000 AXNT20 KNHC 071725 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE APR 07 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 THE STRONG SURFACE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC EXTENDING TO THE CENTRAL CARIBBEAN AND AN ELONGATED AREA OF LOW PRESSURE OVER WESTERN COLOMBIA. 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 05N09W TO 03N11W. THE ITCZ CONTINUES FROM 03N11W TO THE EQUATOR ALONG 20W TO 01S33W TO THE COAST OF NORTHERN BRAZIL NEAR 03S40W. SCATTERED MODERATE CONVECTION AND TSTMS ARE WITHIN 200 NM N OF THE ITCZ BETWEEN 15W AND 30W. SCATTERED SHOWERS ARE WITHIN 140 NM S OF THE ITCZ BETWEEN 16W AND 24W. ...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. A WEAKNESS IN THE SURFACE RIDGE ON THE SW GULF IS BEING ANALYZED AS A TROUGH FROM 23N93W TO 17N94W WITH POSSIBLE ISOLATED SHOWERS WITHIN 75 NM W OF ITS AXIS. MIDDLE TO UPPER LEVEL RIDGING DOMINATES ACROSS THE BASIN ALONG WITH LOW-LEVEL DRY AIR...THUS PROVIDING STABILITY AND SUPPORTING FAIR WEATHER. OVER THE NW GULF N OF 26N W OF 93W FOG IS BEING REPORTED ...COINCIDING WITH MEDIUM FOG PROBABILITIES DEPICTED BY THE GOES- 13 IFR. SURFACE RIDGING IS FORECAST TO CONTINUE FOR THE NEXT THREE DAYS AS WELL AS FAIR WEATHER. CARIBBEAN SEA... MAINLY FAIR WEATHER DOMINATES ACROSS THE REGION BEING SUPPORTED BY DRY AIR SUBSIDENCE FROM ALOFT AS INDICATED BY WATER VAPOR IMAGERY. HOWEVER...SSMI TPW IMAGERY SHOW PATCHES OF SHALLOW MOIST AIR MOVING ACROSS THE EASTERN CARIBBEAN...WHICH ALONG WITH LIFTING PROVIDED BY A MIDDLE LEVEL TROUGH ENHANCES ISOLATED TO SCATTERED SHOWERS OVER THE LESSER ANTILLES...PUERTO RICO AND HISPANIOLA. STRONG SURFACE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE ATLC EXTENDING TO THE CENTRAL CARIBBEAN AND AN ELONGATED AREA OF LOW PRESSURE OVER WESTERN COLOMBIA SUPPORT GALE CONDITIONS OVER THE SW BASIN. SEE SPECIAL FEATURES SECTION. TRADES OF 20 KT ARE OVER THE CENTRAL CARIBBEAN WITH 15 KT DOMINATING ELSEWHERE. HISPANIOLA... LOW LEVEL MOISTURE CONTINUES TO MOVE ACROSS THE ISLAND ENHANCING ISOLATED TO SCATTERED 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 AS SHALLOW MOIST AIR CONTINUES TO MOVE ACROSS THE CARIBBEAN. ATLANTIC OCEAN... A TROUGH EXTENDS FROM 29N64W TO 22N68W WITH ONLY ISOLATED MODERATE CONVECTION WITHIN 120 NM EAST OF THE TROUGH. SCATTERED MODERATE CONVECTION ALSO EXISTS NORTH OF 26N BETWEEN 52W AND 57W ASSOCIATED WITH AN UPPER-LEVEL TROUGH TO THE WEST. ELSEWHERE ...SURFACE HIGH PRESSURE DOMINATES THE REMAINDER OF THE BASIN AS WELL AS FAIR WEATHER. THE TROUGH SHOULD CONTINUE WESTWARD WITH NO SIGNIFICANT WEATHER FOR THE NEXT TWO DAYS. THE AREA OF CONVECTION ASSOCIATED WITH THE UPPER-LEVEL TROUGH MAY CONTINUE FOR ANOTHER DAY OR SO 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/CL