000 AXNT20 KNHC 092317 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU APR 09 2015 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. ...SPECIAL FEATURES... A GALE WARNING WILL GO INTO EFFECT AT 0600 UTC FRIDAY MORNING FROM 11N-13N BETWEEN 74W AND 77W DUE TO A STRONG SURFACE PRESSURE GRADIENT BETWEEN THE HIGH PRESSURE OVER THE ATLANTIC EXTENDING TO THE NORTHERN CARIBBEAN AND THE LOW PRESSURE OVER N COLOMBIA. GALE FORCE WINDS ARE FORECAST TO DIMINISH BY FRIDAY AFTERNOON. PLEASE SEE LATEST NWS HIGH SEAS FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE TROPICAL ATLANTIC NEAR 06N11W TO 02N14W WHERE THE ITCZ BEGINS AND CONTINUES S OF THE EQUATOR REACHING THE COAST OF BRAZIL NEAR 04S38W. SCATTERED MODERATE CONVECTION IS FROM 01S-04N BETWEEN 12W-22W. ...DISCUSSION... GULF OF MEXICO... A SURFACE RIDGE PREVAILS ACROSS THE ATLANTIC EXTENDING W ACROSS THE GULF SUPPORTING FAIR WEATHER. THIS PATTERN ALSO SUPPORTS A SLIGHT TO GENTLE ANTICYCLONIC FLOW THAT PREVAILS ACROSS THE BASIN. ISOLATED LIGHT TO MODERATE CONVECTION IS DEVELOPING AHEAD OF A FRONTAL BOUNDARY THAT EXTENDS ACROSS SOUTH-CENTRAL US. THIS ACTIVITY IS EXPECTED TO AFFECT THE NW GULF THIS EVENING AND DURING THE OVERNIGHT HOURS. THE FRONT IS EXPECTED TO BECOME NEARLY STATIONARY ALONG THE GULF STATES COASTLINE ENHANCING CONVECTION ACROSS THE NORTHERN GULF WITHIN THE NEXT 24 HOURS. THE FRONT WILL THEN BECOME WEAK BUT STILL SUPPORTING CONVECTION ACROSS THE NORTHERN GULF DURING THE WEEKEND. CARIBBEAN SEA... A STRONG PRESSURE GRADIENT BETWEEN HIGHER PRESSURES OVER THE ATLANTIC AND LOWER PRESSURE OVER SOUTH AMERICA IS PRODUCING GENTLE TO MODERATE TRADE WINDS ACROSS THE CARIBBEAN WITH A LOCALIZED AREA OF NEAR-GALE FORCE WINDS N OF COLOMBIA COAST FROM 11N-13N BETWEEN 74W-77W. A GALE WARNING WILL BE IN EFFECT BY 06Z FOR THIS AREA. PLEASE REFER TO THE SPECIAL FEATURES SECTION FOR MORE DETAILS. LOW LEVEL MOISTURE CONTINUES TO BE TRANSPORTED BY THE TRADES PRODUCING ISOLATED MODERATE CONVECTION AFFECTING THE WHOLE BASIN. EXPECT A SIMILAR WEATHER PATTERN TO PREVAIL OVER THE NEXT 24-48 HOURS. HISPANIOLA... ISOLATED CONVECTION IS MOVING QUICKLY ACROSS THE ISLAND WITH THE TRADES. THIS WEATHER PATTERN WILL CONTINUE OVER THE NEXT 24-48 HOURS. ATLANTIC OCEAN... A BROAD SURFACE RIDGE EXTENDS ACROSS THE WHOLE BASIN ANCHORED BY A 1030 MB HIGH LOCATED NEAR 35N38W AND A 1025 MB HIGH LOCATED NEAR 32N74W. A WEAK SURFACE TROUGH WAS DEPICTED IN SCATTEROMETER DATA ACROSS THE W ATLANTIC BETWEEN THE HIGH PRESSURE CENTERS EXTENDING FROM 31N70W TO 28N72W. SLIGHT TO GENTLE EASTERLY FLOW PREVAILS ACROSS THE N ATLANTIC MAINLY N OF 25N WHILE GENTLE TO MODERATE EASTERLIES ARE OBSERVED IN SCATTEROMETER DATA S OF 25N. LITTLE CHANGE IS FORECAST OVER THE NEXT 24-48 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ ERA