000 AXNT20 KNHC 132353 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN MAR 13 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED ALONG 05N09W CROSS THE EQUATOR NEAR 17W THEN CONTINUING ALONG 03S25W TO 02S35W AND INTO NE BRAZIL NEAR 04S39W. SCATTERED MODERATE TO STRONG CONVECTION IS OVER INTERIOR PORTIONS OF W AFRICA FROM 05N-10N BETWEEN 06W-12W. ELSEWHERE... FARTHER WEST...A SURFACE TROUGH IS ANALYZED ON THE WESTERN EXTENT OF THE ITCZ AXIS FROM 01N42W TO 09S38W. SCATTERED MODERATE CONVECTION IS OCCURRING OVER THE ATLC WATERS FROM 02N TO 07N BETWEEN 38W-53W. ...DISCUSSION... GULF OF MEXICO... NEARLY ZONAL WESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY THIS EVENING WITH MODERATELY DRY AIR LOCATED OVER THE SOUTHEASTERN HALF OF THE GULF BASIN. HOWEVER...INCREASED UPPER LEVEL MOISTURE IS LOCATED OVER THE NW HALF OF THE GULF AHEAD OF AN APPROACHING MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH CURRENTLY ACROSS THE INTERMOUNTAIN WEST. HOWEVER THIS EVENING...THE RELATIVELY BENIGN UPPER LEVELS ARE CONTINUING TO SUPPORT AN ELONGATED SURFACE RIDGE ANCHORED BY A 1026 MB HIGH CENTERED OFF THE COAST OF FLORIDA IN THE SW NORTH ATLC NEAR 28N78W. THE RIDGE AXIS EXTENDS ALONG 28N ACROSS THE NORTHERN GULF WITH SE WINDS IN THE RANGE OF 10 TO 20 KT. THE RIDGE IS EXPECTED TO REMAIN NEARLY STATIONARY OVER THE SW NORTH ATLC...WHILE THE NEXT COLD FRONT IS FORECAST TO EMERGE OFF THE TEXAS AND LOUISIANA GULF COASTS LATE MONDAY INTO EARLY TUESDAY. THE FRONT IS EXPECTED TO LARGELY IMPACT THE GULF WATERS N OF 25N. CARIBBEAN SEA... A BROAD UPPER LEVEL RIDGE AXIS EXTENDS FROM THE TROPICAL ATLC NEAR 10N54W W-NW OVER THE CARIBBEAN SEA BASIN TO 18N80W PROVIDING MOSTLY S TO SW FLOW ALOFT. STRONG SUBSIDENCE AND DRY STABLE AIR ACCOMPANY THIS UPPER LEVEL FEATURE WHICH CONTINUES TO PROVIDE OVERALL FAIR CONDITIONS OVER MUCH OF THE CARIBBEAN THIS EVENING. ENHANCED E-NE TRADES CONTINUE DUE TO A STRONG PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE RIDGE LOCATED OVER THE SW NORTH ATLC AND LOWER PRESSURE OVER NORTHERN SOUTH AMERICA. EARLIER MORNING AND AFTERNOON ASCAT PASSES DEPICTED THESE TRADES IN THE RANGE OF 15 TO 25 KT WITH THE STRONGEST NE WINDS NOTED SOUTH OF HISPANIOLA...IN THE VICINITY OF THE WINDWARD PASSAGE... AND ALONG THE IMMEDIATE COAST OF NORTHERN COLOMBIA. ASIDE FROM THE WIND FIELD...LOW-LEVEL MOISTURE CONTINUES TO ADVECT WESTWARD WITH ISOLATED SHOWERS OVER THE NE CARIBBEAN...INCLUDING THE PUERTO RICO AND THE MONA PASSAGE...AS WELL AS AN AREA S OF 14N BETWEEN 64W-74W...INCLUDING THE ABC ISLANDS...AND AN AREA SOUTH OF JAMAICA FROM 14N-18N BETWEEN 73W-83W. ATLANTIC OCEAN... UPPER LEVEL TROUGHING IS LOCATED OVER MUCH OF THE WESTERN ATLC DIPPING SOUTHWARD TO 29N BETWEEN 55W-80W. WATER VAPOR IMAGERY INDICATES MOSTLY DRY AND AND SUBSIDENCE ACCOMPANIES THE BASE OF THE TROUGHING THAT CONTINUES TO SUPPORT A 1026 MB HIGH CENTERED OFF THE FLORIDA COAST NEAR 28N78W. THE RIDGE AXIS EXTENDS E-NE TO BERMUDA...AND WESTWARD ALONG 28N INTO THE NORTHERN GULF OF MEXICO. MOSTLY FAIR CONDITIONS ARE ASSOCIATED WITH THE SURFACE RIDGE...HOWEVER...STRONG NE WINDS ARE LOCATED WITHIN 210 NM NW OF A SHEAR LINE ANALYZED FROM 25N65W TO THE WINDWARD PASSAGE NEAR 20N75W. ISOLATED SHOWERS ARE ALSO OCCURRING WITHIN 75 NM EITHER SIDE OF THE SHEAR LINE. FARTHER EAST...A DISSIPATING STATIONARY FRONT ENTERS THE DISCUSSION AREA NEAR 32N58W AND EXTENDS S-SW TO 24N63W. STRONGER UPPER LEVEL DYNAMICS ARE LOCATED N OF THE REGION WITH ISOLATED SHOWERS OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC BETWEEN 25W-55W IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1032 MB HIGH CENTERED NORTH OF THE REGION NEAR 40N40W. A RELATIVELY STRONG PRESSURE GRADIENT STILL REMAINS OVER THE AREA FROM 20N-28N BETWEEN 30W-50W. ELSEWHERE... AN UPPER LEVEL TROUGH AXIS EXTENDS ALONG 32N19W TO 21N32W OVER THE NE TROPICAL ATLC AND CONTINUES TO SUPPORT A COMPLEX AREA OF SURFACE LOW PRESSURE OVER THE IBERIAN PENINSULA AND NORTHERN MOROCCO. A DISSIPATING COLD FRONT EXTENDS ALONG THE W AFRICA COAST FROM 30N12W TO 25N16W TO 21N26W WITH A SECONDARY WAVE OF ENERGY IN THE FORM OF A SURFACE TROUGH ANALYZED TO THE WEST ALONG 32N13W TO 25N22W. POSSIBLE ISOLATED SHOWERS ARE REMAINING N OF 20N E OF 25W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN