000 AXNT20 KNHC 172344 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU MAY 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A STRONG TROPICAL WAVE IS CURRENTLY MOVING OFF THE AFRICAN COAST FROM 16N15W TO 6N15W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS CURRENTLY OFFSHORE FROM 6N-8N BETWEEN 13W-16W...AND OVER LAND FROM 9N-13N BETWEEN 11W-14W. MODEL GUIDANCE CONTINUES TO INDICATE THAT THE WAVE WILL REMAIN WELL DEFINED FOR THE NEXT SEVERAL DAYS AS IT MOVES OVER THE ATLC WATERS. A TROPICAL WAVE IS E OF THE LESSER ANTILLES ALONG 16N56W TO 6N58W MOVING W NEAR 15 KTS. THE WAVE LIES IN AN AREA OF ENHANCED MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS W OF THE AXIS FROM 13N-16N BETWEEN 57W-61W...AND E OF THE AXIS FROM 5N-12N BETWEEN 52W-59W. THE WAVE ALSO LIES E OF AN UPPER LEVEL TROUGH PLACING UNDER THE AREA OF MAXIMUM DIFFLUENCE. THIS COMBINATION IS HELPING ENHANCE THE CONVECTION NEAR THE WAVE. SOME OF THE WAVE ENERGY WILL LIKELY GET DRAWN TOWARDS THE NE BY THE UPPER TROUGH AS THE TWO FEATURES INTERACT...WHICH WILL SHORTEN THE AMPLITUDE OF THE WAVE AS IT MOVES INTO THE ERN CARIBBEAN. MODEL GUIDANCE INDICATES THAT IT MAY RE-AMPLIFY IN THE WRN CARIBBEAN AS IT INTERACTS WITH ANOTHER UPPER TROUGH. ...THE ITCZ/THE MONSOON TROUGH... THE ITCZ BEGINS ON THE W OF SIDE OF THE TROPICAL WAVE ALONG THE AFRICAN COAST AND EXTENDS ALONG 6N18W 4N35W 4N51W. SCATTERED MODERATE/STRONG CONVECTION IS FROM 6N-8N BETWEEN 18W-21W. SCATTERED MODERATE CONVECTION IS FROM 3N-6N BETWEEN 26W-32W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LEVEL LOW IS CURRENTLY OVER GEORGIA NEAR 34N84W WITH UPPER TROUGH AXIS EXTENDING S ALONG 83W. THIS PATTERN IS PROVIDING MOIST SWLY FLOW ALOFT ACROSS MUCH OF THE FAR ERN GULF OF MEXICO. AS OF 2100 UTC...A SERIES OF SURFACE TROUGHS ARE ANALYZED ACROSS THIS AREA. THE FIRST IS ALONG THE FLORIDA/GEORGIA BORDER EXTENDING FROM A 1010 MB SURFACE LOW AT 31N82W TO 31N86W. SCATTERED SHOWERS/THUNDERSTORMS ARE WITHIN 60 NM S OF THE AXIS. THE SECOND TROUGH EXTENDS FROM THE W ATLC AT 31N79W TO CENTRAL FLORIDA NEAR 27N81W. PATCHES OF STRONG SHOWERS/THUNDERSTORMS DOT MUCH OF THE FLORIDA PENINSULA MOSTLY CONCENTRATED ON THE E COAST. A THIRD SURFACE TROUGH EXTENDS FROM 23N87W AND ACROSS THE ERN YUCATAN PENINSULA TO NRN HONDURAS. SCATTERED SHOWERS/THUNDERSTORMS ARE E OF THE AXIS EXTENDING ACROSS THE FLORIDA STRAITS AND CUBA. DRY AIR ALOFT AND WEAK SURFACE RIDGING AROUND A 1017 MB HIGH NEAR 28N97W ARE KEEPING THE REMAINDER OF THE GULF OF MEXICO UNDER MOSTLY FAIR CONDITIONS WITH LIGHT WINDS AND CLEAR SKIES. MOIST CONDITIONS ARE EXPECTED TO REMAIN OVER THE ERN GULF FOR THE NEXT 24 HOURS. THE CARIBBEAN SEA... MOIST CONDITIONS COVER MUCH OF THE YUCATAN PENINSULA...NRN CENTRAL AMERICA...AND THE NW CARIBBEAN ASSOCIATED WITH MOIST SWLY FLOW ALOFT AROUND AN UPPER LEVEL RIDGE EXTENDING FROM THE ERN BAHAMAS TO NICARAGUA ALONG WITH A SURFACE TROUGH ALONG THE YUCATAN PENINSULA COAST FROM 23N87W TO 16N87W. STRONG SHOWERS/THUNDERSTORMS ARE OVER SRN GUATEMALA....EL SALVADOR...SRN HONDURAS AND PORTIONS OF NICARAGUA...COSTA RICA...AND PANAMA. WEAKER ACTIVITY IS NEAR THE SURFACE TROUGH AXIS AS WELL AS OVER CUBA AND HISPANIOLA. OVERCAST SKIES AND POSSIBLE SHOWERS ARE OVER THE NW CARIBBEAN WATERS. DRY AIR ALOFT COVERS THE CENTRAL AND ERN CARIBBEAN BETWEEN THE UPPER RIDGE AND AN UPPER LEVEL TROUGH JUST E OF THE LESSER ANTILLES. TRADEWIND FLOW OF 15-20 KTS IS PRESENT ACROSS MUCH OF THE AREA. THE UPPER TROUGH E OF THE LESSER ANTILLES IS PRODUCING SHOWERS/THUNDERSTORMS E OF THE ISLANDS ALSO ENHANCED BY A TROPICAL WAVE. SOME OF THIS ACTIVITY COULD IMPACT THE ISLANDS. SHOWERS/THUNDERSTORMS WILL REMAIN OVER THIS AREA AND SPREAD WWD AS THE WAVE MOVES W. THE ATLANTIC OCEAN... AN UPPER LEVEL LOW OVER GEORGIA IS HELPING PRODUCE SHOWERS/THUNDERSTORMS ACROSS THE SE CONUS. UPPER LEVEL DIFFLUENCE BETWEEN THIS UPPER TROUGH/LOW AND AN UPPER LEVEL RIDGE EXTENDING FROM THE MONA PASSAGE TO 41N55W IS HELPING SUPPORT SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS W OF 67W. THE UPPER RIDGE SUPPORTS A SURFACE RIDGE ANCHORED BY A 1034 MB HIGH NEAR 46N40W...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER THE W ATLC AND THE CENTRAL ATLC. HOWEVER...AN UPPER LEVEL TROUGH ALONG 33N43W TO E OF THE LESSER ANTILLES NEAR 11N60W IS INTERACTING WITH A TROPICAL WAVE AND HELPING PRODUCE SHOWERS/THUNDERSTORMS E OF THE LESSER ANTILLES W OF 51W. THE REMAINDER OF THE TROPICAL ATLC IS DOMINATED BY AN UPPER LEVEL RIDGE CENTERED NEAR 12N31W WHICH IS HELPING PROVIDE MOSTLY FAIR CONDITIONS. THE LAST VISIBLE SATELLITE IMAGES OF THE DAY ALONG WITH GOES-R ENHANCEMENTS INDICATE THAT A LARGE AREA OF DUST EXTENDS FROM THE COAST OF AFRICA TO NEAR 40W. THIS DUST IS HELPING INHIBIT CONVECTION NEAR THE ITCZ REGION. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON