000 AXNT20 KNHC 201806 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE JUL 20 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 1645 UTC... ...SPECIAL FEATURES... AN AREA OF DISTURBED WEATHER REMAINS ACROSS PUERTO RICO AND HISPANIOLA ASSOCIATED WITH A TROPICAL WAVE THAT HAS NOW MOVED W OVER HAITI. SEE THE TROPICAL WAVE SECTION FOR MORE DETAILS ABOUT THE WAVE. A SURFACE TROUGH IS LEFT IN ITS WAKE EXTENDING FROM 23N64W TO 16N68W ACROSS THE MONA PASSAGE. SURFACE CONVERGENCE NEAR THE TROUGH ALONG WITH DIFFLUENCE ALOFT BETWEEN AN UPPER LEVEL LOW NEAR 27N68W AND UPPER LEVEL RIDGING CENTERED NEAR 19N61W ARE ENHANCING SCATTERED MODERATE/STRONG CONVECTION FROM 16N-23N BETWEEN 64W-67W...AND FROM 16N-21N BETWEEN 67W-71W. ISOLATED MODERATE/STRONG CONVECTION IS ALSO FARTHER E FROM 18N-20N BETWEEN 61W-63W. ENVIRONMENTAL CONDITIONS ARE FAVORABLE FOR DEVELOPMENT AND THIS SYSTEM HAS A HIGH CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT 48 HRS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 33W/34W S OF 21N MOVING W NEAR 20 KT. SATELLITE IMAGERY INDICATES CLEAR LOW-LEVEL CYCLONIC FLOW ABOUT THE WAVE AXIS WITH AN INVERTED-V STRUCTURE. A SURGE OF DEEP LAYER MOISTURE IS ALSO PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS SW OF THE WAVE AXIS FROM 2N-7N BETWEEN 36W-40W. TROPICAL WAVE IS ACROSS HAITI TO NW VENEZUELA ALONG 71W-72W S OF 23N MOVING W NEAR 15 KT. LOW-LEVEL CYCLONIC FLOW IS IN THE VICINITY OF THE WAVE AXIS CONFIRMED BY A WINDSAT SCATTEROMETER PASS. AS THIS WAVE PASSED OVER PUERTO RICO AND THE DOMINICAN REPUBLIC OVER THE PAST DAY IT SPAWNED UP SIGNIFICANT CONVECTION AS IT INTERACTED WITH AN UPPER LEVEL LOW. THIS CONVECTION REMAINS OVER THOSE AREAS AND IS NOW ASSOCIATED WITH A SURFACE TROUGH. SEE SPECIAL FEATURES ABOVE. THE WAVE IS NOW ENHANCING ISOLATED MODERATE/STRONG CONVECTION WITHIN 90 NM EITHER SIDE OF THE AXIS FROM 17N-21N. TROPICAL WAVE IS IN THE ERN GULF AND FAR W CARIBBEAN ALONG 85W S OF 25N TO CENTRAL NICARAGUA MOVING W NEAR 10 KT. WAVE LIES EMBEDDED WITHIN A LARGE AREA OF DEEP LAYER MOISTURE THAT IS MOVING ACROSS THE W CARIBBEAN AND E GULF. MID-LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS INDICATED BY VISIBLE SATELLITE IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ACROSS THE W CARIBBEAN FROM 18N-22N BETWEEN 76W-85W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 16N-19N BETWEEN 85W-87W...AND FROM 22N-27N BETWEEN 83W-89W. TROPICAL WAVE IS ACROSS THE WRN GULF OF MEXICO EXTENDING FROM 26N92W 22N94W 15N93W MOVING W NEAR 12 KT. WAVE LIES EMBEDDED WITHIN A MAXIMUM IN DEEP LAYER MOISTURE THAT COVERS THE WRN GULF EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 18N-22N BETWEEN 93W-96W ACROSS THE BAY OF CAMPECHE...AND FROM 24N-27N BETWEEN 92W-95W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N13W 8N26W 10N35W 10N50W 13N60W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION HAS MOVED OFF THE W AFRICAN COAST FROM 7N-14N BETWEEN 13W-25W. SIMILAR ACTIVITY IS WITHIN 90 NM EITHER SIDE OF THE AXIS FROM 50W-60W. ...DISCUSSION... GULF OF MEXICO... A PAIR OF TROPICAL WAVES IN THE GULF OF MEXICO REMAIN THE MAIN FEATURES ACROSS THE BASIN BRINGING SIGNIFICANT MOISTURE AND ENHANCING SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE AREA. SEE TROPICAL WAVE SECTION FOR MORE DETAILS. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO ALONG THE NW GULF COAST N OF 29N BETWEEN 88W-92W AFFECTING COASTAL MISSISSIPPI AND ERN LOUISIANA. THIS ACTIVITY IS ASSOCIATED WITH AN AREA OF DIFFLUENCE ALOFT. ELSEWHERE ALOFT...AN UPPER LEVEL LOW IS N OF THE BAY OF CAMPECHE NEAR 23N93W ENHANCING CONVECTION NEAR THE TROPICAL WAVE IN THE ERN GULF. EXPECT SHOWERS/THUNDERSTORMS TO CONTINUE ACROSS MUCH OF THE BASIN AS THE TROPICAL WAVES MOVE WWD. CARIBBEAN SEA... SIGNIFICANT MOISTURE AND UNSTABLE CONDITIONS ARE ACROSS MUCH OF THE CARIBBEAN ASSOCIATED WITH A SERIES OF TROPICAL WAVES. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. A SURFACE TROUGH IS ALSO LOCATED ACROSS THE MONA PASSAGE ENHANCING NUMEROUS SHOWERS/SCATTERED THUNDERSTORMS ACROSS THE NE CARIBBEAN ISLANDS. THIS AREA OF DISTURBED WEATHER HAS THE POTENTIAL TO DEVELOP INTO A TROPICAL CYCLONE OVER THE NEXT 48 HRS. SEE SPECIAL FEATURES ABOVE. WATER VAPOR IMAGERY INDICATES AN AREA OF DRY AIR OVER THE S CENTRAL AND SE CARIBBEAN WHICH IS KEEPING CONDITIONS FAIR ACROSS THESE AREAS. ALOFT...UPPER LEVEL RIDGING COVERS THE WRN CARIBBEAN CENTERED OVER WRN CUBA. ELY FLOW ALOFT COVERS THE REMAINDER OF THE ERN AND CENTRAL PORTIONS OF THE BASIN. EXPECT CONTINUED SHOWER ACTIVITY ACROSS MUCH OF THE N CENTRAL AND WRN CARIBBEAN AS THE TROPICAL WAVES MOVE WWD. THE NE CARIBBEAN IS ALSO EXPECTED TO CONTINUE TO RECEIVE SIGNIFICANT RAINFALL AS THE AREA OF DISTURBED WEATHER MENTIONED IN THE SPECIAL FEATURES MOVES WNW. ATLANTIC OCEAN... MODERATE DRY AIR ALOFT COMBINED WITH SURFACE RIDGING IS MAINTAINING FAIR WEATHER ACROSS THE FAR W ATLC. AN AREA OF DISTURBED WEATHER ACROSS THE NE CARIBBEAN EXTENDS INTO THE ATLC ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM NEAR 23N64W ACROSS THE MONA PASSAGE INTO THE CARIBBEAN. CONVECTION NEAR THE TROUGH IS ENHANCED BY DIFFLUENCE ALOFT BETWEEN AN UPPER LEVEL LOW NEAR 27N68W AND UPPER LEVEL RIDGING CENTERED NEAR 19N61W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON THIS AREA OF DISTURBED WEATHER. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING AROUND A 1027 MB AND A 1030 MB HIGH NEAR 36N47W AND 35N31W RESPECTIVELY. A WEAK SURFACE TROUGH IS EMBEDDED WITHIN THE RIDGE ALONG 32N47W TO 29N51W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 90 NM NW OF THE AXIS. ALOFT...ANOTHER UPPER LEVEL LOW IS CENTERED NEAR 30N47W WITH UPPER LEVEL RIDGING COVERING THE ENTIRE E ATLC CENTERED NEAR 26N35W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON/RAMOS