000 AXNT20 KNHC 211015 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN JUN 21 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. ...SPECIAL FEATURES... A TIGHT PRESSURE GRADIENT BETWEEN STRONG HIGH PRES N OF THE AREA AND LOW PRESSURE OVER THE SW CARIBBEAN ASSOCIATED WITH A TROPICAL WAVE AND A LOW OVER NORTHERN COLOMBIA IS SUPPORTING PULSES OF GALE FORCE WINDS ALONG THE COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA...EXPECTED TO CONTINUE 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... A TROPICAL WAVE IS OVER THE EAST TROPICAL ATLC WITH AXIS APPROXIMATELY LOCATED AT 18W MOVING W AT 10 KT. SSMI TPW IMAGERY INDICATE THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT WHILE METEOSAT IMAGERY SHOW SAHARAN DUST AND DRY AIR ENGULFING THE NORTHERN REGION OF IT. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 08N TO 12N E OF 20W. A TROPICAL WAVE IS OVER THE CENTRAL TROPICAL ATLC WITH AXIS NEAR 39W MOVING W AT 15 KT OVER THE PAST 24 HOURS. SSMI TPW IMAGERY SHOW THE WAVE IS EMBEDDED IN A MODERATE MOIST ENVIRONMENT EXCEPT IN THE NORTHERN REGION WHERE METEOSAT SATELLITE IMAGERY DEPICT SAHARAN DRY AIR AND DUST. NO CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME. A TROPICAL WAVE IS IN THE WESTERN TROPICAL ATLC WITH AXIS ALONG 55W MOVING W AT APPROXIMATELY 15 KT OVER THE PAST 24 HOURS. SSMI TPW IMAGERY SHOWS THE WAVE IS MAINLY EMBEDDED WITHIN A MODERATE MOIST ENVIRONMENT EXCEPT FROM 09N TO 13N BETWEEN 47W AND 55W WHERE ABUNDANT MOISTURE SUPPORTS SCATTERED MODERATE CONVECTION. A TROPICAL WAVE IS IN THE SW CARIBBEAN BASIN WITH AXIS ALONG 81W FROM 17N TO CENTRAL PANAMA MOVING W NEAR 10 KT OVER THE PAST 24 HOURS. THE SSMI TPW IMAGERY SHOWS THE WAVE IS MAINLY EMBEDDED WITHIN AN AREA OF RELATIVELY DRY AIR THAT IS HINDERING DEEP CONVECTION N OF 12N. SCATTERED MODERATE CONVECTION IS IN THE SOUTHERN WAVE ENVIRONMENT S OF 12N W OF 80W...INCLUDING COSTA RICA. ISOLATED SHOWERS ARE E OF THE WAVE AXIS S OF 13N. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA TO 18N15W...THEN RESUMES W OF A TROPICAL WAVE NEAR 07N20W AND CONTINUES TO 07N33W. THE ITCZ BEGINS NEAR 05N41W AND CONTINUES TO E OF A TROPICAL WAVE NEAR 05N52W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES...ISOLATED MODERATE CONVECTION IS WITHIN 75 NM EITHER SIDE OF THE MONSOON TROUGH BETWEEN 20W AND 32W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LOW REMAINS ANCHORED OVER THE NW YUCATAN PENINSULA ENHANCING A FEW SHOWERS OFF THE NORTHERN COAST OF YUCATAN INTO THE CENTRAL GULF. ISOLATED SHOWERS AND TSTMS ARE OVER THE SE GULF FROM 24N TO 26N E OF 84W BEING SUPPORTED BY MOISTURE INFLOW FROM THE CARIBBEAN AND MIDDLE LEVEL DIFFLUENCE. ISOLATED SHOWERS AND TSTMS ARE ALSO OFF THE E COAST OF MEXICO FROM 19N TO 24N W OF 95W. OTHERWISE GENERALLY FAIR SKIES PREVAIL ACROSS THE GULF DUE TO THE SUBSIDENCE AROUND THE UPPER LOW. SCATTEROMETER DATA INDICATE E TO SE WINDS OF 10 TO 15 KT ARE OVER THE SE GULF AND AHEAD OF A SURFACE TROUGH OVER THE BAY OF CAMPECHE FROM 22N90W TO 17N93W. VARIABLE WINDS OF 5 KT CONTINUE TO DOMINATE THE NE BASIN AROUND HIGH PRES CENTERED NEAR 27N85W. NO MAJOR CHANGES ARE EXPECTED IN THE WEATHER PATTERN OVER THE NEXT SEVERAL DAYS. THE CARIBBEAN SEA... A TIGHT PRESSURE GRADIENT BETWEEN STRONG HIGH PRES N OF THE AREA AND LOW PRESSURE OVER THE SW CARIBBEAN ASSOCIATED WITH A TROPICAL WAVE ALONG 81W AND A LOW OVER NORTHERN COLOMBIA IS SUPPORTING PULSES OF GALE FORCE WINDS ALONG THE COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA...EXPECTED TO CONTINUE OVER THE NEXT COUPLE OF DAYS. SEE THE SPECIAL FEATURES AND TROPICAL WAVES SECTIONS FOR MORE DETAILS. A DIFFLUENT ENVIRONMENT BETWEEN AN UPPER LOW CENTERED OVER THE NW YUCATAN PENINSULA AND A RIDGE COVERING PORTIONS OF THE NW AND SW CARIBBEAN ALONG WITH SHALLOW MOISTURE SUPPORT SCATTERED SHOWERS AND TSTMS WITHIN 60 NM OFF THE SW COAST OF CUBA. A SECOND UPPER LOW IS CENTERED NE OF THE LEEWARD ISLANDS...HOWEVER WITH DRY AIR AROUND IT...THUS HINDERING THE DEVELOPMENT OF CONVECTION. OTHERWISE...SAHARAN DRY AIR AND DUST CONTINUES TO SUPPORT HAZY CONDITIONS ACROSS THE EASTERN BASIN...INCLUDING THE LESSER ANTILLES. THE NEXT TROPICAL WAVE ENTERS THE EASTERN CARIBBEAN TUESDAY MORNING. ...HISPANIOLA... MAINLY DRY AIR IS ACROSS HISPANIOLA THIS MORNING FAVORING CLEAR SKIES AND FAIR WEATHER. SHALLOW MOISTURE SURROUNDS THE WESTERN HALF OF THE ISLAND...ENHANCING ISOLATED SHOWERS AND TSTMS ON THE WINDWARD PASSAGE. EXCEPT FOR THE TYPICAL AFTERNOON SHOWERS...FAIR WEATHER IS EXPECTED THROUGH MONDAY EVENING WHEN A MOIST AIRMASS APPROACHES THE ISLAND INCREASING THE PROBABILITIES OF SHOWERS. THE ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE ATLC BEING ANCHORED BY A 1025 MB HIGH NEAR 30N37W. METEOSAT SATELLITE IMAGERY INDICATE SAHARAN DRY AIR AND DUST COVERING MOST OF THE TROPICS S OF 20N...THUS LIMITING SHOWER ACTIVITY. FOR INFORMATION ON TROPICAL WAVES SEE SECTION ABOVE. SURFACE RIDGING WILL BE THE DOMINANT FEATURE THE NEXT THREE DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR