000 AXNT20 KNHC 020005 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN SEP 01 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... TROPICAL WAVE APPROACHING THE LESSER ANTILLES EXTENDS FROM 21N56W THROUGH A 1009 MB LOW NEAR 15N60W TO 13N60W MOVING W TO W- NW AT 10-15 KT. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 12N-16N BETWEEN 53W-60W. SURFACE OBSERVATIONS INDICATE THAT THE CIRCULATION IS RATHER ELONGATED. ALTHOUGH UPPER-LEVEL WINDS APPEAR TO BE CONDUCIVE...THE PROXIMITY TO DRY AIR IN THE MIDDLE LEVELS OF THE ATMOSPHERE COULD INHIBIT DEVELOPMENT OF THIS DISTURBANCE. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. ...TROPICAL WAVES... TROPICAL WAVE OVER THE CAPE VERDE ISLANDS EXTENDS FROM 20N23W THROUGH A 1009 MB LOW NEAR 15N23W TO 11N23W MOVING W NEAR 10 KT. WAVE IS EMBEDDED WITHIN A BROAD AREA OF DEEP MOISTURE THAT COVERS THE E ATLC E OF 33W AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...NO ASSOCIATED SHOWERS OR CONVECTION. TROPICAL WAVE IN THE CENTRAL TROPICAL ATLC EXTENDS FROM 18N46W TO A 1011 MB LOW NEAR 11N48W MOVING W NEAR 10 KT. WAVE IS EMBEDDED WITHIN A SURGE OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 10N-15N BETWEEN 43W-50W. TROPICAL WAVE IS OVER THE YUCATAN PENINSULA EXTENDING FROM 20N88W INTO THE E PACIFIC REGION NEAR 11N88W MOVING W NEAR 15 KT. S PORTION OF THE WAVE IS EMBEDDED WITHIN A SURGE OF DEEP MOISTURE AS DEPICTED ON THE TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED TO HEAVY SHOWERS WITH SCATTERED TO NUMEROUS THUNDERSTORMS HAVE DEVELOPED INLAND OVER THE YUCATAN AND ARE MOVING W INTO THE GULF OF MEXICO WITHIN 60 NM ALONG THE N AND W COASTS BETWEEN 87W-92W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 13N16W AND CONTINUES ALONG 11N23W 9N34W TO 9N37W WHERE THE ITCZ BEGINS AND CONTINUES TO 12N46W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE FROM 4N-10N BETWEEN 21W-46W. ...DISCUSSION... GULF OF MEXICO... A WELL DEFINED BUT DRY UPPER LOW IS CENTERED OVER SE TEXAS AND OVER THE FAR NW GULF WATERS. AN UPPER RIDGE ANCHORED OVER THE N GULF COAST NEAR 31N89W AND COVERS THE N GULF N OF 26N BETWEEN 83W-92W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE INLAND AND WITHIN 45 NM ALONG THE N GULF COAST BETWEEN APALACHICOLA FLORIDA AND GULFPORT MISSISSIPPI. AN UPPER LOW IS CENTERED OVER THE NW CORNER OF THE YUCATAN PENINSULA COVERING THE S GULF AND GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS S OF 24N E OF 91W TO OVER CUBA AND THE YUCATAN PENINSULA AND THROUGH THE STRAITS OF FLORIDA. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE INLAND OVER THE CENTRAL FLORIDA PENINSULA WITH ISOLATED SHOWERS AND POSSIBLE ISOLATED THUNDERSTORMS FROM 25N-28 E OF 84W. A WEAK 1016 MB HIGH IS ANCHORED IN THE W GULF NEAR 26N92W LEAVING THE REMAINDER OF THE GULF UNDER MOSTLY CLEAR SKIES THIS EVENING. THE N EXTENSION OF THE TROPICAL WAVE WILL MOVE W INTO THE BAY OF CAMPECHE EARLY MON THROUGH EARLY THU. A WEAK TROUGH WILL PASS E ACROSS THE FAR N CENTRAL GULF ON TUE AND THROUGH THE FAR NE GULF ON WED. WEAK SURFACE RIDGE WILL MEANDER FROM CENTRAL FLORIDA TO THE NE TEXAS COAST THROUGH FRI. CARIBBEAN SEA... THE UPPER TROUGH OVER THE S GULF OF MEXICO COVERS THE NW CARIBBEAN N OF 17N W OF 80W. SCATTERED TO HEAVY SHOWERS WITH SCATTERED TO NUMEROUS THUNDERSTORMS ARE N OF 18N TO ACROSS CUBA W OF 80W TO OVER THE YUCATAN PENINSULA. AN UPPER RIDGE OVER THE E PACIFIC REGION EXTENDS AN AXIS SE OF THE ABOVE UPPER LOW ACROSS CENTRAL AMERICA. AN UPPER LOW IS CENTERED ALONG THE S COAST OF HISPANIOLA NEAR 19N71W AND EXTENDING AN UPPER TROUGH S TO JUST W OF THE ABC ISLANDS. SCATTERED TO HEAVY SHOWERS WITH SCATTERED TO NUMEROUS THUNDERSTORMS ARE N OF 18N TO OVER HISPANIOLA AND CUBA BETWEEN 69W-80W WITH SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS FROM 16N-18N BETWEEN 73W-79W INCLUDING JAMAICA. THE MONSOON TROUGH EXTENDS ALONG 10N FROM COLOMBIA TO OVER COSTA RICA GENERATING CLUSTERS OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS S OF 15N W OF 78W. AN UPPER RIDGE COVERS THE E CARIBBEAN ANCHORED E OF THE LESSER ANTILLES PROVIDING DIFFLUNCE ALOFT TO GENERATE SCATTERED SHOWERS WITH CLUSTERS OF SCATTERED THUNDERSTORMS FROM 13N-17N E OF 67W TO OVER THE LESSER ANTILLES. TROPICAL WAVE OVER THE YUCATAN PENINSULA WILL MOVE INTO THE GULF OF MEXICO EARLY MON. THE TROPICAL WAVE IN THE SPECIAL FEATURES WILL ENTER THE CARIBBEAN TONIGHT REACHING THE CENTRAL CARIBBEAN TUE...AS A POSSIBLE TROPICAL CYCLONE. HISPANIOLA... SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ACROSS THE ISLAND W OF 71W THIS EVENING WITH NUMEROUS THUNDERSTORMS OVER HAITI. THE UPPER LOW CURRENTLY OVER HISPANIOLA WILL SHIFT W THROUGH EARLY WED. A TROPICAL WAVE WILL ENTER THE CARIBBEAN TONIGHT AND PASS OVER THE ISLAND TUE THROUGH EARLY THU. THEREFORE SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH AT LEAST EARLY THU. ATLANTIC OCEAN... A BROAD UPPER RIDGE DOMINATES THE W ATLC N OF 23N BETWEEN 61W- 80W ANCHORED NEAR 27N71W. THIS UPPER RIDGE IS PROVIDING DIFFLUNCE ALOFT TO GENERATE CLUSTERS OF SCATTERED SHOWERS/ ISOLATED THUNDERSTORMS FROM 22N-27N BETWEEN 75W-79W AND FROM 26N- 28N BETWEEN 70W-75W. AN UPPER TROUGH IS N OF 30N BETWEEN 58W-68W SUPPORTING A COLD FRONT THAT ENTERS THE REGION NEAR 32N59W TO 28N63W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 90 NM SE OF THE COLD FRONT MAINLY S OF 29N. THE REMAINDER OF THE ATLC IS DOMINATED BY A SURFACE RIDGE WITH A 1019 MB HIGH NEAR 28N67W AND A 1020 MB HIGH NEAR 34N45W. THE N PORTION OF THE TROPICAL WAVE APPROACHING THE LESSER ANTILLES WILL PASS THROUGH THE W ATLC S OF 21N FROM THE LEEWARD ISLANDS TO PUERTO RICO THROUGH TONIGHT AND APPROACHING TO THE MONA PASSAGE ON MON AND TUE THEN THROUGH THE ATLC APPROACHES TO THE WINDWARD PASSAGE ON WED. THE WAVE WILL WEAKEN SOME AS IT CONTINUES W THROUGH THE SW ATLC WATERS BETWEEN CUBA AND THE BAHAMAS LATE IN THE WEEK. MEANWHILE THE WEAK SURFACE RIDGE WILL MEANDER ACROSS THE WATERS N OF 27N THROUGH FRI. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW