000 AXNT20 KNHC 310545 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT WED AUG 31 2011 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...SPECIAL FEATURE... TROPICAL STORM KATIA IS CENTERED NEAR 13.3N 37.5W AS OF 31/0300 UTC...OR ABOUT 885 MI...1425 KM W OF THE SOUTHERNMOST CAPE VERDE ISLANDS MOVING WNW AT 19 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. PLEASE SEE THE LATEST INTERMEDIATE PUBLIC ADVISORY UNDER AWIPS/WMO HEADER MIATCPAT2/WTNT32 KNHC AND THE FULL FORECAST/ ADVISORY UNDER AWIPS/WMO HEADER MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. KATIA IS IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY WARM WATER AND VERY LOW SHEAR. EXPECT GRADUAL INTENSIFICATION OF THIS SYSTEM OVER THE NEXT COUPLE OF DAYS. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 10N-15N BETWEEN 36W-41W. ...TROPICAL WAVES... A TROPICAL WAVE IS OVER THE NW CARIBBEAN FROM 22N85W TO 15N87W MOVING W AT 5-10 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 18N-23N BETWEEN 80W-88W. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH IS ANALYZED FROM THE COAST OF MAURITANIA AT 17N16W TO 13N20W TO S OF THE CAPE VERDE ISLANDS NEAR 13N28W. THE CIRCULATION OF KATIA HAS DISRUPTED THE MONSOON TROUGH TO THE W OF THE CAPE VERDE ISLANDS. A SMALL PORTION OF THE ITCZ EXISTS TO THE W OF KATIA FROM 11N48W TO THE COAST OF VENEZUELA NEAR 11N62W. THE CONVERGENCE ALONG THE ITCZ AXIS IS GENERATING SCATTERED SHOWERS WITHIN 90 NM OF THE AXIS. ...DISCUSSION... GULF OF MEXICO... TROPICAL MOISTURE WITH CONVECTION IS ADVECTING INTO THE SE GULF OF MEXICO AND THE YUCATAN CHANNEL DUE TO A TROPICAL WAVE OVER THE NW CARIBBEAN. ISOLATED MODERATE CONVECTION IS ALSO OVER S FLORIDA AND THE STRAITS OF FLORIDA. ELSEWHERE...A SURFACE TROUGH IS OVER THE BAY OF CAMPECHE FROM 23N94W TO 20N95W. ISOLATED MODERATE CONVECTION IS WITHIN 30 NM OF THE TROUGH AXIS. MOSTLY FAIR WEATHER IS OVER THE NW GULF. IN THE UPPER LEVELS... AN UPPER LEVEL LOW IS CENTERED OVER THE NE GULF NEAR 29N89W. DIFFLUENCE SE OF THE LOW IS ENHANCING SHOWERS OVER FLORIDA. EXPECT TROPICAL MOISTURE TO SPREAD NW OVER THE GULF OVER THE NEXT 24 HOURS WITH CONVECTION. CARIBBEAN SEA... A TROPICAL WAVE IS OVER THE NW CARIBBEAN. SEE ABOVE. A GOOD AMOUNT OF TROPICAL MOISTURE WITH ISOLATED MODERATE CONVECTION IS OVER VENEZUELA...COLOMBIA...THE CENTRAL CARIBBEAN...THE WESTERN CARIBBEAN...AND CENTRAL AMERICA...W OF 70W. THE E CARIBBEAN HAS MOSTLY FAIR WEATHER WITH STRONG SUBSIDENCE ALOFT. 15-25 TRADEWINDS ARE OVER THE CARIBBEAN SEA WITH STRONGEST WINDS ALONG THE COAST OF N COLOMBIA. IN THE UPPER LEVELS...AN UPPER LEVEL LOW IS CENTERED NEAR HAITI AT 18N75W MOVING W. UPPER LEVEL DIFFLUENCE W OF THE LOW IS ENHANCING THE CONVECTION OVER THE W CARIBBEAN. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... THE MAIN FEATURE OF INTEREST IS TROPICAL STORM KATIA IN THE EASTERN ATLANTIC. SEE ABOVE. ELSEWHERE TWO PROMINENT SURFACE TROUGHS ARE EVIDENT OVER THE CENTRAL ATLANTIC. ONE EXTENDS FROM 28N43W TO 23N45W. SCATTERED SHOWERS ARE WITHIN 60 NM OF THE TROUGH AXIS. A SECOND TROUGH IS FROM 31N53W TO 25N53W. SCATTERED SHOWERS ARE WITHIN 90 NM OF THE TROUGH AXIS. A 1026 MB HIGH IS OVER THE CENTRAL ATLANTIC NEAR 38N41W. THE TRADEWINDS ARE QUITE WEAK ACROSS THE TROPICAL NORTH ATLANTIC. THIS SHOULD CONTINUE FOR THE NEXT DAY OR TWO. ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORMOSA