000 AXNT20 KNHC 301044 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU MAY 30 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 12N17W TO 08N22W. THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 08N22W TO 03N51W. ISOLATED MODERATE CONVECTION IS FROM 03N-06N BETWEEN THE PRIME MERIDIAN AND 08W...AND FROM 03N-06N BETWEEN 14W-21W. SCATTERED MODERATE CONVECTION IS FROM 04N-08N BETWEEN 27W-49W. ISOLATED MODERATE CONVECTION IS FROM 07N-09N BETWEEN 51W-58W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE AXIS EXTENDS ALONG 87W BETWEEN TWO AREAS OF TROUGHING ON EITHER SIDE OF THE RIDGE OVER THE GULF THIS MORNING. ONE MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE FLORIDA PENINSULA AND PORTIONS OF THE SW NORTH ATLC THAT CONTINUES TO GENERATE ISOLATED SHOWERS ACROSS THE SOUTHERN FLORIDA PENINSULA AND SE GULF S OF 26N E OF 83W. THE OTHER MIDDLE TO UPPER LEVEL TROUGH AXIS EXTENDS FROM THE NORTHERN ROCKIES SE TO OVER THE FAR NW GULF AND TEXAS GULF COAST NEAR 27N95W. MOST CONVECTION ASSOCIATED WITH THIS TROUGH REMAINS WELL NORTH OF THE BASIN OVER THE CENTRAL U.S. PLAINS. THE MOST INFLUENTAL FEATURE IS A SURFACE RIDGE ANCHORED IN THE SW NORTH ATLC WITH AXIS EXTENDING ACROSS NORTHERN FLORIDA TO THE NW GULF NEAR 27N95W. E-SE WINDS CONTINUE IN THE RANGE OF 10 TO 20 KT AND THIS OVERALL SYNOPTIC PATTERN IS EXPECTED TO PERSIST THROUGH EARLY SATURDAY. MOIST SOUTHERLY RETURN FLOW ALONG WITH MARGINAL LOW-LEVEL CONVERGENCE IS GENERATING A FEW AREAS OF ISOLATED SHOWERS AND TSTMS...WITH ONE FOUND WITHIN 30 NM EITHER SIDE OF A LINE FROM 24N84W TO 25N88W. THE CIRCULATION ASSOCIATED WITH TROPICAL STORM BARBARA LOCATED JUST NORTH OF THE GULF OF TEHUANTEPEC IN THE EAST PACIFIC REGION IS PROVIDING FOR SCATTERED SHOWERS AND TSTM ACTIVITY OVER THE SW GULF WATERS S OF 22N BETWEEN 90W-97W. BARBARA IS EXPECTED TO CONTINUE ON A WEAKENING TREND AS IT TRACKS SLOWLY NORTHWARD AND ITS REMNANTS BECOME EMBEDDED WITHIN THE S-SE RETURN FLOW ACROSS THE WESTERN GULF DESCRIBED ABOVE. CARIBBEAN SEA... A WEAK MIDDLE TO UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY OVER THE FLORIDA PENINSULA AND SW NORTH ATLC WITH THE BASE OF THIS TROUGH DIPPING SOUTHWARD OVER CENTRAL CUBA. A CONSIDERABLE AMOUNT OF MIDDLE TO UPPER LEVEL DIFFLUENCE IS LOCATED OVER THE WESTERN CARIBBEAN W OF 62W AS AN UPPER LEVEL RIDGE EXTENDS EASTWARD FROM OVER CENTRAL AMERICA NEAR 14N84W TO 14N64W. THESE UPPER LEVEL LIFTING DYNAMICS ALONG WITH LOW-LEVEL MOISTURE CONVERGENCE AT THE SURFACE DUE TO PERSISTENT E-SE TRADES ARE GENERATING SCATTERED SHOWERS AND TSTMS N OF 17N BETWEEN 67W-82W...INCLUDING PORTIONS OF HISPANIOLA...JAMAICA... EASTERN CUBA...AND THE WINDWARD PASSAGE. ANOTHER AREA OF SCATTERED SHOWERS AND TSTMS IS LOCATED PRIMARILY ALONG THE COAST OF NICARAGUA AND EASTERN HONDURAS FROM 12N-17N BETWEEN 82W-85W. ISOLATED SHOWERS AND TSTMS ARE ALSO POSSIBLE ACROSS THE NW CARIBBEAN N OF 16N BETWEEN 78W-88W. MOIST SOUTHWESTERLY FLOW ALOFT IS NOTED EAST OF THE LESSER ANTILLES...HOWEVER LINGERING WESTWARD MOVING LOW-LEVEL MOISTURE IS GENERATING ISOLATED SHOWERS E OF 70W. 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 MAXIMUM MIDDLE TO UPPER LEVEL DIFFLUENCE EAST OF A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH NOTED ON WATER VAPOR IMAGERY WITH AXIS ALONG 79W. THE DIFFLUENCE ALOFT COUPLED WITH PERSISTENT MOIST LOW-LEVEL SOUTHEASTERLY FLOW IS CONTINUING TO SUPPORT SCATTERED SHOWERS ACROSS THE ISLAND THIS MORNING WITH AREAS TO THE WEST SEEING MORE INTENSE CONVECTION IN THE VICINITY OF THE WINDWARD PASSAGE AND ALL APPROACHES. LOOKING AHEAD...WITH THE UPPER LEVEL TROUGH SLOW TO MOVE EASTWARD...SUPPORTING DYNAMICS ALOFT WILL REMAIN OVER HISPANIOLA THURSDAY WITH SCATTERED SHOWERS AND TSTMS EXPECTED...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS DUE TO PEAK DAYTIME HEATING AND INSTABILITY. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH OVER THE FLORIDA PENINSULA HAS BEEN SLOW TO MOVE INTO THE SW NORTH ATLC AND CONTINUES AMPLIFYING AN UPPER LEVEL RIDGE EXTENDING FROM OVER THE NORTH-CENTRAL CARIBBEAN SEA NEAR 18N73W TO BEYOND 32N67W. MIDDLE TO UPPER LEVEL DIFFLUENCE BETWEEN THE TROUGHING AND RIDGE IS GENERATING SCATTERED SHOWERS AND TSTMS ACROSS A LARGE AREA FROM 18N-29N BETWEEN 68W-78W. OTHERWISE...THE REMAINDER OF THE SW NORTH ATLC OUTSIDE OF THE CONVECTIVE ACTIVITY IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1030 MB HIGH CENTERED NEAR 36N59W. BRIDGING THIS RIDGE AND A STRONGER SURFACE RIDGE OVER THE EASTERN ATLC...IS A FRONTAL TROUGH HIGHLIGHTED BY A STATIONARY FRONT ANALYZED FROM 33N51W TO 31N53W WHERE IT BECOMES A SURFACE TROUGH TO 25N58W. ISOLATED SHOWERS ARE OCCURRING WITHIN 180 NM EITHER SIDE OF THE BOUNDARY. FINALLY...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC ARE UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1034 MB HIGH CENTERED N OF THE AZORES NEAR 41N27W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN