000 AXNT20 KNHC 210016 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0000 UTC. ...SPECIAL FEATURES... STRONG HIGH PRES N OF THE AREA BUILDING IN THE WAKE OF A TROPICAL WAVE MOVING INTO THE SW CARIBBEAN IS SUPPORTING PULSES OF GALE FORCE WINDS COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA OVER THE NEXT COUPLE OF DAYS. WINDS TO GALE FORCE CAN BE EXPECTED PRIMARILY AT NIGHT AND IN THE EARLY MORNING HOURS...BUT STRONG TO NEAR GALE FORCE WINDS WILL PERSIST THROUGHOUT THE DAY AND NIGHT ACROSS MUCH OF THE CENTRAL CARIBBEAN INTO SUNDAY. THE WINDS WILL DIMINISH SLIGHTLY MONDAY AS THE NEXT TROPICAL WAVE MOVES INTO THE AREA...BUT INCREASE AGAIN BY MID WEEK. PLEASE READ THE HIGH SEAS FORECAST... MIAHSFAT2/FZNT02 KNHC...AND THE OFFSHORE FORECAST...MIAOFFNT3/ FZNT23 KNHC...FOR MORE DETAILS. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 34W FROM 11N SOUTHWARD MOVING WESTWARD 10 TO 15 KT. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THAT THE CENTRAL AND SOUTHERN WAVE ENVIRONMENT CONTINUES IS EMBEDDED WITHIN A MODERATE TO HIGH SURGE OF MOISTURE. METEOSAT SATELLITE IMAGERY DEPICTS SAHARAN DRY AIR AND DUST IN THE NORTHERN WAVE ENVIRONMENT. ITCZ-RELATED CONVECTIVE PRECIPITATION IS NEAR THE TROPICAL WAVE. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 51W FROM 13N SOUTHWARD. IT HAS BEEN MOVING WESTWARD 15 KT DURING THE LAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THAT THE WAVE IS MAINLY EMBEDDED WITHIN A MODERATE SURGE OF MOISTURE. CONVECTIVE PRECIPITATION...ISOLATED TO WIDELY SCATTERED MODERATE FROM 10N TO 13N BETWEEN 45W AND 51W. A CARIBBEAN SEA TROPICAL WAVE NEAR 80W FROM SOUTHWESTERN JAMAICA TO PANAMA...MOVING WESTWARD 10 TO 15 KT. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THAT THE WAVE MAINLY IS EMBEDDED WITHIN AN AREA OF RELATIVELY DRY AIR. CONVECTIVE PRECIPITATION...WIDELY SCATTERED MODERATE TO ISOLATED STRONG IS IN THE COASTAL WATERS OF COSTA RICA AND EXTREME SOUTHEASTERN NICARAGUA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH PASSES THROUGH COASTAL SECTIONS OF GUINEA NEAR 10N14W TO 08N25W 08N30W. THE ITCZ CONTINUES FROM 08N35W TO 07N50W. CONVECTIVE PRECIPITATION...SCATTERED MODERATE CONVECTION IS NOTED WITHIN 60 NM EITHER SIDE OF THE MONSOON TROUGH AND WITHIN 120 NM EITHER SIDE OF THE ITCZ BETWEEN 35W AND 45W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LOW REMAINS ANCHORED OVER THE NW POINT OF THE YUCATAN PENINSULA THIS EVENING...ENHANCING A FEW SHOWERS OFF THE NORTHERN COAST OF YUCATAN INTO THE CENTRAL GULF. HIGH LEVEL CLOUDINESS IS NOTED OVER THE EAST CENTRAL GULF AND STRAITS OF FLORIDA RELATED TO THUNDERSTORMS OVER THE FLORIDA PENINSULA AND WESTERN CUBA RESPECTIVELY. OTHERWISE GENERALLY FAIR SKIES PREVAIL ACROSS THE GULF DUE TO THE SUBSIDENCE AROUND THE UPPER LOW. SCATTEROMETER DATA FROM EARLIER IN THE DAY INDICATED MODERATE TO FRESH SE WINDS OFF THE WESTERN COAST OF THE YUCATAN PENINSULA...BETWEEN HIGH PRES CENTERED OVER THE NE GULF AND A TROPICAL WAVE FARTHER SOUTH MOVING THROUGH GUATEMALA TOWARD SOUTHERN MEXICO. ELSEWHERE LIGHT TO GENTLE BREEZES PREVAIL ACROSS THE GULF WITH 2 TO 4 FT SEAS. NO MAJOR CHANGES ARE EXPECTED IN THE WEATHER PATTERN OVER THE NEXT SEVERAL DAYS. THE CARIBBEAN SEA... HIGH PRES BUILDING IN THE WAKE OF THE TROPICAL WAVE MOVING INTO THE SW CARIBBEAN IS SUPPORTING CONTINUAL STRONG TO NEAR GALE FORCE WINDS OVER MAINLY THE S CENTRAL CARIBBEAN...PULSING TO GALE FORCE AT NIGHT OFF COLOMBIA AND OCCASIONALLY IN THE GULF VENEZUELA. RECENT SCATTEROMETER DATA INDICATE THESE WINDS ARE 30 KT OFF COLOMBIA...BUT ARE LIKELY TO INCREASE TO GALE FORCE LATE THIS EVENING. THESE WINDS WILL DIMINISH SLIGHTLY MON AS THE NEXT TROPICAL WAVE MOVES THROUGH THE CENTRAL CARIBBEAN. AN UPPER LOW CENTERED OVER THE YUCATAN PENINSULA IS SUPPORTING SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS THE NW CARIBBEAN AND WESTERN CUBA. NORTHERLY FLOW ON THE WEST SIDE OF A SECOND UPPER LOW CENTERED OVER THE LEEWARD ISLANDS IS SHEARING THE TOPS OF THE AFTERNOON CONVECTION TRYING TO FORM OVER THE HIGHER ELEVATIONS OF PUERTO RICO...HISPANIOLA AND EASTERN CUBA. TRADE WIND CONVERGENCE IS RESPONSIBLE FOR GENERATING A FEW SHOWERS OFF COSTA RICA AND WESTERN PANAMA. OTHERWISE FAIR SKIES ARE NOTED ACROSS THE BASIN EXCEPT FOR A FEW HIGH CLOUDS ARE NOTED OVER THE SW AND S CENTRAL CARIBBEAN...THE UPPER OUTFLOW OF CONVECTION OVER THE TROPICAL EASTERN PACIFIC. ...HISPANIOLA... SCATTERED THUNDERSTORMS FORMED ALONG THE NORTHERN AND CENTRAL MOUNTAIN RANGES OF THE DOMINICAN REPUBLIC AND THE TIBURON PENINSULA OF SOUTHERN HAITI EARLIER THIS AFTERNOON DUE TO DAYTIME HEATING. NORTHERLY FLOW ALOFT ON THE WEST SIDE OF AN UPPER LOW OVER THE LEEWARD ISLANDS KEPT THIS ACTIVITY SHORT LIVED. THIS PATTERN WILL LIKELY REPEAT SUNDAY INTO EARLY NEXT WEEK. CONVECTION MAY BE LONGER LASTING WITH THE POTENTIAL FOR LOCALIZED HEAVY RAINFALL MONDAY AND TUESDAY HOWEVER AS THE UPPER LOW DRIFTS WESTWARD...EVENTUALLY DIRECTLY OVER THE ISLAND BY EARLY TUE. THE ATLANTIC OCEAN... W OF 60W...THE SUBTROPICAL RIDGE EXTENDS EAST TO WEST ALONG ROUGHLY 29N/30N...MAINTAINING GENERALLY LIGHT TO GENTLE BREEZES NORTH OF 22N...WITH MODERATE TO OCCASIONALLY FRESH TRADE WINDS S OF 22N. A FEW SHOWERS ARE NOTED NE OF THE BAHAMAS BETWEEN AN UPPER RIDGE CENTERED NEAR BERMUDA AND AN UPPER LOW OVER THE LEEWARD ISLANDS. A FEW AFTERNOON SHOWERS WERE ACTIVE ACROSS THE ISLANDS OF THE BAHAMAS AND CAY SAL BUT HAVE SINCE DISSIPATED. NO MAJOR CHANGES IN THE PATTERN FOR THE NEXT SEVERAL DAYS. FOR THE CENTRAL ATLC...AN UPPER LOW IS CENTERED OVER THE LEEWARD ISLANDS...THE SW PORTION OF A BIGGER TUTT THAT REACHES NE TOWARD THE AZORES. THE UPPER TROUGHING IS INTERACTING WITH A TROPICAL WAVE BETWEEN 50W AND 55W S OF 15N TO ENHANCE A FEW SHOWERS AND THUNDERSTORMS NEAR 12N50W. A BROAD SUBTROPICAL RIDGE ANCHORED BY SURFACE HIGH PRES CENTERED NEAR 31N45W MAINTAINING GENTLE BREEZES N OF 20N. MODERATE TO FRESH TRADE WINDS ARE NOTED S OF 20N BETWEEN THE RIDGE TO THE NORTH AND THE PAIR OF TROPICAL WAVES MIGRATING WESTWARD THROUGH THE DEEP TROPICS. TRADE WIND CONVERGENCE IS SUPPORTING AREAS OF MAINLY SHOWERS S OF 13N BETWEEN 35W AND 45W. IN THE EASTERN ATLC...ANOTHER PLUME OF SAHARAN DUST IS EMERGING OFF THE COAST OF NORTH AFRICA. THE DRY PATTERN IS KEEPING THE REGION MAINLY CLOUD FREE N OF 10N...WITH ONLY A FEW SHOWERS NOTED FARTHER SOUTH ALONG THE MONSOON TROUGH/ITCZ. THIS MAY CHANGE SLIGHTLY OVER THE NEXT 24 HOURS AHEAD OF THE NEXT TROPICAL WAVE EMERGING OFF THE COAST OF AFRICA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ CHRISTENSEN