000 AXNT20 KNHC 151752 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED AUG 15 2012 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1700 UTC. ...SPECIAL FEATURES... A 1013 MB SURFACE LOW IS CENTERED IN THE CENTRAL ATLC NEAR 28N55W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO THE N TO 32N55W. THE SYSTEM HAS BECOME BETTER ORGANIZED FROM 24 HOURS AGO. CURRENTLY SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 27N-32N BETWEEN 53W-57W. THE LOW IS EXPECTED TO MOVE NNW BEFORE TURNING SLIGHTLY EAST. IF THE SYSTEM BECOMES BETTER ORGANIZED IT COULD FORM A TROPICAL DEPRESSION. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 19N24W TO 12N23W MOVING W AT 15-20 KT. THE WAVE LIES IN THE MIDDLE OF A LARGE AREA OF ENHANCED DEEP LAYER MOISTURE. A RECENT SCATTEROMETER PASS INDICATES THAT THERE IS SOME LOW-LEVEL CYCLONIC FLOW AROUND THE NORTHERN EXTENT OF THE WAVE...AND SATELLITE IMAGERY ALSO INDICATES MID-LEVEL TURNING IS ALSO AROUND THE WAVE AXIS. DUE TO A LARGE DRY AIRMASS ASSOCIATED WITH A SAHARAN AIR LAYER...NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ALONG 18N41W TO 10N36W MOVING W AT 20-25 KT. THE WAVE HAS BEEN MOVING QUICKLY AND THE WIND SURGE ASSOCIATED WITH IT IS MAKING IT MORE AND MORE ELONGATED. THIS ELONGATION CAN BE SEEN IN THE MOISTURE FIELD IN TOTAL PRECIPITABLE WATER. THE MOIST AIR NEAR THE NORTHERN EXTENT OF THE WAVE IS OUTRUNNING THE SOUTHERN PORTION AND DRIER AIR IS WRAPPING AROUND THE WEST SIDE. THIS DRY AIR CAN ALSO BE SEEN IN ANALYSIS OF THE SAHARAN AIR LAYER. DUE TO THE DRY AIR...NO DEEP CONVECTION IS ASSOCIATED WITH THE WAVE BESIDES A SMALL AREA OF MODERATE CONVECTION S OF THE AXIS FROM 7N-9N BETWEEN 35W-36W. TROPICAL WAVE EXTENDS FROM 16N64W TO 11N64W MOVING W NEAR 20 KT. THE WAVE HAS LOST MOST OF ITS ENERGY TO THE SURFACE TROUGH/LOW TO THE N...WHICH BROKE OFF OF THE WAVE SEVERAL DAYS AGO. THE WAVE STILL ALIGNS WITH A WEAK SURGE OF MODERATE DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE. TROPICAL WAVE...REMNANTS OF T.D. SEVEN...IS MOVING W AT 15 KT THROUGH THE WESTERN CARIBBEAN AND INTO THE YUCATAN PENINSULA FROM 21N89W TO 15N86W. SATELLITE IMAGERY ALONG WITH SURFACE OBSERVATIONS INDICATE CYCLONIC SURFACE FLOW IS STILL AROUND THE AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS MAINLY E OF THE AXIS FROM 12N-16N BETWEEN 78W-84W...AND FROM 16N-20N BETWEEN 81W-87W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF SENEGAL AT 15N17W TO 10N34W. THE ITCZ BEGINS AT 9N40W TO 6N56W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM EQ-6N BETWEEN 52W-55W. ...DISCUSSION... GULF OF MEXICO... WEAK SURFACE RIDGING COVERS THE MAJORITY OF THE GULF OF MEXICO CENTERED AROUND A 1017 MB HIGH NEAR 27N88W. THE RIDGE IN COMBINATION WITH DRY AIR ALOFT AROUND THE EASTERN SIDE OF AN UPPER LEVEL RIDGE CENTERED OVER CENTRAL MEXICO IS HELPING PROVIDE FAIR CONDITIONS OVER MUCH OF THE AREA. HOWEVER...AN AREA OF SHOWERS/THUNDERSTORMS IS OVER THE FLORIDA PANHANDLE AND S OF THE NORTHERN GULF COAST DUE TO DIFFLUENCE ALOFT AROUND A SHORTWAVE UPPER TROUGH MOVING THROUGH THE SE CONUS. A FEW ISOLATED SHOWERS ARE ALSO EMBEDDED WITHIN THE LIGHT ANTI-CYCLONIC FLOW AROUND THE SURFACE HIGH CENTER. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. MOISTURE FROM A TROPICAL WAVE IN THE WESTERN CARIBBEAN MAY BEGIN TO IMPACT THE SE GULF OR BAY OF CAMPECHE. CARIBBEAN SEA... A TROPICAL WAVE MOVING INTO THE YUCATAN PENINSULA IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS OVER THE WESTERN CARIBBEAN FROM 12N-19N BETWEEN 78W-86W. AS THE WAVE MOVES OVER THE YUCATAN PENINSULA...HEAVY SHOWERS AND FLOODING WILL BE POSSIBLE OVER NORTHERN CENTRAL AMERICA AND THE YUCATAN. THE REMAINDER OF THE BASIN IS EXPERIENCING MOSTLY FAIR WEATHER DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE IN THE W ATLC. A SECOND TROPICAL WAVE IS IN THE EASTERN CARIBBEAN...BUT IT IS VERY WEAK DUE TO LOSING MOST ITS ENERGY TO THE SURFACE TROUGH/LOW IN THE CENTRAL ATLC. IT IS ONLY PRODUCING A FEW SHOWERS OVER THE LESSER ANTILLES. TRADEWIND FLOW OF 15-20 KT IS PRESENT ACROSS THE EASTERN AND CENTRAL CARIBBEAN. EXPECT BOTH WAVES TO CONTINUE WESTWARD WITH LITTLE CHANGE ELSEWHERE. ATLANTIC OCEAN... AN UPPER LEVEL RIDGE COVERS THE W ATLC CENTERED NEAR THE NW BAHAMAS SUPPORTING A WEAK SURFACE RIDGE. HOWEVER...AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS N OF 28N BETWEEN 65W-73W...AND ISOLATED SHOWERS/THUNDERSTORMS N OF 27N BETWEEN 75W-78W. AN UPPER LEVEL RIDGE COVERS THE CENTRAL ATLC CENTERED NEAR 31N51W SUPPORTING A 1024 MB SURFACE HIGH NEAR 32N46W. A SURFACE LOW/TROUGH IS SW OF THE HIGH CENTER CAUSING AN AREA OF SHOWERS/THUNDERSTORMS. THIS SYSTEM MAY DEVELOP INTO A TROPICAL DEPRESSION. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS. THE SURFACE RIDGE IS HELPING PROVIDE FAIR CONDITIONS ACROSS THE REMAINDER OF THE EASTERN ATLC. ALOFT...AN UPPER LEVEL RIDGE DOMINATES THE TROPICAL ATLC WITH A BROAD UPPER TROUGH OVER THE NE ATLC EXTENDING OVER THE AZORES ISLANDS TO NEAR THE CANARY ISLANDS. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW AN AREA OF DUST EXTENDS FROM THE COAST OF AFRICA AROUND BOTH TROPICAL WAVES IN THE ATLC. THE DRY AIR MASS IS LIMITING CONVECTION NEAR THE WAVES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON