Based on 1200 UTC surface analysis and satellite imagery through 1830 UTC.
Tropical Storm Isaias was located by noaa doppler weather radars and surface observations near 40.9N 75.1W at 04/1800 UTC, or about 65 miles west of New York city moving quickly nne at 35 kt. The estimated minimum central pressure is 994 mb. Maximum sustained winds are near 55 kt (65 mph) with higher gust. The noaa doppler weather radars along with surface observations and satellite imagery indicate widespread areas of rain with embedded squalls and strong to severe thunderstorms over most of the southern new england states, including the coastal waters of New Jersey, New York Connecticut and Massachusetts. This activity is spreading north- northeastward.
The present motion of Isaias, accompanied by some increase in forward speed, is expected through tonight. On the forecast track, the center of Isaias will continue to move near or along the coast of the mid-Atlantic states this afternoon and and move across the rest of the northeastern United States into southern Canada tonight. Only slow weakening is expected this afternoon, followed by a faster rate of weakening tonight. Isaias is forecast to become post-tropical tonight or early on wed.
Please read the latest NHC public advisory at https://www.nhc.noaa.gov/text/MIATCPAT4.shtml and forecast/advisory at https://www.nhc.noaa.gov/text/MIATCMAT4.shtml for more details.
A far eastern Atlantic tropical wave has its axis along 23W from 03N-18N, moving westward at 10-15 kt. The wave is embedded within deep tropical moisture south of 13N. Scattered moderate isolated strong convection is seen from 02N-13N between 20W-27W south of the african Monsoon Trough.
An eastern Atlantic tropical wave has its axis along 35W from 02N-18N, moving westward at about 10-15 kt. This wave is embedded within deep tropical moisture south of 16N. Scattered showers and thunderstorms are seen south of The Monsoon Trough in that area of the Atlantic, from 02N to 09N between 31W and 40W.
A central Atlantic tropical wave has its axis along 48W, from 16N south, moving westward at 15 kt. Scattered showers and thunderstorms are noted ahead of the wave, from 08N-13N between 46W and 51W.
A central Caribbean tropical wave has its axis along 79W from 00N-18N, moving westward at 15-20 kt. Scattered moderate convection is enhanced by the Pacific Monsoon Trough from the coast of Panama to 11N. Scattered showers and thunderstorms are seen over and north of Jamaica.
The Monsoon Trough axis extends from the coast Africa near 16W to 3W to 46W. The ITCZ extends west of a tropical wave from 51W to 59W. Aside to the convection associated to the tropical waves, scattered moderate convection is within 300 nm south of The Monsoon Trough. Also, an area of scattered moderate isolated strong convection is observed along the coast of Africa from Guinea to Senegal. Scattered showers are noted along the ITCZ from 07N-11N between the coast of Brazil to 51W.
Gulf of Mexico
Surface ridging prevails across the basin, anchored by a 1015 mb high entered near 90W. Scatterometer data depicted light to gentle anticyclonic winds across the whole area, with seas ranging between 2-4 ft. Scattered showers are noted over the bay of Campeche and the southeast Gulf.
In the forecast, the weak high pressure will persist over the north Gulf this week, maintaining gentle flow across much of the region with moderate to fresh winds expected across the eastern bay of Campeche.
Refer to the section above for details on the tropical wave over the central part of the basin.
Scattered showers and thunderstorms are noted across the waters from Jamaica west to 84W. To the south, the epac Monsoon Trough extends along 11N between 75W-83W where active convection prevails. Ascat data indicated gentle to moderate trades across the basin except south of 15N between 64W-75W, where moderate to fresh easterly winds were noted. Dry conditions remained elsewhere.
The Bermuda high north of the area along with the typical eastward extension of the northeast Pacific Monsoon Trough to Colombia will contribute toward fresh to strong east trades over the central Caribbean through sat night. Elsewhere winds and seas are at or below normal. No tropical cyclone formation is expected in these waters for the next several days.
Refer to the sections above for details on Tropical Storm Isaias and the tropical waves moving across the basin.
Scattered moderate convection continues over the northwest waters west of 75W, extending from north of the Bahamas to 31N. To the east, a surface trough extends from 72W to 65W will continue towards the northwest across the Atlantic waters then weaken tonight and wed. A second trough is noted from 39W to 39W. No significant convection is noted with the trough. Surface ridging extends from the northeast Atlantic southwestward and south of a stationary front that extends from a 1016 mb low near 48W to 57W to 64W. Scattered showers and thunderstorms are 160 nm southeast of the boundary between 56W to 50W.
In the forecast, high seas north of 29N associated with Tropical Storm Isaias will shift northward and exit the waters west of 75W, allowing seas to gradually subside there today through tonight. Weak troughing will linger across the waters north of 25N and west of 50W through fri, leading to gentle to moderate winds across most of the area waters. The surface trough northeast of the southern Bahamas will move northwest across the area today then weaken tonight and wed. Moderate to locally fresh easterly winds are expected across the great bahama bank and north of Hispaniola through the weekend.
Posted 10 hours ago by NHC Forecaster Torres/Aguirre