000 AXNT20 KNHC 291755 TWDAT TROPICAL WEATHER DISCUSSION NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN SEP 29 2013 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 FEATURE... TROPICAL DEPRESSION ELEVEN IS CENTERED NEAR 26.0N 48.6W AT 29/1500 UTC OR ABOUT 931 NM E-NE OF THE NORTHERN LEEWARD ISLANDS AND ABOUT 929 NM E-SE OF BERMUDA MOVING NE AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1010 MB. MAXIMUM SUSTAIN WIND SPEED IS 30 KT WITH GUSTS TO 40 KT. PLEASE SEE LATEST NHC PUBLIC ADVISORY UNDER AWIPS/WMO HEADERS MIATCPAT1/WTNT31 KNHC AND THE FULL ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. SCATTERED MODERATE CONVECTION IS NE OF THE LOW PRESSURE CENTER FROM 27N-30N BETWEEN 45W-49W. ...TROPICAL WAVES... A TROPICAL WAVE AXIS EXTENDS WEST OF THE CAPE VERDE ISLANDS FROM 19N28W TO 07N29W AND MOVES W NEAR 15 KT. THE WAVE REMAINS EMBEDDED WITHIN A VERY MOIST ENVIRONMENT AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. MIDDLE-LEVEL DIFFLUENCE FROM A HIGH CENTERED NW OF MAURITANIA AND AN INVERTED TROUGH WEST OF THE CAPE VERDE ISLANDS IS SUPPORTING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS FROM 10N-16N BETWEEN 24W-31W. TROPICAL WAVE AXIS EXTENDS FROM 20N62W INTO THE CARIBBEAN TO 13N66W MOVING W-NW NEAR 20 KT. THE WAVE IS MOVING AROUND THE BROAD SURFACE RIDGE THAT DOMINATES THE CENTRAL AND E ATLC AND REMAINS EMBEDDED WITHIN AN AREA OF MODERATE MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED SHOWERS AND TSTMS ARE WITHIN 110 NM WEST OF THE AXIS FROM 14N-16N. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 10N15W TO 10N20W. THE ITCZ BEGINS W OF THE TROPICAL WAVE NEAR 07N32W AND CONTINUES ALONG 07N45W TO SOUTH AMERICA NEAR 06N57W. A CLUSTER OF MODERATE CONVECTION AND TSTMS IS FROM 05N-11N E OF 19W. SCATTERED MODERATE CONVECTION IS WITHIN 100 NM EITHER SIDE OF THE ITCZ AXIS BETWEEN 30W-50W. SCATTERED MODERATE CONVECTION AND TSTMS ARE FROM 06N-12N BETWEEN 50W-59W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER RIDGE DOMINATES THE GULF ANCHORED ALONG THE COAST NEAR CORPUS CHRISTI TEXAS. A NARROW UPPER TROUGH EXTENDS FROM THE BROAD UPPER TROUGH OVER W ATLC AND NW CARIBBEAN ACROSS THE YUCATAN TO INLAND OVER S MEXICO. THIS UPPER TROUGH IS SUPPORTING A FRONTAL BOUNDARY IN THE W ATLC AND NW CARIBBEAN WITH A SHEAR LINE EXTENDING ACROSS NE YUCATAN PENINSULA NEAR 21N87W ALONG 23N92W TO 27N95W. A WEAK SURFACE TROUGH IS OVER THE E GULF EXTENDING FROM 29N87W TO 23N83W. EXCEPT FOR THE FAR NW BASIN...TOTAL PRECIPITABLE WATER AND WATER VAPOR IMAGERY DEPICT VERY DRY STABLE AIR COVERING THE GULF WHICH CONTINUES TO SUPPORT FAIR WEATHER. OVER THE NW GULF...SCATTERED SHOWERS ARE NEAR THE TAIL OF THE SHEAR LINE N OF 25N W OF 94W. SURFACE TROUGHINESS IN THE EASTERN GULF WILL CONTINUE UNTIL LATE SUNDAY. A SURFACE RIDGE IS EXPECTED TO BUILD MONDAY MORNING THROUGH TUESDAY AFTERNOON. A BROAD TROUGH OR POSSIBLE LOW WILL LIFT OUT OF THE NW CARIBBEAN INTO THE SOUTHEASTERN GULF EARLY WED. CARIBBEAN