Special Feature

Tropical Storm Bertha is near 28.7N 86.4W, or about 110 nm S of Panama City, Florida at 5 AM EDT, and is moving northwest at 4 kt. Maximum sustained winds have increased to 45 kt with gusts to 55 kt, and the minimum central pressure is 998 mb. Peak seas are to 12 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. This convective activity consists of the numerous moderate to strong type intensity from 25N to 28N between 84W and 88W, and from 25N to 29N between 88W and 92W. Bertha is forecast to maintain a slow northwestward to west-northwestward motion is expected today followed by a turn westward by the middle part of this week. On the forecast track, Bertha will move near or along the northern Gulf coast during the next several days. 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 areas of 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

A far eastern Atlantic tropical wave is near the Cabo Verde Islands with axis along 26W from 08N to 20N moving westward near 10 kt. No significant deep convection is presently noted near the wave as it is surrounded by a rather dry and stable environment.

A central Atlantic tropical wave has its axis along 44W from 09N to 23N. It is moving westward at 10 to 15 kt. Scattered moderate convection is near the northern portion of the wave from 20N to 23N, and near its southern portion from 09N to 10N between 42W and 45W.

A tropical wave is over the southwestern Caribbean along 82W south of 18N. It is moving westward at an estimated speeds of about 15t kt. Scattered moderate convection is within 180 nm east of the wave from 11N to 12N. Isolated showers and thunderstorms are elsewhere south of 15N west of 76W.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic through the coast of Senegal near 14N17W, and continues southwestward to 10N24W and to 09N35W, where it transitions to the ITCZ to 10N35W 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, within 60 nm north of the trough between 21W-24W and within 30 nm of the trough between 35W-39W.

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, which is located over the NE Gulf, roughly about 110 nm S of Panama City, Florida and is the main feature over the basin, weak high pressure of 1014 mb is centered over the western Gulf at near 24N92W. The related gradient is supporting moderate or weaker winds W of 90W and over the southeastern Gulf waters.

For the forecast, Tropical Storm Bertha will move to near 29.0N 86.8W this afternoon with maximum sustained winds 50 kt gusts 60 kt, then begin to weaken as it moves to near 29.4N 87.6W late tonight, to near 29.5N 88.7W Wed afternoon with maximum sustained winds 40 kt gusts 50 kt and inland to near 29.3N 90.5W late Wed night. Bertha is forecast to weaken to a tropical depression near 29.3N 92.2W Thu afternoon, move to near 29.6N 94.2W late Thu night and become a remnant low as it moves to near 30.4N 96.5W late Fri night. Otherwise, the weak high pressure over the western Gulf will not be evident by midweek. After midweek, Atlantic high pressure will extend westward to the central Gulf.

Caribbean Sea

The pressure gradient between the Azores-Bermuda High and relatively lower pressure over NW Colombia is resulting in mainly moderate to fresh easterly winds over most of the central, southwest and eastern 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. Except for this part of the sea, the central and SW basin have moderate seas while slight seas dominate both the E and NW Caribbean regions. Aside from the convection associated with the tropical wave, clusters of scattered moderate convection are present over the offshores between Colombia and Panama, associated with the eastern extension of the E Pacific monsoon.

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. Pulsing winds reaching fresh speeds are forecast in the Gulf of Honduras through Wed night. Moderate or weaker winds with slight to moderate seas will prevail elsewhere.

Atlantic Ocean

A surface trough is located over the central Atlantic along a position from near 27N57W to 22N59W and to 16N61W. Another surface trough is to its NE from 31N51W to 24N55W. Satellite imagery shows increasing scattered moderate convection over the waters from 22N to 29N between 53W and 62W, and 25N to 28N between 43W and 53W. Overnight satellite scatterometer data depicts moderate to fresh northeast winds between 56W and 64W. The scatterometer data also indicates fresh trades over the adjacent waters of Hispaniola. The remainder subtropical Atlantic is under the influence of the Azores-Bermuda High, which is supporting moderate to fresh NE winds over the E waters E of 35W with locally strong winds and rough seas in the vicinity of the Canary Islands. Moderate to fresh southerly flow is offshore central and NE Florida due to the gradient of pressure between the ridge and Tropical Storm Bertha, located in the NE Gulf of America. Seas are in the moderate range between 20W and 67W and mainly slight W of 67W.

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 Aguirre