000 AXNT20 KNHC 310604 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT AUG 31 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURES... A TROPICAL WAVE ASSOCIATED WITH A 1008 MB LOW PRESSURE IS COMING OFF THE AFRICAN COAST WITH AXIS EXTENDING FROM 20N15W TO THE LOW NEAR 14N16W TO 12N16N. THE WAVE IS MOVING W-NW NEAR 5 KT. THE LOW CYCLONIC CIRCULATION AND A MAXIMUM OF RELATIVE VORTICITY ALIGNED OR CLOSELY ALIGNED TO THE CIRCULATION CENTER EXTEND UP TO THE MIDDLE LEVELS. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED IN A MODERATE TO HIGH MOIST ENVIRONMENT. A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION IS NW OF THE LOW FROM 13N-18N BETWEEN 17W-21W. ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE FOR DEVELOPMENT AND THIS SYSTEM HAS THE POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS AS IT MOVES TOWARD THE CAPE VERDE ISLANDS. CLOUDINESS AND THUNDERSTORMS ARE EXPECTED IN PORTIONS OF THE CAPE VERDE ISLANDS IN THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... A TROPICAL WAVE ASSOCIATED WITH A 1013 MB LOW EXTENDS AN AXIS FROM 18N49W TO THE LOW NEAR 11N51W TO 09N52W WHICH IS MOVING W- NW NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW A HIGH MOIST ENVIRONMENT IN THE NORTHERN PART OF THE WAVE N OF 14N BUT A DRIER ENVIRONMENT IN THE VICINITY OF THE LOW PRESSURE. SMALL CLUSTERS OF MODERATE CONVECTION ARE WITHIN 220 NM EAST OF THE WAVE AXIS FROM 13N-18N. A TROPICAL WAVE IS ENTERING THE WESTERN CARIBBEAN SEA WITH AXIS EXTENDING ALONG 20N76W TO 10N77W AT 0300 UTC. IT CONTINUES MOVING WESTWARD BUT SLIGHTLY FASTER...NEAR 15-20 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE TO HIGH MOIST ENVIRONMENT. SCATTERED SHOWERS AND TSTMS ARE BEING ENHANCED BY MIDDLE TO UPPER LEVEL DIFFLUENCE NEAR THE WINDWARD PASSAGE AND EXTEND TO HAITI. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR 14N16W TO 10N30W 08N40W 11N49W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED MODERATE CONVECTION IS FROM 05N-12N E OF 18W AS WELL AS FROM 12N- 15N BETWEEN 39W-42W. SIMILAR CONVECTION IS WITHIN 160 NM EITHER SIDE OF THE MONSOON AXIS BETWEEN 29W-36W AS WELL AS WITHIN 200 NM S BETWEEN 34W-45W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATE NORTHERLY UPPER LEVEL FLOW CONTINUES TO DOMINATE ACROSS MUCH OF THE GULF THIS MORNING WITH RELATIVELY DRY AND STABLE CONDITIONS ALOFT W OF 88W. THIS OVERALL STABILITY IS SUPPORTING A 1015 MB HIGH CENTERED NEAR 27N90W THAT IS PROVIDING MUCH OF THE BASIN N OF 22N WITH ANTICYCLONIC WIND GENERALLY IN THE RANGE OF 5-10 KT. AN UPPER LEVEL TROUGH OFFSHORE THE EASTERN CONUS IS SUPPORTING A COLD FRONT AND A 1013 MB LOW OVER NORTHERN FLORIDA. THIS FRONTAL SYSTEM IS GENERATING SCATTERED MODERATE CONVECTION AND TSTMS OVER THE NE GULF N OF 28N E OF 87W. OTHERWISE...A SURFACE TROUGH ALONG THE WESTERN YUCATAN PENINSULA IS GENERATING SHOWERS OVER THE EASTERN BAY OF CAMPECHE S OF 21N E OF 93W. FAIR WEATHER IS EXPECTED TO DOMINATE ACROSS THE GULF THIS WEEKEND SUPPORTED BY SURFACE RIDGING AND STABLE DRY AIR IN THE LOWER TO MIDDLE LEVELS. CARIBBEAN SEA... A TROPICAL WAVE IS ENTERING THE WESTERN CARIBBEAN SEA WITH AXIS EXTENDING ALONG 20N76W TO 10N77W AT 0300 UTC. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS WITHIN A MODERATE TO HIGH MOIST ENVIRONMENT. MIDDLE TO UPPER LEVEL DIFFLUENCE IS ENHANCING SCATTERED SHOWERS AND TSTMS IN THE WINDWARD PASSAGE AND HAITI. A MIDDLE TO UPPER LEVEL LOW CENTERED IN THE FLORIDA STRAITS IS SUPPORTING SCATTERED/ISOLATED SHOWERS WITHIN 140 NM OF THE SOUTHERN COAST OF CUBA. UPPER LEVEL DIFFLUENCE FROM THAT UPPER LOW AND A RIDGE CENTERED OVER THE SW GULF IS ENHANCING ISOLATED SHOWERS S OF 20N W OF 84W. AN UPPER LEVEL LOW CENTERED N OF PUERTO RICO EXTENDS A TROUGH AXIS OVER THE EASTERN BASIN WHICH IS SUPPORTING A CLUSTER OF MODERATE CONVECTION FROM 18N-20N BETWEEN 66W-69W INCLUDING THE MONA PASSAGE. ISOLATED SHOWERS ARE FROM 16N-19N BETWEEN 63W-65W. A TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE LESSER ANTILLES BY MONDAY MORNING. HISPANIOLA... SHOWERS AND TSTMS ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE ARE AFFECTING HAITI AND ADJACENT WATERS OF THE WINDWARD PASSAGE. AN UPPER LEVEL LOW CENTERED N OF PUERTO RICO IS SUPPORTING A CLUSTER OF MODERATE CONVECTION FROM 18N-20N BETWEEN 66W-69W INCLUDING THE MONA PASSAGE AND EASTERN DOMINICAN REPUBLIC E OF 69W. CONVECTIVE ACTIVITY IS EXPECTED ACROSS HISPANIOLA ON SATURDAY AND SUNDAY. ATLANTIC OCEAN... UPPER LEVEL TROUGHINESS OVER THE SW N ATLC IS SUPPORTING SCATTERED SHOWERS AND TSTMS OVER THE NORTHERN BAHAMAS FROM 26N- 28N W OF 76W. FARTHER EAST...AN UPPER LEVEL ELONGATED LOW SUPPORTS A SURFACE TROUGH ALONG 25N66W TO 21N71W AND NUMEROUS MODERATE CONVECTION FROM 24N-29N BETWEEN 59W-66W. OTHERWISE...BESIDES THE TROPICAL WAVES ALREADY DISCUSSED...SURFACE RIDGING AND DRY STABLE AIR DOMINATES THE REMAINDER BASIN SUPPORTING FAIR WEATHER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR