winds and slight seas. A modest cold front will move S through the eastern Gulf late Wed through Thu, followed by moderate to locally fresh N to NE winds E of 90W through Sat morning. Popocatepetl Volcano in Mexico near 19N99W has been active since Sun and continues to erupt this morning. Ash has moved E to NE away from the volcano and over the Bay of Campeche, S of 22N and W of 90W. Visibility may be restricted in this area due to volcanic ashfall through tonight. Mariners should exercise caution. CARIBBEAN SEA... An upper level trough extends from the western Atlantic S-SE across the Mona Passage into the NE Caribbean, and is shifting slowly eastward. This feature is supporting scatted showers and isolated thunderstorms from eastern Puerto Rico, east and southeast across the eastern Caribbean, the Lesser Antilles, and to the Atlantic waters W of 5W. The rest of the Caribbean Sea experiences generally dry conditions. The weak pressure regime maintains gentle to moderate easterly trade winds in the central and eastern Caribbean, while light to gentle easterly breezes are found in the remainder of the basin. Seas are slight to moderate across the Caribbean. For the forecast, elongated low pressure extending from the SE Bahamas to near 30N70W will lift N-NE and exit the region early Wed. Low pressure is then expected to develop over central Florida Wed night and move slowly NE through Sat. This pattern will maintain a weak pressure gradient across the central and western Caribbean through Sat, supporting light to gentle winds. Over the E Caribbean, the Azores High ridge will support gentle to moderate SE trade winds through the forecast period. Expect scattered showers and thunderstorms across the waters between 65W and 55W through Tue night. ATLANTIC OCEAN... A surface trough extends from low pressure near Bermuda through 1008 mb low pressure near 25.5N71.5W to offshore of Haiti near 21N71W. An upper level trough across the western Atlantic W of 70W and extends S-Se through the MOna Passage. This deep layered feature is supporting scattered moderate to isolated strong convection to the east of the surface trough to west of 63W, and north of 22N. Overnight scatterometer satellite data depicted fresh northerly winds within 180 nm of the low in the W and NW quadrants. Gentle to moderate winds, in cyclonic fashion, are noted elsewhere within 360 nm of the low and trough. Seas of 6-9 ft are present over the waters north of 22N and east of the Bahamas to 60W. Farther west, a weak stationary front is along about 31N and reaches NE Florida, where and a few thunderstorms are seen near the boundary. The remainder of the tropical Atlantic is dominated by an extensive subtropical ridge positioned north of the Azores. The pressure gradient is supporting moderate to fresh easterly winds over most of the central and eastern Atlantic waters. Localized strong winds are evident in the areas of the ITCZ where strong convection resides. Moderate seas of 6 to 8 ft are prevalent in the central and eastern Atlantic. Elsewhere in the basin, moderate or weaker winds and moderate seas prevail. For the forecast W of 55W, the elongated low pressure will move N-NE and reach near 30N70W early Wed, when it will interact with a weak cold front approaching from the NW, then move NE and exit the region Wed night. Fresh to strong SE winds, rough seas, with scattered showers and tstms will prevail E of the low and trough through Wed. New low pressure is forecast to develop over central Florida late Wed, move N-NE off the peninsula Thu, and across the far NW waters through Sat. The pressure gradient between high pressure over the eastern U.S. and the low will support fresh to locally strong NE winds and large NE swell across the NE Florida offshore waters beginning Thu night through Sat. Gale-force NE winds are possible late Fri across these waters. $$ Stripling