000 AXNT20 KNHC 051756 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN MAY 05 2013 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 5N9W THEN ALONG 4N14W TO 3N19W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 2N30W 1N40W TO 1S46W. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM THE EQUATOR TO 7N E OF 20W ACROSS THE PRIME MERIDIAN INCLUDING THE COAST OF SW AFRICA. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 2N-5N BETWEEN 22W-47W AND FROM THE EQUATOR TO 7S WEST OF 32W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER LOW CENTERED OVER W TENNESSEE IS SUPPORTING A 1010 MB SURFACE LOW OVER ALABAMA. A COLD FRONT EXTENDS FROM THE LOW AND ENTERS THE N GULF WATERS NEAR 30N87W TO 28N91W TO 27N97W. SURFACE RIDGING ANCHORED BY A 1018 MB HIGH NEAR 24N91W DOMINATES THE REMAINDER OF THE GULF S OF THE COLD FRONT. DEWPOINTS ACROSS THE GULF N OF 21N AS WELL AS SATELLITE IMAGERY INDICATE THE PRESENCE OF VERY DRY AIR WHICH IS SUPPORTING CLEAR SKIES AND FAIR WEATHER. POSSIBLE ISOLATED SHOWERS COVER THE SW GULF S OF 21N DUE BANKING OF LOW LEVEL CLOUDS BY 5-10 KT NE WINDS. IN THE MIDDLE TO UPPER LEVELS NEAR ZONAL WESTERLY FLOW COVERS THE GULF. THE FRONT OVER THE N GULF WILL DRIFT TOWARDS THE NE GULF THIS EVENING...THEN IT MOVES ACROSS FLORIDA POSSIBLY ENHANCING RAINSHOWERS. THE HIGH OVER THE W GULF WILL DISSIPATE BY THIS EVENING BUT RIDGING WILL PREVAIL FOR THE MOST PART S OF 26N AND W OF 86W. CARIBBEAN SEA... SURFACE RIDGING OVER THE GULF OF MEXICO EXTENDING TO THE W CARIBBEAN AS WELL AS DRY AIR ALOFT SUPPORT FAIR WEATHER CONDITIONS N OF 13N W OF 75W. THIS SURFACE RIDGING COMBINED WITH A RIDGE AXIS EXTENDING FROM THE E ATLC TO S OF PUERTO RICO IS INDUCING A WEAKNESS OVER THE CENTRAL CARIBBEAN REFLECTED AS A SURFACE TROUGH. THIS SURFACE TROUGH EXTENDS FROM THE TAIL OF A COLD FRONT OVER THE CENTRAL ATLC THEN ACROSS THE DOMINICAN REPUBLIC TO 17N71W TO 12N73W. RAINSHOWERS ARE OCCURRING OVER THE E DOMINICAN REPUBLIC AS WELL AS THE MONA PASSAGE OR WITHIN 180 NM E OF THE SURFACE TROUGH. UPPER LEVEL DIFFLUENCE OVER COLOMBIA...VENEZUELA AS WELL AS OVER THE EASTERNMOST PORTION OF THE MONSOON TROUGH AXIS OVER THE E PACIFIC IS ADVECTING MOISTURE TO THE E CARIBBEAN WHICH MAY ENHANCE SCATTERED SHOWERS. SCATTERED SHOWERS ARE ALSO POSSIBLE S OF 13N OVER THE S CARIBBEAN BEING SUPPORTED BY THE MONSOON TROUGH. A WEAK PRESSURE PATTERN WILL CONTINUE DURING THE NEXT 24 HOURS. A FRONTAL SYSTEM CURRENTLY OVER THE W ATLC IS EXPECTED TO MERGE WITH THE COLD FRONT OVER THE CENTRAL ATLC AND EXTEND ACROSS THE GREATER ANTILLES BY THIS EVENING. A PREFRONTAL TROUGH MAY DEVELOP ACROSS THE LESSER ANTILLES BY THEN. TRADEWINDS ARE EXPECTED TO RETURN TO THE E AND CENTRAL CARIBBEAN BY MONDAY MORNING. ATLANTIC OCEAN... AS OF 1500 UTC...A BROAD UPPER LOW CENTERED OVER W TENNESSEE WITH ASSOCIATED TROUGH EXTENDING ACROSS THE GULF TO THE COASTAL WATERS OF E FLORIDA SUPPORTS A COLD FRONT OVER THE W ATLC ALONG 30N79W 26N77W TO 24N76W. RAINSHOWERS ASSOCIATED TO THIS FRONT ARE MOSTLY N OF THE DISCUSSION AREA...HOWEVER ISOLATED SHOWERS ARE POSSIBLE N 0F 24N W OF 76W. A BROAD UPPER LEVEL TROUGH ACROSS THE CENTRAL ATLC SUPPORTS A 1010 MB LOW NEAR 25N72W WITH A STATIONARY FRONT ALONG 27N76W...THE LOW TO 25N69W TO 25N63W. ISOLATED SHOWERS ARE POSSIBLE ALONG THE FRONTAL BOUNDARY. THE SAME UPPER LEVEL TROUGH SUPPORTS AN ELONGATED COLD FRONT ACROSS THE CENTRAL ATLC ALONG 30N35W 24N50W TO 21N63W. SCATTERED MODERATE CONVECTION IS WITHIN 260 NM S OF THE FRONT BETWEEN 27W AND 56W. UPPER LEVEL RIDGING COVERS THE E ATLC N OF THE EQUATOR SUPPORTING SURFACE RIDGING ANCHORED BY A 1023 MB HIGH NEAR 37N12W THAT EXTENDS AN AXIS TOWARDS THE E CARIBBEAN. THIS IS SUPPORTING FAIR WEATHER ACROSS THIS REGION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE AT THE REQUEST OF METEO-FRANCE AND THE METEOROLOGICAL SERVICES OF HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES ON THE ISLAND OF HISPANIOLA. THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL. $$ NR