000 AXNT20 KNHC 071052 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT WED AUG 07 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 1022 UTC. ...TROPICAL WAVES... A TROPICAL WAVE HAS COME OFF THE AFRICAN COAST WITH AXIS EXTENDING FROM 20N17W TO 06N17W. THE WAVE IS EMBEDDED WITHIN A HIGH MOIST ENVIRONMENT AS DEPICTED IN TOTAL PRECIPITABLE WATER IMAGERY AND SCATTERED MODERATE CONVECTION IS FROM 07N-15N E OF 20W. THE METEOSAT-9 SAL TRACKING IMAGERY SHOW DRY AIR ENGULFING THE WAVE N OF 15N WITHIN 200 NM OF THE AXIS. A TROPICAL WAVE IS OVER THE E CARIBBEAN WITH AXIS EXTENDING FROM 21N65W TO 10N65W MOVING W NEAR 10 KT. TOTAL PRECIPITABLE WATER IMAGERY DEPICT A DRY ENVIRONMENT AHEAD OF IT S OF 18N WHILE MODERATE MOISTURE LIES BEHIND ITS AXIS. DRY AIR SUBSIDENCE AS WELL AS STRONG DEEP LAYER WIND SHEAR ARE HINDERING CONVECTION IN THE GULF WATERS...HOWEVER RAINSHOWERS ARE OCCURRING ACROSS NORTHERN PUERTO RICO AND ADJACENT WATERS OFF THE NORTHERN COAST. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM THE WEST AFRICAN COAST NEAR 15N16W TO 09N25W 06N36W. THE INTERTROPICAL CONVERGENCE ZONE AXIS STARTS NEAR 06N36W AND CONTINUES ALONG 07N42W TO 09N47W. BESIDES THE CONVECTION ASSOCIATED WITH THE WAVE COMING OFF THE W AFRICAN COAST ALREADY DISCUSSED...A CLUSTER OF MODERATE CONVECTION IS FROM 07N-11N BETWEEN 25W-29W. OTHERWISE...ISOLATED SHOWERS ARE WITHIN 100 NM EITHER SIDE OF THE AXES BETWEEN 30W-45W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 0900 UTC...ANTICYCLONIC FLOW IN THE RANGE OF 5-15 KT SPREADS ACROSS THE BASIN W OF 86W ANCHORED BY A 1015 MB HIGH NEAR 26N91W WHICH IS BEING SUPPORTED BY A BROAD MIDDLE TO UPPER LEVEL RIDGE CENTERED OVER TEXAS. A COLD FRONT EXTENDS FROM A 1012 MB LOW IN THE FLORIDA PANHANDLE TO 30N86W 29N87W 30N88W. A SURFACE TROUGH EXTENDS FROM THE SAME LOW TO ANOTHER 1012 MB LOW JUST WEST OF TAMPA TO 25N82W 23N82W...ACROSS WESTERN CUBA TO 21N83W IN THE W CARIBBEAN. ISOLATED SHOWERS ARE OVER THE EASTERN GULF E OF 86W ASSOCIATED WITH THIS FRONTAL SYSTEM. OTHERWISE...DRY AIR SUBSIDENCE IS SUPPORTING FAIR WEATHER OVER THE WESTERN GULF. THE CENTER OF HIGH PRESSURE IS EXPECTED TO DRIFT NW AND THEN DISSIPATE EARLY ON THURSDAY. THE SURFACE TROUGH THAT EXTENDS OVER THE SE GULF IS EXPECTED TO DRIFT WESTWARD AND MOVE TO THE PENINSULA OF YUCATAN THURSDAY NIGHT. RAINSHOWERS ARE LIKELY TO CONTINUE OVER THE EASTERN GULF. THE CARIBBEAN SEA... AS DEPICTED IN TOTAL PRECIPITABLE WATER AND WATER VAPOR IMAGERY...DRY AIR SPREADS ACROSS THE BASIN MAINLY S OF 18N PROVIDING A STABLE...CONVECTION FREE ENVIRONMENT. N OF 18 N...A MODERATE MOIST ENVIRONMENT AND UPPER LEVEL DIFFLUENCE FROM A BROAD RIDGE EXTENDING TO THE W CARIBBEAN AND A LOW CENTERED N OF THE HISPANIOLA ARE ENHANCING SCATTERED MODERATE CONVECTION AND TSTMS OVER THE WINDWARD PASSAGE AS WELL AS BETWEEN SE CUBA AND JAMAICA. ISOLATED SHOWERS ARE OCCURRING WITHIN 180 NM OFF THE SOUTHERN COAST OF CUBA W OF 79W ASSOCIATED WITH THE SURFACE TROUGH THAT EXTENDS FROM THE EASTERN GULF TO THE W CARIBBEAN. A TROPICAL WAVE IS MOVING ACROSS THE EASTERN CARIBBEAN WITH AXIS CURRENTLY MOVING ACROSS EASTERN PUERTO RICO GENERATING SCATTERED RAINSHOWERS ACROSS THE ISLAND AND NORTHERN ADJACENT WATERS. A SURFACE TROUGH ASSOCIATED WITH A 1011 MB LOW NEAR 13N60W IS GENERATING A CLUSTER OF MODERATE CONVECTION AND TSTMS OVER THE LESSER ANTILLES FROM 12N-15N BETWEEN 60W-63W. THE VIRGIN ISLANDS REPORTED RAINSHOWERS WITHIN THE LAST HOUR ASSOCIATED WITH THE PASSAGE OF THIS WAVE. TRADEWINDS UP TO 20 KT ARE OVER THE CENTRAL-SOUTHERN CARIBBEAN NEAR THE COAST OF COLOMBIA WHILE WINDS OF 5-15 KT DOMINATE ELSEWHERE IN THE BASIN. ISOLATED MODERATE CONVECTION IS S OF 10N ASSOCIATED WITH THE MONSOON TROUGH AXIS. WINDS OVER THE CENTRAL-SOUTHERN CARIBBEAN ARE EXPECTED TO SUBSIDE TO 15 KT WEDNESDAY AFTERNOON. RAINSHOWERS ACTIVITY IS EXPECTED FOR THE GREATER ANTILLES AND ADJACENT WATERS DURING THE NEXT 48 HOURS...ASSOCIATED WITH THE WESTWARD PASSAGE OF THE TROPICAL WAVE AS WELL AS A FAVORABLE UPPER LEVEL SYNOPTIC PATTERN. HISPANIOLA... THE UPPER LEVEL LOW FORMERLY ASSISTING IN GENERATING CONVECTIVE ACTIVITY ACROSS THE ISLAND HAS DRIFTED WESTWARD JUST N OF THE WINDWARD PASSAGE WHERE UPPER LEVEL DIFFLUENCE IS SUPPORTING SCATTERED MODERATE CONVECTION AND TSTMS. RAINSHOWERS ARE EXPECTED FOR THE ISLAND AND ADJACENT WATERS DURING THE NEXT 48 HOURS...ASSOCIATED WITH THE WESTWARD PASSAGE OF A TROPICAL WAVE AS WELL AS A FAVORABLE UPPER LEVEL SYNOPTIC PATTERN. THE ATLANTIC OCEAN... AS OF 0900 UTC...A SURFACE TROUGH FORMERLY PART OF THE TROPICAL WAVE AXIS IN THE E CARIBBEAN IS MOVING W-NW AROUND THE PERIPHERY OF A RIDGE WITH AXIS EXTENDING FROM 30N60W TO 22N70W. SCATTERED MODERATE CONVECTION ASSOCIATED WITH THIS TROUGHINESS IS FROM 23N- 32N BETWEEN 58W-67W. A SURFACE TROUGH ASSOCIATED WITH A 1011 MB LOW NEAR 13N60W IS GENERATING A CLUSTER OF MODERATE CONVECTION AND TSTMS OVER THE LESSER ANTILLES FROM 12N-15N BETWEEN 60W-63W. ANOTHER SURFACE TROUGH EXTENDS FROM 14N49W TO 09N51W WITH ISOLATED MODERATE CONVECTION WITHIN 150 NM EITHER SIDE OF THE AXIS N OF 11N. OTHERWISE...SURFACE RIDGING AND FAIR WEATHER SUPPORTED BY LOWER-MIDDLE LEVEL DRY AIR DOMINATE THE REMAINDER BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ RAMOS