000 AXNT20 KNHC 182338 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU JUN 18 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 2315 UTC. ...SPECIAL FEATURES... ...GALE IN THE CARIBBEAN... A GALE WARNING IS IN EFFECT FOR THE SW CARIBBEAN OVERNIGHT ALONG THE NW COAST OF COLOMBIA AND IN THE GULF OF VENEZUELA THROUGH FRI EVENING. THE GALE FORCE WINDS WILL REOCCUR FRI NIGHT THROUGH SAT EVENING. THESE WINDS ARE GENERATED BY A TIGHT PRESSURE GRADIENT BETWEEN THE SURFACE RIDGE OVER THE W ATLC AND THE LOWER PRESSURE OVER SOUTH AMERICA. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...TROPICAL WAVES... TROPICAL WAVE IN THE TROPICAL ATLC EXTENDS ALONG 35W/36W FROM 4N- 14N MOVING W NEAR 20 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN A MODERATE SURGE OF MOISTURE. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM OF THE WAVE S OF 9N. TROPICAL WAVE IN CENTRAL CARIBBEAN EXTENDS ALONG 70W FROM 15N TO INLAND OVER SOUTH AMERICA 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. NO ASSOCIATED DEEP CONVECTION. TROPICAL WAVE IN THE SW CARIBBEAN EXTENDS ALONG 80W/81W FROM 16N TO OVER PANAMA MOVING W-SW NEAR 10 KT OVER THE PAST 24 HOURS. THE TOTAL PRECIPITABLE WATER IMAGERY SHOWS THE WAVE IS EMBEDDED WITHIN A BROAD SURGE OF DEEP MOISTURE. NO ASSOCIATED DEEP CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLC NEAR 12N16W AND CONTINUES ALONG 10N19W TO 9N25W WHERE THE ITCZ BEGINS AND CONTINUES TO E OF THE TROPICAL WAVE NEAR 8N36W THEN RESUMES W OF THE WAVE NEAR 6N40W ALONG 5N45W TO SOUTH AMERICA NEAR 4N51W. SCATTERED MODERATE CONVECTION IS FROM 8N-11N BETWEEN 20W-22W. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE ANCHORED OVER CENTRAL MEXICO EXTENDS AN AXIS NE INTO THE GULF NEAR BROWNSVILLE TO OVER LOUISIANA NEAR VERMILION BAY. THE REMAINDER OF THE GULF IS UNDER A LARGE UPPER LOW THAT IS CENTERED OVER THE E COAST OF THE YUCATAN PENINSULA. AN OUTFLOW BOUNDARY/SURFACE TROUGH IS RACING OFF THE W COAST OF THE YUCATAN AND AT 18/2100 UTC EXTENDS FROM 22N90W ALONG 20N92W INLAND OVER S MEXICO TO 17N93W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE W OF THIS BOUNDARY TO INLAND OVER THE YUCATAN. A SURFACE RIDGE EXTENDS FROM THE W ATLC ACROSS FLORIDA OVER THE E GULF TO 92W WITH A 1021 MB HIGH NEAR 29N87W. A SEABREEZE TROUGH IS INLAND OVER THE FLORIDA PENINSULA AND IS GENERATING SCATTERED THUNDERSTORMS INLAND ALONG A LINE FROM NAPLES JUST W OF ORLANDO TO JUST W OF JACKSONVILLE. THESE THUNDERSTORMS COULD BRING SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS TO THE COASTAL WATERS OF THE FLORIDA PENINSULA LEAVING THE REMAINDER OF THE GULF WITH FAIR WEATHER THIS EVENING. THE SURFACE HIGH IN THE NE GULF WILL LINGER THROUGH THE FIRST OF NEXT WEEK. CARIBBEAN SEA... THE LARGE UPPER LOW IS CENTERED ALONG THE E COAST OF THE YUCATAN NEAR CANCUN COVERING THE NW CARIBBEAN N OF 16N W OF 80W. AN UPPER RIDGE ANCHORED IN THE SW TROPICAL ATLC EXTENDS A RIDGE AXIS ALONG THE COAST OF VENEZUELA AND COLOMBIA TO S NICARAGUA LEAVING THE REMAINDER OF THE CARIBBEAN WITH NEAR ZONAL WESTERLY FLOW ALOFT. AFTERNOON SHOWERS/SCATTERED THUNDERSTORMS ARE ACROSS PUERTO RICO...HISPANIOLA...JAMAICA...AND PARTS OF CUBA. ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS DOT THE REMAINDER OF THE W CARIBBEAN W OF 80W. NOAA/NESDIS AEROSOL PRODUCT AND VISIBLE SATELLITE IMAGERY INDICATES THAT DENSE AEROSOLS OR SAHARAN DUST COVERS THE CARIBBEAN THIS EVENING. THE SW CARIBBEAN TROPICAL WAVE WILL MOVE ACROSS THE W CARIBBEAN THROUGH FRI NIGHT. THE CENTRAL CARIBBEAN TROPICAL WAVE WILL WILL MOVE INTO THE W CARIBBEAN THE FIRST OF NEXT WEEK. OTHERWISE THE ATLC SURFACE RIDGE WILL MAINTAIN STRONG TO GALE FORCE TRADE WINDS ACROSS THE S/CENTRAL CARIBBEAN THROUGH THE FIRST OF NEXT WEEK. ...HISPANIOLA... AFTERNOON SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE ISLAND THIS EVENING. THESE SHOWERS/THUNDERSTORMS ARE THE RESULT OF HIGH TEMPERATURES...INSTABILITY AND THE PASSING OF THE TROPICAL WAVE. THIS SCENARIO WILL PERSIST THROUGH THROUGH THE FIRST OF NEXT WEEK. ATLANTIC OCEAN... AN UPPER RIDGE COVERS THE W ATLC N OF 23N W OF 65W ANCHORED N OF THE DISCUSSION AREA. THE BROAD UPPER TROUGH COVERS THE CENTRAL ATLC AND EXTENDS A NARROW UPPER TROUGH ACROSS THE TURKS AND CAICOS TO 22N75W. TWO UPPER LOWS ARE EMBEDDED WITHIN THE BROAD UPPER TROUGH COVERING THE CENTRAL ATLC...ONE CENTERED NEAR 23N61W AND A SECOND ONE NEAR 25N41W. THIS UPPER TROUGH IS SUPPORTING A COLD FRONT THAT LIES ALONG THE N PERIPHERY NEAR BERMUDA AND IS GENERATING SCATTERED SHOWERS/THUNDERSTORMS FROM 26N-31N BETWEEN 63W-67W. THE SURFACE ATLC IS DOMINATED BY HIGH PRESSURE AGAIN THIS EVENING. A SURFACE RIDGE EXTENDS FROM THE E ATLC THROUGH 32N33W TO A 1023 MB HIGH NEAR 27N45W ALONG 26N63W TO A 1021 MB HIGH OVER THE W ATLC NEAR 28N76W CONTINUING ACROSS FLORIDA INTO THE E GULF OF MEXICO. NOAA/NESDIS AEROSOL PRODUCT AND VISIBLE SATELLITE IMAGERY INDICATES THAT AEROSOLS OR SAHARAN DUST COVERS THE TROPICS S OF 23N INTO THE CARIBBEAN THUS LIMITING SHOWER ACTIVITY. THE NW/SE SURFACE RIDGE WILL REMAIN ACROSS THE ATLC THROUGH FRI THEN WILL ALIGN ALONG 28W/29N OVER THE WEEKEND THROUGH THE FIRST OF NEXT WEEK. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW