000 AXNT20 KNHC 050004 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU OCT 04 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 VALID THROUGH 2315 UTC. ...SPECIAL FEATURE... THE CENTER OF TROPICAL STORM OSCAR AT 04/2100 UTC IS NEAR 21.3N 41.0W ABOUT 1015 NM WNW OF THE CAPE VERDE ISLANDS MOVING NE AT 11 KNOTS. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1000 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 40 KNOTS WITH GUSTS TO 50 KNOTS. PUBLIC ADVISORIES ON TROPICAL STORM OSCAR ARE ISSUED UNDER WMO HEADER WTNT35 KNHC AND UNDER AWIPS HEADER MIATCPAT5. FORECAST/ADVISORIES ARE ISSUED UNDER WMO HEADER WTNT25 KNHC AND UNDER AWIPS HEADER MIATCMAT5. OSCAR IS EXPERIENCING STRONG WESTERLY SHEAR...WHICH IS MAINTAINING DEEP CONVECTION WELL E OF THE CENTER. NUMEROUS STRONG CONVECTION IS FROM 19N-22N BETWEEN 35W-39W. SCATTERED MODERATE CONVECTION 17N-23N BETWEEN 34W-40W OUTSIDE OF THE NUMEROUS STRONG CONVECTION. ...TROPICAL WAVES... AN EASTERN CARIBBEAN TROPICAL WAVE EXTENDS FROM 18N65W TO 10N67W MOVING WNW AT 15 KT. AN ENHANCED AREA OF MOISTURE IS NOTED ON SSMI TOTAL PRECIPITABLE WATER IMAGERY ON THE EASTERN SIDE OF THE WAVE AXIS. LITTLE TO NO DEEP CONVECTION IS PRESENT WITH THIS WAVE...HOWEVER...SCATTERED SHOWERS ARE WITHIN 120 NM OF THE WAVE AXIS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL AT 14N17W TO 12N22W. THE ITCZ CONTINUES FROM 12N22W TO 6N38W TO 12N55W TO THE COAST OF VENEZUELA AT 10N63W. SCATTERED MODERATE CONVECTION IS OFF THE COAST OF WEST AFRICA SOUTH OF THE MONSOON TROUGH AND ITCZ FROM 5N-10N BETWEEN 20W-30W. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM OF THE ITCZ BETWEEN 32W-42W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N OF THE ITCZ BETWEEN 53W-57W. ...DISCUSSION... THE GULF OF MEXICO... AS OF 2100 UTC...A SMALL 1013 MB LOW HAD DEVELOPED NEAR 19N93W AT THE SOUTHERN END OF A SURFACE TROUGH. THE LOW WAS IDENTIFIED BY A COMBINATION OF AN ASCAT PASS AT 1622 UTC...SURFACE OBSERVATIONS FROM MEXICO...AND VISIBLE SATELLITE IMAGERY. THE TROUGH EXTENDS FROM THE LOW NORTH-NORTHEASTWARD TO THE BIG BEND AREA OF FLORIDA NEAR 30N84W. THE TROUGH IS HELPING TO INDUCE THE DEEP CONVECTION SEEN OVER THE WESTERN CARIBBEAN...CENTRAL AMERICA...CUBA...AND THE FLORIDA PENINSULA. A SHARP UPPER LEVEL TROUGH IN THE WESTERN GULF OF MEXICO IS ALSO PROVIDING SOME DYNAMICAL SUPPORT FOR THE SURFACE TROUGH AND THE DEEP CONVECTION. ON FRIDAY...TROUGHING MAY BECOME RESTRICTED TO THE SOUTHERN HALF OF THE GULF AND MOVE WESTWARD. EXPECT SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IN THE SOUTHWESTERN GULF OF MEXICO AND NORTHERN CENTRAL AMERICA IN THE NEXT DAY OR SO. SURFACE WINDS ARE GENERALLY WEAK THROUGHOUT MOST OF THE GULF...LESS THAN 20 KT. THE CARIBBEAN SEA... A TROPICAL WAVE IS IN THE E CARIBBEAN AS NOTED ABOVE. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS OCCURRING IN THE W CARIBBEAN N OF 12N W OF 82. THIS IS IN ASSOCIATION WITH THE AFOREMENTIONED TROUGH OVER THE GULF OF MEXICO AND AN UPPER LOW IN THE CARIBBEAN NEAR 19N80W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS ALSO SEEN WITHIN 180 NM OF THE PANAMA AND COSTA RICA COASTS. THIS CONVECTION IS RELATED TO THE MONSOON TROUGH EXTENDING E FROM THE NORTHEASTERN PACIFIC. THE CONVECTION WILL GRADUALLY SHIFT WESTWARD AND CONTINUE TO IMPACT WESTERNMOST CARIBBEAN AND CENTRAL AMERICA ON FRIDAY. SURFACE E-NE TRADEWINDS REMAIN LIGHT...PRIMARILY BELOW 20 KT. THE ATLANTIC OCEAN... A 1023 MB HIGH IS OVER THE W ATLANTIC AT 32N74W WHICH IS INDUCING RELATIVELY FAIR WEATHER AND WINDS LESS THAN 20 KT W OF 60W. A SECOND HIGH OF 1016 MB IS IN THE E ATLANTIC NEAR 26N21W AND WINDS ARE LESS THAN 20 KT E OF TROPICAL STORM OSCAR. AN UPPER LOW CENTERED NEAR 22N58W IS KICKING OFF SCATTERED SHOWERS WITHIN 180 NM OF THE CENTER. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ LANDSEA