SEA... A NARROW UPPER-LEVEL TROUGH OVER THE WEST NORTH ATLC DIPS S OVER THE NW CARIBBEAN SUPPORTING A COLD FRONT IN THE W ATLC THAT ENTERS THE CARIBBEAN AS A STATIONARY FRONT ACROSS SOUTHERN CUBA TO THE ISLE OF YOUTH WHERE IT BECOMES A SHEAR LINE INTO THE GULF OF MEXICO OVER NE YUCATAN PENINSULA. A WEAK UPPER RIDGE AXIS EXTENDS FROM COLOMBIA TO HISPANIOLA AND IS PROVIDING DIFFLUENT FLOW ALOFT TO GENERATE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE CENTRAL CARIBBEAN FROM 11N-20N BETWEEN 72W-79W. A SURFACE TROUGH IS BENEATH THIS UPPER RIDGE EXTENDING FROM 19N75W TO 11N76W. THE MONSOON TROUGH AXIS EXTENDS FROM NORTHERN COLOMBIA TO N OF PANAMA TO COSTA RICA GENERATING SCATTERED MODERATE CONVECTION AND ISOLATED TSTMS S OF 13N BETWEEN 76W-83W. A TROPICAL WAVE IS OVER THE EASTERN BASIN. SEE THE TROPICAL WAVES SECTION ABOVE. LOCALLY HEAVY RAINFALL AND GUSTY WINDS WILL BE POSSIBLE OVER PORTIONS OF JAMAICA AND HAITI TODAY AND MONDAY ASSOCIATED WITH THE LOW PRESSURE TROUGH OVER THE CENTRAL AND SOUTHWESTERN CARIBBEAN SEA. THIS PRECIPITATION IS EXPECTED TO GRADUALLY SPREAD ACROSS THE CAYMAN ISLANDS AND EASTERN CUBA BY EARLY TUESDAY. A LOW PRESSURE CENTER IS EXPECTED TO DEVELOP ACROSS THE SW CARIBBEAN LATE TONIGHT AND THEN DRIFT NW TOWARD THE NW CARIBBEAN THROUGH WED. THE TROPICAL WAVE OVER THE EASTERN BASIN WILL MOVE N-NW AROUND THE SW PERIPHERY OF THE SURFACE RIDGE AND WILL BE ABSORBED BY THE COLD FRONT IN THE WEST ATLC. HISPANIOLA... CURRENTLY SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 20N W OF 70W INCLUDING THE GULF OF GONAVE AND THE WINDWARD PASSAGE. SOUTHERLY FLOW ALOFT WILL CONTINUE THROUGH MON WHEN WINDS WILL SHIFT TO WESTERLY THEN NORTHERLY ON TUE AS AN UPPER RIDGE MOVES ACROSS THE N/CENTRAL CARIBBEAN AND BE W OF THE ISLAND BY WED. THIS WILL INCREASE THE CHANCE OR INTENSIFY AFTERNOON SHOWERS AND THUNDERSTORMS THROUGH MON. TUE THROUGH FRI WILL BE A SLIGHTLY LESS CHANCE OF HEAVY AFTERNOON SHOWERS/THUNDERSTORMS. ATLANTIC OCEAN... THE HIGHLIGHT IS TROPICAL DEPRESSION ELEVEN IN THE CENTRAL ATLC. SEE SPECIAL FEATURES ABOVE. AN UPPER-LEVEL NARROW TROUGH COVERS THE W ATLC W OF 67W AND DIPS S OVER THE NW CARIBBEAN SUPPORTING A FRONTAL BOUNDARY THAT EXTENDS FROM A 1008 MB LOW NEAR 32N66W WITH AN OCCLUDED FRONT EXTENDING TO A TRIPLE POINT NEAR 33N63W AND THE COLD FRONT EXTENDING ALONG 30N63W 23N69W TO 19N74W WHERE IT BECOMES STATIONARY INTO THE NW CARIBBEAN. A SURFACE TROUGH EXTENDS FROM THE LOW TO 30N67W TO 25N73W. SCATTERED SHOWERS AND TSTMS ASSOCIATED WITH THE FRONTAL SYSTEM ARE N OF 20N BETWEEN 61W-71W. THE REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED BY A 1020 MB HIGH NEAR 25N39W WITH A WEAKNESS IN THE IMMEDIATE VICINITY OF THE TROPICAL DEPRESSION ELEVEN. FRONT WILL DRIFT SE AND WEAKEN THROUGH TONIGHT. ELONGATED LOW PRESSURE JUST TO THE NW OF FRONT WILL LIFT N AND EXIT THE REGION TONIGHT. A WEAK RIDGE WILL DOMINATE THE ATLC TUE THROUGH THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS