000 AXNT20 KNHC 181155 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT MON JUN 18 2012 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... BROAD UPPER LEVEL TROUGHING IS NOTED ON WATER VAPOR IMAGERY ACROSS THE WESTERN NORTH ATLC THIS MORNING THAT SUPPORTS A 1005 MB GALE FORCE SURFACE LOW CENTERED NEAR 36N63W. THIS SLIGHTLY OCCLUDED LOW EXTENDS A COLD FRONT FROM 37N61W TO 34N60W TO 31N61W WITH SCATTERED SHOWERS AND ISOLATED TSTMS OCCURRING WITHIN 240 NM EAST OF THE COLD FRONT AND ISOLATED SHOWERS AND TSTMS CLOSER TO THE LOW CENTER OCCURRING WITHIN 90 NM OF CENTER. THIS LOW IS EXPECTED TO DRIFT NORTHEASTWARD OVER THE NEXT FEW DAYS AND HAS THE POSSIBILITY TO ACQUIRE SUBTROPICAL CYCLONE CHARACTERISTICS. THIS SYSTEM HAS A MEDIUM CHANCE...30 PERCENT... OF BECOMING A SUBTROPICAL OR TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE WAS ADDED FROM 11N35W TO 3N37W MOVING W NEAR 15-20 KT BASED ON VISIBLE SATELLITE IMAGERY FROM SUN...MODEL DATA... UPPER LEVEL DATA FROM DAKAR. NO ASSOCIATED DEEP CONVECTION. TROPICAL WAVE IS ALONG 52W S OF 13N MOVING W 15-20 KT. WAVE POSITION IS BASED ON MODEL DATA AND SATELLITE IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 6N-8N BETWEEN 51W-53W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL ATLC NEAR 17N16W CONTINUING ALONG 13N21W TO 8N28W WHERE THE ITCZ CONTINUES TO 7N35W THEN RESUMES W OF THE TROPICAL WAVE NEAR 6N39W TO 6N51W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 120 NM ALONG THE COAST OF SW AFRICA FROM GUINEA TO THE PRIME MERIDIAN AND WITHIN 90/120 NM OF LINE FROM 7N17W TO 5N29W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 60 NM OF LINE FROM 7N37W TO 11N47W. ...DISCUSSION... GULF OF MEXICO... THE W GULF IS UNDER NNW FLOW ALOFT WHILE AN UPPER HIGH IS OVER THE NE GULF AND AN UPPER LOW IS OVER THE SE GULF. THE WEAK SURFACE TROUGH OVER THE NW GULF HAS DISSIPATED. DIFFLUENCE ALOFT BETWEEN THE UPPER FLOW OVER THE W GULF AND THE UPPER HIGH OVER THE NE GULF IS GENERATING CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 25N BETWEEN 89W-94W TO INLAND OVER LOUISIANA. THE NE SURFACE FLOW OVER THE SW GULF CONTINUES TO BANK LOW LEVEL CLOUDS WITH ISOLATED SHOWERS/THUNDERSTORMS OVER THE BAY OF CAMPECHE WITHIN 75/90 NM ALONG THE COAST OF MEXICO S OF TAMPICO AND E OF CIUDAD DEL CARMEN. A BAND OF ISOLATED SHOWERS/ THUNDERSTORMS ARE OVER THE NE GULF WITHIN 45 NM OF LINE FROM 25N85W TO 29N84W. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS MORNING. HIGH PRESSURE WILL BUILD OVER THE E GULF TODAY. A WEAK LOW PRESSURE AREA WILL MOVE OFF YUCATAN INTO THE S/CENTRAL GULF WED THEN DRIFT INTO THE SW GULF THU AND FRI AS AN ACCOMPANYING TROUGH MOVES FROM THE NW CARIBBEAN INTO THE SE GULF. CARIBBEAN SEA... BROAD UPPER RIDGE EXTENDS FROM OVER CENTRAL AMERICA NEAR THE TIP OF HONDURAS/NICARAGUA TO ACROSS THE VIRGIN ISLANDS/PUERTO RICO INTO THE W/CENTRAL ATLC. THIS IS PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED TO HEAVY SHOWERS WITH ISOLATED THUNDERSTORMS ARE WITHIN 120 NM OF LINE FROM 14N81W TO OVER HISPANIOLA 19N60W INCLUDING THE MONA PASSAGE AND W PUERTO RICO. EMBEDDED BENEATH THIS FLOW IS A 1008 MB SURFACE LOW CENTERED NEAR 15N82W WITH A SURFACE TROUGH EXTENDING FROM THE LOW ALONG 18N76W THROUGH THE WINDWARD PASSAGE INTO THE W/CENTRAL ATLC. SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS ARE FROM 10N-15N W OF 80W TO THE COAST OF NICARAGUA. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE OVER THE FAR W CARIBBEAN S OF 20N W OF 83W TO INLAND OVER CENTRAL AMERICA AND THE YUCATAN PENINSULA. THIS IS LEAVING ONLY THE FAR E CARIBBEAN AND THE LESSER ANTILLES UNDER MOSTLY CLEAR SKIES THIS MORNING. LOW/SURFACE TROUGH WILL DRIFT NW THROUGH EARLY WED. A TROPICAL WAVE E OF THE LESSER ANTILLES WILL ENTER THE E CARIBBEAN TONIGHT MOVING INTO THE CENTRAL CARIBBEAN BY LATE TUE BEFORE BECOMING DIFFUSE OVER THE SW CARIBBEAN WED. A SECOND TROPICAL WAVE WILL INTO THE E CARIBBEAN BY LATE WED. ATLANTIC OCEAN... A BROAD UPPER TROUGH COVERS THE W ATLC N OF 22N W OF 62W TO OVER FLORIDA SUPPORTING 1005 MB LOW N OF THE DISCUSSION AREA AND A SURFACE TROUGH ENTERING THE W/CENTRAL ATLC NEAR 32N61W AND EXTENDING ALONG 29N65W 23N72W THEN CONTINUING THROUGH THE WINDWARD PASSAGE INTO THE CARIBBEAN. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 21N-26N W OF 62W TO THE SURFACE TROUGH. CLEAR SKIES PREVAIL N OF 24N W OF THE SURFACE TROUGH. AN UPPER RIDGE EXTENDS FROM THE CARIBBEAN ACROSS THE VIRGIN ISLANDS/PUERTO RICO ALONG 26N57W TO BEYOND 32N53W PROVIDING DIFFLUENCE ALOFT TO GENERATE SCATTERED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS WITHIN 150 NM OF LINE FROM 26N62W TO BEYOND 32N59W. A LARGE SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC E OF 60W ANCHORED BY A 1026 MB HIGH NEAR 30N37W. TROUGH WILL REMAIN NEARLY STATIONARY THROUGH TODAY THEN WILL DRIFT NW TUE APPROACHING FLORIDA WED AND THU. SURFACE RIDGE WILL BUILD IN FROM THE E BEHIND THE TROUGH WED THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW