000 AXNT20 KNHC 290604 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... ...CARIBBEAN SEA GALE WARNING... A TIGHT PRESSURE GRADIENT IS FOUND OVER THE SOUTH CENTRAL CARIBBEAN SEA BETWEEN A RIDGE EXTENDING FROM STRONG 1037 MB HIGH PRESSURE CENTERED IN THE CENTRAL ATLC NEAR 36N54W AND LOWER PRESSURE ACROSS THE NORTHWESTERN SOUTH AMERICAN CONTINENT. GALE FORCE WINDS ARE CURRENTLY FOUND ALONG THE COAST OF COLOMBIA FROM 11N TO 13N BETWEEN 74W AND 77W AS A RESULT OF THIS TIGHT PRESSURE GRADIENT. WINDS HERE 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 06N11W AND CONTINUES SOUTHWEST TO THE EQUATOR NEAR 19W. THE ITCZ FOLLOWS ALONG 03S23W 04S29W TO 05S35W. ISOLATED SHOWERS AND TSTMS ARE FROM 04S-09N BETWEEN 07W-20W AND FROM 07S-03S BETWEEN 20W-29W. ...DISCUSSION... GULF OF MEXICO... A BROAD SURFACE RIDGE ANCHORED BY A 1037 MB HIGH PRESSURE CENTER IN THE NORTHERN-CENTRAL ATLC EXTENDS INTO THE BASIN TO PROVIDE SOUTHEASTERLY-SOUTHERLY WIND OF 10-20 KT. THESE WINDS CONTINUE TO FEED MOISTURE INTO THE NORTHERN AND EASTERN GULF THUS FUELING HEAVY SHOWERS AND TSTMS ASSOCIATED WITH A SQUALL LINE OVER THE LOWER MISSISSIPPI VALLEY AND HEAVY SHOWERS ACROSS THE NORTHERN FLORIDA PENINSULA. THESE AREAS OF CONVECTION CONTINUE TO BE ENHANCED BY DIFFLUENT FLOW ALOFT. CONVECTIVE ACTIVITY IS EXPECTED TO CONTINUE FOR THE N-NE GULF THROUGH SATURDAY MORNING BY THE TIME A NEW COLD FRONT ENTERS THE NW GULF WATERS. 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. THIS ENVIRONMENT IS SUPPRESSING THE DEVELOPMENT OF DEEP CONVECTION ACROSS THE CARIBBEAN. HOWEVER...AT THE LOWER LEVELS...PATCHES OF MOISTURE MOVE ACROSS THE GREATER ANTILLES AND THE WINDWARD ISLANDS TO SUPPORT SCATTERED PASSING SHOWERS TONIGHT. 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 IN THE LOWER LEVELS. ISOLATED SHOWERS ARE OCCURRING OVER THE EASTERN DOMINICAN REPUBLIC ASSOCIATED WITH A MOIST AIRMASS STARTING TO MOVE ACROSS THE ISLAND. ISOLATED SHOWERS ARE FORECAST TO CONTINUE SATURDAY BUT ARE EXPECTED SHIFT EAST OF THE AREA ON SUNDAY AS MOISTURE POOLS EASTWARD AHEAD OF THE COLD FRONT FORECAST TO MOVE INTO THE NW CARIBBEAN SEA. ATLANTIC OCEAN... MIDDLE TO UPPER LEVEL DIFFLUENCE ALONG WITH LOW LEVEL MOISTURE ADVECTION FROM THE GULF IS ENHANCING SCATTERED MODERATE CONVECTION OVER THE FAR SW N ATLC N OF 25N W OF 78W. 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. A SHORT WAVE TROUGH ALOFT BETWEEN 50W-65W SUPPORT A DISSIPATING FRONTAL BOUNDARY FROM 30N42W TO 25N55W TO 22N67W. UPPER LEVEL DIFFLUENCE SUPPORTS SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS W OF THE FRONT FROM 24N-30N BETWEEN 50W-62W. OTHERWISE...THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A BROAD SURFACE RIDGE THAT EXTENDS FROM THE A 1037 MB HIGH CENTER NORTH OF THE AREA. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR