000 AXNT20 KNHC 091744 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURES... A GALE WARNING WILL GO INTO EFFECT AT 0600 UTC FRIDAY MORNING FROM 10.5N TO 13N BETWEEN 74W AND 77W DUE TO A STRONG SURFACE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC EXTENDING TO THE NORTHERN CARIBBEAN AND LOW PRESSURE OVER 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 ATLC NEAR 8N13W TO 01N17W WHERE THE ITCZ BEGINS AND CONTINUES S OF THE EQUATOR NEAR 20W TO THE COAST OF S AMERICA NEAR 03S40W. SCATTERED MODERATE CONVECTION IS FROM 03S TO 04N BETWEEN 10W AND 21W. ISOLATED MODERATE CONVECTION IS FROM 03S TO 03N BETWEEN 21W AND 44W. ...DISCUSSION... GULF OF MEXICO... ATLC RIDGING EXTENDS WESTWARD ACROSS THE GULF OF MEXICO WITH AN AXIS ACROSS N FLORIDA AND THE N GULF COAST. THIS IS PRODUCING MAINLY SE FLOW ACROSS THE ENTIRE BASIN WITH WIND SPEEDS OF 5 TO 10 KT OVER THE NE BASIN AND 15 TO 20 KT OVER THE REMAINDER OF THE GULF. GENERALLY FAIR WEATHER IS OCCURRING ACROSS THE GULF THIS AFTERNOON WITH JUST ISOLATED SHOWERS OVER THE FL STRAITS AND KEYS...AND SOME SPRINKLES UNDERNEATH A MIDDLE TO UPPER LEVEL CLOUD CANOPY OVER THE NW GULF. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE EXTENDS ACROSS MEXICO AND THE SW AND CENTRAL GULF WITH A NARROW TROUGH AXIS OVER THE BAHAMAS AND FL STRAITS. THIS IS PRODUCING PRIMARILY NW FLOW ALOFT OVER THE GULF. SIMILAR CONDITIONS ARE FORECAST TO PERSIST FOR THE NEXT 24 HOURS. THEREAFTER...A COLD FRONT IS FORECAST TO APPROACH THE NORTHERN GULF FROM TEXAS TO ALABAMA ON FRIDAY WITH CONVECTION. THE FRONT WILL DISSIPATE OVER THE WEEKEND. HOWEVER...ONGOING CONVECTION WILL BE LIKELY ACROSS THE NORTHERN GULF DURING THE WEEKEND TIME PERIOD. CARIBBEAN SEA... TRADE WINDS PRIMARILY BETWEEN 15 TO 25 KT COVER THE CARIBBEAN WITH A LOCALIZED AREA OF 30 KT N OF THE COLOMBIA COAST TO 13N. THE PRESSURE GRADIENT BETWEEN ATLC HIGH PRESSURE AND LOW PRESSURE OVER COLOMBIA WILL TIGHTEN TONIGHT WHICH WILL RESULT IN WINDS REACHING GALE FORCE N OF THE COAST OF COLOMBIA. SEE THE SPECIAL FEATURES SECTION FOR MORE DETAILS. PATCHES OF SHOWERS ARE N OF 15N ACROSS THE CARIBBEAN. ISOLATED THUNDERSTORMS ARE ARE ALSO POSSIBLE N OF 15 N W OF 75W IN THE VICINITY OF AN UPPER LEVEL TROUGH THAT EXTENDS FROM THE BAHAMAS TO HONDURAS. UPPER LEVEL RIDGING COVERS THE CENTRAL AND EASTERN CARIBBEAN. OTHER THAN THE INCREASING TRADE WIND FLOW...SIMILAR CONDITIONS ARE FORECAST OVER THE NEXT 24 HOURS. HISPANIOLA... SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON. SHOWERS MAY CONTINUE OVERNIGHT TONIGHT WITH ISOLATED THUNDERSTORMS BECOMING POSSIBLE AGAIN FRIDAY AFTERNOON. ATLANTIC OCEAN... A WEAKNESS IN THE SUBTROPICAL HIGH OVER THE ATLC IN THE FORM OF A SURFACE TROUGH EXTENDS FROM 29N69W TO 25N76W. SHOWERS AND ISOLATED MODERATE CONVECTION ARE WITHIN 50 NM OF EITHER SIDE OF THE TROUGH AXIS. A LARGE RIDGE ANCHORED BY A 1032 MB HIGH SW OF THE AZORES DOMINATES THE CENTRAL AND EASTERN ATLC WITH GENERALLY FAIR WEATHER AND ANTICYCLONIC FLOW. LITTLE CHANGE IS FORECAST OVER THE NEXT 24 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LATTO