000 AXNT20 KNHC 062351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT MON APR 06 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 TONIGHT FOR A FEW HOURS ALONG THE COASTAL WATERS OF COLOMBIA DUE TO THE STRENGTHENING PRESSURE GRADIENT BETWEEN THE LOWER PRESSURE ACROSS SOUTH AMERICA AND HIGH PRESSURE ANCHORED ACROSS THE W ATLC. THESE WINDS WILL PULSE TO GALE FORCE AGAIN TUE NIGHT WITH POSSIBLE ON WED NIGHT. 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 12N16W ALONG 6N13W THEN S OF THE EQUATOR NEAR 22W. THE ITCZ IS NOT EVIDENT THIS EVENING. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 3N TO S OF THE EQUATOR BETWEEN 16W-29W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE COVERS THE GULF EXTENDING FROM THE YUCATAN PENINSULA N TO NEAR MOBILE ALABAMA. A SHORTWAVE UPPER TROUGH IS MOVING ACROSS THE MISSISSIPPI VALLEY AND COUPLED WITH LINGERING LOW LEVEL MOISTURE ARE GENERATING HEAVY SHOWERS WITH ISOLATED THUNDERSTORMS INLAND OVER ALABAMA... LOUISIANA...AND MISSISSIPPI. SCATTERED SHOWERS ARE WITHIN 60 NM ALONG THE COAST FROM THE FLORIDA/ALABAMA BORDER TO GALVESTON TEXAS. A SURFACE RIDGE EXTENDS FROM THE W ATLC OVER THE SE CONUS INCLUDING THE GULF OF MEXICO E OF 96W. THE REMAINDER OF THE GULF HAS FAIR WEATHER THIS EVENING. SURFACE RIDGE WILL CONTINUE TO MAINTAIN MODERATE TO FRESH RETURN SE FLOW ACROSS THE GULF THROUGH THU. CARIBBEAN SEA... NEAR ZONAL NW FLOW ALOFT COVERS THE CARIBBEAN THIS EVENING. A WEAK SURFACE TROUGH IS IN THE CENTRAL CARIBBEAN EXTENDING FROM 19N78W ACROSS JAMAICA TO 15N76W GENERATING SCATTERED SHOWERS WITHIN 90 NM EITHER SIDE OF THE TROUGH AXIS. SATELLITE WATER VAPOR IMAGERY CONTINUES TO INDICATE STRONG SUBSIDENCE AND THUS DRY STABLE AIR ACROSS ALL BUT THE FAR NW CARIBBEAN WHERE UPPER MOISTURE IS BEING ADVECTED INTO THE BASIN FROM THE GULF OF MEXICO. AFTERNOON SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS HAVE AGAIN DEVELOPED INLAND OVER PUERTO RICO AND HISPANIOLA. E SURFACE WINDS ARE SHIFTING THE SHOWERS INTO THE CARIBBEAN WATERS AND THE MONA PASSAGE. EASTERLY TRADE WINDS ARE GENERATING ISOLATED SHOWERS ACROSS THE LESSER ANTILLES LEAVING THE REMAINDER OF THE CARIBBEAN WITH FAIR WEATHER THIS EVENING. SURFACE RIDGE OVER THE W ATLC WILL SHIFT E-NE MAINTAINING MODERATE TO FRESH TRADE WINDS ACROSS THE AREA. STRONG WINDS OFF THE COAST OF COLOMBIA WILL REACH MINIMAL GALE FORCE TONIGHT AND AGAIN TUE NIGHT. HISPANIOLA... AFTERNOON SHOWERS AND POSSIBLE THUNDERSTORMS HAVE DEVELOPED ACROSS MOST OF THE ISLAND THIS EVENING. LOW LEVEL MOISTURE IS INCREASING AND IS ALREADY PRODUCING MORE WIDESPREAD SHOWERS. THIS SCENARIO WILL CONTINUE THROUGH THU. ATLANTIC OCEAN... AN UPPER TROUGH N OF THE DISCUSSION AREA IS SUPPORTING A STATIONARY FRONT N OF THE AREA WITH A DISSIPATING STATIONARY FRONT EXTENDING THROUGH 32N60W TO 29N69W. A SURFACE RIDGE COVERS THE NW ATLC ANCHORED BY A 1035 MB HIGH ABOUT 750 NM NE OF BERMUDA AND A RIDGE AXIS EXTENDING SW TO OVER THE SE CONUS. A LINGERING UPPER TROUGH OVER THE CENTRAL ATLC IS SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 29N61W ALONG 25N64W TO 21N64W. SCATTERED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS ARE WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH N OF 25N. A SURFACE RIDGE COVERS MOST OF THE ATLC E OF THE ABOVE FRONT TO 30W. AN UPPER TROUGH EXTENDS OVER THE NE ATLC N OF 24N E OF 30W SUPPORTING A COLD FRONT THAT ENTERS THE E ATLC NEAR 32N19W TO 29N24W WHERE IT DISSIPATES TO 29N28W. THE W ATLC FRONT WILL DISSIPATE TONIGHT. THE SURFACE TROUGH WILL SHIFT W TO ALONG 67W BY EARLY TUE AFTERNOON THEN WEAKEN AS IT REACHES NEAR 69W EARLY ON WED AND DISSIPATE AS IT APPROACHES THE CENTRAL AND SE BAHAMAS WED NIGHT. THE W ATLC SURFACE RIDGE WILL WEAKEN WED AND WED NIGHT THEN BE REPLACED BY ANOTHER SURFACE RIDGE NEAR 31N ON THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW