Hurricane Center - Atlantic
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 AM EDT Sunday September 19 2021
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
The National Hurricane Center is issuing advisories on recently upgraded Tropical Storm Peter, located several hundred miles east of the northernmost Leeward Islands, and on newly formed Tropical Depression Seventeen, located a few hundred miles southwest of the southernmost Cabo Verde Islands.
A tropical wave is forecast to emerge off the west coast of Africa later today or tonight. Environmental conditions appear conductive for gradual development thereafter as the system moves generally westward at about 10 mph over the eastern tropical Atlantic during the next several days.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...low...20 percent.
Public Advisories on Tropical Storm Peter are issued under WMO header WTNT31 KNHC and under AWIPS header MIATCPAT1. Forecast/Advisories on Tropical Storm Peter are issued under WMO header WTNT21 KNHC and under AWIPS header MIATCMAT1.
Forecasters: Andrew Hagen, Andrew Latto, National Hurricane Center
2021 Storm Names
• Anna (May 22 - 23, 45 mph, 1004mb)
• Bill (June 14 - 16, 60 mph, 998mb)
• Claudette (June 19 - 22, 45 mph, 1004mb)
• Danny (June 28 - 29, 45 mph, 1009mb)
• Elsa (July 1 - 9, 85 mph, 991mb)
• Fred (Aug 11 - 18, 65 mph, 993mb)
• Grace (Aug 13 - 21, 125 mph, 962mb)
• Henri (Aug 16 - 24, 75 mph, 986mb)
• Ida (Aug 26 - Sept 2, 150 mph, 933mb)
• Julian (Aug 29 - 30, 60 mph, 995mb)
• Kate (Aug 28 - Sept 1, 40 mph, 1004mb)
• Larry (Aug 31 - Sept 11, 125 mph, 955mb)
• Mindy (Sept 8 - 10, 45 mph, 1002mb)
• Nicholas (Sept 12 - 17, 75 mph, 988mb)
• Odette (Sept 17 - current, 45 mph, 1002mb)
• NEXT: Peter
Atlantic Tropical Weather Discussion
NWS National Hurricane Center Miami FL
8:05AM EDT (1205 UTC) Sunday September 19 2021
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.
Active and Developing Storms
Recently upgraded Tropical Storm Peter is centered near 18.0N 53.5W at 19/0900 UTC or 550 nm E of the Northern Leeward Islands moving NW at 13 kt. Estimated minimum central pressure is 1005 mb. Maximum sustained wind speed is 35 kt with gusts to 45 kt. Numerous moderate to isolated strong convection is observed within 150 nm in the northeast semicircle of the center of Peter. An earlier Sentinel altimeter pass indicate seas were already reaching 12 ft on the north side of the storm. The center of Peter will pass to the northeast of the Leeward Islands Mon, then continue to move northward toward Bermuda through the latter part of the week. Heavy rain and large swells are expected to impact the N Leeward Islands, Virgin Islands and Puerto Rico. Interests across these areas should monitor this system closely.
Newly formed Tropical Depression Seventeen is centered near 11.8N 28.2W at 19/0900 UTC or 290 nm SW of the Southernmost Cabo Verde Islands moving NNW at 12 kt. Estimated minimum central pressure is 1007 mb. Maximum sustained wind speed is 30 kt with gusts to 40 kt. Scattered moderate to isolated strong convection is noted within 180 nm on the western semicircle of the center of T.D. Seventeen. The depression is expected to move NW over the next several days, and cross west of 35W by late Tuesday as a minimal tropical storm. For sea conditions near this system, please read the Meteo-France High Seas Forecast at: http://weather.gmdss.org/II.html
An Atlantic tropical wave extends from 19N26W southward through Tropical Depression Seventeen near 11.8N 28.2W, to 04N29W, and is moving W near 10 kt. Scattered moderate to isolated strong convection is noted within 180 nm on the western semicircle of the center of T.D. Seventeen.
Monsoon Trough And Intertropical Convergence Zone - ITCZ
(The ITCZ is also known by sailors as the doldrums)
A monsoon trough extends across the Mauritania coast at 17N16W through T.D. Seventeen, and another low near 08N35W. The ITCZ then continues from 08N35W to 07N45W. Numerous moderate to strong convection is occurring S of the monsoon trough along the coast of Senegal, Gambia, Guinea-Bissau and Guinea. Scattered moderate convection is present near the second low from 05N to 07N between 36W and 39W.
The E end of the E Pacific monsoon trough is triggering a cluster of showers and scattered thunderstorms near Portobelo, Panama.
...Discussion: Gulf Of Mexico
A persistent surface trough meanders east-northeastward from the Crystal River, Florida to just off the mouth of the Mississippi River, to near 26N95W. Scattered showers and thunderstorms are noted along another trough extending just off the coast of the state of Veracruz, Mexico. Gentle to moderate winds and slight seas are evident across the Gulf this morning.
For the forecast, weak high pressure will extend across the E and central Gulf of Mexico through the early part of the week. This pattern will support continued gentle to moderate winds and mostly slight seas across the Gulf through the next several days. Looking ahead, a weak cold front may move into the NW and N central Gulf by mid week.
...Discussion: Caribbean Sea
In addition to the showers and thunderstorms off Panama, another cluster is ongoing off the southern Peninsula of Haiti again this morning. A ship reported strong to near gale force winds in this area of thunderstorm, likely due to strong downdrafts. Elsewhere trade winds are well below average with mostly gentle to moderate breezes and slight to moderate seas noted in all areas. This relatively relaxed period is courtesy of fairly weak high pressure centered north of the area off the northern Bahamas.
For the forecast, Peter will move to 18.8N 55.3W this afternoon, then continue to move to the northeast of the Leeward Islands and reach 19.8N 57.8W Monday morning and 20.8N 60.1W Monday afternoon. Expect large swell off the Leeward Islands into mid week. Peter will continue to move northward and away from the Leewards thereafter through mid week. Peter will displace the weakening Atlantic ridge currently north of the region, allowing trades winds over the south-central Caribbean to diminish over the next several days.
...Discussion: Atlantic Ocean
Please read the Active and Developing Storms section above for details on newly formed Tropical Storm Peter E of the Leeward Islands and a newly formed Tropical Depression Seventeen SW of the Cabo Verde Islands.
Convergent trade winds are coupling with divergent flow aloft to generate scattered moderate to isolated strong convection ahead of Peter and northeast of the Leeward Islands from 21N to 24N between 51W and 60W. A modest surface trough is producing scattered moderate convection from 29N to 31N between 55W and 61W. Refer to the Tropical Waves and Monsoon Trough/ITCZ sections for additional convection across the Atlantic Basin.
The Atlantic ridge extends southwestward from a 1029 mb Azores high, passing S of Bermuda to another high 1018 mb N of the Bahamas. These features are providing light to gentle winds with seas at 2 to 4 ft N of 24N between 40W and the Georgia-N Florida coast. Other than the areas within 180 nm of Peter and T.D. Seventeen, generally moderate winds and seas persist elsewhere across the Atlantic Basin.
For the forecast west of 60W, Peter will move to 18.8N 55.3W this afternoon, 19.8N 57.8W Monday morning, 20.8N 60.1W Monday afternoon, 21.7N 62.2W Tuesday morning, 22.7N 63.9W Tuesday afternoon, and 23.7N 64.9W Wednesday morning. Peter will change little in intensity as it moves to the southeast of Bermuda by late Wed. Elsewhere west of 70W, gentle to moderate winds and slight to moderate seas will persist over open waters through the early part of the week, with swell to 8 ft associated with the tropical storm reaching the waters east of 72W by Wed.
Forecaster: Eric Christensen, National Hurricane Center