BEFORE THE STORM
DURING THE STORM
For the North Atlantic, Caribbean Sea and the Gulf of Mexico:
Active Systems: The National Hurricane Center is issuing advisories on Tropical Storm Philippe, located several hundred miles east of the northern Leeward Islands.
Central Tropical Atlantic (AL91): Showers and thunderstorms continue to show signs of organization in association with an area of low pressure located roughly halfway between the Cabo Verde Islands and the Lesser Antilles. Environmental conditions are forecast to be conducive for development, as long as this system remains far enough removed from Tropical Storm Philippe to its west. A tropical depression or storm is expected to form later today or on Friday while the system moves northwestward across the central tropical Atlantic. Additional information on this system, including gale warnings, can be found in High Seas Forecasts issued by the National Weather Service. * Formation chance through 48 hours, high, 90 percent. * Formation chance through 7 days, high, 90 percent.
High Seas Forecasts issued by the National Weather Service can be found under AWIPS header NFDHSFAT1, WMO header FZNT01 KWBC, and online at ocean.weather.gov/shtml/NFDHSFAT1.php
Posted 3 hours ago by NHC Forecaster Forecaster Cangialosi
Tropical Storm Philippe is centered near 18.8N 54.6W at 28/0900 UTC or 485 nm E of the northern Leeward Islands, and moving WNW at 5 kt. Estimated minimum central pressure is 1002 mb. Maximum sustained winds are 45 kt with gusts to 55 kt. Peak seas near and just northeast of the center are 20 to 22 ft. Seas of 12 ft or greater extend outward up to 300 nm from the center in the N semicircle, 180 nm SE quadrant and 120 nm SW quadrant. Scattered moderate to strong convection is within 300 nm E semicircle, 120 nm SW quadrant and 180 nm NW quadrant. A slow west-northwestward to westward motion is forecast during the next day or so, followed by a slower westward to west-southwestward motion by this weekend. Little change in strength is forecast during the next day or so, with slow weakening forecast this weekend. 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 Philippe NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details.
Gale Warning Associated with Invest Area (AL91): A 1006 mb low pressure (AL91) is near 15.5N44.5W, and moving NNW at 10 kt. Maximum sustained winds are near 30 kt and peak seas are about 13 ft. Numerous moderate scattered strong convection is noted within 180 nm of the center. Scattered moderate convection is elsewhere from 11N to 21N between 38W and 49W. Strong to near gale force winds and 10-13 ft seas are present from 14N to 21N between 41W and 47W. Winds are forecast to reach gale force later this morning. By early Sat, the system could develop winds up to 40-45 kt and seas up to 16-20 ft as the low reaches near 19.5N49W. The chance of tropical cyclone formation within the next 48 hours is high. 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 Tropical Weather Outlook at hurricanes.gov for more information.
A tropical wave extends southward from AL91 and is moving slowly westward.
The monsoon trough enters the Atlantic along the Mauritania coast near 18N16W to 07N26W. Scattered moderate isolated strong convection is noted from 06N to 16N between 13W and 20W.
Gulf Of Mexico
A stationary front extends westward from near the Florida Big Bend area to just south of New Orleans, Louisiana. Scattered moderate convection is seen near and up to 60 nm along either side of this front. A surface trough is analyzed from near Naples, FL to near Cancun, Mexico. Isolated to scattered thunderstorms are along and southeast of this trough axis. Another broad surface trough extends from the NW Gulf near 28N91W southward to the east-central Bay of Campeche. Isolated thunderstorms are located within 60 nm of the coast of southern Texas. Fresh E winds and 4-5 ft seas are likely occurring to the north of the aforementioned stationary front. Elsewhere, gentle winds and 1-3 ft seas prevail.
For the forecast, the stationary front should move southward as a cold front by Sunday. To the north of the front, fresh E winds are expected over the northern Gulf through the forecast period due to strong high pressure ridging over the southeastern United States.
Total precipitable water imagery shows very moist air over the northwest Caribbean. A surface trough is located off the coast of southern Cuba, where scattered moderate convection is occurring. Scattered thunderstorms are also noted in the Yucatan Channel and in the Gulf of Honduras. Only isolated showers and thunderstorms are seen over the central Caribbean, and over the SW Caribbean attributed to the East Pacific monsoon trough. Moderate trades prevail over much of the basin, except for gentle over the far western Caribbean and over the far SE portion of the basin. Seas range from 2 to 5 ft across the basin.
For the forecast, Tropical Storm Philippe will move to near 18N58W early Sun morning, and weaken to a remnant low near 18N59W early Mon morning. Rough seas across the forecast zones east of the Leeward Islands generated by Tropical Storm Philippe will start to subside toward the end of the week south of 17N, but will continue 8 to 12 ft north of 17N into the weekend. Mainly moderate trade winds will prevail across the central Caribbean, with gentle to moderate winds elsewhere through the weekend.
Refer to the Special Features section above on Tropical Storm Philippe and a Gale Warning related to Invest AL91.
A stationary front extends west-southwestward from 32N60W to Daytona Beach, FL. Fresh to strong NE winds and 8 to 9 ft seas prevail north of 30N and west of 79W. Scattered showers and isolated thunderstorms are located west of a line from 31N72W to 22N78W. Elsewhere west of 65W, winds are moderate or weaker with 5 to 7 ft seas in mixed swell. Farther east, the subtropical surface ridge extends east-west along 28/29N between 30W and 60W, anchored by a 1020 mb high pressure centered near 29N32W. From 26N to 31N between 30W and 60W, winds are light to moderate with 6 to 9 ft seas in mixed swell. Winds of 20 to 45 kt and seas of 9 to 22 ft associated with Tropical Storm Philippe and AL91 cover the area from 14N to 25N between 40W and 60W. Fresh to locally strong NE winds and 7 to 9 ft seas prevail north of the Cabo Verde Islands to 25N between the coast of Africa and 35W.
For the forecast west of 55W, Tropical Storm Philippe will move to near 19N57W by early Sat morning, 18N58W early Sun morning, and weaken to a remnant low near 18N59W early Mon morning. Rough seas ahead of the storm are east of 62W, and will continue to spread east of 68W through the end of the week. Elsewhere, fresh to strong NE winds and seas 8 to 9 ft will prevail through this evening north of the Bahamas and east of Florida in NE swell. Looking ahead, AL91 could move west of 55W by Mon as a tropical cyclone.
Posted 3 hours ago by NHC Forecaster Hagen