Special Feature

Bertha's center made landfall on the eastern side of St. Bernard Parish, Louisiana, around 2 pm CDT. At 22/2100, Tropical Storm Bertha is centered near 29.8N 89.8W or 20 nm SE of New Orleans Louisiana, moving W at 6 kt. Estimated minimum central pressure is 1000 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Peak seas are 18 ft. Numerous moderate and isolated strong convection is occurring SW of the center of Bertha, particularly N of 25N between 90W and 94W. On the forecast track, the center of Bertha will move near or along the Louisiana and upper Texas coasts through Thursday, and then move farther inland into Texas Thursday night. Little change in strength is expected during the next day or so, and Bertha is forecast to maintain tropical storm intensity up until it reaches the upper Texas coast on Thursday. Bertha is expected to dissipate inland over Texas by Thursday night or Friday. Bertha is expected to produce total rainfall amounts of 1 to 4 inches with isolated higher totals of 6 inches through Friday along the central to western Gulf Coast from Northwest Florida to southern Texas. This rainfall may produce isolated flash flooding, especially in urban areas. Swells generated by Bertha will continue spreading westward along the northern Gulf Coast during the next few days. These swells are likely to 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 Bertha NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details.

Tropical Waves

A tropical wave is about to emerge off the west coast of Africa. Its axis is near 17W based on wave diagnostics. A cluster of moderate to scattered strong convection follows the wave and is affecting mainly northern Senegal and the SW part of Mauritania.

A tropical wave is along 40W south of 20N, moving westward around 20 kt. No significant deep convection is noted with the wave at this time.

Another tropical wave has its axis along 51W south of 16N, moving westward around 10 to 15 kt. Convection is limited near the wave axis.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic from coastal Senegal at 13N17W and extends southwestward to 12N26W. The ITCZ starts at 08N42W and continues westward to northern Guyana into eastern Venezuela. Scattered moderate convection is noted from 10N to 12.5N between 20W and 23W, from 06N to 11N between 32W and 36W and in the vicinity of 07N50W.

Gulf Of America

Please refer to the Special Features section for details on Tropical Storm Bertha located 20 nm SE of New Orleans, Louisiana. Latest scatterometer data indicate that the fresh to strong winds outside of the circulation of Bertha cover the waters N of 26N between 88W and 94W. Seas of 8 to 12 ft generating by Bertha are spreading across the NE Gulf based on a pair of altimeter passes. Elsewhere, moderate or weaker winds and moderate seas prevail.

For the forecast, Tropical Storm Bertha will move to 29.6N 91.3W Thu morning, 29.5N 93.9W Thu afternoon, weaken to a remnant low near 29.4N 96.9W Fri morning, and dissipate Fri afternoon. Swells generated by Bertha will continue spreading westward along the northern Gulf Coast through Thu. In the wake of Bertha, weak high pressure centered over the south-central Gulf will be replaced by ridging associated to a new high center that forms over the NE Gulf providing for a light to gentle wind flow across the basin, except for pulsing moderate to fresh winds off the Yucatan Peninsula and near NE Mexico and the Texas coast. These conditions are expected to persist through the weekend.

Caribbean Sea

The usual north-south pressure gradient over the Caribbean is reduced today due to a surface trough located just north of Hispaniola. As a result, fresh to locally strong winds are noted in the south-central Caribbean, including the Gulf of Venezuela, as well as over the SW part of the basin. Seas are 8 to 12 ft with these winds based on altimeter data. Moderate to locally fresh easterly winds are in the lee of Cuba, with seas of 2 to 4 ft. Elsewhere, trades are moderate or weaker with seas of 2 to 5 ft. An upper-level low spinning over the SE Bahamas is helping to induce showers and thunderstorms over the SE Bahamas, the Turks and Caicos Islands, Hispaniola and eastern Cuba.

For the forecast, the Atlantic ridge combined with the Colombian low will support fresh to strong winds with moderate to rough seas across the south-central Caribbean through the forecast period. Fresh to locally strong NE to E winds in the Windward Passage will pulse tonight. Fresh winds will pulse across the Gulf of Honduras from this afternoon into tonight. Moderate or weaker winds with slight to moderate seas will prevail elsewhere. Looking ahead, fresh to strong winds will pulse across the Gulf of Honduras Sat and Sun.

Atlantic Ocean

A surface trough is analyzed over the western Atlantic and runs from 29N66W to 21N70W. Fresh to strong winds are on either side of the trough axis, with moderate seas. An upper-level trough supports this trough, and is also enhancing convection across a large area, mainly from 22N to 29N between 52W and 74W. Winds and seas could be higher near thunderstorms. High pressure dominates the remainder of the Atlantic forecast region. Its associated ridge combined with lower pressures over NW Africa is promoting fresh to strong northerly winds between the Canary Islands and downwind to about 26N. In addition, the moderate pressure gradient between the ridge and lower pressure with the ITCZ and monsoon trough is supporting only moderate to locally fresh trades and seas 4 to 7 ft across the remainder of the waters north of the ITCZ/monsoon trough.

For the forecast west of 55W, the aforementioned surface trough will continue westward reaching the Bahamas Thu afternoon and to central and South Florida Fri. Scattered showers and thunderstorms will accompany the trough. Fresh trade winds are expected offshore Hispaniola, including approaches to the Windward Passage through Sat night. Moderate or weaker winds along with moderate seas are forecast elsewhere. Looking ahead, a cold front will approach the waters east of northern Florida Sat night through Sun night preceded by mostly moderate to fresh southwest to winds north of 29N and east of 75W.

Posted 4 hours ago by NHC Forecaster Gr