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AXNT20 KNHC 280945
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT THU AUG 28 2014

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0945 UTC.


...TROPICAL WAVES...

A TROPICAL WAVE IS IN THE EASTERN ATLC WITH AXIS EXTENDING FROM 21N28W TO 10N29W MOVING W AT 20 KT. MODERATE LOW-LEVEL MOISTURE ALONG WITH A MIDDLE-LEVEL DIFFLUENT ENVIRONMENT ENHANCE ISOLATED SHOWERS AND TSTMS FROM 13N-15N WITHIN 130 NM WEST OF THE WAVE AXIS. NO CONVECTION IS ELSEWHERE AS SAHARAN DRY AIR AND DUST CONTINUE IN THE ENVIRONMENT OF THE WAVE.

A TROPICAL WAVE IS OVER THE CENTRAL ATLC WITH AXIS EXTENDING FROM 19N40W TO 10N39W MOVING W AT 20 KT. NO CONVECTION IS ASSOCIATED WITH THE WAVE AS SAHARAN DRY AIR AND DUST CONTINUE IN THE ENVIRONMENT OF THE WAVE.

A TROPICAL WAVE IS ON THE EASTERN CARIBBEAN WITH AXIS EXTENDING FROM 18N63W TO 10N66W...MOVING W AT 20-25 KT. DEEP LAYER MOISTURE ACCOMPANIES THIS WAVE MAINLY S OF 17N WHICH ALONG WITH UPPER-LEVEL DIVERGENCE SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 14N-17N EAST OF 68W.

A TROPICAL WAVE IS ON THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 22N79W TO 9N81W...MOVING WEST AT 20-25 KT. AN UPPER LEVEL INVERTED TROUGH SUPPORTS THIS WAVE THAT IS ASSOCIATED WITH DEEP LAYER MOISTURE. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE N OF 19N BETWEEN 78W-83W AND S OF 17N BETWEEN 75W-85W. ISOLATED SHOWERS ARE ELSEWHERE BETWEEN 75W-85W.


...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W AND CONTINUES ALONG 10N27W TO 9N37W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 6N-10N BETWEEN 24W-28W.


...DISCUSSION...

GULF OF MEXICO...

SURFACE LOW PRESSURE DOMINATES ACROSS THE GULF BEING SUPPORTED BY A MIDDLE LEVEL ELONGATED INVERTED TROUGH. THIS TROUGHINESS ALOFT SUPPORT A 1009 MB LOW BEING ANALYZED IN THE NW GULF NEAR 26N96W AND A SURFACE TROUGH ALONG 24N89W...ACROSS THE EASTERN BAY OF CAMPECHE TO 17N91W. MIDDLE-LEVEL DIFFLUENCE BEING GENERATED BY AN ANTICYCLONIC CIRCULATION ANCHORED ON THE SW N ATLC ALONG WITH HIGH LOW-LEVEL MOISTURE SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS ON THE NORTHERN PORTION OF THE TROUGH FROM 21N-25N BETWEEN 85W-91W. SIMILAR CONVECTION IS ANALYZED NEAR THE LOW CENTER N OF 25N W OF 94W. A SURFACE TROUGH EXTENDS FROM THE NORTHERN BAHAMAS SW TO 24N81W TO 20N85W...ENHANCING ISOLATED SHOWERS ACROSS THE FLORIDA STRAITS...INCLUDING THE FLORIDA KEYS. E-SE WIND FLOW OF 10-15 KT DOMINATES THE EASTERN AND NW GULF WHILE NORTHEASTERLY FLOW OF SIMILAR MAGNITUDE IS PRESENT ON THE SW BASIN. THE AREA OF LOW PRESSURE ON THE NW GULF IS EXPECTED TO MOVE SW INTO NE MEXICO LATER TODAY. THE TROUGH OVER THE YUCATAN WILL CONTINUE TO MOVE WESTWARD TO CENTRAL BAY OF CAMPECHE WHERE IT DISSIPATES THU NIGHT. RAINSHOWERS ASSOCIATED WITH THESE FEATURES WILL CONTINUE THROUGH FRIDAY NIGHT.

CARIBBEAN SEA...

AN UPPER-LEVEL INVERTED TROUGH CONTINUES OVER THE WEST CARIBBEAN SUPPORTING A TROPICAL WAVE WITH AXIS FROM CENTRAL CUBA TO THE SW BASIN. ANOTHER TROPICAL WAVE IS ON THE EASTERN BASIN GENERATING SHOWERS. SEE THE TROPICAL WAVE SECTION FOR MORE DETAILS. DEEP LAYER MOISTURE ALONG A REGION OF UPPER-LEVEL DIFFLUENCE GENERATED BY WEAK RIDGE ON THE EASTERN BASIN SUPPORT SCATTERED SHOWERS AND TSTMS WITHIN 150 NM OF THE SOUTHERN DOMINICAN REPUBLIC COASTLINE. THE PASSAGE OF THE TROPICAL WAVE ALONG WITH A TIGHT PRESSURE GRADIENT ACROSS THE NE CARIBBEAN SUPPORT TRADES OF 20-25 KT IN THIS REGION OF THE BASIN...INCLUDING PUERTO RICO ADJACENT WATERS. TRADES OF 15 KT DOMINATE ELSEWHERE. RAINSHOWER ACTIVITY ASSOCIATED WITH THE WAVES WILL PREVAIL ACROSS GREAT PORTIONS OF THE BASIN THROUGH FRIDAY NIGHT.


...HISPANIOLA...

A LOW-LEVEL DRY ENVIRONMENT PREVAILS ACROSS GREAT PORTIONS OF THE ISLAND. HOWEVER...A DIFFLUENT ENVIRONMENT S-SE OF THE ISLAND ALONG WITH MODERATE MOISTURE SUPPORT SCATTERED SHOWERS AND TSTMS WITHIN 150 NM OF THE SOUTHERN DOMINICAN REPUBLIC COASTLINE. A TROPICAL WAVE WILL MOVE NEAR THE ISLAND THURSDAY THROUGH FRIDAY ENHANCING SHOWERS MAINLY IN SOUTHERN HISPANIOLA AND COASTAL WATERS.

ATLANTIC OCEAN...

A COL OR AREA OF LOW PRESSURE IN THE MIDDLE TO UPPER LEVELS ALONG WITH LOW-LEVEL MOISTURE CONVERGENCE ON THE SW N ATLC CONTINUE TO SUPPORT SCATTERED SHOWERS AND TSTMS N OF 26N BETWEEN 70W-75W. NEARBY TO THE SW...A SURFACE TROUGH EXTENDS FROM THE NORTHERN BAHAMAS SW ACROSS THE STRAITS OF FLORIDA TO THE NW CARIBBEAN ENHANCING ISOLATED SHOWERS IN THAT REGION. SIMILAR CONVECTION IS NOTED FARTHER EAST FROM 25N-27N BETWEEN 58W-61W. OTHERWISE...BESIDES THE TROPICAL WAVES ALREADY DISCUSSED...THE REMAINDER OF THE ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE ANCHORED BY A 1022 MB HIGH CENTERED NEAR 30N55W.

FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE

$$ NR

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