000 AXNT20 KNHC 211036 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT MAR 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 7N12W 1N20W CROSSING THE EQUATOR ALONG 25W EXTENDING TO 1S35W INTO NE BRAZIL NEAR 3S43W. ISOLATED MODERATE CONVECTION IS S OF 1N BETWEEN 25W AND 28W...AND S OF 2N BETWEEN 42W AND 47W. ...DISCUSSION... GULF OF MEXICO... A 1034 MB HIGH PRES CENTERED OVER THE NE CONUS EXTENDS A RIDGE ACROSS THE EASTERN U.S. AND THE GULF OF MEXICO. A 1023 MB HIGH IS ALSO ANALYZED INLAND OVER MEXICO NEAR TAMPICO. MOSTLY FAIR WEATHER PREVAILS ACROSS THE GULF...EXCEPT FOR A FEW BROKEN CLOUDS AND ISOLATED SHOWERS MAINLY S OF 25N ASSOCIATED WITH A SMALL REGION OF WEAK INSTABILITY. SIMILAR CLOUDINESS WITH SOME CYCLONIC TURNING IS NOTED OVER THE YUCATAN PENINSULA AND COASTAL WATERS. A WEAK FRONTAL BOUNDARY REMAINS OVER CENTRAL FLORIDA PRODUCING SCATTERED MODERATE SHOWERS ALONG THE EAST COAST MAINLY SOUTH OF MELBOURNE. NE WINDS AHEAD OF THE FRONT ARE ALSO TRANSPORTING SCATTERED SHOWERS ACROSS THE STRAITS OF FLORIDA. THIS ACTIVITY IS APPROACHING THE N COAST OF WEST-CENTRAL CUBA. THE FRONT IS EXPECTED TO MOVE ACROSS SOUTH FLORIDA THIS AFTERNOON PRODUCING SCATTERED FAST MOVING SHOWERS AND INCREASING NE WINDS. AN EARLIER QSCAT PASS SHOWED NE WINDS OF 20 TO 25 KT BEHIND THE FRONT OVER THE FAR W ATLC. IN THE UPPER LEVELS...A WEAK UPPER LEVEL TROUGH IS DROPPING SE ACROSS FLORIDA AND THE SE GULF...DOWNSTREAM OF AN AMPLIFYING UPPER RIDGE THAT EXTENDS OVER EASTERN MEXICO AND TEXAS. THIS TROUGH SUPPORTS THE ABOVE MENTIONED WEAK COLD FRONT. MODERATE TO STRONG SUBSIDENCE/DRY AIR ALOFT COVERS MUCH OF THE GULF REGION. CARIBBEAN SEA... NE TO E WINDS OF 15 TO 20 KT ARE BLOWING ACROSS MUCH OF THE EAST AND CENTRAL CARIBBEAN PER A RECENT ASCAT PASS AND SFC DATA. THE STRONGEST WINDS ARE JUST OFFSHORE THE COLOMBIAN COAST WHERE SHIP 9H5B9 IS REPORTING 28 KT. LIGHTER WINDS OF 5-10 KT ARE NOTED IN THE NW CARIBBEAN. LOW TOPPED TRADE WINDS SHOWERS ARE OBSERVED ACROSS THE BASIN PARTICULARLY JUST OFFSHORE THE COAST OF COLOMBIA INCLUDING THE GULF OF URABA...AS CYCLONIC TURNING AROUND THE LOW OVER COLOMBIA NEAR 9N75W HAS CREATED CONVERGENT FLOW IN THE AREA. THE TRADE WINDS ARE ALSO ADVECTING LOW LEVEL MOISTURE ACROSS WESTERN PANAMA AND THE CARIBBEAN SIDE OF COSTA RICA. AT THE UPPER LEVELS...WATER VAPOR IMAGERY INDICATES SUBSIDENCE ACROSS THE CARIBBEAN. A SUBTROPICAL JET STREAK EXTENDS FROM THE YUCATAN PENINSULA ACROSS CUBA AND INTO THE SE BAHAMAS WITH CORE SPEEDS OF 80-90 KT. THIS IN COMBINATION WITH LIFT AHEAD OF AN UPPER LEVEL TROUGH SWEEPING SE ACROSS FLORIDA AND THE SE GULF OF MEXICO IS CAUSING BROKEN HIGH CLOUDS OVER THE NW CARIBBEAN... CUBA...THE STRAITS OF FLORIDA AND THE BAHAMAS. A SFC TROUGH REMAINS OVER THE WINDWARD PASSAGE GENERATING SOME LOW LEVEL CLOUDINESS BETWEEN EASTERN CUBA AND HISPANIOLA. ATLANTIC OCEAN... A COLD FRONT ENTERS THE FORECAST AREA NEAR 32N35W THEN CONTINUES SW TO NEAR 23N48W. AT THIS POINT...IT BECOMES STATIONARY AND EXTENDS TO 22N55W TO 26N61W...THEN CONTINUES AS A WARM FRONT TO A 1012 MB LOW NEAR 2868W. A LOW PRES TROUGH EXTENDS SW FROM THE LOW TO THE WINDWARD PASSAGE. AN AREA OF SCATTERED MODERATE CONVECTION IS WITHIN AROUND 130 NM NE OF THE LOW CENTER. A BAND OF MULTILAYERED CLOUDS WITH EMBEDDED SHOWERS AND ISOLATED TSTMS IS 125 NM AHEAD OF THE TROUGH AXIS. A DIFFLUENT PATTERN ALOFT... BETWEEN A TROUGH ALONG THE EASTERN SEABOARD AND A RIDGE OVER THE CENTRAL ATLC...IS ENHANCING THIS CONVECTIVE ACTIVITY. THE LOW PRESSURE IS FORECAST TO MOVE NE AND AWAY FROM THE FORECAST AREA TO NEAR 35N56W BY 24 HOURS. ELSEWHERE...A 1023 MB HIGH PRESSURE N OF THE AREA NEAR 38N51W IS CURRENTLY EXTENDING A RIDGE INTO THE REGION BEHIND THE COLD FRONT. THIS SYSTEM IS FORECAST TO APPROACH THE DISCUSSION AREA IN ABOUT 24 HOURS. OTHERWISE... POCKETS OF LOW LEVEL MOISTURE DOMINATE THE WEATHER OVER THE REMAINDER OF THE ATLANTIC WHILE ANOTHER RIDGE...ANCHORED ON A STRONG HIGH LOCATED WELL N OF THE AREA...COVERS THE E ATLC. AT THE UPPER LEVELS...A TROUGH/RIDGE/TROUGH/RIDGE PATTERN DOMINATES THE ENTIRE AREA. A BROAD AREA OF STRONG SUBSIDENCE IS NOTED OVER THE OCEAN WITHIN THE RIDGE GENERALLY FROM 15N TO 25N BETWEEN 30W AND 60W. MOSTLY ZONAL FLOW IS FOUND ACROSS THE DEEP TROPICS. $$ GR