000 AXNT20 KNHC 162347 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON MAR 16 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 2315 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 6N10W 3N20W CROSSING THE EQUATOR NEAR 30W EXTENDING INTO NE BRAZIL NEAR 5S39W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS S OF 6N BETWEEN 4W-9W. ISOLATED MODERATE CONVECTION IS S OF 3N BETWEEN 20W-32W. SIMILAR CONVECTION IS ALSO FOUND BETWEEN 30 NM EITHER SIDE OF AXIS FROM 12N-15N. ...DISCUSSION... GULF OF MEXICO... A FRONTAL BOUNDARY CONTINUES TO MEANDER OVER THE GULF REGION ALTHOUGH THE NORTHERN PORTION IS BEGINNING TO MOVE SE DUE TO THE PRESENCE OF AN AMPLIFYING UPPER-LEVEL TROUGH MOVING EWD ACROSS THE SOUTHEAST CONUS. AS OF 2100 UTC...THE FRONT EXTENDS FROM A WEAK 1018 MB LOW CENTERED OVER SE GEORGIA ACROSS APALACHICOLA FLORIDA INTO THE NORTHERN GULF WATERS TO NEAR 26N92W. AT THIS POINT...THE FRONT BECOMES STATIONARY AND LIES ALONG 24N95W TO 20.5N96.5W WHERE VIS SATELLITE IMAGERY INDICATES THE PRESENCE OF A WEAK LOW THAT HAS FORMED ALONG THE FRONTAL BOUNDARY NEAR THE COAST OF MEXICO. A BAND OF SHOWERS WITH ISOLATED TSTMS IS DEVELOPING JUST AHEAD OF THE FRONT MAINLY N OF 27N. THE FRONT IS FORECAST TO MOVE SE TONIGHT REACHING NEAR THE LAKE OKEECHOBEE REGION BY TUE MORNING AND PUSHING INTO SOUTH FLORIDA TUE AFTERNOON. FAIR WEATHER IS OVER THE REMAINDER OF THE GULF...THE FLORIDA PENINSULA...AND THE YUCATAN PENINSULA AS A RIDGE OF HIGH PRESSURE EXTENDS WWD ACROSS THE E GULF FROM THE W ATLC. ALOFT... SWLY WINDS AHEAD OF THE AFOREMENTIONED UPPER-LEVEL TROUGH DOMINATES MUCH OF THE GULF REGION WHILE A RIDGE FROM THE NW CARIBBEAN CLIPS THE SE PORTION OF THE GULF AND SOUTH FLORIDA. A PLUME OF MID/UPPER LEVEL MOISTURE EXTENDS MAINLY BEHIND AND ALONG THE SURFACE FRONTAL BOUNDARY. MODERATE TO STRONG SUBSIDENCE DOMINATES THE REMAINDER OF THE GULF WATERS. CARIBBEAN SEA... FRESH TO STRONG TRADEWINDS CONTINUES TO BLOW ACROSS THE CARIBBEAN SEA. AN EARLIER QSCAT PASS SHOWED NE WINDS OF 20 TO 30 KT JUST OFFSHORE THE COAST OF COLOMBIA. WIND SPEEDS ARE EXPECTED TO DIMINISH TUE NIGHT THROUGH SAT AS HIGH PRES N OF THE AREA SHIFTS E AND WEAKENS...AND A SERIES OF COLD FRONTS PASS ACROSS THE WESTERN ATLC OVER THE NEXT FEW DAYS. AS USUAL FOR THIS TIME OF THE YEAR...POCKETS OF LOW LEVEL MOISTURE WITH EMBEDDED MAINLY LIGHT SHOWERS ARE BEING ADVECTED WWD ACROSS THE BASIN. THE MOST CONCENTRATED AREA OF THIS ACTIVITY IS OVER THE NE CARIBBEAN AFFECTING FROM THE N LEEWARD ISLANDS TO PUERTO RICO. SIMILAR CLOUDINESS ARE ALSO NOTED OVER PARTS OF HISPANIOLA AND JAMAICA. IN THE UPPER LEVELS...A RIDGE IS SITUATED ACROSS CENTRAL AMERICA AND THE WRN CARIBBEAN WITH CONFLUENT FLOW LOCATED ACROSS THE ERN CARIBBEAN. THIS UPPER LEVEL PATTERN IS PRODUCING STRONG SUBSIDENCE OVER THE CARIBBEAN BASIN. ATLANTIC OCEAN... A 1025 MB SURFACE HIGH IS OVER THE W ATLC NEAR 28N63W WITH A RIDGE COVERING MOST OF THE WEST AND CENTRAL ATLC FROM 40W TO THE FLORIDA/GEORGIA COAST. THIS SURFACE HIGH IS SUPPORTED BY AN UPPER LEVEL RIDGE EXTENDING FROM THE WRN CARIBBEAN ACROSS CUBA TO BEYOND 32N72W. FARTHER EAST...A 1005 MB LOW CENTERED NEAR 31N28W CONTINUES TO SPIN ACROSS THE E ATLC. A SURFACE TROUGH EXTENDS FROM THE LOW ALONG 28N22W 21N23W WITH ISOLATED SHOWERS WITHIN 60 NM E OF THE TROUGH N OF 27N. THE REMAINDER OF THE E ATLC IS UNDER THE INFLUENCE OF A NARROW SURFACE RIDGE ANCHORED WELL N OF THE FORECAST AREA. ACROSS THE DEEP TROPICS...A BROAD UPPER LEVEL RIDGE CENTERED ON A HIGH NEAR 4N28W IS ENHANCING CONVECTION ASSOCIATED WITH THE ITCZ. MOSTLY ZONAL FLOW IS NOTED FROM 10-20N BETWEEN THE LESSER ANTILLES AND WEST AFRICA. A JET STREAM BRANCH WITH CORE WINDS OF 70-90 KT EXTENDS MAINLY W-E ALONG 20N FROM THE N LEEWARD ISLANDS TO THE COAST OF AFRICA NEAR 20N26W CROSSING JUST N OF THE CAPE VERDE ISLANDS. A NARROW BAND OF TRANSVERSE HIGH CLOUDS IS NOTED ON SATELLITE IMAGERY RELATED TO THE JET OVER WEST AFRICA. $$ GR