000 AXNT20 KNHC 192349 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU AUG 19 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 2315 UTC. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 12N33W TO 17N37W TO 24N38W MOVING W AT 15-20 KT. SATELLITE PRESENTATION INDICATES LOW-LEVEL CYCLONIC FLOW ALONG THE WAVE AXIS AND THIS WAS ALSO NOTED ON AN EARLIER MORNING ASCAT PASS AROUND 19/1234 UTC OVER THE NORTHERN PORTION OF THE WAVE. AN AREA OF MAXIMUM DEEP LAYER MOISTURE IS OBSERVED ON THE TPW IMAGERY FROM 06N-27N E OF 42W...HOWEVER MUCH OF THIS MOISTURE IS POSITIONED BENEATH A STABLE SAHARAN AIR LAYER THAT COVERS MUCH OF THE ATLC E OF 50W. NO SIGNIFICANT DEEP ORGANIZED CONVECTION ACCOMPANIES THE WAVE THIS EVENING. TROPICAL WAVE EXTENDS FROM 10N83W TO 17N85W TO 24N85W MOVING W AT 15-20 KT. LOW-LEVEL CYCLONIC FLOW IS NOTED ON SATELLITE IMAGERY ACROSS THE WESTERN CARIBBEAN SEA AND CENTRAL AMERICA THAT ALSO COINCIDES WITH AN AREA OF ENHANCED MOISTURE EVIDENT ON TPW IMAGERY FROM 09N-22N BETWEEN 78W-90W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 11N-24N BETWEEN 78W-91W. WATER VAPOR IMAGERY ALSO INDICATES AN UPPER LEVEL TROUGH IS LOCATED ACROSS THE YUCATAN PENINSULA EXTENDING SOUTHWARD TO SW GUATEMALA THAT IS ENHANCING ONGOING CONVECTION WEST OF THE WAVE. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 13N38W 11N47W 13N55W. EAST OF THE TROPICAL WAVE BETWEEN 33W-38W...A MONSOONAL TROUGH IS ANALYZED AS A SURFACE TROUGH IN PLACE OF THE ITCZ FROM EASTERN MAURITANIA NEAR 19N06W TO THE W AFRICA COAST NEAR 14N17W AND INTO THE E ATLC TO 13N27W. THIS MONSOONAL TROUGH HAS PERSISTED OVER THE PAST FEW DAYS WITH WESTERLY LOW-LEVEL FLOW OBSERVED S OF 13N. AN EARLIER MORNING ASCAT PASS AROUND 19/1054 UTC INDICATED THE BEGINNINGS OF A BROAD LOW-LEVEL CIRCULATION SW OF THE CAPE VERDE ISLANDS NEAR 13N26W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION REMAINS UNORGANIZED AND FOCUSED IN THE VICINITY OF THIS MONSOONAL TROUGH FROM 08N-14N BETWEEN 16W-30W. ELSEWHERE... SCATTERED MODERATE CONVECTION IS S OF THE ITCZ AXIS FROM 04N-11N BETWEEN 30W-39W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER CENTRAL TEXAS NEAR 30N100W AND IS PROVIDING MUCH OF THE GULF WITH NE UPPER LEVEL FLOW FROM THE FLORIDA PENINSULA TO OVER MUCH OF MEXICO N OF 20N. THIS UPPER LEVEL RIDGE SUPPORTS A 1018 MB HIGH CENTERED OVER THE EASTERN GULF NEAR 27N85W. NORTH OF THE RIDGE AXIS WHICH EXTENDS FROM THE CENTRAL FLORIDA PENINSULA THROUGH 25N90W TO TAMPICO MEXICO...LOW-LEVEL WARM AIR ADVECTION... CONVERGENT SW WINDS...AND ATMOSPHERIC INSTABILITY ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE NW GULF N OF 27N W OF 92W. ELSEWHERE...NORTH OF A LINE FROM GAINESVILLE FLORIDA TO 27N92W ISOLATED SHOWERS ARE OCCURRING...BUT MOST OF THE ONGOING ACTIVITY REMAINS OVER INTERIOR PORTIONS OF THE NE GULF COAST STATES. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A TROPICAL WAVE IMPACTING THE SE GULF AND YUCATAN CHANNEL ALONG 86W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING S OF 24N BETWEEN 84W-92W...INCLUDING THE YUCATAN PENINSULA. SOME OF THE LOW-LEVEL MOISTURE DRAWN NORTHEAST FROM THE TROPICAL WAVE...AND AFTERNOON SEABREEZE DYNAMICS ARE GENERATING SCATTERED SHOWERS AND TSTMS OVER THE SOUTHERN FLORIDA PENINSULA THIS EVENING FROM 24N-28N BETWEEN 80W-84W. CARIBBEAN SEA... A TROPICAL WAVE EXTENDS FROM THE YUCATAN CHANNEL TO EASTERN HONDURAS AND INTO THE SW CARIBBEAN OFF THE COAST OF COSTA RICA NEAR 10N83W. SCATTERED SHOWERS AND TSTMS COVER MUCH OF THE WESTERN CARIBBEAN AND CENTRAL AMERICA W OF 78W. AN UPPER LEVEL TROUGH IS ACROSS THE YUCATAN PENINSULA PROVIDING DIFFLUENCE ALOFT NEAR THE WAVE AXIS FURTHER SUPPORTING CONVECTION. FARTHER EAST....THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF AN UPPER LEVEL LOW CENTERED OVER ANGUILLA NEAR 18N62W. MIDDLE TO UPPER LEVEL MOISTURE ADVECTING SW FROM THE TROPICAL NORTH ATLC IS PROVIDING FOR WIDELY SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE NE CARIBBEAN N OF 16N E OF 68W...INCLUDING INTERIOR PORTIONS OF PUERTO RICO AND HISPANIOLA THIS EVENING. ELSEWHERE E OF 78W...OVERALL DRY UPPER LEVEL AIR IS ASSOCIATED WITH THE UPPER LEVEL LOW S OF 16N...HOWEVER...ISOLATED SHOWERS ARE OBSERVED OVER THE WINDWARD ISLANDS AND SE CARIBBEAN THIS EVENING. ATLANTIC OCEAN... SURFACE RIDGING COVERS THE W ATLC AROUND A 1018 MB HIGH CENTERED NEAR 27N71W PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE AREA SUPPORTED BY AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 32N70W. DAYTIME INSTABILITY IS GENERATING ISOLATED SHOWERS AND TSTMS OVER THE NW BAHAMAS FROM 23N-27N BETWEEN 76W-80W. FARTHER EAST...SCATTERED SHOWERS AND ISOLATED TSTMS ARE FOCUSED NEAR A SURFACE TROUGH ANALYZED FROM 19N-27N ALONG 61W LOCATED IN THE VICINITY OF AN UPPER LEVEL LOW CENTERED NEAR 18N62W. THE CONVECTIVE ACTIVITY IS OCCURRING FROM 16N-28N BETWEEN 58W-68W. ANOTHER SURFACE TROUGH E OF THE LESSER ANTILLES EXTENDS FROM 12N57W TO 23N55W AND IS A WESTWARD PROPAGATING PIECE OF ENERGY THAT ORIGINATED DAYS AGO FROM A MIDDLE TO UPPER LEVEL TROUGH OVER THE NE ATLC. ISOLATED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE SURFACE TROUGH. ELSEWHERE ACROSS THE REMAINDER OF THE CENTRAL AND EASTERN ATLC...SURFACE RIDING DOMINATES N OF 27N ANCHORED BY A 1019 MB HIGH CENTERED NEAR 32N36W MAINTAINING GENERALLY FAIR WEATHER. ALOFT...AN UPPER LEVEL ANTICYCLONE COVERS THE EASTERN ATLC CENTERED NEAR 23N41W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN