000 AXNT20 KNHC 162343 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI SEP 16 2011 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 2330 UTC. ...SPECIAL FEATURES... THE CENTER OF MARIA MADE LANDFALL JUST NORTHWEST OF CAPE PINE ON THE AVALON PENINSULA OF NEWFOUNDLAND ABOUT 1830Z THIS AFTERNOON AND HAS RACED ACROSS THE PENINSULA INTO THE ATLANTIC OCEAN. MARIA HAS LOST ENOUGH TROPICAL CHARACTERISTICS TO BE CONSIDERED POST-TROPICAL...AND IN ADDITION IT APPEARS TO BE LOSING ITS CLOSED CIRCULATION. THE CYCLONE SHOULD BECOME ABSORBED WITHIN A FRONTAL ZONE WITHIN 12 HOURS WITH A DECREASE IN WINDS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF GUINEA BISSAU NEAR 12N16W TO A 1010 MB LOW NEAR 11N18W TO ANOTHER 1012 MB LOW NEAR 10N32W TO NEAR 7N42W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 7N42W TO THE EASTERN COAST OF VENEZUELA NEAR 9N61W. THE LARGE AND STRETCHED OUT MONSOON GYRE IS PRODUCING WIDELY SCATTERED MODERATE TO ISOLATED STRONG CONVECTION WITHIN 200 NM ON EITHER SIDE OF THE MONSOON TROUGH AXIS. SCATTERED WEAK CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE ITCZ AXIS W OF 55W...MOST LIKELY ASSOCIATED TO THE SW MID-UPPER LEVEL FLOW FROM THE UPPER LEVEL CYCLONIC CIRCULATION CENTERED E OF PUERTO RICO. ...DISCUSSION... GULF OF MEXICO... A WEAK STATIONARY FRONT IS ANALYZED ACROSS THE NORTHERN GULF WATERS FROM THE TEXAS COAST TO THE NORTHERN COAST OF FLORIDA ALONG 29N96W 27N88W 29N83W. NO SIGNIFICANT CONVECTION IS OCCURRING ALONG THIS BOUNDARY. THIS FRONT HAS INTRODUCED A MILDER AIRMASS TO THE NORTH-CENTRAL AND PORTIONS OF THE NE GULF WATERS. THIS FRONT IS EXPECTED TO CONTINUE TO WEAKEN AND BECOME MORE DIFFUSE THROUGH SATURDAY. OTHERWISE...SATELLITE VISIBLE IMAGERY SHOWS MOSTLY CLEAR SKIES WITH A FEW ISOLATED WEAK SHOWERS...MOVING WITH THE LIGHT ANTICYCLONIC FLOW PRESENT ACROSS THE BASIN. WATER VAPOR IMAGERY SHOWS A LARGE RIDGE OF HIGH PRESSURE CENTERED OVER THE CENTRAL MEXICO REGION PROVIDING MUCH OF THE GULF WITH MIDDLE TO UPPER LEVEL DRY AIR AND SUBSIDENCE. THE RIDGE IS FORECAST TO DISSIPATE OVER THE NEXT 24 HOURS. CARIBBEAN SEA... BROAD SURFACE CYCLONIC FLOW IS WEST OF 75W. WHILE SCATTERED HEAVY SHOWERS ROAM THIS AREA...STRONGER ACTIVITY FOCUSES ALONG A SLOW MOVING SURFACE TROUGH ANALYZED FROM 17N81W TO 10N81W... GENERATING GUSTY SCATTERED SHOWERS AND THUNDERSTORMS S OF 17N W OF 78W. MOST OF THE ACTIVITY IS ALSO ENHANCED BY THE MONSOON TROUGH ANALYZED OVER THE FAR SW BASIN EXTENDING ACROSS COSTA RICA INTO NORTHERN COLOMBIA. THIS AREA OF CONVECTION IS ALREADY MOVING INLAND OVER CENTRAL AMERICA...WITH THE ACTIVITY EXPECTED TO LAST THROUGH THE WEEKEND. WATER VAPOR IMAGERY SHOWS A BROAD UPPER LEVEL CYCLONIC CIRCULATION JUST EAST OF PUERTO RICO NEAR 18N64W. THIS CIRCULATION IS ADVECTING MOISTURE NORTHWARD FROM THE INTERTROPICAL CONVERGENCE ZONE AND ENHANCING AN AREA OF SCATTERED MODERATE TO STRONG CONVECTION AFFECTING THE FAR SE CARIBBEAN S OF DOMINICA E OF 64W. THE ACTIVITY LIES AHEAD OF A SURFACE TROUGH ANALYZED JUST E OF THE LESSER ANTILLES AND IT IS EXPECTED TO MOVE INTO THE EAST CARIBBEAN OVER THE NEXT 24 HOURS. THE REMAINDER OF THE BASIN REMAINS UNDER FAIR WEATHER CONDITIONS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH MOVES OFF THE EASTERN CONUS SEABOARD THIS EVENING...WATER VAPOR IMAGERY SHOWS SSW FLOW ALOFT AHEAD OF THE UPPER TROUGH...MOVING MID-UPPER LEVEL MOISTURE FROM THE WESTERN CARIBBEAN INTO THE SW NORTH ATLC. LOW-LEVEL CONVERGENCE LIES UNDERNEATH THIS AREA OF MOISTURE FOCUSED ON A SURFACE TROUGH ANALYZED FROM 30N70W TO 22N75W. SCATTERED SHOWERS ARE WITHIN 70 NM ON EITHER SIDE OF THE SURFACE TROUGH AXIS. A BROAD UPPER LEVEL CYCLONIC CIRCULATION IS CENTERED JUST EAST OF PUERTO RICO NEAR 18N64W. THIS FEATURE IS PROVIDING MOISTURE NORTHWARD FROM THE INTERTROPICAL CONVERGENCE ZONE AND ENHANCING AN AREA OF SCATTERED MODERATE TO STRONG CONVECTION FROM 10N-18N BETWEEN 54W-64W. A SURFACE TROUGH IS ANALYZED WITHIN THIS AREA FROM 16N57W TO 11N60W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A WEAK BROAD SURFACE RIDGE N OF THE AREA. HOWEVER...AN UPPER LEVEL LOW CENTERED SOUTH OF THE AZORES NEAR SUPPORTS A WEAK LOW PRESSURE SYSTEM AND AND ASSOCIATED COLD FRONT WITH A NARROW LINE OF ISOLATED SHOWERS EXTENDING ALONG THE BOUNDARY. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA