000 AXNT20 KNHC 291039 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 AM EDT SAT MAR 29 2014 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1030 UTC. ...SPECIAL FEATURES... ...CARIBBEAN SEA GALE WARNING... A TIGHT PRESSURE GRADIENT IS ON THE SOUTH CENTRAL CARIBBEAN SEA BETWEEN A RIDGE EXTENDING FROM A 1035 MB HIGH PRESSURE CENTERED IN THE CENTRAL N ATLC NEAR 36N52W AND LOWER PRESSURE ACROSS THE NORTHWESTERN SOUTH AMERICAN CONTINENT. GALE FORCE WINDS ARE CURRENTLY ALONG THE COAST OF COLOMBIA FROM 11N TO 13N BETWEEN 74W AND 77W AS A RESULT OF THE TIGHT PRESSURE GRADIENT. WINDS ARE EXPECTED TO DIMINISH BELOW GALE FORCE BY SATURDAY AFTERNOON. SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH PASSES OFF THE COAST OF AFRICA NEAR 06N10W AND CONTINUES SOUTHWEST TO 01N16W. THE ITCZ BEGINS NEAR 01N16W AND THEN CONTINUES ALONG 02S25W TO 03S39W. ISOLATED SHOWERS AND TSTMS ARE FROM 05S-06N E OF 21W. SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS ARE FROM 07S-04S BETWEEN 20W-29W. ...DISCUSSION... GULF OF MEXICO... A BROAD SURFACE RIDGE ANCHORED BY A 1035 MB HIGH PRESSURE CENTER ON THE NORTHERN-CENTRAL ATLC EXTENDS TO THE FLORIDA PENINSULA THUS PROVIDING SOUTHERLY WIND OF 10-20 KT E OF 90W. THESE WINDS CONTINUE TO FEED MOISTURE INTO THE N-NE GULF THUS FUELING HEAVY SHOWERS AND TSTMS N OF 28N BETWEEN 85W-90W THAT CONTINUE TO BE SUPPORTED BY A BROAD REGION OF MIDDLE TO UPPER LEVEL DIFFLUENCE. CONVECTIVE ACTIVITY IS EXPECTED TO CONTINUE FOR THE N-NE GULF AND PORTIONS OF FLORIDA THROUGH SATURDAY NIGHT. HEAVY SHOWERS AND TSTMS ARE ALSO OVER THE SE GULF FROM 24N-27N E OF 86W. A DEEP LAYER TROUGH WITH AXIS OVER THE MISSISSIPPI VALLEY SUPPORTS A COLD FRONT THAT AT 0900 UTC EXTENDS OVER THE FAR NW GULF ALONG 30N93W SW TO SOUTHERN TEXAS NEAR 26N97W. THE TROUGH ALOFT ALSO SUPPORTS A SURFACE TROUGH AHEAD OF THE COLD FRONT ALONG 30N85W TO 28N90W TO 26N94W. THE COLD FRONT WILL REACH FROM THE FLORIDA BIG BEND TO THE YUCATAN PENINSULA LATE SAT AND PASS SE OF THE AREA ON SUN. HIGH PRESSURE AND DRIER CONDITIONS WILL MOVE IN BEHIND THE FRONT. CARIBBEAN SEA... WEST TO NORTHWESTERLY FLOW ALOFT IS OVER THE CARIBBEAN BASIN WITH WATER VAPOR IMAGERY INDICATING RELATIVELY DRY AIR AND A SUBSIDENT ENVIRONMENT S OF 17N. THIS ENVIRONMENT IS SUPPRESSING THE DEVELOPMENT OF DEEP CONVECTION ACROSS MUCH OF THE CARIBBEAN. AT THE LOWER LEVELS...REMNANT MOISTURE ASSOCIATED WITH A FORMER FRONT MOVES ACROSS THE GREATER ANTILLES TO SUPPORT SCATTERED PASSING SHOWERS. A MOIST AIRMASS IS ENTERING THE SE CARIBBEAN AND SUPPORT RAINSHOWERS OVER THE WINDWARD ISLANDS. A GALE WARNING CONTINUE IN EFFECT FOR THE SOUTHERN CARIBBEAN WATERS OFF THE COAST OF COLOMBIA AND IS EXPECTED THROUGH SATURDAY AFTERNOON. SEE THE SPECIAL FEATURES SECTION ABOVE FOR DETAILS. THE STRONG PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED SURFACE RIDGE OVER THE NW CARIBBEAN AND LOWER PRESSURE OVER NORTHWESTERN SOUTH AMERICA IS ALSO DRIVING TRADE WINDS OF 20 KT OVER THE REMAINDER OF THE CENTRAL CARIBBEAN INCLUDING THE WINDWARD PASSAGE. LOOK FOR THESE WINDS TO DIMINISH AS THE RIDGE WEAKENS AHEAD OF A COLD FRONT FORECAST TO MOVE INTO THE NW CARIBBEAN SUN MORNING. THE CHANCE OF PRECIPITATION IN THE NORTHWEST CARIBBEAN IS EXPECTED TO INCREASE BEGINNING SATURDAY NIGHT AHEAD OF THE FRONT. ...HISPANIOLA... CURRENTLY...FAIR WEATHER DOMINATES ACROSS MUCH OF THE ISLAND BEING SUPPORTED BY DRY AIR ALOFT AND AT THE LOWER LEVELS. ISOLATED SHOWERS ARE OCCURRING OVER WESTERN DOMINICAN REPUBLIC ADJACENT WATERS ASSOCIATED WITH LINGERING MOISTURE FROM A FORMER FRONT. ISOLATED SHOWERS ARE FORECAST TO CONTINUE SATURDAY INTO SUNDAY AS MOISTURE POOLS EASTWARD AHEAD OF A COLD FRONT FORECAST TO MOVE INTO THE NW CARIBBEAN SEA. ATLANTIC OCEAN... MIDDLE TO UPPER LEVEL DIFFLUENCE CONTINUE TO ENHANCE SCATTERED MODERATE CONVECTION OVER THE FAR SW N ATLC N OF 25N W OF 75W. CONVECTION OVER THIS REGION WILL CONTINUE AND WILL AMPLIFY AHEAD OF THE NEXT COLD EXPECTED TO ENTER THIS PORTION OF THE BASIN LATE SAT NIGHT. DIFFLUENCE EAST OF A SHORT WAVE TROUGH ALOFT BETWEEN 50W-65W SUPPORT SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS N OF 24N BETWEEN 47W-64W. OTHERWISE...THE ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE THAT EXTENDS FROM THE A 1035 MB HIGH CENTERED NORTH OF THE AREA NEAR 36N52W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR