000 AXNT20 KNHC 032344 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST TUE MAR 03 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...SATELLITE IMAGERY THROUGH 1745 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 5N10W 1N20W CROSSING THE EQUATOR NEAR 22W EXTENDING TO 2S30W INTO NE BRAZIL NEAR 3S44W. A LARGE CLUSTER OF MODERATE TO STRONG CONVECTION COVERS FROM 5N-9N BETWEEN 5W-10W INCLUDING MUCH OF LIBERIA. SIMILAR CONVECTION IS ALSO NOTED ALONG NORTHERN BRAZIL WHERE A 1007 MB LOW IS NEAR 3S44.5W. ISOLATED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF AXIS BETWEEN 10W-17W. ISOLATED MODERATE CONVECTION IS ALSO FOUND ALONG THE EQUATOR BETWEEN 19W-21W...AND BETWEEN 41W-43W. ...DISCUSSION... GULF OF MEXICO... THE GULF REGION IS UNDER THE INFLUENCE OF SURFACE RIDGE ANCHORED ON A 1035 MB HIGH OVER THE OHIO VALLEY. THIS SYSTEM IS PRODUCING MOSTLY FAIR WEATHER AND LIGHT TO MODERATE WINDS ACROSS THE GULF. COLD AIR ADVECTION OVER THE RELATIVELY WARMER GULF WATERS IS RESULTING IN SCATTERED STRATOCUMULUS CLOUDS ACROSS MUCH OF THE AREA. THE SFC HIGH IS FORECAST TO MOVE SE TOWARDS THE CAROLINAS DURING THE NEXT 24 HOURS. AS A RESULT...SLY RETURN FLOW WILL INCREASE OVER THE W GULF BEGINNING TOMORROW. ALOFT...STRONG NORTHERLY FLOW IS RESULTING IN SUBSIDENCE ACROSS MUCH OF THE GULF REGION...WHERE A DEEP LAYERED DRY AIR MASS IS IN PLACE. THESE WINDS ARE ADVECTING SOME MID/UPPER LEVEL MOISTURE ACROSS THE NE CORNER OF THE GULF...WHERE SCATTERED HIGH LEVEL CLOUDS ARE PRESENT. CARIBBEAN SEA... A DEEP LAYERED TROUGH OVER THE E CONUS AND W ATLC EXTENDS INTO THE NW CARIBBEAN/GULF OF HONDURAS. THE ATTENDANT FRONTAL ZONE ENTERS THE CARIBBEAN SEA...AS A STATIONARY FRONT...THROUGH HISPANIOLA THEN CONTINUES SWWD TO COSTA RICA. MODERATE TO FRESH NLY WINDS BEHIND THE FRONTAL BOUNDARY ARE ADVECTING LOW LEVEL MOISTURE WITH EMBEDDED LIGHT TO OCCASIONALLY MODERATE RAIN OVER THE CARIBBEAN SIDE OF COSTA RICA AND WESTERN PANAMA. THE FRONT IS ALSO GENERATING ABUNDANT CLOUDINESS AND SCATTERED SHOWERS OVER HISPANIOLA. MOISTURE AHEAD OF THIS FRONTAL SYSTEM IS ALSO ENHANCING SOME SHOWER ACTIVITY ACROSS THE MONA PASSAGE AND PUERTO RICO. THE FRONT IS FORECAST TO SLOWLY MOVE ACROSS PUERTO RICO WED NIGHT AND THURSDAY AS SFC HIGH PRES CURRENTLY OVER THE OHIO VALLEY MOVES SEWD OVER THE CAROLINAS WED AND THEN INTO THE W ATLC WED NIGHT. THERE IS A RISK OF HEAVY RAINS WITH THE POTENTIAL FOR FLASH FLOODING IN PUERTO RICO WED AND THU WITH THE FRONTAL PASSAGE. ACROSS THE E CARIBBEAN...MID/UPPER LEVEL MOISTURE CONTINUES TO BE DRAWN NORTHWARD BETWEEN A RIDGE OVER THE TROPICAL ATLC AND THE AFOREMENTIONED DEEP LAYERED TROUGH. ATLANTIC OCEAN... THE DEEP LAYERED TROUGH OVER THE E CONUS AND W ATLC SUPPORTS A COLD FRONT THAT ENTERS THE FORECAST AREA NEAR 32N63W THEN CONTINUES SW TO NEAR 28N64W, AT THIS POINT...THE FRONT BECOMES STATIONARY EXTENDING OVER HISPANIOLA AND THE CENTRAL CARIBBEAN TO COSTA RICA. LOW LEVEL CONVERGENCE IS ASSISTING IN THE DEVELOPMENT OF SCATTERED SHOWERS WITHIN 180 NM EITHER SIDE OF THIS FRONT. THIS ACTIVITY IS BEING SUPPORTED BY STRONG UPPER LEVEL DIVERGENCE ASSOCIATED WITH AN UPPER LEVEL JET MAXIMUM TO THE W OF THE FRONT. IN THE WAKE OF THE FRONT...A RELATIVELY COOLER AND DRIER AIRMASS IS PRESENT ASSOCIATED WITH THE 1035 MB HIGH OVER THE OHIO VALLEY. FARTHER TO THE E...A 1018 MB SURFACE LOW IS LOCATED NEAR 28N48W. A WELL DEFINED SWIRL OF LOW CLOUDS IS ASSOCIATED WITH THE LOW FORECAST TO DISSIPATE IN ABOUT 24 HOURS OR SO. A SFC TROUGH EXTENDS FROM THE LOW TO 25N46W TO 21N48W. AN AREA OF SCATTERED SHOWERS IS AHEAD OF THE TROUGH COVERING THE AREA N OF 24N BETWEEN 40W-44W. TIGHT PRES GRADIENT BETWEEN THIS LOW AND STRONG 1042 SFC HIGH LOCATED JUST WEST OF THE AZORES IS PRODUCING A SWATH OF GALE FORCE WINDS JUST N OF AREA AND WITHIN AROUND 300 NM NE OF THE LOW CENTER. A RIDGE EXTENDS FROM THE ABOVE MENTIONED STRONG SFC HIGH ACROSS THE REMAINDER OF THE ATLANTIC FORECAST AREA PRODUCING MOSTLY FAIR WEATHER AND MODERATE TO FRESH TRADE WINDS...PARTICULARLY EAST OF 40W. AN UPPER-LEVEL HIGH CENTERED NEAR 5N50W DOMINATES MUCH OF THE DEEP TROPICS. THIS RIDGE IS HELPING TO INDUCE MODERATE TO STRONG CONVECTION OVER N SOUTH AMERICA. $$ GR