000 AXNT20 KNHC 170003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUL 16 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE CENTRAL ATLC ASSOCIATED WITH A 1012 MB LOW PRESSURE CENTER NEAR 10N36W...MOVING W AT NEARLY 15-20 KT. SSMI TPW IMAGERY DEPICT THE WAVE IS EMBEDDED IN A BROAD AREA OF HIGH MOISTURE CONTENT THAT ALONG WITH MIDDLE-LEVEL DIVERGENT WIND FLOW SUPPORT A CLUSTER OF MODERATE CONVECTION FROM 05N TO 14N BETWEEN 30W AND 42W. A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN WITH AXIS APPROXIMATELY ALONG 73W...MOVING W AT 20-25 KT DURING THE LAST 24 HOURS. SSMI TPW IMAGERY DEPICT A MODERATE MOIST AIRMASS ASSOCIATED WITH THE TROPICAL WAVE ACROSS THE NORTH-CENTRAL AND PORTIONS OF THE E CARIBBEAN. AN ELONGATED UPPER LOW EXTENDING FROM NE OF THE LEEWARD ISLANDS TO CENTRAL CUBA SUPPORT SCATTERED SHOWERS AND TSTMS ACROSS PUERTO RICO...THE MONA PASSAGE AND HISPANIOLA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N16W TO 10N30W TO THE 1012 MB LOW NEAR 10N36W TO 08N41W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 07N44W TO 05N53W. ASIDE FROM CONVECTION ASSOCIATED WITH THE TROPICAL WAVE...SCATTERED MODERATE CONVECTION IS FROM 08N-11N E OF 18W. ...DISCUSSION... GULF OF MEXICO... A BROAD RIDGE COVERING GREAT PORTIONS OF THE ATLC BASIN EXTENDS AN AXIS SW ACROSS THE CENTRAL AND SOUTHERN FLORIDA PENINSULA AND THE CENTRAL AND SE GULF OF MEXICO WHERE IS ANCHORED BY A 1018 MB HIGH NEAR 27N88W. ALOFT...AN UPPER LOW IS OBSERVED CENTERED OVER SOUTHERN MEXICO AND EXTENDING EASTWARD ACROSS THE BAY OF CAMPECHE WHERE MOISTURE INFLOW FROM THE CARIBBEAN SUPPORT SCATTERED MODERATE CONVECTION FROM 18N TO 21N E OF 92W. MIDDLE TO UPPER LEVEL RIDGING DOMINATES ACROSS THE REMAINDER BASIN. SSMI TPW IMAGERY SHOW MOISTURE INFLOW FROM THE SE CONUS AND THE NW CARIBBEAN TO THE NE GULF...WHICH CONVERGENCE SUPPORTS SCATTERED SHOWERS AND TSTMS ALONG NORTHERN FLORIDA. A MIDDLE LEVEL TROUGH IS OVER THE E CONUS SEABOARD WITH BASE EXTENDING SW ACROSS CENTRAL-SOUTHERN FLORIDA...THUS SUPPORTING SCATTERED SHOWERS AND TSTMS FROM 25N TO 29N E OF 85W. VARIABLE WINDS OF 5 TO 10 KT DOMINATE ACROSS THE BASIN. THE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY THROUGH SATURDAY. CARIBBEAN SEA... A TROPICAL WAVE IS MOVING ACROSS THE CENTRAL CARIBBEAN ASSOCIATED WITH A MODERATE MOIST AIRMASS OVER THE NORTH-CENTRAL AND PORTIONS OF THE E CARIBBEAN. THIS MOISTURE ALONG WITH A BROAD AND ELONGATED UPPER LEVEL LOW EXTENDING FROM NE OF THE LEEWARD ISLANDS TO CENTRAL CUBA SUPPORT SCATTERED SHOWERS AND TSTMS ACROSS PUERTO RICO...THE MONA PASSAGE AND HISPANIOLA. ANOTHER MODERATE MOIST AIRMASS IS OVER THE NW CARIBBEAN ASSOCIATED WITH A TROPICAL WAVE THAT MOVED ACROSS CENTRAL AMERICA EARLY TODAY. A MIDDLE-LEVEL DIFFLUENT WIND FLOW OVER THIS REGION ALONG THE MOISTURE SUPPORT SCATTERED MODERATE CONVECTION N OF 18N W OF 80W...INCLUDING WESTERN CUBA. OVER THE SW CARIBBEAN...LOW PRESSURE ASSOCIATED WITH A LOW CENTER OVER N COLOMBIA AND THE EPAC MONSOON TROUGH SUPPORT SCATTERED MODERATE CONVECTION S OF 12N W OF 79W. STRONG DEEP LAYER WIND SHEAR AND DRY AIR INHIBIT CONVECTION ELSEWHERE. A GENERALLY TIGHT PRESSURE GRADIENT BETWEEN A RIDGE OVER THE ATLC EXTENDING ACROSS THE NORTHERN BASIN AND LOWER PRESSURE OVER COLOMBIA SUPPORT WINDS OF 20 KT TO 25 KT FROM 11N TO 14N BETWEEN 74W AND 77W. TRADES OF 15 KT DOMINATE ELSEWHERE. FRESH TO OCCASIONAL STRONG E-NE WINDS ARE EXPECTED TO PERSIST THROUGH THE UPCOMING WEEKEND. ...HISPANIOLA... MOISTURE ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE WITH AXIS CURRENTLY NEAR 73W ALONG WITH MIDDLE-LEVEL DIFFLUENT WIND FLOW SUPPORT SCATTERED MODERATE CONVECTION AND TSTMS ACROSS THE ISLAND AND MONA PASSAGE. SHOWERS ACTIVITY IS FORECAST THROUGH FRIDAY NIGHT. ATLANTIC OCEAN... AN MIDDLE-LEVEL TROUGH IS OVER THE E CONUS SEABOARD AND W ATLC W OF 66W SUPPORTING A 1008 MB LOW CENTERED NEAR 39N65W WITH STATIONARY FRONT EXTENDING SW TO 32N80W. TO THE SOUTH OF THE FRONT...LOW-LEVEL MOISTURE CONVERGENCE COUPLED WITH MIDDLE-LEVEL DIFFLUENCE IS GENERATING ISOLATED SHOWERS AND TSTMS ACROSS MUCH OF THE SW NORTH ATLC W OF 70W. FARTHER EAST...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1024 MB HIGH CENTERED NEAR 31N53W AND A 1023 MB HIGH CENTERED NEAR 31N32W. A WEAKNESS BETWEEN THESE TWO HIGHS IS ANALYZED AS A SURFACE TROUGH FROM 30N44W TO 26N51W. HIGH PRESSURE AND RIDGING WILL CONTINUE TO BE THE MAIN FEATURE ACROSS THE BASIN DURING THE NEXT TWO DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR