000 AXNT20 KNHC 180002 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SAT JUL 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2350 UTC... ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 55W FROM 7N TO 19N MOVING W NEAR 20 KT. SATELLITE IMAGERY SHOWS WELL-DEFINED CYCLONIC TURNING ABOUT THE WAVE AXIS. THE WAVE IS EMBEDDED IN A REGION OF ELEVATED VALUES IN DEEP LAYER MOISTURE SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. SAHARAN AIR LAYER IN THE VICINITY OF THE WAVE IS SUPPRESSING DEEP CONVECTION FROM DEVELOPING...LEAVING ONLY SCATTERED WEAK TO ISOLATED MODERATE CONVECTION EAST OF THE WAVE AXIS FROM 11N TO 13N BETWEEN 47W AND 50W. TROPICAL WAVE IS OVER THE EASTERN CARIBBEAN ALONG 69W FROM 10N TO 19N MOVING W ABOUT 10 KT. THIS WAVE IS MOSTLY EMBEDDED IN THE ITCZ AND WITHIN A REGION OF ELEVATED VALUES IN DEEP LAYER MOISTURE SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OVER A GREAT PORTION OF THE E CARIBBEAN FROM 11N TO 21N BETWEEN 61W AND 75W. TROPICAL WAVE IS OVER THE WESTERN CARIBBEAN ALONG 80W FROM 11N TO 20N MOVING W AT ABOUT 5 KT. THIS WAVE IS MOSTLY EMBEDDED IN THE ITCZ AND WITHIN A REGION OF ELEVATED VALUES IN DEEP LAYER MOISTURE SEEN IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE TO STRONG CONVECTION IS OVER A GREAT PORTION OF THE W CARIBBEAN W OF 75W...INCLUDING INLAND PORTIONS OF CENTRAL AMERICA...THE YUCATAN PENINSULA...NW VENEZUELA AND COLOMBIA. ...ITCZ... THE ITCZ AXIS IS ANALYZED FROM THE WESTERN AFRICAN COAST OF GUINEA NEAR 10N14W WESTWARD ALONG 8N20W 4N30W 6N40W 10N50W 11N60W. SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 150 NM SOUTH OF ITCZ BETWEEN 12W AND 30W. ISOLATED MODERATE TO STRONG CONVECTION IS WITHIN 100 NM ON EITHER SIDE OF THE ITCZ AXIS E OF 30W. A TROPICAL WAVE CURRENTLY INLAND OVER WEST AFRICA WILL BE ENTERING THE ATLANTIC WATERS W OF 13W OVER THE NEXT 24 HOURS. ...DISCUSSION... GULF OF MEXICO... THE SURFACE TROUGH THAT HAS BEEN GENERATING THE WEATHER ACROSS THE GULF OVER THE PAST FEW DAYS IS NOW HEADING TO THE WESTERN GULF COAST EXTENDING FROM N TO S ALONG 95W/96W...FROM NEAR MATAGORDA BEACH TEXAS TO VERACRUZ MEXICO. AT THIS POINT...MOST OF THE MOISTURE AND ENERGY FROM THIS SYSTEM HAVE BEEN TRANSFERRED ALOFT TO THE NE ACROSS THE NORTH CENTRAL GULF COAST AFFECTING THE COASTAL WATERS OF LOUISIANA AND MISSISSIPPI WITHIN 150 NM OFFSHORE WITH SCATTERED MODERATE TO ISOLATED HEAVY SHOWERS. A BROADER AREA OF LOWER PRESSURE/CYCLONIC FLOW CURRENTLY OVER THE NW CARIBBEAN IS STARTING TO ENTER THE S AND SE LIMITS OF THE GULF THROUGH THE WESTERN YUCATAN PENINSULA...THE YUCATAN CHANNEL...AND WESTERN CUBA...GENERATING HEAVY SHOWERS AND THUNDERSTORMS S OF 23N E OF 92W. THIS AREA OF LOWER PRESSURE WILL CONTINUE TO MOVE WEST WITH SHOWERS AND THUNDERSTORMS SPREADING ACROSS THE SOUTHERN GULF OVER THE NEXT FEW DAYS. EXPECT SHOWERS AND THUNDERSTORMS TO SPREAD WESTWARD ACROSS THE TEXAS AND MEXICO COASTS OVER THE NEXT 24 HOURS...AS THE SURFACE TROUGH CONTINUES TO MOVE WESTWARD. THE REMAINDER OF THE BASIN WILL REMAIN UNDER MORE STABLE CONDITIONS WITH A FEW ISOLATED SHOWERS EMBEDDED IN THE ESE FLOW. CARIBBEAN SEA... MOST OF THE CARIBBEAN SEA IS UNDER THE INFLUENCE OF A VERY UNSTABLE ATMOSPHERE AND CONSIDERABLE HIGH AMOUNTS OF PRECIPITABLE WATER. ALONG WITH THESE TWO MAIN INGREDIENTS...TWO TROPICAL WAVES ARE MOVING ACROSS THE REGION...ONE ALONG 69W AND THE OTHER ONE ALONG 79W. THESE TWO WAVES ARE EMBEDDED IN THE ITCZ...WHICH IS FURTHER PRODUCING SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHERN BASIN. A BROAD AREA OF LOW PRESSURE/CYCLONIC FLOW IS OVER CENTRAL AMERICA AROUND NICARAGUA AND HONDURAS. THIS SYSTEM IS INTERACTING WITH THE TROPICAL WAVE ALONG 79W TO PRODUCE HEAVY SHOWERS AND THUNDERSTORMS OVER A LARGE PORTION OF THE WESTERN CARIBBEAN SEA. FURTHERMORE...AN UPPER LEVEL LOW EAST OF THE BAHAMAS SUPPORTS A SURFACE TROUGH THAT ENTERS THE N CARIBBEAN THROUGH THE WINDWARD PASSAGE TO NEAR 18N75W PRODUCING HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE N CARIBBEAN. WEATHER CONDITIONS ACROSS THE BASIN WILL CONTINUE THIS PATTERN OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS ARE OFF THE N COAST OF PUERTO RICO AND DOMINICAN REPUBLIC WITHIN 200 NM...DUE TO THE PASSAGE OF A SURFACE TROUGH CURRENTLY ALONG 24N71W 21N73W 19N74W. THIS SYSTEM IS SUPPORTED BY A MID/UPPER LEVEL LOW SPINNING NEAR 25N66W. SCATTERED SHOWERS ARE OVER THE SOUTHERN BAHAMAS E OF 75W...ASSOCIATED WITH THE PASSAGE OF A TROPICAL WAVE OVER THE NW CARIBBEAN. FARTHER EAST ACROSS THE ATLANTIC...SURFACE RIDGING DOMINATES THE BASIN ANCHORED BY A 1025 MB HIGH NEAR 31N55W...AND A 1027 MB HIGH OVER THE AZORES NEAR 38W26N. A DRY SAHARAN AIR LAYER ACCOMPANIED BY DUST COVERS MUCH OF THE TROPICAL ATLC SUPPRESSING CONVECTION IN THIS REGION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA