000 AXNT20 KNHC 030557 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE SEP 03 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. ...TROPICAL WAVES... A TROPICAL WAVE EXTENDS AN AXIS FROM 21N35W TO 09N32W AND MOVES WEST NEAR 5 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW MOSTLY A MODERATE MOIST ENVIRONMENT AT THE LOWER LEVELS SURROUNDING THIS WAVE. HOWEVER...THE METEOSAT SAL TRACKING PRODUCT DEPICT THIS WAVE IS BEING ENGULFED BY DRY AIR WHICH IS HINDERING CONVECTIVE ACTIVITY. A TROPICAL WAVE EXTENDS AN AXIS FROM 20N53W TO 09N51W AND IS MOVING WEST NEAR 5 KT. TOTAL PRECIPITABLE WATER IMAGERY SHOW THE WAVE IS EMBEDDED WITHIN A MODERATE TO HIGH MOIST ENVIRONMENT. SCATTERED MODERATE CONVECTION AND TSTMS COINCIDE WITH THE AREA WHERE MOISTURE VALUES ARE HIGHER FROM 12N-18N BETWEEN 48W-52W. ISOLATED SHOWERS ARE ELSEWHERE FROM 13N-21N BETWEEN 48W-58W. A TROPICAL WAVE ASSOCIATED WITH A 1009 MB LOW PRESSURE OVER THE EASTERN CARIBBEAN HAS BECOME DIFFICULT TO LOCATE AS IT IS MOVING W IN PHASE WITH AN UPPER-LEVEL CYCLONE NEAR 21N60W EMBEDDED IN THE ATLC TUTT. AN AREA OF SCATTERED MODERATE CONVECTION HAS REMAINED OVER THE LEEWARD ISLANDS AND THE LOW-LEVEL CYCLONE CONTINUES TO SPIN NEAR 14N61W. THUS THE WAVE HAS BEEN HELD NEARLY STATIONARY ALONG 61W AND IS EXPECTED TO BECOME ORIENTED FROM NE TO SW AS IT CONTINUES W REACHING ALONG 70W ON WED NIGHT. A TROPICAL WAVE AXIS EXTENDS FROM 20N94W IN THE BAY OF CAMPECHE TO 11N95W IN THE EASTERN PACIFIC AND IS MOVING W NEAR 5 KT. AN UPPER-LEVEL LOW CENTERED OVER THE WESTERN GULF IS SUPPORTING SCATTERED SHOWERS AND TSTMS FROM S OF 22N W OF 92W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 13N16W AND CONTINUES ALONG 09N30W TO 07N40W 08N49W. BESIDES THE CONVECTION ASSOCIATED WITH THE TROPICAL WAVES ALREADY DISCUSSED...SCATTERED MODERATE CONVECTION IS FROM 07N-14N E OF 20W AND FROM 03N-09N BETWEEN 20W-44W. ...DISCUSSION... THE GULF OF MEXICO... TOTAL PRECIPITABLE WATER IMAGERY SHOW THAT MOISTURE HAS BEEN AUGMENTING ACROSS MOST OF THE GULF TODAY. IN THE UPPER- LEVEL...AN ELONGATED LOW COVERS THE WESTERN GULF S OF 28N WHILE AN ELONGATED RIDGE EXTENDS FROM SOUTHERN FLORIDA TO HONDURAS. THIS IS GENERATING UPPER-LEVEL DIFFLUENCE WHICH IS SUPPORTING SCATTERED MODERATE CONVECTION AND TSTMS ALONG THE YUCATAN PENINSULA...THE YUCATAN CHANNEL AND THE SE GULF S OF 25N E OF 90W. THE NORTHERN EXTENSION OF A TROPICAL WAVE IS MOVING OVER THE WESTERN BAY OF CAMPECHE ENHANCING SCATTERED SHOWERS AND TSTMS S OF 21N W OF 93W. FAIR WEATHER DOMINATES ELSEWHERE IN