000 AXNT20 KNHC 081803 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED APR 08 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 1745 UTC. ...SPECIAL FEATURES... A GALE WARNING IS IN EFFECT ALONG COASTAL WATERS OF COLOMBIA FROM 11N TO 12.5N BETWEEN 74W AND 77W DUE TO STRONG SURFACE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC EXTENDING TO THE NORTHERN CARIBBEAN AND AN ELONGATED AREA OF LOW PRESSURE OVER COLOMBIA. GALE FORCE WINDS ARE FORECAST TO DIMINISH THIS 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 07N11W TO 04N15W. THE ITCZ CONTINUES FROM 04N15W TO 01S26W TO THE COAST OF NORTHERN BRAZIL NEAR 01S45W. A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION AND TSTMS IS FROM 03N TO 06N E OF 17W. SCATTERED MODERATE CONVECTION IS FROM 04S TO 03N BETWEEN 19W AND 37W. ...DISCUSSION... GULF OF MEXICO... BROAD SURFACE HIGH PRESSURE OVER THE ATLC OCEAN EXTENDS A RIDGE AXIS SW ACROSS THE FLORIDA PENINSULA AND THE GULF OF MEXICO ...THUS PROVIDING RETURN WIND FLOW OF 10 TO 15 KT ACROSS THE BASIN...EXCEPT THE SW GULF WHERE WINDS INCREASE UP TO 20 KT. HIGHER WINDS IN THE SW GULF ARE ASSOCIATED WITH A SURFACE TROUGH FROM 25N93W TO 17N94W WITH POSSIBLE ISOLATED SHOWERS WITHIN 75 NM W OF ITS AXIS. MAINLY MIDDLE TO UPPER LEVEL RIDGING DOMINATES ACROSS THE BASIN ALONG WITH DRY AIR...THUS FAVORING FAIR WEATHER. OVER THE NW GULF N OF 26N W OF 92W FOG IS BEING REPORTED...COINCIDING WITH LOW TO MEDIUM FOG PROBABILITIES IN THE GOES-13 IFR PRODUCT. SURFACE RIDGING IS FORECAST TO DOMINATE THROUGH THU ALONG WITH FAIR WEATHER. A COLD FRONT IS FORECAST TO ENTER THE NORTHERN GULF FRIDAY MORNING...STALLING ON NORTHERN GULF WATERS SATURDAY. SHOWERS ARE EXPECTED ALONG THE NORTHERN GULF COAST AND ADJACENT WATERS. CARIBBEAN SEA... AN ELONGATED UPPER TROUGH EXTENDS FROM THE FLORIDA PENINSULA...ACROSS THE FAR WESTERN CARIBBEAN TO THE EPAC WATERS WHILE RIDGING PROVIDES SW TO W FLOW TO THE REMAINDER BASIN. HOWEVER...AT THE MIDDLE LEVELS...A RIDGE COVERS THE WESTERN AND CENTRAL CARIBBEAN WHILE A TROUGH EXTENDS FROM THE CENTRAL ATLC SW TO THE EASTERN BASIN TO A BASE OVER NORTHERN VENEZUELA. SSMI TPW IMAGERY CONTINUE SHOW PATCHES OF SHALLOW MOISTURE MOVING ACROSS THE BASIN...WHICH ALONG WITH LIFTING PROVIDED BY THE UPPER TROUGHING ENHANCES ISOLATED TO SCATTERED SHOWERS OVER THE NW CARIBBEAN N OF 15N BETWEEN 72W AND 84W...EASTERN HISPANIOLA...THE MONA PASSAGE...PUERTO RICO AND THE WINDWARD ISLANDS. SIMILAR SHOWERS ACTIVITY IS ALONG THE COAST OF COLOMBIA ENHANCED BY A LOW PRESSURE INLAND. STRONG SURFACE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC EXTENDING TO THE NORTHERN CARIBBEAN AND AN ELONGATED AREA OF LOW PRESSURE OVER COLOMBIA SUPPORT GALE CONDITIONS OVER THE SW BASIN. SEE SPECIAL FEATURES SECTION. OVER THE CENTRAL CARIBBEAN BETWEEN 69W AND 79W...TRADES OF 20 KT DOMINATE INCREASING UP TO 30 KT S OF 14N. TRADES OF 15 KT DOMINATE ELSEWHERE. NO SIGNIFICANT CHANGES EXPECTED DURING THE NEXT TWO DAYS. HISPANIOLA... LOW LEVEL MOISTURE IS MOVING ACROSS THE EASTERN ISLAND ENHANCING ISOLATED TO SCATTERED SHOWERS EXTENDING TO ADJACENT WATERS...INCLUDING THE MONA PASSAGE. ANOTHER SHALLOW AIR MASS IS MOVING OVER SW COASTAL WATERS ENHANCING SHOWERS. STABLE CONDITIONS ALOFT PROVIDED BY RIDGING AND DRY AIR SUBSIDENCE HINDER THE DEVELOPMENT OF DEEP CONVECTION. SIMILAR PRECIPITATION ACTIVITY IS FORECAST TO CONTINUE THROUGH FRIDAY MORNING. ATLANTIC OCEAN... A TROUGH EXTENDS FROM 30N66W TO 25N70W WITH ONLY ISOLATED MODERATE CONVECTION WITHIN 120 NM EAST OF THE TROUGH. SCATTERED SHOWERS ALSO EXISTS NORTH OF 23N BETWEEN 38W AND 51W ASSOCIATED WITH A MIDDLE TO UPPER LEVEL TROUGH OVER THE CENTRAL ATLC. ELSEWHERE...SURFACE HIGH PRESSURE DOMINATES THE REMAINDER OF THE BASIN AS WELL AS FAIR WEATHER. THE TROUGH SHOULD CONTINUE WESTWARD THROUGH THU MORNING WITH NO SIGNIFICANT WEATHER. THE AREA OF CONVECTION ASSOCIATED WITH THE UPPER-LEVEL TROUGH MAY CONTINUE FOR ANOTHER DAY BEFORE DISSIPATING. ELSEWHERE SURFACE RIDGING WILL BE THE DOMINANT FEATURE THE NEXT THREE DAYS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR