000 AXNT20 KNHC 170538 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI JUL 17 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0530 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AXIS APPROXIMATELY ALONG 75W AND FROM 10N TO 19N...MOVING W AT 20-25 KT DURING THE LAST 24 HOURS. SSMI TPW IMAGERY DEPICT A MODERATE MOIST AIRMASS ASSOCIATED WITH THIS WAVE PREVAILING ACROSS THE NORTHERN PORTION OF THE WAVE AND EXTENDING ACROSS THE E CARIBBEAN MAINLY N OF 15N. SAHARAN DUST IS ALSO PREVAILING ACROSS THIS AREA THUS NO SIGNIFICANT CONVECTION IS OBSERVED AT THIS TIME. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 12N16W TO A 1011 MB SURFACE LOW CENTERED NEAR 10N35W TO 08N41W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N41W TO 06N57W. SCATTERED MODERATE CONVECTION IS OBSERVED SURROUNDING THE LOW FROM 03N-13N BETWEEN 25W-43W. ...DISCUSSION... GULF OF MEXICO... A BROAD SURFACE RIDGE COVERING A GREAT PORTION OF THE ATLANTIC BASIN EXTENDS W REACHING THE GULF WATERS AND ANCHORED BY A 1017 MB HIGH NEAR 26N87W. ALOFT...AN UPPER-LEVEL LOW IS OBSERVED CENTERED OVER SOUTHERN MEXICO AND EXTENDING EASTWARD ACROSS THE BAY OF CAMPECHE BRINGING MOISTURE FROM THE CARIBBEAN AND EPAC INTO THE W GULF. AN UPPER-LEVEL HIGH IS CENTERED NEAR 30N89W AND EXTENDING ACROSS THE CENTRAL AND E GULF. A DIFFLUENT FLOW PREVAILS ACROSS THE E PORTION OF THE BASIN AND THE FLORIDA PENINSULA SUPPORTING ISOLATED CONVECTION E OF 87W. SCATTEROMETER DATA DEPICTS A LIGHT ANTICYCLONIC FLOW ACROSS MOST OF THE BASIN EXCEPT N OF THE YUCATAN PENINSULA S OF 24N BETWEEN 88W-91W WHERE LIGHT TO GENTLE FLOW IS OBSERVED. THE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH THE NEXT 24 HOURS. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN. PLEASE REFER TO THE SECTION ABOVE FOR MORE DETAILS. AN AREA OF MODERATE MOISTURE PREVAILS ACROSS THE NE AND CENTRAL CARIBBEAN N OF 14N AND E OF 73W. THIS MOISTURE ALONG WITH AN UPPER-LEVEL LOW CENTERED NE OF THE LEEWARD ISLANDS IS SUPPORTING ISOLATED CONVECTION ACROSS PUERTO RICO...THE MONA PASSAGE...AND HISPANIOLA. ANOTHER AREA OF MODERATE MOISTURE PREVAILS ACROSS THE W CARIBBEAN W OF 75W AND WITH SUPPORT OF AN UPPER-LEVEL LOW CENTERED OVER W CUBA...ISOLATED CONVECTION PREVAILS N OF 18N BETWEEN 75W-79W. OVER THE SW CARIBBEAN...THE PROXIMITY OF THE MONSOON TROUGH S OF PANAMA AND A SURFACE LOW OVER NE COLOMBIA ARE PRODUCING SCATTERED MODERATE CONVECTION THAT IS MOVING OVER THE SOUTHERN CARIBBEAN WATERS MAINLY S OF 11N. A STRONG DEEP LAYER WIND SHEAR AND DRY AIR CONTINUES TO INHIBIT CONVECTION ELSEWHERE. A GENERALLY TIGHT PRESSURE GRADIENT BETWEEN THE RIDGE OVER THE ATLANTIC EXTENDING ACROSS THE NORTHERN BASIN AND LOWER PRESSURES OVER COLOMBIA AND SOUTH AMERICA SUPPORTS GENTLE TO MODERATE TRADES ACROSS MOST OF THE BASIN EXCEPT N OF 18N AND W OF 73W WHERE A LIGHT EASTERLY FLOW PREVAILS. OVER THE NEXT 24 HOURS...EXPECT FOR THE TROPICAL WAVE TO CONTINUE MOVING W ACROSS THE W CARIBBEAN INDUCING AN INCREASE IN MOISTURE. A SIMILAR WEATHER PATTERN WILL PREVAIL ACROSS THE BASIN. ...HISPANIOLA... THE MOISTURE ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE WITH AXIS S OF THE ISLAND NEAR 74W COMBINED WITH A MID-LEVEL DIFFLUENT FLOW SUPPORTS ISOLATED MODERATE CONVECTION ACROSS THE AREA. SIMILAR ACTIVITY IS POSSIBLE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... AN UPPER-LEVEL TROUGH PREVAILS OVER THE W ATLANTIC WITH BASE N OF OUR AREA AND SUPPORTING A STATIONARY FRONT THAT IS CURRENTLY GENERATING SCATTERED MODERATE CONVECTION N OF 29N AND W OF 78W. A BROAD UPPER-LEVEL LOW CENTERED OVER W CUBA EXTENDS ACROSS THE BAHAMAS SUPPORTING ISOLATED CONVECTION S OF 24N AND W OF 76W. THE CENTRAL AND E ATLANTIC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1023 MB HIGH CENTERED NEAR 32N55W AND A 1022 MB HIGH CENTERED NEAR 33N28W. A WEAKNESS BETWEEN THESE TWO HIGHS IS ANALYZED AS A SURFACE TROUGH FROM 26N51W TO 31N45W. OVER THE NEXT 24 HOURS...EXPECT FOR THE SURFACE RIDGE TO PREVAIL ACROSS THE BASIN WITH FAIR WEATHER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA