000 AXNT20 KNHC 091030 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT FRI AUG 09 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0952 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS WEST OF THE CAPE VERDE ISLANDS WITH AXIS EXTENDING FROM 21N33W TO 09N29W MOVING W NEAR 5 KT. METEOSAT SATELLITE IMAGERY SHOW SAHARAN DRY AIR SPREADING OVER THE WAVE ENVIRONMENT WHICH IS HINDERING CONVECTION. A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 24N79W TO 11N79W MOVING W NEAR 5 KT. THE WAVE IS EMBEDDED IN A LIGHT TO MODERATE MOIST ENVIRONMENT AS DEPICTED ON TOTAL PRECIPITABLE WATER IMAGERY. AN UPPER LEVEL LOW CENTERED NEAR 23N80W WHICH EXTENDS A TROUGH ACROSS THE WESTERN CARIBBEAN SUPPORTS SCATTERED MODERATE CONVECTION AND TSTMS OVER CUBA AND ADJACENT WATERS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR 13N16W TO 09N29W 07N40W. THE INTERTROPICAL CONVERGENCE ZONE AXIS STARTS NEAR 07N40W AND CONTINUES ALONG 07N50W TO 07N58W. SCATTERED MODERATE CONVECTION IS FROM 04N-10N BETWEEN 14W-20W AS WELL AS FROM 05N-10N BETWEEN 21W-33W. ...DISCUSSION... GULF OF MEXICO... AS OF 0900 UTC...SURFACE TROUGHINESS AND ABUNDANT MOISTURE CONTINUE TO DOMINATE ACROSS THE BASIN ASSOCIATED WITH A SURFACE TROUGH WITH AXIS EXTENDING FROM 27N89W TO 18N91W. STRONG NORTHEASTERLY WIND FLOW AROUND AN UPPER LEVEL RIDGE EXTENDING ALONG THE EASTERN CONUS INTO THE GULF IS LIMITING CONVECTIVE ACTIVITY ASSOCIATED WITH THE TROUGH TO ISOLATED RAINSHOWERS WITHIN 100 NM EITHER SIDE OF ITS AXIS N OF 20N. OTHERWISE...FAIR WEATHER IS W OF 95W AND E OF 87W FAVORED BY DRY AIR SUBSIDENCE AND HIGH VALUES OF DEEP LAYER ENVIRONMENTAL WIND SHEAR...RESPECTIVELY. SURFACE RIDGING WILL START TO BUILD AGAIN ACROSS THE BASIN STEERING THE SURFACE TROUGH TOWARDS THE SW GULF. THE TROUGH IS EXPECTED TO ENTER SE MEXICO VERY EARLY ON SUNDAY. THE UPPER LEVEL LOW CURRENTLY ENHANCING SHOWERS OVER THE BAHAMAS AND WESTERN CARIBBEAN WILL ENTER THE SE GULF LATER TODAY AND IS EXPECTED TO PERSIST OVER THE GULF WITHIN 48 HOURS...THUS RAINSHOWERS ARE LIKELY DURING THIS PERIOD. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN WITH AXIS EXTENDING FROM 24N79W TO 11N79W. AN UPPER LEVEL LOW CENTERED NEAR 23N80W WHICH EXTENDS A TROUGH ACROSS THE WESTERN CARIBBEAN SUPPORTS SCATTERED MODERATE CONVECTION AND TSTMS OVER CUBA AND ADJACENT WATERS N OF 18N W OF 78W. A SURFACE TROUGH EXTENDS FROM THE DOMINICAN REPUBLIC NEAR 18N69W TO 11N70W. SCATTERED MODERATE CONVECTION ASSOCIATED WITH THIS TROUGH IS FROM 16N-18N BETWEEN 66W-71W. CLUSTERS OF MODERATE CONVECTION WITH EMBEDDED TSTMS ARE IN THE SOUTHERN BASIN S OF 13N E OF 81W ASSOCIATED WITH THE MONSOON TROUGH AXIS WHICH MOVES ACROSS PANAMA TO A LOW CENTER OVER NORTHERN COLOMBIA. THE WAVE WILL CONTINUE TO MOVE WESTWARD AND IS EXPECTED TO BE ALONG HONDURAS AND NICARAGUA BY SATURDAY MORNING. THE TRAILING SURFACE TROUGH IS EXPECTED TO DISSIPATE FRIDAY AFTERNOON...HOWEVER ANOTHER SURFACE TROUGH IS EXPECTED TO MOVE ACROSS THE LESSER ANTILLES FRIDAY MORNING INCREASING THE CHANCES OF PRECIPITATION FOR THIS PART OF THE BASIN. HISPANIOLA... A SURFACE TROUGH EXTENDS FROM THE DOMINICAN REPUBLIC NEAR 18N69W TO 11N70W ENHANCING SCATTERED MODERATE CONVECTION OVER ITS ADJACENT WATERS FROM 16N-18N BETWEEN 66W-71W. CONVECTION WILL BUILD ACROSS THE ISLAND IN THE AFTERNOON/EARLY EVENING HOURS ASSOCIATED WITH DAYTIME HEATING. WEATHER CONDITIONS ARE EXPECTED TO IMPROVE EARLY ON SATURDAY DUE TO THE WESTWARD TRANSIT OF A DRY AIRMASS. ATLANTIC OCEAN... AN UPPER LEVEL LOW CENTERED NEAR 23N80W WHICH EXTENDS A TROUGH ACROSS THE WESTERN CARIBBEAN SUPPORTS LOW VALUES OF DEEP LAYER ENVIRONMENTAL WIND SHEAR...THUS ENHANCING SCATTERED MODERATE CONVECTION AND TSTMS OVER THE ADJACENT WATERS OF NORTHERN CUBA AND THE BAHAMAS S OF 25N W OF 74W. A SURFACE TROUGH EXTENDS FROM 16N58W TO 09N56W WITH ISOLATED RAINSHOWERS WITHIN 100 NM EITHER SIDE OF ITS AXIS FROM 13N-15N. OTHERWISE...BESIDES THE TROPICAL WAVE ALREADY DISCUSSED...SURFACE RIDGING AND FAIR WEATHER SUPPORTED BY LOWER-MIDDLE LEVELS DRY AIR DOMINATE THE REMAINDER BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR