000 AXNT20 KNHC 121139 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST WED NOV 12 2008 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1115 UTC. ...THE ITCZ... THE AXIS IS ANALYZED ALONG 10N10W 7N23W 9N48W 7N59W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 225 NM N OF THE ITCZ FROM 32W-42W AND WITHIN 225 NM S OF THE ITCZ FROM 38W-43W. CLUSTERS OF SCATTERED MODERATE DOT THE AREA WITHIN 12O NM OF THE ITCZ E OF 20W TO THE COAST OF W AFRICA. ...DISCUSSION... GULF OF MEXICO... BROAD UPPER RIDGE COVERS THE GULF EXTENDING FROM THE CARIBBEAN. MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR REMAIN OVER THE GULF WITH THE EXCEPTION OF UPPER LEVEL MOISTURE STREAMING ACROSS MEXICO TO OVER THE N GULF COAST STATES CLIPPING THE FAR NW GULF. A SURFACE RIDGE COVERS THE NE GULF ANCHORED OVER NEW ENGLAND WITH A COLD FRONT APPROACHING THE NW GULF BUT FOR NOW REMAINS INLAND OVER TEXAS. THIS FRONT WILL MOVE INTO THE GULF WATERS LATER TODAY. RETURN FLOW AROUND THE SURFACE RIDGE COUPLED WITH THE APPROACHING FRONT IS GIVING THE THE FAR NW GULF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 26N W OF 94W TO INLAND OVER TEXAS AND A SQUALL LINE EXTENDING FROM W LOUISIANA N OF LAFAYETTE INTO THE GULF TO NEAR 29N94W. ISOLATED SHOWERS ARE THE E GULF WITHIN 45/60 NM OF 83.5W FROM 24N-28W AND S OF 24N E OF 87W THROUGH THE FLORIDA STRAITS INCLUDING THE FLORIDA KEYS BROUGHT IN BY A SURFACE LOW IN THE N CARIBBEAN. OTHERWISE THE REMAINDER OF THE GULF REMAINS TRANQUIL THIS MORNING. CARIBBEAN SEA... BROAD UPPER RIDGE DOMINATES THE W CARIBBEAN ANCHORED INLAND OVER NICARAGUA EXTENDING A RIDGE AXIS ACROSS CUBA INTO THE W ATLC AND COVERING THE GULF OF MEXICO. AN UPPER TROUGH EXTENDS OVER THE E CARIBBEAN FROM AN UPPER LOW IN THE W/CENTRAL ATLC. ALTHOUGH THE ENTIRE CARIBBEAN IS DOMINATED BY MODERATE/STRONG SUBSIDENCE... UPPER DIFFLUENCE OVER THE SW CARIBBEAN IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 12N W OF 82W TO INLAND OVER PANAMA/COSTA RICA AND TO THE COAST OF S NICARAGUA. A WEAK SURFACE 1010 MB LOW IS OFF THE S COAST OF CUBA NEAR NEAR 21N80W GENERATING ISOLATED SHOWERS N OF 19N W OF 76W TO THE THE COAST OF THE YUCATAN PENINSULA AND INLAND OVER CUBA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE SE CARIBBEAN S OF 15N TO THE COAST OF SOUTH AMERICA BETWEEN 64W-74W WITH LOW LEVEL ISOLATED SHOWERS POSSIBLE OVER THE CENTRAL N/CARIBBEAN N OF 15N BETWEEN 66W-74W AND APPROACHING THE LESSER ANTILLES. ATLANTIC OCEAN... THE UPPER RIDGE OVER THE W CARIBBEAN EXTENDS INTO THE W ATLC ACROSS CUBA NEAR 22N79W N TO BEYOND 32N77W. A COLD FRONT ENTERS THE REGION NEAR 32N64W SW TO 31N67W CONTINUING AS A SURFACE TROUGH ALONG 30N74W ACROSS THE N BAHAMA ISLANDS TO 26N79W. ISOLATED LOW LEVEL SHOWERS ARE OVER THE FAR SW ATLC S OF 26N W OF 76W. AN UPPER TROUGH EXTENDS OVER THE REMAINDER OF THE W ATLC INTO THE W/CENTRAL ATLC THROUGH 32N61W TO AN UPPER LOW NEAR 23N66W TO OVER THE E CARIBBEAN TO THE COAST OF SOUTH AMERICA NEAR 10N65W. A NARROW UPPER RIDGE TO THE E IS PROVIDING UPPER LEVEL DIFFLUENCE TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 20N-25N BETWEEN 62W-67W. AN UPPER TROUGH IS OVER THE E/CENTRAL N OF 22N FROM 30W-45W WITH A SURFACE 1015 MB LOW CENTERED NEAR 28N37W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE E OF THE SURFACE LOW FROM 26N-29N BETWEEN 31W-37W. AN UPPER LOW IS IN THE W TROPICAL ATLC NEAR 15N51W WITH A SURFACE TROUGH TO THE N EXTENDING FROM 24N54W TO 18N58W. SCATTERED SHOWERS ARE FROM 17N-23N BETWEEN 50W AND THE SURFACE TROUGH WITH ISOLATED SHOWERS FROM 10N-18N W OF 58W APPROACHING THE LESSER ANTILLES. BROAD UPPER RIDGE COVERS THE ENTIRE E ATLC ANCHORED NEAR 10N31W PROVIDING UPPER DIFFLUENCE ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ WALLACE