000 AXNT20 KNHC 311042 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI MAY 31 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 14N17W TO 06N30W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 06N30W TO 07N38W TO 04N51W. NUMEROUS MODERATE AND SCATTERED STRONG CONVECTION IS FROM 03N-10N BETWEEN 10W-21W. SCATTERED MODERATE CONVECTION IS FROM 05N-08N BETWEEN 21W-34W. ...DISCUSSION... GULF OF MEXICO... A WEAK UPPER LEVEL TROUGH EXTENDS OVER THE WESTERN GULF WITH AXIS FROM 26N93W TO OVER CENTRAL MEXICO NEAR 21N100W. THIS TROUGHING...WHILE PRODUCING INSIGNIFICANT WEATHER AT THE SURFACE...IS PROVIDING MIDDLE TO UPPER LEVEL STEERING FOR THE REMNANTS OF BARBARA WHICH HAVE WEAKENED INTO A SURFACE TROUGH ANALYZED FROM 19N94W TO 22N93W. WHILE A WEAK MID-LEVEL CIRCULATION CONTINUES TO GRADUALLY DISSIPATE AND BECOME EMBEDDED WITHIN SOUTHEASTERLY FLOW OVER THE WESTERN GULF...SCATTERED SHOWERS AND TSTMS ARE OCCURRING PRIMARILY TO THE EAST OF THE TROUGH AXIS S OF 25N BETWEEN 84W-94W. OTHERWISE...THE REMAINDER OF THE NORTHERN AND EASTERN GULF IS UNDER WESTERLY UPPER LEVEL FLOW AND RELATIVELY QUIETER CONDITIONS THIS MORNING. THIS LARGELY SUPPORTS A THE SURFACE RIDGE ANCHORED OVER THE SW NORTH ATLC OFFSHORE OF THE CAROLINAS NEAR 33N66W AND EXTENDS W-SW TO THE NW GULF NEAR 28N95W. THIS RIDGE IS EXPECTED TO REMAIN IN PLACE ACROSS THE GULF THROUGH THE WEEKEND PROVIDING E-SE WINDS. BY SUNDAY...A WEAK FRONTAL BOUNDARY WILL APPROACH THE TEXAS AND LOUISIANA COAST AND SLOWLY PROGRESS EASTWARD ACROSS THE NORTHERN GULF COAST AND SE CONUS. CARIBBEAN SEA... MOST OF THE CARIBBEAN IS UNDER IN THE INFLUENCE OF UPPER LEVEL RIDGING WITH ONE ANTICYCLONE CENTERED OVER THE NW CARIBBEAN NEAR 16N83W AND THE OTHER ANTICYCLONE CENTERED OVER THE SE CARIBBEAN NEAR 11N62W. THIS RESULTS IN AN OVERALL DIFFLUENT ATMOSPHERIC ENVIRONMENT. COUPLED WITH SUSTAINED MOIST E-SE LOW-LEVEL FLOW ON THE SOUTHERN PERIPHERY OF A SURFACE RIDGE ANCHORED IN THE SW NORTH ATLC...AREAS OF CONVECTION PERSIST THIS MORNING. ONE SUCH AREA IS SCATTERED SHOWERS AND TSTMS FROM 12N-23N BETWEEN 75W- 84W. OTHERWISE...OTHER AREAS REMAIN AS ISOLATED SHOWERS AND TSTMS ACROSS PUERTO RICO AND HISPANIOLA...AS WELL AS THE SE CARIBBEAN S OF 13N E OF 64W. FINALLY...THE MONSOON TROUGH AXIS EXTENDS ALONG 10N/11N FROM NORTHERN COLOMBIA TO NICARAGUA AND HONDURAS. ISOLATED SHOWERS AND TSTMS ARE OCCURRING OVER THE AREA S OF 13N BETWEEN 72W-86W. THE OVERALL SYNOPTIC PATTERN OF E-SE TRADES IS EXPECTED TO PERSIST THROUGH EARLY NEXT WEEK AS HIGH PRESSURE REMAINS ANCHORED TO THE NORTH IN THE SW NORTH ATLC. HISPANIOLA... HISPANIOLA REMAINS UNDER THE INFLUENCE OF MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH NOTED ON WATER VAPOR IMAGERY WITH AXIS ALONG 71W. THE DIFFLUENCE ALOFT COUPLED WITH PERSISTENT MOIST LOW-LEVEL SOUTHEASTERLY FLOW IS CONTINUING TO SUPPORT ISOLATED SHOWERS ACROSS THE ISLAND THIS MORNING. LOOKING AHEAD...AS THE UPPER LEVEL TROUGH SLOWLY PROGRESSES EASTWARD...LINGERING SUPPORTING DYNAMICS ALOFT WILL REMAIN OVER HISPANIOLA FRIDAY INTO SATURDAY WITH SCATTERED SHOWERS AND TSTMS EXPECTED...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS DUE TO PEAK DAYTIME HEATING AND INSTABILITY. ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL LOW IS NOTED ON WATER VAPOR IMAGERY CENTERED NEAR 31N72W WITH AXIS EXTENDING SOUTHWARD TO 20N ALONG 72W. WHILE THIS UPPER LEVEL FEATURE IS FOUND LARGELY ABOVE SURFACE RIDGING ACROSS THE SW NORTH ATLC...LIFTING DYNAMICS CONTINUE TO PRODUCE EXTENSIVE CLOUDINESS WITH WIDELY SCATTERED SHOWERS AND TSTMS ACROSS THE REGION FROM 18N-35N BETWEEN 65W- 74W. OTHERWISE...THE SW NORTH ATLC REMAINS UNDER THE INFLUENCE OF A SURFACE RIDGE W OF 60W WITH SUSTAINED E-SE WINDS IN THE RANGE OF 10-20 KT. THIS OVERALL SYNOPTIC PATTERN IS EXPECTED TO PERSIST THROUGH EARLY SUNDAY. FARTHER EAST...BRIDGING THE PREVIOUSLY MENTIONED RIDGE AND A STRONGER SURFACE RIDGE OVER THE EASTERN ATLC...IS A FRONTAL TROUGH HIGHLIGHTED BY A STATIONARY FRONT ANALYZED FROM 33N44W TO 31N46W AND A SURFACE TROUGH ANALYZED FROM 28N56W TO 33N50W. ISOLATED SHOWERS ARE OCCURRING WITHIN 180 NM EITHER SIDE OF A LINE FROM 33N44W TO 29N55W. FINALLY...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC ARE UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1034 MB HIGH CENTERED NE OF THE AZORES NEAR 41N25W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN