000 AXNT20 KNHC 111052 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT JUL 11 2015 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 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 11N25W TO 18N23W MOVING W AT 15 KT. THE WAVE COINCIDES WITH A 700 MB TROUGH BETWEEN 19W-27W AND A MAXIMUM IN 850 MB RELATIVE VORTICITY ALONG THE WAVE AXIS. NO SIGNIFICANT CONVECTION IS NOTED ON SATELLITE IMAGERY DUE TO SAHARAN DUST THAT COVERS A LARGE PORTION OF THE TROPICAL NORTH ATLC. TROPICAL WAVE EXTENDS FROM 07N41W TO 17N40W MOVING W AT 15 KT. THE WAVE COINCIDES WITH A RELATIVELY BROAD 700 MB GLOBAL MODEL INDICATED TROUGH BETWEEN 35W-45W. IN ADDITION...A MAXIMUM IN 850 MB RELATIVE VORTICITY IS NOTED IN GUIDANCE ALONG THE WAVE AXIS NEAR 11N. NO SIGNIFICANT CONVECTION IS NOTED ON SATELLITE IMAGERY DUE LARGELY TO SAHARAN DUST THAT COVERS A LARGE AREA OF THE TROPICAL NORTH ATLC. TROPICAL WAVE EXTENDS FROM 10N63W TO 18N63W MOVING W AT 15 KT. THE WAVE COINCIDES WITH A SUBTLE 700 MB SHORTWAVE TROUGH AND A MAXIMUM OF 850 MB RELATIVE VORTICITY CENTERED IN THE VICINITY OF 15N66W. NO SIGNIFICANT CONVECTION IS NOTED ON SATELLITE IMAGERY AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO 11N25W TO 09N31W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 09N31W TO 07N41W TO 06N57W. SCATTERED MODERATE CONVECTION IS FROM 05N-09N BETWEEN 19W-25W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL RIDGING IS NOTED ON WATER VAPOR IMAGERY OVER THE SW GULF WATERS AND SOUTHERN MEXICO S OF 24N W OF 90W. MIDDLE TO UPPER LEVEL DIFFLUENCE ASSOCIATED WITH THE RIDGING IS GENERATING AN AREA OF ISOLATED SHOWERS AND TSTMS ACROSS THE SW GULF AND SOUTHERN MEXICO S OF 21N BETWEEN 92W-98W. OTHERWISE...THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A PAIR OF 1021 MB HIGHS ONE CENTERED IN THE NE GULF WATERS NEAR 29N86W AND THE OTHER CENTERED ACROSS LOUISIANA NEAR 31N91W. GENERALLY LIGHT TO MODERATE EAST-SOUTHEAST WINDS PREVAIL AND ARE EXPECTED TO PERSIST THROUGH SATURDAY AS THE HIGH DRIFTS SLOWLY WESTWARD TO THE NW GULF BY SUNDAY. CARIBBEAN SEA... NORTHWESTERLY FLOW ALOFT BECOMES MORE WESTERLY E OF 80W AS AN OVERALL STABLE ENVIRONMENT EXISTS OVER MUCH OF THE BASIN THIS MORNING WITH THIS SYNOPTIC SETUP. THE WESTERLY FLOW LIES ON THE SOUTHERN PERIPHERY OF A BROAD AND ELONGATED UPPER LEVEL LOW CENTERED OVER THE WINDWARD PASSAGE NEAR 20N73W. WHILE MOSTLY CLEAR SKIES PREVAILED EARLIER...THE UPPER LEVEL LOW IN TANDEM WITH A DEVELOPING MID-LEVEL TROUGH IS GENERATING MORE EXTENSIVE CLOUDINESS BETWEEN 65W-79W WITH A FEW ISOLATED SHOWERS AND TSTMS ACROSS PORTIONS OF PUERTO RICO...HISPANIOLA...AND A LARGE PORTION OF THE CENTRAL CARIBBEAN. SCATTERED SHOWERS AND TSTMS ARE ALSO OCCURRING WITHIN S OF 13N W OF 78W...INCLUDING PANAMA...COSTA RICA...AND NICARAGUA DUE TO CLOSE PROXIMITY OF THE MONSOON TROUGH AXIS ALONG 08N/09N. A TROPICAL WAVE IS ALONG 65W AND IS INCREASING LOW-LEVEL CONVERGENCE EAST OF THE WAVE AXIS PRODUCING ISOLATED SHOWERS AND TSTMS ACROSS THE LESSER ANTILLES. FINALLY...THE PRIMARY IMPACT FOR THE CARIBBEAN REMAINS THE FRESH TO STRONG TRADES OCCURRING S OF 16N BETWEEN 68W-80W. THE PRESSURE GRADIENT IS EXPECTED TO RELAX SOMEWHAT BY LATE MONDAY. ...HISPANIOLA... AN ELONGATED UPPER LEVEL LOW IS CENTERED N OF THE WINDWARD PASSAGE NEAR 20N73W PROVIDING AMPLE LIFTING DYNAMICS TO GENERATE A FEW ISOLATED SHOWERS AND TSTMS OCCURRING ACROSS THE ISLAND THIS MORNING...INCLUDING MUCH OF THE ADJACENT COASTAL ATLC AND CARIBBEAN WATERS. WITH THE UPPER LEVEL LOW SLOW TO MOVE ON SATURDAY...WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE FORECAST DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. ATLANTIC OCEAN... AN UPPER LEVEL LOW IS CENTERED NORTH OF THE WINDWARD PASSAGE NEAR 20N73W SUPPORTING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ACROSS PORTIONS OF THE SW NORTH ATLC FROM 19N-27N BETWEEN 66W-78W. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1020 MB HIGH CENTERED NEAR 29N71W. FARTHER EAST...THE CENTRAL AND EASTERN ATLC ARE DOMINATED BY AN INFLUENCE OF ANOTHER SURFACE RIDGE ANCHORED BY A NEARLY STATIONARY 1028 MB HIGH CENTERED SE OF THE AZORES NEAR 37N27W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN