000 AXNT20 KNHC 122347 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT OCT 12 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... THE AREA OF LOW PRESSURE LOCATED ABOUT MIDWAY BETWEEN THE CAPE VERDE ISLANDS AND THE LESSER ANTILLES IS LESS ORGANIZED AND UPPER LEVEL WINDS ARE NOT FAVORABLE FOR DEVELOPMENT. THIS SYSTEM NOW HAS A LOW CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE IN THE E CARIBBEAN EXTENDS FROM 21N64W TO 13N66W MOVING W NEAR 15 KT. WAVE IS BENEATH THE WESTERN PORTION OF AN UPPER TROUGH WITH NO ASSOCIATED DEEP CONVECTION. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 15N17W AND CONTINUES THROUGH A WEAK 1011 MB LOW NEAR 8N30W TO 11N40W. THE ITCZ BEGINS NEAR 12N46W AND CONTINUES ALONG 10N55W TO 10N61W. A 1008 MB LOW IS BETWEEN THE MONSOON TROUGH AND THE ITCZ NEAR 12N43W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ASSOCIATED WITH THE 1008 MB LOW COVERING THE AREA WITHIN 240 NM OF THE LOW IN THE NE QUADRANT. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 10N-13N BETWEEN 23W-34W AND BETWEEN 47W-56W. SIMILAR CONVECTION IS MOVING ACROSS W AFRICA TO WITHIN 90 NM ALONG THE COAST OF LIBERIA TO SIERRA LEONE. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE DOMINATES THE GULF ANCHORED OVER MEXICO JUST W OF TAMPICO. WATER VAPOR SATELLITE IMAGERY SHOWERS DRY STABLE AIR ALOFT COVERING ALL BUT THE NW GULF. A SURFACE RIDGE COVERS THE N GULF ANCHORED BY A 1019 MB HIGH JUST OFFSHORE NEAR MOBILE ALABAMA GIVING THE NW GULF RETURN SURFACE FLOW. THIS SURFACE FLOW IS GENERATING ISOLATED SHOWERS AND A POSSIBLE ISOLATED THUNDERSTORM N OF 26N W OF 92W. THE REMAINDER OF THE GULF IS UNDER CLEAR SKIES AGAIN THIS EVENING. SURFACE RIDGE WILL BE REPLACED BY SLIGHTER STRONGER HIGH PRESSURE FROM THE N ON SUN AND MON THEN BEGIN TO GRADUALLY SLIDE EASTWARD TUE THROUGH THU AS A COLD FRONT MOVES OFF THE TEXAS COAST BY LATE WED. THE COLD FRONT IS EXPECTED TO REACH FROM NEAR SE LOUISIANA TO NE MEXICO/FAR S TEXAS BY LATE THU. CARIBBEAN SEA... THE UPPER RIDGE OVER THE GULF OF MEXICO EXTENDS OVER THE W CARIBBEAN W OF 84W. ISOLATED SHOWERS DOT THE AREA N OF 17N W OF 84W. A CUTOFF UPPER LOW IS CENTERED S OF THE CAYMAN ISLANDS NEAR 17N80W COVERING THE AREA BETWEEN 72W-84W. SCATTERED TO HEAVY SHOWERS WITH EMBEDDED CLUSTERS OF THUNDERSTORMS ARE WITHIN 150/180 NM OF LINE FROM 14N78W TO OVER THE GREATER ANTILLES NEAR THE WINDWARD PASSAGE. THE MONSOON TROUGH EXTENDS FROM COLOMBIA NEAR 9N75W ALONG 10N79W TO ACROSS COSTA RICA NEAR 9N83W AND COUPLED WITH THE UPPER LOW ARE GENERATING SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS S OF 14N TO OVER PANAMA W OF 76W TO THE COAST OF COSTA RICA AND NICARAGUA. AN UPPER TROUGH OVER THE E ATLC EXTENDS ACROSS THE W TROPICAL ATLC COVERING THE E CARIBBEAN E OF 66W. AN UPPER RIDGE IS WEDGE BETWEEN THIS UPPER TROUGH AND THE UPPER LOW FURTHER W. AFTERNOON SCATTERED SHOWERS/ISOLATED THUNDERSTORMS HAVE DEVELOPED OVER PUERTO RICO AND THE DOMINICA REPUBLIC. TROPICAL WAVE IN THE E CARIBBEAN WILL MOVE INTO THE CENTRAL CARIBBEAN SUN AND THE W CARIBBEAN MON. HISPANIOLA... SCATTERED TO HEAVY SHOWERS WITH EMBEDDED CLUSTERS OF THUNDERSTORMS ARE CURRENTLY ACROSS MOST OF THE ISLAND THIS EVENING. THE SOUTHERLY FLOW ALOFT IS DUE TO THE UPPER LOW FURTHER W WHICH IS DRAWING TROPICAL MOISTURE OVER THE ISLAND. THIS FLOW WILL CONTINUE THROUGH THE FIRST OF THE WEEK AND COUPLED WITH THE TROPICAL WAVE MOVING ACROSS THE ISLAND THROUGH SUN NIGHT WILL CONTINUE TO PRODUCE SHOWERS/THUNDERSTORMS. STARTING MON PEAK DAYTIME HEATING AND INSTABILITY COULD STILL GENERATE AFTERNOON SHOWERS/THUNDERSTORMS. ATLANTIC OCEAN... A NARROW UPPER TROUGH COVERS THE FAR W ATLC W OF 76W TO THE FLORIDA PENINSULA SUPPORTING A SURFACE TROUGH THAT EXTENDS FROM 31N67W ALONG 26N71W TO E CUBA NEAR 20N75W. AN UPPER RIDGE IS TO THE E ANCHORED NEAR 26N61W COVERING THE AREA N OF 20N BETWEEN 50W-76W AND IS PROVIDING DIFFLUNCE ALOFT TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 250 NM E OF THE SURFACE TROUGH N OF 23N AND SCATTERED TO HEAVY SHOWERS WITH EMBEDDED CLUSTERS OF THUNDERSTORMS S OF 23N TO OVER HISPANIOLA AND CUBA BETWEEN 69W-76W. ANOTHER UPPER TROUGH EXTENDS INTO THE E ATLC THROUGH 32N22W ALONG 25N34W THEN S OF THE ABOVE UPPER RIDGE ACROSS THE LESSER ANTILLES INTO THE E CARIBBEAN NEAR DOMINICA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 75/90 NM OF LINE FROM 12N54W ALONG 14N59W TO 22N62W. A SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC BASIN W OF 60W ANCHORED BY A PAIR OF 1022 MB HIGHS N OF THE DISCUSSION AREA. SURFACE TROUGH WILL MOVE LITTLE THROUGH WED. A SURFACE LOW IS EXPECTED TO FORM ALONG THE TROUGH LATE SUN THEN LIFT NE OF THE AREA BY LATE WED ALLOWING A WEAK PRES PATTERN TO BECOME ESTABLISHED ACROSS THE BASIN THROUGH INTO THU. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW