Tropical Weather Discussion

TROPICAL WAVES

An eastern Atlantic tropical wave is along 39W, south of 21N, moving westward at 15-20 kt. Scattered moderate convection is depicted from 07N to 15N between 34W and 41W.

A well-defined tropical wave in the central Atlantic is along 56W, south of 23N, moving westward at around 15 kt. The wave is interacting with an upper level trough to it's west, and producing scattered to numerous moderate convection from 17N to 23N between 52W and 57W.

MONSOON TROUGH/ITCZ

The monsoon trough enters the Atlantic near 18.5N16W and continues southwestward to 09N46W. The ITCZ extends from 09N46W to 10N53W. Scattered moderate convection is depicted from 05N to 08N and west of 23.5W.

GULF OF AMERICA

Scattered moderate convection associated with Tropical Depression Edouard continue to affect the water north of 28.5N between 92W and 95. Scattered moderate convection is also present over the eastern Gulf in association to an upper level trough. In the wake of Tropical Depression Edouard, which continues to move inland, a weak pressure gradient prevails across the basin. Moderate or weaker anticyclonic winds and slight seas are noted over most of the Gulf waters.

For the forecast, the relatively weak high pressure over the region will generally allow for moderate or weaker winds and slight to moderate seas across the Gulf for the next few days.

CARIBBEAN SEA

An upper level low from the Cayman Islands to NW Cuba continues to combine with ample low level moisture moving in from the southeast to produce lingering scattered showers and thunderstorms over Cuba, western Haiti and the surrounding waters between the Bahamas and Jamaica. A surface trough extends from central Cuba to near 18N80W. Scattered showers and thunderstorms also prevail across SW portions and into the coastal waters of NE Nicaragua, Costa Rica, and Panama. Weak Bermuda High pressure north of the basin is promoting a modest pressure gradient to the south, and yielding moderate to fresh easterly trade winds across the central and east-central Caribbean between 64W and 80W. Seas are 4 to 6 ft across these waters. Gentle to moderate easterly winds and moderate seas prevail elsewhere the eastern Caribbean. Elsewhere, light to gentle winds and slight seas are prevalent.

For the forecast, the aforementioned trough will continue moving WNW through Fri. Elsewhere across the basin, the pressure gradient between the subtropical ridge and relatively lower pressure in northern South America will continue to sustain fresh to strong trades along with moderate seas over the central and eastern Caribbean through the next few days, while moderate or weaker winds and slight to moderate seas remain over the remainder of the basin.

ATLANTIC OCEAN

A low to middle level trough extends from near Bermuda to the NW Bahamas and the SE Florida coastal waters. Meanwhile, another low level trough is moving across eastern Cuba and the SE Bahamas, with abundant low level moisture behind it. These features are combining to produce scattered moderate isolated strong convection from the NW Bahamas to just SW of Bermuda, and across the coastal waters of NE and central Cuba, that is being sustained by divergent flow aloft associated with an upper level low over the Florida Panhandle. Scattered moderate convection also continues across the near and offshore waters of Florida W of 78W. Moderate SE surface winds generally prevail south of 27N between 70W and 76W along with seas 4 to 6 ft.

The remainder of the tropical Atlantic is dominated by a broad subtropical ridge centered south of the Azores, anchored on a 1027 mb high near 36N29W. Moderate to fresh easterly winds and moderate seas are found S of 24N between 22W and 58W. Meanwhile, fresh to strong northerly winds and moderate to rough seas are present north of 19N and east of 22W. Light to gentle winds and slight seas prevail elsewhere N of 25N.

For the forecast west of 55W, scattered showers and thunderstorms will continue over the waters W of about 70W through the rest of the week as an upper low gradually shifts westward while abundant tropical moisture remains in place. A cold front will then approach from the NW Sat through Sun night enhancing the potential for scattered and thunderstorms over the NW portion of the area. Moderate to fresh east to southeast winds are over the waters south of about 27N between 70W and 77W. Otherwise, the subtropical ridge will provide for generally moderate or weaker winds and moderate seas over the forecast waters.

SPECIAL FEATURES

Hurricane Karina is centered near 18.9N 133.8W at 02/2100 UTC, moving west-northwest at 10 kt. Estimated minimum central pressure is 943 mb. Maximum sustained wind speed is 120 kt with gusts to 145 kt. Peak seas are around 42 ft. Numerous moderate to scattered strong convection is noted from 18N-21N between 133W-136W. A westward to west-northwestward motion is expected over the next few days. Karina is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. A slow weakening trend is forecast the next few days, followed by a more steady rate of weakening. Karina is likely to remain a hurricane the next couple of days.

Tropical Storm Marie is centered near 18.0N 112.5W at 02/2100 UTC, moving northwest at 10 kt. Estimated minimum central pressure is 992 mb. Maximum sustained wind speed is 60 kt with gusts to 75 kt. Peak seas are around 30 ft. Numerous moderate to scattered strong convection is noted from 12N-19N between 108W-115W. The NW motion should continue through tonight followed by a turn more west-northwestward for the next several days. Additional strengthening is forecast through Friday, and Marie is likely to become a hurricane tonight. Gradual weakening is anticipated to begin by this weekend. Swells generated by Marie will affect portions of the coast of southwest Mexico and the Baja California Peninsula for the next few days and will likely spread northward to southern California over the weekend. 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/MIAHSFEP2.shtml and the latest Marie NHC Forecast/Advisory and Public Advisory at www.hurricanes.gov for more details.

TROPICAL WAVES

A tropical wave is along 92W, extending across SE Mexico to 07N, moving westward at 15 kt. Scattered moderate convection is occurring north of 06N east of 93W.

INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH

The monsoon trough exits the coast of Costa Rica near 10N85W and extends to 09N106W. Scattered moderate convection is occurring north of 06N east of 93W. Numerous moderate and scattered strong is also occurring from 05N-12N between 115W-133W.

OFFSHORE WATERS WITHIN 250 NM OF MEXICO

Please see the Special Features section for more information on Tropical Storm Marie centered southwest of Mexico.

Aside from Marie, winds are NW fresh offshore of Baja California Norte with seas 5-6 ft as well as SE fresh winds over the N Gulf of California with seas 2-4 ft. Elsewhere, seas are 4-7 ft over Pacific waters and 1-4 ft over the central and S Gulf of California.

For the forecast, Marie will strengthen to a hurricane near 18.7N 113.5W Thu morning, move to 19.5N 115.0W Thu afternoon, 20.2N 116.5W Fri morning, 20.8N 117.8W Fri afternoon, 21.5N 119.1W Sat morning, and 22.1N 120.3W Sat afternoon. Marie will weaken to a tropical storm over 23.5N 122.5W Sun afternoon. Elsewhere, a tighter pressure gradient will result in fresh to strong S to SE winds in the N Gulf of California through Fri night.

...OFFSHORE WATERS WITHIN 250 NM OF CENTRAL AMERICA, COLOMBIA, AND WITHIN 750 NM OF ECUADOR...

Winds are moderate or weaker with seas 4-6 ft are present across the forecast waters this afternoon. Scattered moderate convection is occurring north of 06N east of 93W.

For the forecast, a moderate pressure gradient across Central America will sustain moderate to locally fresh strong E winds over the Gulf of Papagayo through the next several days. Elsewhere, moderate or lighter winds will prevail across forecast waters.

REMAINDER OF THE AREA

Please see the Special Features section for more information about Hurricane Karina centered between Mexico and Hawaii, and Tropical Storm Marie located southwest of Mexico.

Aside from the impacts of Hurricane Karina and Tropical Storm Marie, moderate or weaker winds with seas 5-7 ft dominate the tropical NE Pacific. Otherwise, a small area of cross equatorial swell from the southwest is noted well west of the Galapagos Islands producing seas to 8 ft.

For the forecast, Karina will move to 19.3N 135.2W Thu morning, 19.8N 137.2W Thu afternoon, 20.2N 139.0W Fri morning, and move west of our forecast waters Fri afternoonn. Marie will strengthen to a hurricane near 18.7N 113.5W Thu morning, move to 19.5N 115.0W Thu afternoon, 20.2N 116.5W Fri morning, 20.8N 117.8W Fri afternoon, 21.5N 119.1W Sat morning, and 22.1N 120.3W Sat afternoon. Marie will weaken to a tropical storm over 23.5N 122.5W Sun afternoon.

Elsewhere, the cross equatorial SW swell will diminish below 8 ft by tomorrow. Looking ahead, an area of low pressure could form well offshore of southwestern Mexico over the weekend. Gradual development is possible during the early to middle part of next week as the system moves west-northwestward around 10 kt and is likely to remain well offshore of Mexico.