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AXNT20 KNHC 251803
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT WED MAY 25 2016

Tropical Weather Discussion for North America, Central America, Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar, and meteorological analysis.

Based on 1200 UTC surface analysis and satellite imagery through 1745 UTC.


...TROPICAL WAVES...

Tropical wave over Africa extends from 5N8W to 14N3W moving west 10 to 15 kt. Wave coincides with an amplified 700 mb trough and is embedded within an area of moderate moisture from the surface to 700 mb behind the wave trough as indicated by CIRA layer precipitable water imagery. Isolated showers are within the wave environment.

Tropical wave over the central Tropical Atlantic extends along 38W from 2N to 11N moving west near 15 kt. Wave coincides with a weak 700 mb trough and is embedded in a moderate moist environment from the surface to 700 mb as indicated by CIRA layer precipitable water imagery. However, the Saharan Air Layer imagery show dry air in the northern wave environment that along with strong deep layer wind shear hinder convection N of 6N. Scattered moderate convection is from 1N to 6N between 34W and 43W mostly associated with the ITCZ.

Tropical wave extends along 62W south of 12N to inland over Venezuela moving west near 20 kt. Wave coincides with a 700 mb trough and is embedded in a low moisture region that along with strong deep layer wind shear hinder convection.

Tropical wave in the southwest Caribbean from 16N76W to a 1011 mb low near 10N to inland Colombia moving west at 5 kt. Abundant moisture at the surface reaches nearly to 700 mb. This moisture along with a diffluent environment aloft between the eastern side of an upper trough over the western caribbean and ridging to the east fuel a cluster of moderate to isolated strong convection and thunderstorms from 12N to 17N between 73W and 79W. Similar convection is nearby the low pres center S of 11N between 75W and 81W.


...ITCZ/MONSOON TROUGH...

The monsoon trough extends over western Africa and into the east Tropical Atlantic near 9N13W to 5N20W where the ITCZ begins and continues along 5N28W to E of a tropical wave near 4N35W then resumes west of the wave near 3N39W to South America near 4N51W. Scattered moderate convection is from 2N to 9N E of 35W and within 345 NM north of the ITCZ W of 43W. For convection associated with the waves see section above.


...DISCUSSION...

GULF OF MEXICO...

A broad upper ridge anchored in the east Pacific region extends over Mexico to east Texas to Alabama while an upper trough covers the remainder basin E of 85W. This is giving the Gulf northwest flow aloft that advects moisture across the west Gulf, however no shower activity is noted partly due to strong deep layer wind shear. A surface ridge extends from the west Atlantic SW across Florida and then across the entire Gulf, which provide gentle to moderate flow basin-wide. The upper trough along with moisture associated with an area of low pres over the SW N Atlantic support scattered showers and thunderstorms in the straits of Florida, including the Florida Keys. The surface ridge will persist over the Gulf through Friday. The pressure gradient will increase over the northwest Gulf Friday morning increasing the southeast winds to fresh to strong. Fresh to locally strong winds will pulse each night into the early morning hours along the north and west coasts of the Yucatan Peninsula due to the local effects of a diurnal surface trough.

CARIBBEAN SEA...

The main feature in the basin is a tropical wave located in the SW Caribbean. See tropical waves section for details. Isolated showers are possible for Hispaniola, Cuba and Puerto Rico this afternoon and early evening. Strong deep layer wind shear and dry air subsidence support fair weather W of 80W. A strong pres gradient between low pres in the SW basin and high pres NE of the area in the Atlantic support fresh to strong winds S of 18N between 68W and 79W. These winds are forecast to diminish Friday before sunrise as a center of low pres forms in the SW Atlantic and the tropical wave move W over Pacific waters. Another tropical wave will enter the Caribbean early Thursday.

HISPANIOLA...

Scattered to isolated showers and isolated thunderstorms are possible across the island this afternoon and evening due to low pres N of the Island and a tropical wave in the SW Caribbean. Chances of showers and possible thunderstorms are expected through Friday.

ATLANTIC OCEAN...

A middle to upper level trough over the W Atlantic with base reaching S to the SW Caribbean support the remnants of a former front being analyzed as a surface trough from 30N67W to 23N73W. The upper trough also supports a surface trough farther east from 28N66W to N of Hispaniola near 20N69W. Scattered showers and thunderstorms are across the Florida straits and the Great Bahama Bank and in the vicinity of the troughs between 62W and 73W. The remainder of the Atlantic is dominated by a broad surface ridge anchored by a 1031 mb high near 35N47W. The surface troughs are forecast to merge today and a low is forecast to form by Friday.

For additional information please visit http://www.hurricanes.gov/marine

$$ Ramos

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