000 AXNT20 KNHC 231750 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU MAY 23 2013 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 01N50W TO 07N49W MOVING W AT 15-20 KT. THE WAVE REMAINS ON THE WESTERN EXTENT OF THE ITCZ AXIS AND IS LOCATED WITHIN AN AREA OF LOW-LEVEL CYCLONIC TURNING. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 07N BETWEEN 45W-51W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 10N14W TO 08N18W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N18W TO 04N29W TO 03N48W. ISOLATED MODERATE CONVECTION IS FROM 05N-12N BETWEEN 16W-21W...AND FROM THE EQUATOR TO 06N BETWEEN 21W-32W. SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN 35W-43W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES THAT MIDDLE TO UPPER LEVEL NORTHWESTERLY FLOW CONTINUES TO PROVIDE AN OVERALL MODERATELY DRY AND STABLE AIRMASS ALOFT OVER MUCH OF THE BASIN THIS AFTERNOON. FURTHER SUPPORTING THE STABLE REGIME IN PLACE A SURFACE RIDGE REMAINS ANCHORED BY A 1018 MB HIGH CENTERED OVER THE NE GULF WATERS NEAR 28N87W. ON THE SOUTHERNWESTERN PERIPHERY OF THIS SURFACE RIDGE...LIGHT SOUTHEASTERLY WINDS PREVAIL IN THE RANGE OF 5 TO 15 KT. EAST OF THE RIDGE...A WEAK AREA OF LOWER PRESSURE IS OBSERVED ACROSS THE FLORIDA PENINSULA AND ADJACENT COASTAL WATERS IN THE SW NORTH ATLC WITH A SURFACE TROUGH ANALYZED FROM OFFSHORE OF THE CAROLINAS ACROSS THE SOUTHERN FLORIDA PENINSULA AND INTO THE SE GULF NEAR 25N84W. MOSTLY CLEAR SKIES ARE NOTED ON SATELLITE IMAGERY AS THE HIGH AND RIDGE IS EXPECTED TO REMAIN IN PLACE THROUGH THE WEEKEND. CARIBBEAN SEA... NORTHWEST TO WESTERLY FLOW ALOFT DOMINATES OVER THE CARIBBEAN WITH WATER VAPOR IMAGERY INDICATING MODERATELY DRY AIR OVER A NARROW AREA FROM THE YUCATAN CHANNEL TO 15N70W. OTHERWISE AT THE SURFACE...THE TROPICAL WAVE PREVIOUSLY ANALYZED IN THE SW CARIBBEAN HAS BECOME TO DIFFICULT TO DISCERN ON SATELLITE IMAGERY AND THE ENERGY ASSOCIATED WITH IT HAS MERGED INTO THE SEMI-PERMANENT LOW-LEVEL COLOMBIAN GYRE. SCATTERED SHOWERS AND ISOLATED TSTMS CONTINUE OVER THE SW CARIBBEAN HOWEVER S OF 14N BETWEEN 75W-81W...AND S OF 11N BETWEEN 81W-84W. FARTHER EAST... LOW-LEVEL MOISTURE INCREASES OVER THE NE CARIBBEAN NEAR THE BASE OF A MIDDLE TO UPPER LEVEL TROUGH THAT EXTENDS FROM THE FAR WESTERN PORTION OF THE SW NORTH ATLC GENERATING WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS EAST OF A LINE FROM SOUTHWESTERN HISPANIOLA NEAR 18N74W TO THE ABC ISLANDS NEAR 12N68W. E-SE TRADES ARE EXPECTED TO PERSIST THROUGH FRIDAY WITH WINDS SHIFTING MORE NORTHEASTERLY OVER THE NW CARIBBEAN AS A FRONTAL TROUGH MOVES ACROSS THE SW NORTH ATLC REGION. HISPANIOLA... CURRENTLY NORTHWEST WINDS ALOFT ARE OVER THE ISLAND WITH SATELLITE IMAGERY INDICATING LOW-LEVEL MOISTURE CONTINUING TO ADVECT ACROSS THE ISLAND INCREASING TO THE EAST OVER PUERTO RICO AND THE LEEWARD ISLANDS. ISOLATED SHOWERS ARE OCCURRING EAST OF 72W AND THIS CONVECTION IS EXPECTED TO CONTINUE AND INCREASE IN COVERAGE THROUGHOUT THE LATE AFTERNOON INTO THE EARLY EVENING HOURS WITH PEAK DAYTIME HEATING AND INSTABILITY IN PLACE. OVERALL SOUTHEAST WINDS ARE EXPECTED TO PERSIST THROUGH EARLY SATURDAY AS A FRONTAL TROUGH MOVES ACROSS THE SW NORTH ATLC AND BY SATURDAY SURFACE TROUGHING WILL LIE ACROSS THE ISLAND PROVIDING FOR INCREASED PRECIPITATION CHANCES OVER THE REMAINDER OF THE WEEKEND INTO EARLY MONDAY. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS INDICATED ON WATER VAPOR IMAGERY WITH AXIS EXTENDING FROM OFFSHORE OF THE CAROLINAS TO A BASE OVER HISPANIOLA...PUERTO RICO...AND THE NE CARIBBEAN SEA. THE STRONGEST UPPER LEVEL DYNAMICS LIE N OF 25N OFF THE FLORIDA PENINSULA COAST AS SCATTERED SHOWERS AND TSTMS ARE OCCURRING N OF 25N BETWEEN 74W AND A SURFACE TROUGH AXIS ANALYZED FROM 32N78W TO THE FLORIDA COAST NEAR 26N80W AND INTO THE SE GULF OF MEXICO WATERS NEAR 24N84W. THE REMAINDER OF THE SW NORTH ATLC AND CENTRAL ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1029 MB HIGH CENTERED EAST OF BERMUDA NEAR 33N59W. LOW-LEVEL MOISTURE PREVAILS ON THE SOUTHERN PERIPHERY OF THE RIDGE WITH POSSIBLE ISOLATED SHOWERS S OF 24N BETWEEN 50W-72W. AN AMPLIFIED UPPER LEVEL RIDGE AND ANTICYCLONE IS CENTERED NEAR 30N54W WITH UPPER LEVEL TROUGHING NOTED ON WATER VAPOR IMAGERY W OF 46W. THIS TROUGHING SUPPORTS A STATIONARY FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N39W TO 28N40W TO 25N45W. ISOLATED SHOWERS ARE OCCURRING WITHIN 210 NM EAST OF THE BOUNDARY. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1034 MB HIGH CENTERED WELL NE OF THE AZORES NEAR 48N21W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN