000 AXNT20 KNHC 170000 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON MAY 16 2011 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ANALYZED IN THE W TROPICAL ATLC FROM 10N44W TO 2N48W DRIFTING WESTWARD. WAVE REMAINS WITHIN A BROAD MOISTURE SURGE ON TOTAL PRECIPITABLE WATER IMAGERY. ...ITCZ... THE ITCZ AXIS IS ANALYZED FROM 7N13W 5N16W TO 4N23W. A SURFACE TROUGH EXTENDS ALONG 25W FROM 2N-7N. CLUSTERS OF SCATTERED MODERATE/STRONG CONVECTION ARE FROM 1N-6N BETWEEN 3W-15W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 180 NM N OF THE ITCZ AXIS BETWEEN 18W-22W...WITHIN 120 NM W OF THE SURFACE TROUGH BETWEEN 4N-6N...AND FROM 2N-4N BETWEEN 42W-45W. SCATTERED MODERATE CONVECTION IS W OF THE TROPICAL WAVE TO 53W BETWEEN 1N-8N. ...DISCUSSION... GULF OF MEXICO... AN UPPER LOW IS CENTERED OVER CENTRAL GEORGIA MOVING TOWARD THE SOUTH CAROLINA BORDER WITH A SHORTWAVE UPPER TROUGH MOVING QUICKLY ACROSS THE NE GULF N OF 25N E OF 86W TO OVER THE FLORIDA PENINSULA. THIS FEATURE IS EMBEDDED WITHIN A BROADER UPPER TROUGH COVERING THE E HALF OF THE CONUS INTO THE W ATLC AND MOST OF THE GULF OF MEXICO E OF 92W SUPPORTING A FRONT THAT PASSED ACROSS FLORIDA YESTERDAY AND THAT CURRENTLY IS IN THE W ATLC. AN UPPER RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED IN THE E PACIFIC REGION EXTENDING AN AXIS N OVER MEXICO AND INTO THE CENTRAL PLAIN STATES. DRY STABLE AIR COVERS THE ENTIRE GULF WATERS AS A WEAK SURFACE RIDGE BUILDS OVER THE W GULF ANCHORED BY A 1019 MB HIGH OVER CENTRAL OKLAHOMA. N TO NE SURFACE FLOW IS BANKING LOW LEVEL CLOUDS WITH SCATTERED SHOWERS W OF 95W TO ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS OF MEXICO S OF THE RIO GRANDE TO VERACRUZ. A SERIES OF FRONTAL TROUGHS WILL MOVE S ACROSS THE NE GULF THROUGH TUE NIGHT. WEAK HIGH PRESSURE WILL DEVELOP OVER THE NW GULF TUE NIGHT AND DRIFT E INTO THE NE PORTION THU THEN E OF THE AREA THROUGH SAT. CARIBBEAN SEA... BROAD UPPER TROUGH COVERS THE W CARIBBEAN EXTENDING ACROSS THE GULF OF MEXICO AND INTO THE W ATLC WHILE THE ASSOCIATED FRONT IS OVER THE W ATLC. THE E CARIBBEAN IS DOMINATED BY AN UPPER RIDGE ANCHORED ALONG THE COAST OF SOUTH AMERICA AND IN THE TROPICAL ATLC. A SURFACE TROUGH IS BETWEEN THESE UPPER LEVEL FEATURES EXTENDING FROM THE S COAST OF THE DOMINICAN REPUBLIC NEAR 18N70W ALONG 16N72W TO 14N74W. DRY STABLE AIR ALOFT COVERS THE CARIBBEAN W OF 70W. LOW LEVEL MOISTURE REMAINS OVER THE E CARIBBEAN E OF 70W AND COUPLED WITH THE DIFFLUENT FLOW ARE GENERATING SCATTERED SHOWERS E OF 70W ACROSS THE LESSER ANTILLES...THE VIRGIN ISLANDS...AND PUERTO RICO LEAVING THE REMAINDER OF THE CARIBBEAN UNDER CLEAR SKIES THIS EVENING. THE SURFACE TROUGH WILL REMAIN OVER THE E CARIBBEAN THROUGH THU THEN MOVE W AS THE SUBTROPICAL HIGH BUILDS OVER THE W ATLC BEFORE DISSIPATING IN THE W CARIBBEAN ON FRI. ATLANTIC OCEAN... BROAD UPPER TROUGH EXTENDS OVER THE W ATLC FROM THE E CONUS AND THE GULF OF MEXICO SUPPORTING AN OCCLUDED FRONT THAT EXTENDS FROM OVER THE CAROLINAS INTO THE DISCUSSION AREA AS A COLD FRONT NEAR 32N75W TO 26N76W WHERE IT DISSIPATES ACROSS THE BAHAMA ISLANDS TO THE STRAITS OF FLORIDA NEAR 24N79W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 75 NM E OF THE FRONT N OF 27N AND ISOLATED SHOWERS WITH POSSIBLE ISOLATED THUNDERSTORMS WITHIN 60 NM E OF THE REMAINDER OF THE FRONTAL BOUNDARY. A BROAD UPPER RIDGE DOMINATES THE REMAINDER OF THE W ATLC AND ALL OF THE CENTRAL ATLC S OF 30N FROM 35W-70W PROVIDING A DIFFLUENT FLOW TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 120/150 NM OF LINE FROM 23N66W TO 29N70W. AN UPPER LOW IS N OF 30N BETWEEN 38W-55W WITH A REMNANT SURFACE TROUGH EXTENDING INTO THE CENTRAL ATLC NEAR 32N43W ALONG 28N45W 25N53W TO 22N65W. THE SAME DIFFLUENT FLOW DESCRIBED ABOVE IS GENERATING A BROAD AREA OF DENSE CLOUD COVER WITH EMBEDDED ISOLATED SHOWERS FROM 18N-29N BETWEEN 40W-62W. AN UPPER TROUGH IS OVER THE E ATLC N OF 22N E OF 35W SUPPORTING A WEAK 1014 MB SURFACE LOW CENTERED NEAR THE MADEIRA ISLANDS WHILE A SURFACE RIDGE COVERS AREA E OF THE CENTRAL ATLC SURFACE TROUGH AND ANCHORED BY A 1033 MB HIGH N OF THE AZORES. THE W ATLC COLD FRONT WILL SLOWLY MOVE E TO 31N72W TO THE CENTRAL BAHAMAS TUE NIGHT BEFORE WEAKENING AND LIFTING NORTHWARD WED INTO THU. THE SUBTROPICAL RIDGE GRADUALLY BUILDS ALONG 28N THU THROUGH SAT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW