000 AXNT20 KNHC 282349 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT MAY 28 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 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS FROM 06N TO 13N ALONG 57W MOVING W AT 10-15 KT. VISIBLE SATELLITE IMAGERY SHOWS AN INVERTED-V STRUCTURE WITH CYCLONIC FLOW ABOUT THE AXIS IN THE LOW-LEVEL CLOUD PATTERN. TOTAL PRECIPITABLE WATER IMAGERY ALSO INDICATES A POLEWARD EXTENSION OF LOW-LEVEL MOISTURE TO 13N IN THE VICINITY OF THE WAVE AXIS. HOWEVER...DRY NW FLOW IN THE MIDDLE TO UPPER LEVELS ABOVE THE LOW-LEVEL WAVE SIGNATURE IS INHIBITING ANY SIGNIFICANT CONVECTION WITH THE WAVE THIS EVENING. TROPICAL WAVE IS FROM 06N TO 14N ALONG 69W MOVING W AT 10-15 KT. WHILE MOST OF THE WAVE AXIS REMAINS OVER NORTHWESTERN VENEZUELA...CYCLONIC FLOW ACROSS THE NORTHERN EXTENT OF THE WAVE AXIS IS NOTED IN THE LOW-LEVEL CLOUDS ON VISIBLE SATELLITE IMAGERY. WESTERLY UPPER LEVEL FLOW ACROSS THE CARIBBEAN SEA WATERS IN THE VICINITY OF THE WAVE IS SHEARING ANY POTENTIAL CONVECTION N OF 12N...HOWEVER WIDELY SCATTERED MODERATE CONVECTION IS OCCURRING INLAND OVER PORTIONS OF NW VENEZUELA FROM 06N-11N BETWEEN 67W-70W. ...ITCZ... ITCZ AXIS IS ALONG 09N13W 04N29W 05N40W 02N50W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 150 NM EITHER SIDE OF THE AXIS BETWEEN 19W AND 39W...AND BETWEEN 41W AND 48W. ...DISCUSSION... GULF OF MEXICO... AN AMPLIFIED UPPER LEVEL RIDGE IS LOCATED ALOFT OVER THE WESTERN GULF AND WATER VAPOR IMAGERY INDICATES VERY DRY AIR AND STRONG SUBSIDENCE. MOSTLY NW FLOW ALOFT COVERS THE ENTIRE GULF AS THE UPPER LEVEL RIDGE AXIS EXTENDS FROM THE TENNESSEE RIVER VALLEY SOUTHWESTWARD TO NE MEXICO. AT THE SURFACE...A RIDGE EXTENDS ACROSS THE NORTHERN FLORIDA PENINSULA THROUGH THE BIG BEND REGION OF FLORIDA W-SW TO 26N96W AND REMAINS ANCHORED BY A 1015 MB HIGH CENTERED NEAR 29N84W. E TO SE WINDS IN THE RANGE OF 10 TO 20 KT ARE NOTED IN RECENT SHIP AND BUOY OBSERVATIONS...WITH THE EXCEPTION OF THE FAR NE GULF NEAR THE HIGH CENTER. SKIES REMAIN REMARKABLY CLEAR THIS EVENING WITH THE LACK OF ABUNDANT SYNOPTIC-SCALE MOISTURE TO WORK WITH...HOWEVER...VISIBLE IMAGERY CONTINUES TO INDICATE A HAZY ATMOSPHERE W OF 92W DUE TO THE ADVECTION OF SMOKE FROM SOUTHERN MEXICO WILDFIRES. A SELECT FEW OFFSHORE OIL RIGS...AND LAND-BASED AIRFIELD METARS ACROSS SE COASTAL TEXAS ARE REPORTING VISIBILITIES BELOW 10 STATUTE MILES...OR 8.7 NM THIS EVENING. CARIBBEAN SEA... WEST-SOUTHWESTERLY FLOW ALOFT IS NOTED ACROSS MUCH OF THE CARIBBEAN SEA THIS EVENING AS MOSTLY DRY AIR IS EVIDENT ON WATER VAPOR IMAGERY N OF 18N W OF 78W. FAIR CONDITIONS AND RELATIVELY CLEAR SKIES PREVAIL OVER MUCH OF THE NW CARIBBEAN WHILE ISOLATED SHOWERS AND TSTMS IN ASSOCIATION WITH PEAK DAYTIME HEATING AND INSTABILITY CONTINUE ACROSS INTERIOR PORTIONS OF CUBA AND HISPANIOLA. THIS ACTIVITY IS EXPECTED TO DIMINISH OVER THE NEXT FEW HOURS. ELSEWHERE...CONVERGENT TRADEWIND FLOW IS NOTED IN THE SW CARIBBEAN FOCUSED ALONG A SURFACE TROUGH ANALYZED FROM NORTHERN COLOMBIA NEAR 11N73W TO EASTERN COSTA RICA NEAR 10N83W. THIS SURFACE FEATURE ALONG WITH UPPER LEVEL DIFFLUENCE EAST OF UPPER LEVEL TROUGHING ACROSS THE SW NORTH ATLC IS GENERATING WIDELY SCATTERED SHOWERS AND TSTMS OVER THE SW CARIBBEAN S OF 16N W OF 70W. AS THE TROPICAL WAVE ALONG 69W CONTINUES TO MOVE WESTWARD...GLOBAL MODELS CONTINUE TO INDICATE ENERGY ASSOCIATED WITH THE WAVE WILL COMBINE WITH ALREADY EXISTING BROAD CYCLONIC FLOW ACROSS THE REGION. CYCLOGENESIS IN THE FORM OF A WEAK LOW PRESSURE CENTER IS FORECAST TO OCCUR IN THE 36 TO 72 HOUR WINDOW ACROSS THE SW CARIBBEAN SEA WATERS. ATLANTIC OCEAN... A SURFACE RIDGE COVERS THE WESTERN ATLC W OF 65W KEEPING CONDITIONS MOSTLY FAIR THIS EVENING. HOWEVER...A FEW ISOLATED SHOWERS AND TSTMS REMAIN OVER THE INTERIOR SOUTHERN FLORIDA PENINSULA S OF 28N. FARTHER EAST...AN UPPER LEVEL LOW CONTINUES TO SPIN NEAR 33N53W SUPPORTING A COMPLEX AREA OF LOW PRESSURE CENTERED BY A 1013 MB LOW NEAR 28N55W. TWO OTHER 1013 MB LOWS CIRCULATE ON THE PERIPHERY OF THE MEAN LOW...ONE CENTERED NEAR 29N59W AND THE OTHER CENTERED NEAR 24N50W. A SURFACE TROUGH EXTENDS FROM THE EASTERNMOST LOW ALONG 21N54W TO 20N60W SUPPORTING ISOLATED SHOWERS WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH AXIS. SCATTERED SHOWERS AND POSSIBLE ISOLATED TSTMS COVER A WIDER AREA FROM 17N-32N BETWEEN 40W-52W DUE TO LOW-LEVEL CONVERGENCE AND UPPER LEVEL DIFFLUENCE IN ASSOCIATION WITH THE TROUGH AXIS ALOFT. THE REMAINDER OF THE EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING SOUTHWARD INTO THE DISCUSSION AREA ALONG 32W. THE RIDGE IS ANCHORED BY A 1032 MB HIGH CENTERED NW OF THE AZORES NEAR 41N35W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN