000 AXNT20 KNHC 162353 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE MAR 16 2010 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 3N15W 2N30W CROSSING THE EQUATOR NEAR 46W AND INTO NE BRAZIL NEAR 1S50W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 60 NM EITHER SIDE OF A LINE FROM 6N14W TO 3N21W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...WATER VAPOR IMAGERY SHOWS A VIGOROUS UPPER LEVEL SHORTWAVE TROUGH MOVING ACROSS EASTERN TEXAS...REACHING INTO THE FAR NW GULF WATERS THIS EVENING. AS THIS UPPER LEVEL FEATURE MOVES EASTWARD...IT CONTINUES TO SUPPORT A SURFACE TROUGH ANALYZED FROM 29N95W TO 18N93W OVER THE WESTERN GULF. MOSAIC DOPPLER RADAR AND VISIBLE SATELLITE IMAGERY DEPICTS SCATTERED TO NUMEROUS SHOWERS ACROSS MUCH OF THE GULF W OF 90W TO INLAND OVER SE TEXAS AND SOUTHERN LOUISIANA. THE SURFACE TROUGH IS FORECAST TO GRADUALLY WEAKEN AS THE UPPER LEVEL SUPPORT WANES BY EARLY WEDNESDAY WHILE A STRONG SURFACE HIGH PRESSURE SLIDES SOUTHWARD FROM NEW MEXICO AND WESTERN TEXAS TO OVER THE MEXICAN PLATEAU. THE RIDGE WILL PROVIDE MUCH OF THE GULF WITH CONTINUED NORTHERLY SURFACE WINDS AND GENERALLY FAIR WEATHER THROUGH EARLY FRIDAY. ELSEWHERE THIS EVENING ACROSS THE GULF E OF 90W...EXTENSIVE MIDDLE TO UPPER LEVEL CLOUDINESS IS BEING ADVECTED FROM SOUTHERN MEXICO ACROSS THE EASTERN GULF AND FLORIDA PENINSULA. HOWEVER...A WEAK SURFACE RIDGE AXIS EXTENDS FROM SE LOUISIANA TO THE STRAITS OF FLORIDA AND ACROSS CUBA... PROVIDING FOR GENERALLY FAIR WEATHER WITH LIGHT NORTHERLY WINDS. CARIBBEAN SEA... A STATIONARY FRONT EXTENDS FROM THE SW NORTH ATLC ACROSS SOUTHERN HISPANIOLA TO 17N76W IN THE NORTH CENTRAL CARIBBEAN SEA. SCATTERED SHOWERS ARE PRIMARILY WITHIN 120 NM NORTH OF THE FRONT BETWEEN 69W-76W. ELSEWHERE...THE REMAINDER OF THE BASIN IS DOMINATED BY GENERALLY FAIR WEATHER AS STRONG SUBSIDENCE AND DRY AIR ARE NOTED ON WATER VAPOR IMAGERY IN THE MIDDLE TO UPPER LEVELS OF THE ATMOSPHERE. MODEL GUIDANCE ALSO INDICATES ZONAL WESTERLY UPPER LEVEL FLOW ACROSS THE ENTIRE CARIBBEAN ON THE NORTHERN PERIPHERY OF A BROAD UPPER LEVEL ANTICYCLONIC CIRCULATION THAT EXTENDS AN EAST TO WEST AXIS ACROSS NORTHERN SOUTH AMERICA ALONG 8N. ATLANTIC OCEAN... A CUT-OFF UPPER LEVEL LOW IS LOCATED IN THE WESTERN NORTH ATLC NEAR 37N62W. IT CONTINUES TO ROTATE SEVERAL UPPER LEVEL SHORTWAVE IMPULSES ACROSS THE W ATLC BETWEEN 29N-37N W OF 50W AND SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N57W THAT CONTINUES SW ALONG 29N60W TO 25N70W. SHIP AND BUOY OBSERVATIONS OVER THE PAST FEW HOURS IN THE VICINITY OF THE FRONT INDICATE LOWER DEWPOINTS WEST OF THE BOUNDARY...AND THEREFORE A DRIER AND COOLER AIRMASS TAKING HOLD OVER THE W ATLC. FARTHER EAST...ANOTHER COLD FRONT ENTERS THE REGION NEAR 32N39W AND EXTENDS W-SW ALONG 26N50W TO 21N66W BECOMING STATIONARY TO EASTERN HISPANIOLA NEAR 19N70W. ISOLATED SHOWERS ARE WITHIN 90 NM EITHER SIDE OF THE FRONT S OF 26N. ELSEWHERE N OF 26N...SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING BETWEEN THE FRONT AND 20W AND CONTINUE TO BE ENHANCED BY UPPER LEVEL DIFFLUENCE OVER THE NE ATLC N OF 25N BETWEEN 15W-35W. THE REMAINDER OF THE TROPICAL ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE WITH AXIS THAT EXTENDS FROM NW OF THE CANARY ISLANDS NEAR 30N20W TO 17N40W THEN WESTWARD TO THE LESSER ANTILLES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN