000 AXNT20 KNHC 060535 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT TUE OCT 06 2009 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0500 UTC. ...SPECIAL FEATURES... AS OF 06/0300 UTC...TROPICAL STORM GRACE HAS BEEN ABSORBED BY A FRONTAL SYSTEM. THE REMNANTS OF GRACE ARE CENTERED NEAR 49.7N 13.4W OR ABOUT 180 NM SW OF CORK IRELAND MOVING NNE NEAR 23 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 986 MB. MAXIMUM SUSTAINED WINDS HAVE DECREASED TO 45 KT WITH GUSTS TO 55 KT. PLEASE READ THE NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/ WTNT24 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. THE 06/0300 ADVISORY IS THE LAST ADVISORY ISSUED BY THE NATIONAL HURRICANE CENTER. FURTHER UPDATES CAN BE FOUND IN HIGH SEAS FORECASTS ISSUED BY THE UNITED KINGDOM METEOROLOGICAL OFFICE UNDER WMO HEADER WONT54 EGRR. AN ACTIVE TROPICAL WAVE IS ALONG 47W/48W S OF 18N MOVING WNW NEAR 13 KT. SATELLITE IMAGERY INDICATES A 1010 MB SURFACE LOW CIRCULATION ALONG THE WAVE AXIS NEAR 14N. THE WAVE COINCIDES WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. A 0109 UTC ASCAT SCATTEROMETER PASS INDICATES GOOD LOW-LEVEL CYCLONIC FLOW AROUND THE WAVE AXIS...AND ALSO INDICATES SOME 30 KT WINDS TO THE NE OF THE LOW CENTER. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 14N-21N BETWEEN 43W-50W. THERE IS A MEDIUM CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HRS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 60W S OF 14N MOVING W NEAR 10 KT. THE WAVE REMAINS VERY LOW AMPLITUDE. HOWEVER...A 0104 UTC ASCAT SCATTEROMETER PASS INDICATES SOME LOW-LEVEL CYCLONIC FLOW NEAR THE WAVE AXIS. ISOLATED MODERATE/STRONG CONVECTION IS FROM 7N-14N BETWEEN 58W-60W. TROPICAL WAVE IS ALONG 85W S OF 16N MOVING W NEAR 12 KT. THE WAVE LIES WITHIN A BROAD AREA OF DEEP LAYER MOISTURE OBSERVED IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 11N-13N BETWEEN 81W-87W OVER PORTIONS OF NICARAGUA AND COSTA RICA. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N13W 5N29W 13N46W 10N54W 12N59W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALONG THE AFRICA COAST FROM 6N-8N BETWEEN 11W-14W...AND FROM 11N-13N BETWEEN 11W-14W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 6N-9N BETWEEN 33W-40W. ...DISCUSSION... THE GULF OF MEXICO... A STATIONARY FRONT EXTENDS JUST N OF THE GULF OF MEXICO ALONG THE COASTAL STATES FROM A 1010 MB SURFACE LOW OVER GEORGIA NEAR 32N83W CONTINUING ALONG 31N88W 30N94W. THE UPPER LEVEL TROUGH SUPPORTING THE FRONT HAS SHIFTED TO THE E DRAWING MOST OF THE ASSOCIATED SHOWERS/THUNDERSTORMS TO THE E AS WELL. A FEW ISOLATED SHOWERS REMAIN N OF 26N E OF 88W. SHOWERS/THUNDERSTORMS HAVE ALSO POPPED UP OVER WRN CUBA AND THE ADJACENT COASTAL WATERS. THE REMAINDER OF THE GULF IS CALM AND CLEAR AS A SURFACE RIDGE BUILDS E-W ALONG 26N. AN UPPER LEVEL RIDGE COVERS THE BASIN CENTERED OVER MEXICO NEAR 21N104W WITH AXIS TO CENTRAL FLORIDA NEAR 27N81W CONTINUING INTO THE W ATLC. DRY AIR AND SUBSIDENCE ALOFT ARE SUPPORTING THE FAIR WEATHER ACROSS THE WRN PORTION OF THE BASIN. ANTI-CYCLONIC SURFACE FLOW IS AROUND THE SURFACE RIDGE WITH WINDS REACHING UP TO 15 KT. EXPECT THE SURFACE RIDGE TO PERSIST FOR THE NEXT FEW DAYS. THE CARIBBEAN SEA... AN UPPER LEVEL RIDGE EXTENDING FROM THE GULF OF MEXICO COVERS THE NW CARIBBEAN BRINGING FAIR WEATHER TO MOST OF THE NW PORTION OF THE BASIN...EXCEPT FOR A FEW SHOWERS/THUNDERSTORMS THAT HAVE POPPED OVER PORTIONS OF CUBA N OF 21N BETWEEN 80W-85W. A TROPICAL WAVE ALONG 85W S OF 16N IS ALSO GENERATING A FEW ISOLATED SHOWERS FROM 16N-18N BETWEEN 82W-86W. STRONGER CONVECTION ASSOCIATED WITH THE WAVE IS FARTHER S OVER PORTIONS OF NICARAGUA AND COAST RICA. SEE ABOVE. AN UPPER LEVEL TROUGH COVERS THE REMAINDER OF THE BASIN EXTENDING FROM THE ATLC ACROSS HISPANIOLA TO THE SW CORNER OF THE BASIN NEAR 12N81W. MOIST SWLY FLOW ALOFT AROUND THE UPPER TROUGH IS SUPPORTING CLOUDINESS AND ISOLATED SHOWERS S OF 16N BETWEEN 73W-82W. A SURFACE TROUGH EXTENDS FROM 15N69W TO 19N69W ACROSS ERN HISPANIOLA. SURFACE CONVERGENCE NEAR THE TROUGH IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 15N-18N BETWEEN 68W-71W. A FEW ISOLATED SHOWERS ARE ALSO ACROSS THE FAR SE CARIBBEAN AND WINDWARD ISLANDS IN ASSOCIATION WITH A TROPICAL WAVE ALONG 60W. MODERATE TO FRESH TRADEWINDS ARE ACROSS MUCH OF THE BASIN WITH STRONGER WINDS IN THE SW AND ERN CARIBBEAN. EXPECT THE TROPICAL WAVE ALONG 60W TO ENTER THE E CARIBBEAN BY LATER THIS MORNING. THE ATLANTIC OCEAN... SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE WRN ATLC WITHIN 300 NM NW OF A LINE FROM S FLORIDA NEAR 25N80W TO 31N62W. THIS ACTIVITY IS SUPPORTED BY DIFFLUENT FLOW ALOFT BETWEEN AN UPPER LEVEL RIDGE EXTENDING FROM THE GULF OF MEXICO ACROSS CENTRAL FLORIDA TO NEAR 31N60W...AN UPPER LEVEL TROUGH N OF 31N BETWEEN 60W-80W...AND A SECOND UPPER LEVEL TROUGH TO THE E WITH AXIS ALONG 32N45W TO HISPANIOLA NEAR 18N70W. SOME OF THE SHOWER ACTIVITY MAY ALSO BE ATTRIBUTED TO A SURFACE TROUGH EXTENDING FROM THE N INTO THE DISCUSSION AREA NEAR 32N63W TO 26N70W. A SERIES OF SURFACE HIGHS DOMINATE THE REMAINDER OF THE ATLC. A 1018 MB HIGH IS NEAR 26N64W. A 1019 MB HIGH IS NEAR 28N48W. A 1020 MB HIGH IS NEAR 31N44W. A FINAL 1019 MB HIGH IS NEAR 25N35W. IN THE UPPER LEVELS...AN UPPER LEVEL RIDGE COVERS THE BASIN S OF 23N W OF 57W CENTERED NEAR 14N30W. UPPER DIFFLUENT FLOW ALONG THE W SIDE OF THE RIDGE IS ENHANCING CONVECTION NEAR THE TROPICAL WAVES ALONG 47W/48W AND 60W. $$ WALTON