000 AXNT20 KNHC 120606 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT MON MAR 12 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA INTO THE E TROPICAL ATLC NEAR 8N13W TO 6N17W WHERE THE ITCZ AXIS CONTINUES ALONG 3N22W 2N30W S OF THE EQUATOR NEAR 36W INTO SOUTH AMERICA NEAR 3S41W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N TO THE EQUATOR BETWEEN 13W-26W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 2N TO THE EQUATOR BETWEEN 4W-10W AND BETWEEN 30W-39W. ...DISCUSSION... GULF OF MEXICO... A STRONG UPPER LOW IS OVER THE CENTRAL PLAIN STATES WITH THE UPPER TROUGH EXTENDING S TO THE W LOUISIANA/E TEXAS COAST SUPPORTING A COLD FRONT THAT AT 12/0300 UTC IS INLAND OVER ARKANSAS AND LOUISIANA WITH A STATIONARY FRONT ENTERING THE GULF NEAR THE LOUISIANA/TEXAS BORDER CONTINUING ALONG 26N95W TO 23N96W WHERE A SURFACE TROUGH CONTINUES INTO THE W BAY OF CAMPECHE TO NEAR 19N96W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 120 NM E OF THE FRONT N OF 26N. AN UPPER RIDGE DOMINATES THE GULF WATERS WITH THE MEAN AXIS EXTENDING THROUGH THE YUCATAN CHANNEL TO INLAND OVER THE SE GULF STATES NEAR PENSACOLA FLORIDA. THIS UPPER RIDGE IS DRAWING MOISTURE ALOFT ACROSS THE SW GULF GENERATING SCATTERED SHOWERS W OF THE FRONT/SURFACE TROUGH TO INLAND OVER MEXICO S OF 25N. A SURFACE RIDGE EXTENDS FROM THE W ATLC AND A 1033 MB HIGH ALONG THE VIRGINIA/NORTH CAROLINA COAST TO SE LOUISIANA. THE SE RETURN OVER THE E GULF IS PRODUCING SCATTERED SHOWERS NE OF A LINE FROM THE STRAITS OF FLORIDA NEAR 23N80W ALONG 28N85W TO THE MISSISSIPPI/LOUISIANA BORDER. THIS IS LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES TONIGHT. FRONT/SURFACE TROUGH OVER THE W GULF WILL SHIFT W OF AREA TODAY AS THE SURFACE RIDGE BUILDS W FROM THE W ATLC ACROSS GULF OF MEXICO THROUGH FRI. CARIBBEAN SEA... WEAK UPPER TROUGH EXTENDS FROM THE W ATLC ACROSS HAITI TO JAMAICA AMPLIFYING AN UPPER RIDGE THAT EXTENDS FROM THE E GULF OF HONDURAS THROUGH THE YUCATAN CHANNEL INTO THE GULF OF MEXICO. A BROAD UPPER RIDGE OVER THE TROPICAL ATLC DOMINATES THE CARIBBEAN E OF 70W WITH NEAR ZONAL WESTERLY FLOW OVER THE SW CARIBBEAN. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR ARE W OF A LINE FROM THE LEEWARD ISLANDS NEAR 17N63W TO COLOMBIA NEAR 11N74W AND S OF 20N W OF 75W. AFTERNOON SHOWERS/THUNDERSTORMS THAT HAD DEVELOPED INLAND OVER HAITI AND JAMAICA HAVE SHIFTED WSW INTO THE CARIBBEAN WATERS DOTTING THE AREA WITHIN 75 NM OF LINE FROM 17N80W TO OVER HAITI NEAR 19N82W. THE UPPER RIDGE OVER THE E CARIBBEAN IS DRAWING MOISTURE ALOFT AND IS GENERATING SCATTERED SHOWERS SE OF LINE FROM THE LEEWARD ISLANDS NEAR 17N63W TO COLOMBIA NEAR 12N71W INCLUDING THE WINDWARD AND ABC ISLANDS. THE TIGHT PRESSURE GRADIENT IS PRODUCING FRESH TO STRONG NE TO E TRADE WINDS ACROSS THE BASIN. LITTLE CHANGE IS EXPECTED THROUGH FRI. ATLANTIC OCEAN... A SURFACE RIDGE COVERS THE W ATLC W OF 60W ANCHORED BY A 1033 MB HIGH ALONG THE VIRGINIA/NORTH CAROLINA COAST. THE TIGHT PRESSURE GRADIENT OVER THE W ATLC IS GENERATING FRESH NW TRADE WINDS ACROSS THE W ATLC. A BROAD UPPER TROUGH EXTENDS INTO THE W ATLC THROUGH 32N56W ALONG 24N8W NARROWING AS IT ENTERS THE CARIBBEAN OVER HAITI SUPPORTING A 1012 MB SURFACE LOW NEAR 32N51W WITH A DISSIPATING COLD FRONT EXTENDING SW ALONG 29N56W TO 26N64W AND A SHEAR AXIS ANALYZED ALONG 25N72W TO THE N BAHAMA ISLANDS NEAR 25N78W. A DEVELOPING COLD FRONT IS TO THE E EXTENDING FROM THE SURFACE LOW ALONG 28N54W TO 25N58W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE N OF 26N E OF THE DEVELOPING COLD FRONT TO 48W. BROAD UPPER RIDGE COVERS THE TROPICAL ATLC S OF 25N BETWEEN 30W-70W WITH A NARROW RIDGE EXTENDING FROM 25N43W TO BEYOND 32N39W WITH NEAR ZONAL WESTERLY FLOW ALOFT E OF 30W. A SURFACE RIDGE DOMINATES THE E ATLC ANCHORED BY A 1027 MB HIGH BOUT 400 NM SW OF THE AZORES AND A 1025 MB HIGH ABOUT 550 NM E OF THE AZORES. THE LAST VISIBLE SATELLITE IMAGES SHOW AN AREA OF AFRICAN DUST COVERING THE E TROPICAL ATLC FROM 7N-30N E OF 36W WHILE THE UW-CIMSS IMAGERY INDICATES THE DUST HAS REACHED AS FAR AS 40W. THE DEVELOPING COLD FRONT WILL MOVE INTO THE CENTRAL ATLC TUE WHERE IT WILL STALL AND WEAKEN THROUGH WED NIGHT AND DISSIPATE BY EARLY FRI. SURFACE RIDGE OVER THE W ATLC WILL WEAKEN MON AND TUE WITH E TO W RIDGE BUILDING ALONG THE NORTHERN PERIPHERY THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW