000 AXNT20 KNHC 302355 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU SEP 30 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...SPECIAL FEATURES... TROPICAL WAVE EXTENDS ALONG 08N47W 13N47W 17N50W MOVING W AT 15-20 KT. BROAD LOW-LEVEL CYCLONIC FLOW IS NOTED IN THE VICINITY OF THE WAVE AXIS FROM THE ITCZ REGION ALONG 11N NORTHWARD TO 20N BETWEEN 40W-50W. TOTAL PRECIPITABLE WATER IMAGERY ALSO SHOWS THE LOW-LEVEL MOISTURE ASSOCIATED WITH THE WAVE BREAKING OVER THE NORTHERN EXTENT OF THE AXIS. A LARGE AREA OF PRECIPITATION IS LOCATED EAST OF THE WAVE AXIS WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION FROM 10N-19N BETWEEN 38W-49W. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 10N17W TO 20N14W MOVING W AT 10-15 KT. A 1006 MB LOW IS ANALYZED ALONG THE WAVE AXIS NEAR 17N15W. WHILE BROAD LOW-LEVEL CYCLONIC FLOW IS IN THE VICINITY OF THE WAVE AXIS AS IT EMERGES OFF THE COAST OF W AFRICA...UPPER AIR TIME SECTION ANALYSIS INDICATES THE WAVE HAS NOT YET PASSED DAKAR SENEGAL. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 13N-18N BETWEEN 12W-15W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 10N19W 06N30W 11N44W 11N49W 12N60W. ISOLATED MODERATE CONVECTION IS WITHIN 90 NM OF THE AXIS BETWEEN 24W-31W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FRO 07N-12N BETWEEN 33W-36W. SIMILAR CONVECTION IS FROM 11N-17N BETWEEN 50W-61W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVEL TROUGHING IS LOCATED OVER THE SE CONUS AND EXTENDS AN UPPER LEVEL TROUGH AXIS TO THE NE GULF NEAR 30N86W THEN SW THROUGH 25N90W TO THE EASTERN MEXICO COAST NEAR 22N98W. WATER VAPOR IMAGERY SHOWS A VERY DRY AND STABLE AIRMASS OVER THE GULF THIS EVENING. THIS STABILITY IS SUPPORTED FURTHER BY NORTHERLY SURFACE WINDS WHICH ARE FORECAST TO PERSIST OVER THE ENTIRE GULF THROUGH LATE SUNDAY. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED NEAR 18N79W AND EXTENDS UPPER LEVEL RIDGING OVER MUCH OF THE BASIN W OF 65W. THIS UPPER LEVEL FEATURE IS PROVIDING FOR AN OVERALL UPPER LEVEL DIFFLUENT ENVIRONMENT. THIS REGIME IS SUPPORTING SCATTERED SHOWERS AND TSTMS EAST OF A SURFACE TROUGH ANALYZED FROM CENTRAL CUBA NEAR 22N79W TO THE GULF OF HONDURAS NEAR 16N89W AND INLAND OVER CENTRAL GUATEMALA. THIS CONVECTIVE ACTIVITY IS PRIMARILY N OF 13N BETWEEN 66W-84W. FARTHER EAST...THE REMAINDER OF THE CARIBBEAN IS UNDER THE INFLUENCE OF ANOTHER UPPER LEVEL RIDGE AXIS EXTENDING FROM THE TROPICAL NORTH ATLC THAT IMPACTS THE LESSER ANTILLES AND ADJACENT COASTAL WATERS E OF 65W. A SURFACE TROUGH ANALYZED FROM 11N62W TO 20N59W IS ALSO PROVIDING LOW-LEVEL CONVERGENCE AND ATMOSPHERIC LIFT TO GENERATE SCATTERED SHOWERS AND ISOLATED TSTMS FROM 12N-18N E OF 63W THIS EVENING. ATLANTIC OCEAN... UPPER LEVEL TROUGHING IS LOCATED ACROSS THE SE CONUS AND SUPPORTS A 997 MB LOW CENTERED OFF THE SOUTH CAROLINA COAST NEAR 32N78W. A COLD FRONT EXTENDS SE FROM THE LOW CENTER TO 29N77W THEN SOUTH TO THE CENTRAL BAHAMAS NEAR 25N77W AND THEN TO CENTRAL CUBA NEAR 22N78W. LOW-LEVEL CONVERGENCE NEAR THE FRONT AND UPPER LEVEL DIFFLUENCE LOCATED EAST OF THE UPPER LEVEL TROUGH AXIS ARE GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS FROM 20N-32N WEST OF A LINE FROM 32N74W TO 20N68W TO 79W. FARTHER EAST...AN UPPER LEVEL LOW IS CENTERED NEAR 31N61W AND IS GENERATING POSSIBLE SHOWERS FROM 24N-31N BETWEEN 54W-61W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC COMES UNDER THE INFLUENCE OF A VERY BROAD SUBTROPICAL RIDGE ANCHORED BY TWO CENTERS...ONE CENTER A 1027 MB HIGH NEAR 38N51W AND THE SECOND A 1025 MB HIGH NEAR 36N31W. A LARGE UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 16N42W AND SUPPORTS TWO WEAKNESS ON THE SOUTHERN PERIPHERY OF THE SURFACE RIDGE...THE TROPICAL WAVE ALONG 48W AND THE SURFACE TROUGH ANALYZED OVER THE LESSER ANTILLES THIS EVENING. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN