000 AXNT20 KNHC 180550 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT FRI MAR 18 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ... ITCZ AXIS IS ALONG 04N08W TO THE EQUATOR NEAR 18W THE ALONG 01S TO 36W AND INTO NE BRAZIL NEAR 03S43W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 06N BETWEEN 15W-24W...AND FROM THE EQUATOR TO 03N BETWEEN 34W-44W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL RIDGE IS OVER THE SE CONUS WITH AXIS FROM LOUISIANA NORTHEASTWARD TO THE OHIO RIVER VALLEY. SOUTH OF THIS UPPER LEVEL RIDGE MOSTLY ZONAL WESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY. DRY AIR AND SUBSIDENCE ACCOMPANY THE RIDGE WHICH FILTERS DOWN TO THE LOW-LEVELS AS A 1026 MB HIGH CENTERED OVER THE NE GULF NEAR 29N85W PROVIDING OVERALL FAIR WEATHER FOR THE OVERNIGHT PERIOD. LIGHT EAST TO SOUTHEAST WINDS ARE ACROSS THE GULF WITH VERY LITTLE SIGNIFICANT PRECIPITATION NOTED ON SATELLITE AND RADAR IMAGERY. HOWEVER...SHORTWAVE INFRARED SATELLITE IMAGERY AND A FEW COASTAL OBSERVATIONS ARE INDICATING THE FORMATION OF LOW-LEVEL STRATUS AND POSSIBLE FOG WITHIN 75 NM OF THE TEXAS AND LOUISIANA GULF COASTS. THE SURFACE RIDGE IS FORECAST TO REMAIN NEARLY STATIONARY OVER THE NEXT SEVERAL DAYS AND CONTINUE TO PROVIDE AN OVERALL STABLE WEATHER PATTERN. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED EAST OF THE LESSER ANTILLES NEAR 10N53W AND CONTINUES TO PROVIDE SOUTHWESTERLY WINDS ALOFT OVER MUCH OF THE CARIBBEAN SEA BASIN. MODERATELY DRY AIR IS ASSOCIATED WITH THE UPPER LEVEL RIDGING WHICH EXTENDS WESTWARD TO 80W. AT THE SURFACE...A STRONG SURFACE HIGH LOCATED OVER THE NE GULF AND PORTIONS OF THE SW NORTH ATLC CONTINUES TO PRODUCE A LARGE AREA OF FRESH TO STRONG E-NE TRADES OVER MUCH OF THE CARIBBEAN. THE STRONGEST WINDS ARE LOCATED IN THE VICINITY OF THE WINDWARD PASSAGE AND ALSO ALONG THE COAST OF COLOMBIA...MAINLY S OF 15N BETWEEN 72W-80W. THE HIGH OVER THE SW NORTH ATLC IS EXPECTED TO REMAIN NEARLY STATIONARY AND RELATIVELY STRONG OVER THE NEXT FEW DAYS...SO AS A RESULT...THE TRADES ARE FORECAST TO REMAIN QUITE BRISK THROUGH THE WEEKEND. ALTHOUGH NO SIGNIFICANT DEEP CONVECTION IS NOTED ON SATELLITE IMAGERY...ISOLATED SHOWERS CONTINUE OVER MUCH OF THE EASTERN HALF OF THE BASIN...WHILE ISOLATED SHOWERS CONTINUE TO PUSH ONSHORE ALONG THE NICARAGUA...COSTA RICA...AND WESTERN PANAMA COASTS. ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS PROGRESSING ACROSS THE W ATLC WATERS WITH AXIS ALONG 36N64W TO 30N68W TO THE FLORIDA COAST NEAR 28N80W. THE UPPER LEVEL TROUGHING SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA 32N68W AND EXTENDS SW TO 28N77W. A PRE-FRONTAL TROUGH IS ALSO ANALYZED FROM 30N70W TO ANDROS ISLANDS IN THE BAHAMAS NEAR 25N78W. MOISTURE IN THE VERTICAL IS VERY LIMITED WITH THIS FRONT...HOWEVER...MARGINAL LOW-LEVEL CONVERGENCE IS GENERATING ISOLATED SHOWERS WITHIN 60 NM EITHER SIDE OF THE FRONT AS IT CONTINUES TO BECOME MORE DIFFUSE. A RECENT ASCAT PASS FROM 18/0224 UTC INDICATES STRONGER NORTHERLY WINDS ARE LOCATED NW OF THE FRONT. THE FRONT IS FORECAST TO SHIFT NORTHEASTWARD OVER THE NEXT 24 HOURS AND LOCATE NORTH OF THE DISCUSSION AREA BY EARLY SATURDAY. FARTHER EAST...ANOTHER UPPER LEVEL TROUGH IS NOTED ON WATER VAPOR IMAGERY ALONG 29W THAT SUPPORTS A COLD FRONT ANALYZED FROM 32N30W TO 28N31W THEN W-SW ALONG 24N40W TO 25N59W. SCATTERED SHOWERS ARE OCCURRING WITHIN 150 NM EAST OF THE FRONT N OF 26N WHILE ISOLATED SHOWERS LINGER WITHIN 60 NM EITHER SIDE OF THE FRONT W OF 33W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN