Special Feature

Tropical Storm Bertha is centered near 29.3N 86.3W at 21/1500 UTC or 60 nm SSW of Panama City Florida, moving NNW at 3 kt. Estimated minimum central pressure is 995 mb. Maximum sustained winds have increased to 50 kt with gusts to 60 kt. Peak seas are to 13 ft in the SE quadrant. Bertha remains a sheared system as observed on satellite imagery, with the low-level center mostly evident north of deep convective activity. The convection consists of numerous strong thunderstorms from 26N to 29N between 84W and 92W. Bertha is forecast to turn WNW then W over the next day or so, then continue moving westward at a slow rate of forward speed through midweek. Bertha is expected to produce rainfall amounts of 2 to 4 inches with isolated higher totals around 6 inches through Thu along the Gulf Coast and adjacent inland locations from western Florida into southern Louisiana, including southern portions of Alabama and Mississippi. This rainfall may produce isolated flash flooding, especially in urban areas. Swells generated by Bertha are affecting portions of the Gulf coast of Florida and are likely to spread westward during the week. 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 Two NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details.

Tropical Waves

An eastern Atlantic tropical wave is just W of the Cabo Verde Islands along 29W from 09N to 19W, moving W at 10 to 15 kt. Dry air surrounding the wave is precluding any convection near it at this time.

A central Atlantic tropical wave is its axis along 47W from 09N to 23N, moving W at around 15 kt. Scattered moderate convection is noted from 20N to 23N between 42W and 51W.

A tropical wave over the far SW Caribbean is moving into central America along 83W, S of 18N. It is moving W at around 10 kt. Scattered moderate convection is mainly inland over Honduras and within 90 nm of the coasts of Nicaragua and Costa Rica.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic through the coast of Senegal near 14N17W, and continues southwestward to 10N25W and to 09N35W, where it transitions to the ITCZ to 07N50W and to inland South America at 07N60W. Scattered moderate convection is from 14N to 18N between the coast of Africa and 20W, also within 120 nm south of the trough between 30W-35W, and within 60 nm north of the trough between 21W-24W.

Gulf Of America

Please refer to the Special Features section for information on Tropical Storm Bertha located in the NE Gulf.

Aside from Tropical Storm Bertha, weak high pressure of 1013 mb is centered over the western Gulf at near 24N91W. This is supporting moderate or weaker winds W of 90W and over the southeastern Gulf waters.

For the forecast, Tropical Storm Bertha is near 29.2N 86.2W at 11 AM EDT, and is moving slowly north-northwest at 3 kt. Maximum sustained winds are 50 kt with gusts to 60 kt, and the minimum central pressure is 996 mb. Bertha will move to 29.4N 87.0W this evening, then weaken slightly as it moves to 29.5N 88.0W Wed morning. Bertha will continue to 29.4N 89.5W Wed evening, then reach 29.3N 91.3W by Thu morning. Bertha will weaken to a tropical depression near 29.4N 93.1W Thu evening off Louisiana, and then move inland near the Sabine Pass to 29.9N 94.9W Fri morning. Elsewhere, weak high pressure over the western Gulf will dissipate by midweek. After midweek, Atlantic high pressure will extend westward to the central Gulf following Bertha.

Caribbean Sea

The pressure gradient between the Azores-Bermuda High and lower pressure over NW Colombia is resulting in moderate to fresh easterly winds over most of the central and SW Caribbean, including the Windward Passage. Moderate to fresh easterlies are also ongoing in the Gulf of Honduras. Offshore Colombia winds are locally strong and seas rough to 9 ft, otherwise moderate seas prevail. For the remainder of the basin, winds are moderate or weaker, with slight to moderate 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. During the same period, fresh to locally strong NE to E winds are expected in the Windward Passage, mainly at night. Fresh winds will pulse across the Gulf of Honduras through Wed night. Moderate or weaker winds with slight to moderate seas will prevail elsewhere.

Atlantic Ocean

A deep layer trough axis extends SW from 31N51W to 16N61W. Scattered moderate to isolated strong convection is occurring W of this axis from 22N to 30N, westward to 65W. Moderate to fresh NE winds are in this zone of convection. E of 45W, from 15N to 25N, moderate to fresh trades dominate. Elsewhere in the basin, winds are moderate or weaker. Moderate seas prevail basin-wide.

For the forecast west of 55W, the aforementioned surface trough will move westward reaching near 70W by Wed afternoon and to near 75W by Thu morning. Moderate to fresh winds and moderate seas are expected on either side of the trough axis. Fresh to locally strong trade winds are expected offshore Hispaniola, including approaches to the Windward Passage through the forecast period. Moderate or weaker winds along with moderate seas are forecast elsewhere E of the Bahamas through Fri, except S of 23N E of about 77W where mostly fresh trades are expected through Sat night.

Posted 0 minutes ago by NHC Forecaster Konarik