000 AXNT20 KNHC 061744 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI MAY 06 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... ITCZ AXIS IS ALONG 10N14W 04N23W 01N30W CROSSING THE EQUATOR NEAR 41W AND INTO NE BRAZIL NEAR 01S48W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 06N BETWEEN 16W-31W. ISOLATED MODERATE CONVECTION IS FROM THE EQUATOR TO 03N BETWEEN 31W-45W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY SHOWS A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS PROGRESSING OVER PORTIONS OF NORTHERN FLORIDA AND THE NE GULF WATERS THAT SUPPORTS A SURFACE TROUGH ANALYZED FROM 30N84W SW TO 26N88W. MOSAIC DOPPLER RADAR AND LIGHTNING DATA INDICATE WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING ACROSS THE CENTRAL FLORIDA PENINSULA THAT STRETCH WESTWARD TO THE SURFACE TROUGH AXIS. ELSEWHERE WITHIN 75 NM EITHER SIDE OF THE SURFACE TROUGH FROM 28N85W TO 23N94W ISOLATED SHOWERS...WHICH REMAIN MOSTLY STATIONARY...ARE NOTED ON VISIBLE SATELLITE IMAGERY THIS AFTERNOON. SE OF THE TROUGH AXIS...LIGHT E TO SE WINDS...ALONG WITH THE POTENTIAL FOR ISOLATED SHOWERS WILL REMAIN OVER THE SE GULF AND SOUTHERN FLORIDA PENINSULA THROUGH EARLY SATURDAY WHEN THE TROUGH IS EXPECTED TO MOVE INTO PORTIONS OF THE SW NORTH ATLC. NW OF THE TROUGH AXIS...A 1020 MB HIGH CENTERED NEAR 29N92W IS EXPECTED TO REMAIN IN PLACE ACROSS THE NORTHERN GULF COAST THROUGH THE WEEKEND AND PROVIDE LIGHT ANTICYCLONIC SURFACE FLOW THROUGH SATURDAY. THEREAFTER... SOUTHERLY RETURN FLOW WILL ESTABLISH ITSELF OVER THE WESTERN GULF SE OF DEVELOPING LOW PRESSURE ACROSS THE U.S. CENTRAL PLAINS. CARIBBEAN SEA... ALOFT THE CARIBBEAN SEA BASIN IS UNDER THE INFLUENCE OF TWO UPPER LEVEL ANTICYCLONIC CIRCULATIONS...ONE CENTERED OVER THE GULF OF HONDURAS NEAR 16N88W...AND THE OTHER CENTERED IN THE TROPICAL NORTH ATLC NE OF BRAZIL NEAR 06N43W. AN UPPER LEVEL RIDGE AXIS BRIDGES THE TWO CIRCULATIONS FROM 06N43W TO 14N76W TO 16N88W. AT THE SURFACE...THE NW CARIBBEAN REMAINS UNDER MOSTLY FAIR CONDITIONS AND CLEAR SKIES IN PART DUE TO THE SUBSIDENCE AND DRY AIR ON THE EASTERN PERIPHERY OF THE GULF OF HONDURAS UPPER LEVEL ANTICYCLONE. FARTHER EAST...THE REMNANTS OF A FRONTAL BOUNDARY...NOW ANALYZED AS A SHEAR LINE...ENTERS THE SE CARIBBEAN NEAR 15N61W AND EXTENDS SW TO 12N67W. TOTAL PRECIPITABLE WATER IMAGERY INDICATES ABUNDANT LOW-LEVEL MOISTURE OVER THIS AREA AND ALONG WITH LOW-LEVEL CONVERGENCE THE BOUNDARY CONTINUES TO BE THE FOCUS FOR WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS S OF 16N E OF 70W. ELSEWHERE OVER THE SW CARIBBEAN...A SURFACE TROUGH EXTENDS ALONG 09N/10N BETWEEN 76W-83W WITH ISOLATED SHOWERS AND TSTMS OCCURRING S OF 11N W OF 80W. ATLANTIC OCEAN... MOSTLY ZONAL WESTERLY UPPER LEVEL FLOW IS LOCATED ACROSS THE SW NORTH ATLC AND THIS RATHER BENIGN PATTERN FOR THE TIME BEING IS SUPPORTIVE OF A 1022 MB HIGH CENTERED NORTH OF THE DISCUSSION AREA NEAR 34N71W. THIS UPPER LEVEL FLOW HOWEVER IS ACCOMPANIED BY MODERATELY MOIST MIDDLE TO UPPER LEVEL AIR AS SHOWERS CONTINUE TO ADVECT WESTWARD AROUND THE SOUTHERN PERIPHERY OF THE RIDGE. THE MOST ORGANIZED AREA OF ISOLATED SHOWERS THIS AFTERNOON CONTINUES TO BE LOCATED OFFSHORE OF SOUTH FLORIDA AND IN THE VICINITY OF THE NW BAHAMAS. THE APPROACH OF AN UPPER LEVEL SHORTWAVE TROUGH CURRENTLY OVER NORTHERN FLORIDA AND THE NE GULF IS GOING TO INCREASE PRECIPITATION CHANCES ACROSS THE W ATLC WEST OF 75W OVER THE NEXT 24 TO 36 HOURS AS CYCLOGENESIS IS FORECAST TO OCCUR OVER SOUTH CAROLINA BY EARLY SATURDAY AND MOVE NE INTO THE VICINITY OF 34N73W BY 07/1200 UTC AS A 1011 MB LOW CENTER. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 32N49W AND REFLECTS TO THE SURFACE AS A 1007 MB OCCLUDED LOW. THE OCCLUDED FRONT EXTENDS FROM THE SURFACE LOW TO 31N43W THEN AS A DISSIPATING COLD FRONT TO 25N45W. SURFACE TROUGHING IS ANALYZED FROM THE COLD FRONT SW TO 17N54W THEN CONTINUES AS A SHEAR LINE INTO THE SE CARIBBEAN SEA NEAR 15N61W. LOW-LEVEL CONVERGENCE ALONG THE BOUNDARIES AND UPPER LEVEL DIFFLUENCE IN ASSOCIATION WITH THE UPPER LEVEL LOW AND TROUGH AXIS ARE GENERATING SCATTERED SHOWERS COVERING THE AREA FROM 20N-28N BETWEEN 35W-44W. ELSEWHERE ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM EITHER SIDE OF THE COLD FRONT...SURFACE TROUGH...AND SHEAR LINE. A SECONDARY WAVE OF ENERGY ASSOCIATED WITH THE DEEP LAYER TROUGHING IS ANALYZED AS A SURFACE TROUGH FROM 29N49W TO 23N61W. ISOLATED SHOWERS ARE WITHIN 150 NM E OF THE TROUGH AXIS FROM 23N-29N. FINALLY...AN UPPER LEVEL TROUGH LOCATED WEST OF THE IBERIAN PENINSULA SUPPORTS A COLD FRONT ANALYZED INTO THE DISCUSSION AREA NEAR 32N17W THAT EXTENDS SW TO 29N28W. ISOLATED SHOWERS ARE NOTED ON SATELLITE IMAGERY WITHIN 60 NM EITHER SIDE OF THE FRONT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN