Special Feature

Tropical Storm Bertha is centered near 29.4N 91.1W at 23/0300 UTC or 70 nm SW of New Orleans Louisiana, moving W at 10 kt. Estimated minimum central pressure is 1002 mb. Maximum sustained wind speed is 40 kt with gusts to 50 kt. Peak seas are 12 ft. Numerous moderate and isolated strong convection is occurring SW of the center of Bertha, particularly N of 24N west of 90W. On the forecast track, the center of Bertha will move near or along the Louisiana and upper Texas coasts through Thursday afternoon, and then move farther inland into Texas Thursday evening and 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. 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 emerged off the west coast of Africa tonight. Its axis is near 18W based on satellite imagery and wave diagnostics. Scattered moderate convection extends from 06N to 20N between the coast of W Africa and 20W.

A tropical wave is in the central Atlantic extending from 07N to 21N with axis near 41W, moving westward around 20 kt. Scattered moderate isolated strong convection is confined to the monsoon/ITCZ region from 05N to 13N between 32W and 48W.

A tropical wave is E of the Lesser Antilles extending from 08N to 21N and with axis near 53W, 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 09N29W. The ITCZ starts at 08N42W and continues westward to 07N58W. Aside from the convection associated with the tropical waves, scattered moderate convection is noted from 08N to 17N between 22W and 31W.

Gulf Of America

Tropical Storm Bertha is along the Louisiana coast near 29.4N 91.1W, or about 35 nm southwest of New Orleans, Louisiana at 11 PM EDT. It is moving westward at 10 kt. Maximum sustained winds are 40 kt with gusts to 50 kt, and the minimum central pressure is 1002 mb. Please refer to the Special Features section for further details on Tropical Storm Bertha. Elsewhere, moderate or weaker winds and slight to moderate seas prevail.

For the forecast, Bertha will move to near 29.2N 92.8W Thu morning, move inland to near 29.1N 95.6W Thu evening, then weaken to a remnant low near 29.0N 98.3W Fri morning, and dissipate Fri evening. In the wake of Bertha, a high pressure center will become established over the NE Gulf through Fri before it shifts to the central Gulf afterward. The high pressure will provide 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 through the weekend.

Caribbean Sea

The usual north-south pressure gradient over the Caribbean although reduced due to a surface trough located E of the Bahamas and extending into Hispaniola continue to support fresh to locally strong winds in the south-central Caribbean, including the Gulf of Venezuela. Seas are 5 to 8 ft with these winds. Moderate to locally fresh easterly winds are in the lee of Cuba, Windward Passage and E Caribbean along with moderate seas. Elsewhere, trades are moderate or weaker with slight seas.

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 NE winds in the Windward Passage will diminish Thu. Fresh winds will pulse across the Gulf of Honduras tonight, then at fresh to strong speeds at night beginning Sat. 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 extends from near 28N68W to just east of the Turks and Caicos. A second surface trough is to the east extending from 22N60W to 28N57W. Both troughs are generating scattered showers from 21N to 30N between 55W and 75W. Aside from the rain, the troughs are freshening the winds in the same region E of the Bahamas. 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 29N. Seas with these winds are moderate to rough. 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 fresh southwest winds north of about 29N and east of 75W.

Posted 4 hours ago by NHC Forecaster Ramos