000 AXNT20 KNHC 280005 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT JUN 27 2009 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC. ...TROPICAL WAVES... A VIGOROUS TROPICAL WAVE EXTENDS FROM 22N87W SOUTHWARD ACROSS CENTRAL AMERICA TO 7N89W IN THE NORTHEAST PACIFIC. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OCCURRING WITHIN 300 NM EAST OF THE WAVE AXIS NORTH OF 18N. ISOLATE MODERATE TO STRONG CONVECTION IS ALSO OCCURRING OVER ALL OF THE CENTRAL AMERICAN COUNTRIES IN PART FROM FORCING BY THE WAVE IN PART FROM NORMAL AFTERNOON HEATING IN THE TROPICS. NUMEROUS STATION...BUOY... AND A 1506Z ASCAT PASS SHOW A DISTINCT TROUGH AT THE SURFACE...BUT AS OF YET NO SURFACE LOW. THE GFS 700 MB ANALYSES SUGGEST THAT THE TROUGH HAS A CLOSED CIRCULATION AT THIS LEVEL. THE WAVE IS ALSO WELL-DEFINED IN THE TOTAL PRECIPITABLE WATER IMAGERY WITH A MAXIMUM EAST OF THE WAVE AXIS. THE WAVE HAS BEEN MOVING WESTWARD AT ABOUT 12 KT. A SECOND WAVE AXIS IS DEPICTED OVER THE CENTRAL CARIBBEAN FROM 19N72W SOUTHWARD TO 7N72W. THIS WAVE IS MUCH MORE INDISTINCT FROM THE ONE TO ITS WEST. INDEED ALL OF THE MODEL ANALYSES... SURFACE OBSERVATIONS...AND TOTAL PRECIPITABLE WATER DO NOT SHOW ANY SIGNIFICANT WAVE SIGNATURE. HOWEVER...THE 12Z CURACAO SOUNDING DID SHOW ANOMALOUS SOUTHEASTERLY FLOW IN THE LOWER TROPOSPHERE...SUGGESTING THE WAVE AXIS IS WEST OF THAT LOCATION. DEEP CONVECTION IS OCCURRING OVER HISPANIOLA AND EASTERN CUBA THIS AFTERNOON...WHICH MAY HAVE BEEN AIDED BY THE WAVE. THE MOTION OF THE WAVE CONTINUES WESTWARD AT ABOUT 10-12 KT. A THIRD WAVE IS IDENTIFIED OVER THE ATLANTIC WITH ITS AXIS EXTENDING FROM 12N38W SOUTHWARD TO 2N40W. SCATTERED SHOWERS ARE OCCURRING WITHIN 300 NM OF THE WAVE AXIS SOUTH OF 8N...BUT LITTLE DEEP CONVECTION IS NOTED. THIS WAVE IS WELL-DEPICTED BY THE TOTAL PRECIPITABLE WATER WITH A MAXIMUM EAST OF THE TROUGH AXIS. THE WAVE ALSO IS IDENTIFIABLE FROM THE WIND SHIFTS NOTED IN THE 2038Z QUIKSCAT OBSERVATIONS. THE GFS ANALYSIS DOES INDICATE THE WAVE...THOUGH IT APPEARS TO HAVE THE TROUGH LINE TOO FAR EAST AT 32W. MOVEMENT OF THE WAVE OVER 24 HOURS WOULD SUGGEST A SLOW - 5 KT - WESTWARD MOTION...THOUGH THE WAVE MAY HAVE BEEN POSITIONED TOO FAR TO THE WEST PREVIOUSLY. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 9N14W 7N28W 9N40W AND INTO NORTHEASTERN SOUTH AMERICA AT 5N52W. ISOLATED MODERATE CONVECTION IS FOUND WITHIN 180 NM NORTH OF THE AXIS EAST OF 20W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING ALONG 27N IS OCCURRING OVER THE GULF. NO SIGNIFICANT AREAS OF DEEP CONVECTION ARE OBSERVED CURRENTLY. SURFACE WINDS ARE WEAK ACROSS THE GULF. IN THE UPPER LEVELS...A SUBSIDENT UPPER LOW IS LOCATED OVER THE SOUTHWESTERN GULF OF MEXICO...WHILE AN UPPER HIGH IS LOCATED TO THE NORTH CENTERED OVER OKLAHOMA AND ARKANSAS. THE RESULTING CONFLUENCE ZONE IN THE CENTRAL GULF MAY BE PARTLY RESPONSIBLE FOR THE LACK OF WIDESPREAD CONVECTION OVER THE EASTERN GULF AND THE FLORIDA PENINSULA AS WAS OBSERVED DURING THE PREVIOUS COUPLE OF DAYS. CARIBBEAN SEA... THE COMBINATION OF THE STRONG TROPICAL WAVE OVER CENTRAL AMERICA AND THE ATLANTIC RIDGING IS PRODUCING BRISK TRADEWINDS ACROSS THE CARIBBEAN TODAY. SURFACE WINDS NORTH OF COLOMBIA AND VENEZUELA ARE UP TO 30 KT. ASIDE FROM THE AFOREMENTIONED CONVECTION ASSOCIATED WITH THE TWO WAVES...NO SIGNIFICANT DEEP CONVECTION IS NOTED THIS AFTERNOON OVER THE CARIBBEAN. IN THE UPPER LEVELS...ANTICYCLONIC FLOW HAS BUILT OVER THE NORTHERN PORTION OF THE CENTRAL AMERICA TROPICAL WAVE AND UPPER LEVEL CLOUDINESS AND MOISTURE HAVE ADVECTED CLOCKWISE OVER THE GREATER ANTILLES AND THE WESTERN CARIBBEAN. UPPER LEVEL WINDS OVER THE EASTERN CARIBBEAN ARE WEAK NORTHWESTERLY UNDER THE INFLUENCE OF A MID TO UPPER LEVEL LOW NORTHEAST OF THE LESSER ANTILLES. ATLANTIC OCEAN... A MODEST 1023 MB SURFACE HIGH IS LOCATED AT 32N48W. TO THE SOUTHEAST OF THE HIGH...A TROUGH EXTENDS FROM 31N26W TO 24N40W TO 23N44W. SOUTHEAST OF THE TROUGH IS A SECONDARY SURFACE HIGH OF 1020 MB AT 21N39W. THE LACK OF A STRONG RIDGE OVER THE ATLANTIC IS PRODUCING RATHER WEAK TRADEWINDS ACROSS THE ATLANTIC THIS AFTERNOON. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED NORTH OF 27N BETWEEN 66W AND 74W AHEAD OF THE FRONT NORTH OF THE AREA. A VIGOROUS MID TO UPPER LEVEL LOW IS AT 24N55W...THOUGH THIS FEATURE IS NOT APPARENT AT THE SURFACE. ISOLATED SHOWERS ARE OCCURRING WITHIN 120 NM OF THIS UPPER LOW. $$ LANDSEA