000 AXNT20 KNHC 301729 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI JUL 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS APPROACHING THE CAPE VERDE ISLANDS ALONG 22W/23W S OF 20N MOVING W NEAR 15 KT. WAVE IS EMBEDDED WITHIN AN AREA OF A HIGH AMPLITUDE MOISTURE MAXIMUM BUT DIFFLUENCE ALONG THE ITCZ IS ENHANCING THE CONVECTION AROUND THE WAVE AXIS AND IS NOT DIRECTLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS IN THE CENTRAL ATLC EXTENDING FROM 15N38W TO 7N35W MOVING W NEAR 15 KT. THE 1010 MB LOW HAS BEEN LEFT BEHIND AND IS DISCUSSED IN THE ITCZ SECTION. WEAK WAVE JUST TO THE SE OF AN UPPER TROUGH AND IS AT A LOW AMPLITUDE WITH ANY ACTIVITY ASSOCIATED WITH THE ITCZ. TROPICAL WAVE IS IN THE E CARIBBEAN EXTENDING FROM 17N61W ACROSS THE LESSER ANTILLES TO INLAND OVER N VENEZUELA NEAR 10N66W MOVING W 20-25 KT. WAVE REMAINS POSITIVELY TILTED AND EMBEDDED WITHIN A MOISTURE MAXIMUM WITH SCATTERED MODERATE/STRONG CONVECTION WITHIN 120 NM OF LINE FROM THE WAVE AXIS NEAR 14N63W TO 13N70W. TROPICAL WAVE IS IN THE W CARIBBEAN FROM 17N83W TO 9N76W MOVING W NEAR 10 KT. WAVE ORIENTATION HAS BECOME NEGATIVELY TILTED AND THEREFORE IS WEAKENING. WAVE REMAINS TO THE W OF AN UPPER RIDGE PROVIDING DIFFLUENCE ALOFT ENHANCING THE ACTIVITY IN THE VICINITY OF THE WAVE. ...THE ITCZ... THE ITCZ AXIS IS ANALYZED ALONG 12N16W 9N26W THROUGH A 1010 MB SURFACE LOW NEAR 9N32W THEN RESUMES ALONG 7N39W 7N50W INTO THE S CARIBBEAN ALONG 11N66W 12N82W ACROSS S NICARAGUA/NW COSTA RICA INTO THE E PACIFIC REGION. CLUSTERS OF SCATTERED MODERATE/ STRONG CONVECTION ARE FROM 7N-13N BETWEEN 18W-28W AND FROM 11N-16N BETWEEN 53-62W INCLUDING THE LESSER ANTILLES. SMALL CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION DOT THE AREA FROM 1N-11N BETWEEN 31W-53W. ...DISCUSSION... GULF OF MEXICO... AN UPPER RIDGE IS ANCHORED OVER THE LOWER MISSISSIPPI VALLEY COVERING THE N GULF N OF 25N WITH AN UPPER LOW OVER S MEXICO NEAR 17N94W COVERING THE S GULF. A SURFACE TROUGH EXTENDS FROM APALACHEE BAY FLORIDA ALONG 24N86W TO 22N93W. THE UPPER RIDGE OVER THE N GULF IS PROVIDING DIFFLUENCE ALOFT TO ENHANCE SCATTERED SHOWERS/THUNDERSTORMS WITHIN 75/90 NM OF LINE FROM 26N87W TO OFF THE LOUISIANA COAST NEAR 29N91W AND SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WITHIN 60 NM EITHER SIDE OF THE TROUGH AXIS. A SURFACE RIDGE DOMINATES THE W GULF WITH A 1019 MB HIGH NEAR 27N93W AND A SECOND 1019 MB HIGH INLAND OVER MEXICO NEAR 20N98W. ALL THIS IS LEAVING THE REMAINDER OF THE GULF UNDER CLEAR SKIES THIS AFTERNOON. CARIBBEAN SEA... AN UPPER RIDGE COVERS THE CARIBBEAN W OF 70W ANCHORED NEAR 16N80W AND COUPLED WITH THE UPPER LOW COVERING THE S GULF OF MEXICO IS PROVIDING DIFFLUENCE ALOFT TO ENHANCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 12N-20N BETWEEN 77W-87W. AN UPPER TROUGH IS OVER THE CENTRAL ATLC AND WITH THE TYPICAL UPPER RIDGE OVER THE TROPICAL ATLC IS ENHANCING THE ACTIVITY DESCRIBED IN THE ITCZ SECTION THAT EXTENDS ACROSS THE LESSER ANTILLES. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE IN THE SW CARIBBEAN S OF 10N BETWEEN COLOMBIA AND COSTA RICA DUE TO THE PRESENCE OF THE ITCZ AND AN UPPER DIFFLUENCE IN THE E PACIFIC REGION. ATLANTIC OCEAN... A BROAD DEEP LAYERED TROUGH IS OVER THE NW ATLC AND WITH A FRONT AND A SURFACE TROUGH N OF THE DISCUSSION AREA BUT IS GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS OVER THE W ATLC FROM 26N-32N BETWEEN 67W-76W. A SHARP NARROW UPPER TROUGH IS IN THE CENTRAL ATLC EXTENDING THROUGH 32N57W TO JUST E OF THE LEEWARD ISLANDS NEAR 17N61W AND IS ENHANCING THE ACTIVITY DESCRIBED IN THE ITCZ SECTION AND EXTENDS ACROSS THE LESSER ANTILLES. OTHERWISE...NO SIGNIFICANT WEATHER IS OCCURRING ACROSS THE REMAINDER OF THE ATLC BASIN. A SURFACE RIDGE DOMINATES THE ATLC ANCHORED BY A HIGH WELL N OF THE AZORES EXTENDING A RIDGE AXIS THROUGH 32N51W TO THE BAHAMA ISLANDS NEAR 24N75W. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW DRY SAHARAN AIR MASS SURGING INTO THE FAR E ATLC S OF 30N TO ABOUT 25W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW