000 AXNT20 KNHC 151109 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU JUL 15 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1000 UTC... ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 20N30W TO 6N31W MOVING W NEAR 20 KT. FIRST VISIBLE SATELLITE IMAGES OF THE DAY SHOW WELL-DEFINED CYCLONIC FLOW ABOUT THE WAVE AXIS. THE WAVE ALSO LIES AHEAD OF A MAXIMUM IN DEEP LAYER MOISTURE SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS W OF THE WAVE AXIS FROM 4N-12N BETWEEN 30W-35W. TROPICAL WAVE IS ALONG 43W/44W S OF 18N MOVING W NEAR 15 KT. THE WAVE LIES AHEAD OF A MAXIMUM IN DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. LOW-AMPLITUDE CYCLONIC FLOW IS ALSO ABOUT THE WAVE AXIS EVIDENT IN SATELLITE DERIVED WINDS. A LARGE AREA OF DRY SAHARAN AIR AND DUST ENCOMPASSES THE WAVE AXIS RESTRICTING CONVECTION TO THE ITCZ. ISOLATED MODERATE CONVECTION IS FROM 9N-13N BETWEEN 41W-44W. TROPICAL WAVE IS ALONG 64W S OF 15N MOVING W NEAR 15 KT. WAVE FOLLOWS A SLIGHT MAXIMUM IN DEEP LAYER MOISTURE SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE CONVECTION IS ACROSS THE WINDWARD ISLANDS FROM 11N-13N BETWEEN 63W-67W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 9N30W 9N43W 7N50W 10N62W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-14N BETWEEN 13W-20W. SCATTERED MODERATE CONVECTION IS FROM 5N-9N BETWEEN 49W-52W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 10N-12N BETWEEN 51W-62W. ...DISCUSSION... GULF OF MEXICO... A DRY AND STABLE AIRMASS REMAINS OVER MUCH OF THE GULF OF MEXICO W OF 85W AROUND AN UPPER LEVEL RIDGE CENTERED OVER THE SRN PLAINS MAINTAINING FAIR CONDITIONS ACROSS THE BASIN. HOWEVER...AN AREA OF MOISTURE THAT HAS BEEN PROGRESSING WWD FROM THE ATLC IS NOW ACROSS FLORIDA AND THE ERN GULF OF MEXICO. THIS MOISTURE ALONG WITH SURFACE CONVERGENCE NEAR A SURFACE TROUGH EXTENDING W OF THE FLORIDA PENINSULA TO WRN CUBA ALONG 29N84W TO 21N84W ARE ENHANCING ISOLATED SHOWERS/THUNDERSTORMS ACROSS THE ERN GULF S OF 30N E OF 86W. ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW BAY OF CAMPECHE S OF 22N W OF 94W AROUND A SHORTWAVE UPPER LEVEL TROUGH EXTENDING FROM THE E PACIFIC AND UP CENTRAL MEXICO. EXPECT SHOWERS/THUNDERSTORMS TO REMAIN ACROSS PORTIONS OF THE ERN GULF AS THE SURFACE TROUGH AND ASSOCIATED MOISTURE MOVE WWD. THE REMAINDER OF THE BASIN WILL REMAIN UNDER HIGH PRESSURE PROVIDING FAIR CONDITIONS. CARIBBEAN SEA... A SURFACE TROUGH EXTENDING FROM THE FLORIDA PENINSULA ACROSS WRN CUBA IS ENHANCING ISOLATED SHOWERS/THUNDERSTORMS OVER THE NW CARIBBEAN N OF 18N BETWEEN 82W-85W. A MID/UPPER LEVEL LOW CONTINUES TO SPIN OVER THE SE BAHAMAS WITH AXIS EXTENDING TO THE SSW SUPPORTING ISOLATED SHOWERS/THUNDERSTORMS FROM 15N-18N BETWEEN 67W-80W...AND SCATTERED SHOWERS/THUNDERSTORMS N OF ERN CUBA. THE COMBINATION OF DIFFLUENCE ALOFT AROUND THE BASE OF THE UPPER LEVEL TROUGH AND SURFACE CONVERGENCE NEAR AN EXTENSION OF THE E PACIFIC ITCZ ACROSS COSTA RICA TO THE COLOMBIAN COAST IS ENHANCING NUMEROUS STRONG CONVECTION S OF 12N BETWEEN 71W-86W. SCATTERED SHOWERS/THUNDERSTORMS ARE IN THE E CARIBBEAN FROM 11N-13N BETWEEN 63W-67W DUE TO A TROPICAL WAVE ALONG 64W. ALOFT...UPPER LEVEL RIDGING IS TO EITHER SIDE OF THE AFOREMENTIONED UPPER LEVEL LOW OVER THE SE BAHAMAS...EXTENDING FROM THE GULF OF MEXICO...AND E OF THE LESSER ANTILLES. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS THE ERN CARIBBEAN AS THE TROPICAL WAVE ALONG 64W PROGRESSES WWD...AS WELL AS ACROSS THE NW CARIBBEAN AS THE UPPER LEVEL LOW MOVES NW. ATLANTIC OCEAN... SCATTERED SHOWERS/THUNDERSTORMS ARE OFF THE NE COAST OF FLORIDA N OF 29N BETWEEN 76W-79W NEAR THE BASE OF A SHORTWAVE UPPER LEVEL TROUGH EXTENDING DOWN THE ERN SEABOARD. SIMILAR ACTIVITY IS ALSO N OF ERN CUBA FROM 20N-23N BETWEEN 73W-76W NEAR AN UPPER LEVEL LOW OVER THE SE BAHAMAS. A SURFACE TROUGH EXTENDS E OF THE LEEWARD ISLANDS FROM 21N55W TO 15N58W SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 19N-20N BETWEEN 54W-58W. AN AREA OF ENHANCED MOISTURE ACCOMPANIES THE SURFACE TROUGH EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. FARTHER E...SURFACE RIDGING DOMINATES THE BASIN ANCHORED BY A SERIES OF 1026 AND 1027 MB HIGHS N OF THE DISCUSSION AREA. A DRY SAHARAN AIR LAYER ACCOMPANIED BY DUST COVERS MUCH OF THE TROPICAL ATLC KEEPING CONDITIONS FAIR. ALOFT...AN UPPER LEVEL LOW IS NEAR 31N51W WITH TROUGH AXIS EXTENDING TO NEAR 21N57W SUPPORTING THE SURFACE TROUGH E OF THE LEEWARD ISLANDS. UPPER LEVEL RIDGING IS TO THE S OF 20N CENTERED NEAR 14N61 W WITH AXIS EXTENDING TO THE NE COVERING THE REMAINDER OF THE BASIN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON