000 AXNT20 KNHC 200603 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT JUN 20 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 0545 UTC. ...SPECIAL FEATURES... A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC EXTENDING INTO THE NORTHERN CARIBBEAN AND LOWER PRESSURE OVER NORTHERN COLOMBIA AND NORTHWEST VENEZUELA SUPPORTS GALE FORCE WINDS FROM 11.5N TO 13.5N BETWEEN 72W AND 77W WITH 10 TO 15 FT SEAS SWELL AND S OF 12N BETWEEN 70W AND 72W WITH SEAS TO 9 FT. GALE-FORCE WINDS ARE FORECAST TO CONTINUE THROUGH SATURDAY AFTERNOON. PLEASE READ THE HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE FORECAST...MIAOFFNT3/FZNT23 KNHC...FOR MORE DETAILS. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE EASTERN TROPICAL ATLC WITH AXIS NEAR 26W MOVING W AT 10 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE CONTINUES EMBEDDED WITHIN A MODERATE SURGE OF MOISTURE. METEOSAT SATELLITE IMAGERY DEPICT SAHARAN DRY AIR AND DUST IN THE WAVE ENVIRONMENT...THUS LIMITING THE CONVECTION TO ISOLATED MODERATE FROM 03N TO 08N BETWEEN 24W AND 28W. A TROPICAL WAVE IS IN THE WESTERN TROPICAL ATLC WITH AXIS ALONG 44W MOVING W NEAR 10 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN A MODERATE SURGE OF MOISTURE EXCEPT WITHIN 175 NM W OF ITS AXIS FROM 09N TO 11N WHERE A HIGH MOIST ENVIRONMENT SUPPORT A CLUSTER OF MODERATE CONVECTION. A TROPICAL WAVE IS IN THE SW CARIBBEAN BASIN WITH AXIS ALONG 76W FROM 16N TO PANAMA MOVING W NEAR 15 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN AN AREA OF RELATIVELY DRY AIR THAT IS HINDERING DEEP CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC NEAR 12N16W AND CONTINUES TO 08N24W. THE ITCZ BEGINS NEAR 08N29W AND CONTINUES TO E OF THE TROPICAL WAVE NEAR 09N43W THEN RESUMES W OF THE WAVE NEAR 08N46W TO NORTHERN SOUTH AMERICA NEAR 06N55W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM 05N TO 12N BETWEEN 28W AND 42W. ISOLATED TSTMS ARE NOTED FROM 06N TO 09N E OF 17W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER RIDGE ANCHORED OVER WESTERN-CENTRAL MEXICO EXTENDS AN AXIS NE INTO THE NW GULF TO OVER SOUTHERN LOUISIANA AND MISSISSIPPI. THE REMAINDER OF THE GULF IS UNDER A LARGE UPPER LOW CENTERED OVER THE NW YUCATAN PENINSULA. A BROAD SURFACE RIDGE OVER THE ATLC EXTENDS AN AXIS SW TO W ACROSS THE FLORIDA PENINSULA AND INTO THE GULF EXCEPT THE SW BASIN WHERE A SURFACE TROUGH IS ANALYZED FROM 23N92W TO 17N94W. SHOWERS AND TSTMS ARE AHEAD OF THE TROUGH S OF 20N W OF 94W. INFLOW OF MOISTURE FROM THE CARIBBEAN ALONG WITH A MIDDLE LEVEL DIFFLUENT ENVIRONMENT SUPPORT SHOWERS AND TSTMS FROM 25N TO 27N E OF 84W. WATER VAPOR IMAGERY SHOW DRY AIR ALOFT ACROSS THE REMAINDER GULF...THUS FAVORING FAIR WEATHER. VARIABLE WINDS OF 5 KT ARE OVER THE EASTERN GULF AROUND A 1019 MB HIGH NEAR 27N83W. EASTERLY TO SOUTHEASTERLY WIND FLOW OF 10 TO 15 KT IS OVER THE REMAINDER BASIN. THE SURFACE HIGH PRESSURE CENTER IN THE NE GULF WILL LINGER THROUGH THE FIRST OF NEXT WEEK. THE CARIBBEAN SEA... A GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN THROUGH SATURDAY AFTERNOON. SEE SPECIAL FEATURES ABOVE. A TROPICAL WAVE IS MOVING ACROSS THE SW BASIN. FOR DETAILS SEE THE TROPICAL WAVES SECTION. AN UPPER RIDGE COVERS THE WESTERN AND THE CENTRAL BASIN WHILE AND UPPER LEVEL LOW CENTERED NE OF PUERTO RICO COVERS THE EASTERN CARIBBEAN. A MODERATE MOIST ENVIRONMENT OVER THE W CARIBBEAN ENHANCES ISOLATED SHOWERS W OF 80W. METEOSAT SATELLITE IMAGERY CONTINUE TO DEPICT SAHARAN DRY AIR AND DUST COVERING THE E CARIBBEAN...THUS SUPPORTING HAZE. THE NEXT TROPICAL WAVE WILL ENTER THE EASTERN CARIBBEAN MONDAY NIGHT THROUGH TUESDAY MORNING. ...HISPANIOLA... A LOW TO MODERATE MOIST AIRMASS IS MOVING ACROSS HISPANIOLA SUPPORTING CLOUDINESS OVER WESTERN DOMINICAN REPUBLIC. HOWEVER...METEOSAT SATELLITE IMAGERY INDICATE THE PRESENCE OF SAHARAN DUST AND DRY AIR...WHICH IS SUPPORTING HAZE OVER THE EASTERN ISLAND. EXCEPT FOR THE TYPICAL AFTERNOON SHOWERS...FAIR WEATHER IS EXPECTED THROUGH THE WEEKEND. THE ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE ATLC BEING ANCHORED BY A 1021 MB HIGH NEAR 28N74W. METEOSAT SATELLITE IMAGERY INDICATE SAHARAN DRY AIR AND DUST COVERING THE TROPICS S OF 20N EXTENDING INTO THE EASTERN CARIBBEAN...THUS LIMITING SHOWER ACTIVITY. SURFACE RIDGING WILL BE THE DOMINANT FEATURE THE NEXT THREE DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR