000 AXNT20 KNHC 191136 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Mon Sep 19 2022 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 1030 UTC. ...SPECIAL FEATURES... Hurricane Fiona is centered near 18.5N 68.6W at 19/0900 UTC or inland the eastern Dominican Republic about 10 nm WSW of Punta Cana moving NW at 7 kt. Estimated minimum central pressure is 977 mb. Maximum sustained wind speed is 80 kt with gusts to 100 kt. Wave heights of 12 ft or greater extend out 120 nm in N semicircle, 90 NM in the SE quadrant and 60 nm in SW quadrant. Peak seas are currently 24 ft in the Mona Passage. Seas are expected to build to 38 ft by the time Fiona strengthens to a major hurricane over the Atlantic late Tue. Numerous strong convection associated with the core of Fiona extends outward to 45 nm E semicircle and 60 nm W semicircle. Satellite imagery shows that Fiona quickly has become more organized in overall pattern structure as a clear eye feature became apparent during the overnight hours. The imagery shows tight and wide banding features around the eye that consist of numerous moderate to strong convection within 60 nm of the eye, except for 45 nm in the NW quadrant. Outer banding features that consist of scattered to numerous moderate to isolated strong convection are noted elsewhere within 270 nm of the eye in the NE quadrant and within 240 nm of the eye in the SE quadrant. Some of these bands are affecting Puerto Rico with catastrophic flooding. Fiona is forecast to produce an additional 4 to 6 inches of ran with local maximum of 10 inches over southern Puerto Rico and over the northern and eastern Dominican Republic. Over northern Puerto Rico, Fiona is forecast to produce additional 1 to 4 inches with local maximum of 6 inches. Storm Total over that part of Puerto Rico is 4 to 12 inches with local maximum of 20 inches. Fiona will continue on its present motion through tonight, followed by a turn toward the north-northwest on Tue and the north on Wed. On the forecast track, the center of Fiona will move over the eastern portion of the Dominican Republic this morning and emerge over the southwestern Atlantic this afternoon. The center is forecast to pass near or to the east of the Turks and Caicos on Tue. Some strengthening is expected during the next few days after the Fiona emerges over the southwestern Atlantic, and Fiona is forecast to become a major hurricane by Wed. Swells generated by Fiona are affecting the Leeward Islands, the northern Windward Islands, the Virgin Islands, Puerto Rico, the northern coast of the Dominican Republic, the Turks and Caicos Islands, and the southeastern Bahamas. These swells will continue to spread westward across the southwestern Atlantic toward the central and northwestern Bahamas and the east coast of the United States through midweek. These conditions could cause life- threatening surf and rip current conditions. Please consult products from your local weather office. Please read the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and the latest NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details. ...TROPICAL WAVES... A central Atlantic tropical wave has its along 45W from 04N to 15N moving westward at 15 kt. Scattered showers and a few thunderstorms are noted from 09N to 14N between 42W-50W. Another central Atlantic tropical wave has its axis along 55W from 06N to 20N. It is moving westward at about 10-15 kt. A surface trough extends from just north of the wave to 25N53W. Isolated showers and thunderstorms are noted within 180 nm either side of the wave axis from 08N to 13N. ...MONSOON TROUGH/ITCZ... The monsoon trough axis passes through the coast of Senegal near 14N17W and extends southwestward to low pressure of 1011 mb near 09N26W and continues to 09N36W and to 09N44W. The ITCZ extends from 09N46W to 09N54W. Scattered moderate to isolated strong convection within 120 nm south of the trough axis between 27W-31W. GULF OF MEXICO... Weak surface ridging over the eastern United States extends southwestward into the Gulf of Mexico, supporting mainly moderate easterly winds across the central and western Gulf. Recent observations from buoys and oil platforms show fresh northeast winds over the NE Gulf. Fresh to locally strong northeast winds are west of the Yucatan Peninsula, over the eastern Bay of Campeche. Recent and current buoy observations along a with a couple of altimeter data passes show wave heights of 2-3 ft, except for slightly higher wave heights of 3-4 ft in the eastern Bay of Campeche. Scattered showers and isolated thunderstorms are over the western Bay of Campeche. Similar activity is noted in the eastern portion of the Straits of Florida, east of 81.5W, due to a surface trough in the area. The rest of the Gulf remains under fairly tranquil weather conditions. For the forecast, high pressure over the southeastern U.S. will maintain gentle to moderate easterly breezes and slight seas the next few days. CARIBBEAN SEA... Please see the Special Features section above for information on Hurricane Fiona. Outside of convection associated with Fiona, scattered showers and thunderstorms are within 60 nm of the coast of Honduras. Scattered moderate isolated strong convection associated with the east Pacific monsoon trough is noted near the coasts of western Venezuela, Colombia and eastern Panama, mainly south of 13N between 72W-79W. Fresh northeast winds are likely occurring in the Windward Passage. Overnight ASCAT data indicates that gentle trades prevail elsewhere. The area of winds over 20 kt and wave heights of 7-10 ft associated with Fiona is confined to areas north of 15N between 63.5W-71W. Lower wave heights of 1-3 ft over the western Caribbean west of 78W. Wave heights of 4-6 ft are elsewhere over the eastern Caribbean outside of Fiona, except for higher wave heights of 7-10 ft due to strong east-southeast winds along the southeast periphery of Fiona's circulation that are north of 16N between 66W-71W. For the forecast, Hurricane Fiona will track over the eastern portion of the Dominican Republic this morning and emerge over the southwestern Atlantic this afternoon. The center is forecast to pass near or to the east of the Turks and Caicos on Tue, with maximum sustained winds 95 kt gusts 115 kt. Fiona will gradually strengthen as it continues to pull farther away from the Caribbean through mid-week. Residual swell over the eastern Caribbean from Fiona will slowly subside early this week. ATLANTIC OCEAN... Refer to the Special Features section above for details on Hurricane Fiona and the tropical waves moving across the basin. Weak low pressure of 1017 mb is analyzed near 28N46W, with a trough extending from it southwest to near 25N50W. Overnight ASCAT data passes indicated mainly fresh winds around and near the low, except in its S and SW quadrants, where gentle winds are noted. An upper-level low located near 25N47W is supporting the surface trough attendant to the low. The base of an upper-level trough is just to the north of the surface low. It is helping to sustain scattered moderate convection from 28N-33N between 43W-48W. Similar activity pivoting to the east-southeast is from 21N to 25N between 47W-51W. This system has a low chance of tropical cyclone formation during the next 48 hours while it moves generally northward. A surface trough extends across the Florida Peninsula from 31N81W to central Florida, and continues southward to the Straits of Florida near 24N82W. Isolated showers and thunderstorms are near the trough over the Straits of Florida. A weak stationary front extends from low pressure of 1013 mb that is north of the area near 33N60W southwestward to 29N64W. Isolated showers and thunderstorms are seen north of 28N between 54W-65W. Relatively weak high pressure that is anchored by a 1023 mb high center north of the area near 34N33W remains elsewhere. Mostly moderate winds along with wave heights of 4-6 ft are across most of the Atlantic. The exception is near Hurricane Fiona. Per an overnight ASCAT pass, fresh to strong winds are south of 23N between 63W-70W in association with Fiona. Wave heights of 8 ft and higher are associated with these winds. The overnight ASCAT data passes revealed large swaths of fresh northeast to east trade winds from 15N to 30N between 24W-33W and from 12N to 21N between 33W-45W. An area of fresh north winds is off the coast of Africa from 18N to 22N between the coast and 22W. For the forecast west of 55W, Fiona, presently inland the eastern Dominican Republic, will gradually strengthen to a major hurricane as it moves to near 19.4N 69.3W this afternoon, then track north-northwestward to near 20.8N 70.3W late tonight, to near 22.2N 71.0W Tue afternoon with maximum sustained winds 95 kt gusts 115 kt, to near 23.6N 71.2W late Tue night with maximum sustained winds 100 kt gusts 120 kt, the turn to the northeast reaching near 25.1N 70.9W Wed afternoon, near 27.0N 70.2W late Wed night with maximum sustained winds 110 kt gusts 135 kt and to north of the forecast waters near 32.5N 66.5W late Thu night. Fiona will weaken as it moves well northeast of the area through Fri night. High pressure will build in the wake of Fiona. $$ Aguirre