THE BASIN. MOISTURE ADVECTION FROM THE CARIBBEAN SEA WILL CONTINUE WHICH ALONG WITH PERSISTENT MIDDLE TO UPPER-LEVEL DIFFLUENCE WILL LIKELY ENHANCE SHOWERS ACROSS THE BASIN UNTIL WEDNESDAY MORNING. THE CARIBBEAN SEA... IN THE UPPER-LEVEL...AN ELONGATED LOW COVERS THE WESTERN GULF S OF 28N WHILE AN ELONGATED RIDGE EXTENDS FROM SOUTHERN FLORIDA TO HONDURAS. THIS IS GENERATING UPPER-LEVEL DIFFLUENCE WHICH IS SUPPORTING A CLUSTER OF MODERATE/ISOLATED STRONG CONVECTION AND TSTMS OVER THE NW BASIN FROM 18N-21N W OF 84W AND SCATTERED MODERATE CONVECTION ELSEWHERE N OF 15N W OF 80W. AN ELONGATED UPPER-LEVEL LOW IS OVER THE CENTRAL CARIBBEAN WHILE A RIDGE AXIS EXTENDS INTO THE EASTERN BASIN FROM A HIGH CENTERED IN THE TROPICAL ATLC NEAR 16N50W. THIS IS GENERATING UPPER LEVEL DIFFLUENCE WHICH IS SUPPORTING CLOUDINESS AS WELL AS ISOLATED SHOWERS AND TSTMS OVER HISPANIOLA. A TROPICAL WAVE ASSOCIATED WITH A 1009 MB LOW PRESSURE OVER THE EASTERN CARIBBEAN HAS BECOME DIFFICULT TO LOCATE AS IT IS MOVING W IN PHASE WITH AN UPPER-LEVEL CYCLONE NEAR 21N60W EMBEDDED IN THE ATLC TUTT. AN AREA OF SCATTERED MODERATE CONVECTION HAS REMAINED OVER THE LEEWARD ISLANDS AND THE LOW-LEVEL CYCLONE CONTINUES TO SPIN NEAR 14N61W. THUS THE WAVE HAS BEEN HELD NEARLY STATIONARY ALONG 61W AND IS EXPECTED TO BECOME ORIENTED FROM NE TO SW AS IT CONTINUES W REACHING ALONG 70W ON WED NIGHT. HISPANIOLA... AN ELONGATED UPPER-LEVEL LOW IS OVER THE CENTRAL CARIBBEAN WHILE A RIDGE AXIS EXTENDS INTO THE EASTERN BASIN FROM A HIGH CENTERED IN THE TROPICAL ATLC NEAR 16N50W. THIS IS GENERATING UPPER LEVEL DIFFLUENCE WHICH IS SUPPORTING CLOUDINESS AS WELL AS ISOLATED SHOWERS AND TSTMS OVER HISPANIOLA. THE TROPICAL WAVE AXIS CURRENTLY IN THE EASTERN CARIBBEAN IS EXPECTED TO BE ALONG 70W ON WED NIGHT...HOWEVER WEATHER CONDITIONS WILL START TO DEGENERATE WED MORNING AS THE WAVE MOVES WESTWARD ACROSS PUERTO RICO PUSHING FORWARD AN ENVELOPE OF HIGH MOISTURE. THE ATLANTIC OCEAN... BESIDES THE TROPICAL WAVES ALREADY DISCUSSED...SURFACE RIDGING ANCHORED BY A 1025 MB HIGH PRESSURE NEAR 36N31W DOMINATES THE REMAINDER BASIN N OF 20N WHICH ALONG WITH DRY STABLE AIR SUPPORTS FAIR WEATHER. A NEW TROPICAL WAVE IS EXPECTED TO COME OFF THE AFRICAN COAST LATE TONIGHT. ENVIRONMENTAL CONDITIONS ARE EXPECTED TO BE MARGINALLY FAVORABLE FOR DEVELOPMENT OF THIS WAVE OVER THE NEXT FEW DAYS WHILE THE DISTURBANCE MOVES WEST- NORTHWESTWARD TO NORTHWESTWARD AT 10 TO 15 MPH. THIS SYSTEM HAS A LOW CHANCE...10 PERCENT...OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR