000 AXNT20 KNHC 011140 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT OCT 01 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURES... MAJOR HURRICANE OPHELIA IS CENTERED NEAR 28.6N 63.0W AT 01/1200 UTC OR ABOUT 240 NM SSE OF BERMUDA MOVING N AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 952 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 130 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 26N-31N BETWEEN 59W-65W. OPHELIA IS FORECAST TO CONTINUE MOVING NORTHWARD FOR THE NEXT 12 HOURS OR SO...AND THEN GRADUALLY TURN TOWARD THE NORTHEAST AND ACCELERATE UNDER THE INFLUENCE OF SOUTHWESTERLY FLOW AHEAD OF THE UPPER TROUGH MOVING OFF THE ERN CONUS SEABOARD. SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. TROPICAL STORM PHILIPPE IS CENTERED NEAR 24.3N 47.4W AT 01/0900 UTC OR ABOUT 1190 MI...1920 KM ESE OF BERMUDA MOVING NW AT 8 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1004 MB. MAXIMUM SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 21N-27N BETWEEN 44W-49W. THE TROPICAL STORM IS STILL MOVING NORTHWESTWARD AT ABOUT 8 KT. PHILIPPE IS FORECAST TO GRADUALLY TURN TOWARD THE WEST DURING THE NEXT FEW DAYS AS IT MOVES TO THE SOUTH OF A STRONG SUBTROPICAL RIDGE. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC FOR MORE DETAILS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST OF MAURITANIA NEAR 17N16W TO 7N30W. THE ITCZ AXIS EXTENDS FROM THIS POINT TO NEAR 4N42W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS IN THE VICINITY OF THE MONSOON TROUGH FROM 3N-11N E OF 30W. SIMILAR ACTIVITY OF WITHIN 130 NM ON EITHER SIDE OF THE ITCZ AXIS W OF 33W. ...DISCUSSION... GULF OF MEXICO... WESTERLY FLOW ALOFT COVERS THE GULF...WITH A 70 KT-PLUS SUB TROPICAL JET STREAK DEVELOPING OVER THE ERN CENTRAL BASIN. THIS FEATURE IS LOCATED AT THE BASE OF AN UPPER LEVEL TROUGH/CUT OFF LOW MOVING ACROSS THE ERN CONUS. THIS SCENARIO SUPPORTS A COLD FRONT EXTENDING WSW ACROSS THE AREA FROM N OF TAMPA BAY FLORIDA NEAR 28N83W ALONG 25N90W TO BROWNSVILLE TEXAS NEAR 26N97W. THIS FRONT CARRIES NO SIGNIFICANT CONVECTION...ONLY A THIN CLOUD LINE CAN BE TRACKED ALONG THE AXIS. THERE IS...HOWEVER...AN AVERAGE 2O DEGREE FAHRENHEIT DROP IN DEWPOINT DEPICTING THE DRIER AIRMASS BEHIND THE BOUNDARY. ALSO...MARINE OBSERVATIONS FROM SHIPS AND OIL PLATFORMS OFF THE COAST OF LOUISIANA AND MISSISSIPPI INDICATED GUSTY NNE WINDS RANGING FROM 25-30 KT N OF 27N BETWEEN 97W-93W. STRONG SUBSIDENCE ALOFT IS IS NOTED BEHIND THE FRONT ON WATER VAPOR IMAGERY...LEADING TO REMARKABLE CLEAR SKIES ON NIGHT VISION SATELLITE IMAGERY THIS MORNING. SURFACE RIDGING WILL BUILD ACROSS THE NRN GULF AS THE FRONT CONTINUES TO EXPAND ESE ACROSS THE AREA. ELSEWHERE...SCATTERED SHOWERS ARE OVER THE WRN BAY OF CAMPECHE W OF 93W S OF 22N. THIS AREA OF RELATIVELY WEAK CONVECTION IS EXPECTED TO LINGER OVER THE NEXT 24 HOURS. CARIBBEAN SEA... MOSTLY DRY CONDITIONS ALOFT ARE OBSERVED ON WATER VAPOR IMAGERY E OF 82W...PROVIDING A FAIR WEATHER ENVIRONMENT ACROSS MOST OF THE BASIN WITH 5-15 KT EASTERLY TRADE WINDS. JUST A FEW ISOLATED MODERATE TO HEAVY SHOWERS AND POSSIBLE THUNDERSTORMS ARE MOVING ACROSS THE WINDWARD PASSAGE N OF 18N BETWEEN 74W-76W...GENERATED BY DIVERGENCE ALOFT ASSOCIATED TO THE RIGHT-REAR QUADRANT OF AN JET STREAK EMBEDDED IN THE BROAD UPPER LEVEL TROUGH THAT IS MOVING OFF THE ERN CONUS SEABOARD. THIS AREA OF CONVECTION IS EXPECTED TO LINGER OVER THE NEXT 24 HOURS. SIMILAR ACTIVITY IS OBSERVED ACROSS THE GULF OF HONDURAS AND THE COAST OF BELIZE S OF 19N W OF 85W DUE TO CONVERGING FLOW AND ELEVATED VALUES OF MOISTURE NOTED ON TOTAL PRECIPITABLE WATER PRODUCT. ISOLATED WEAK CONVECTION IS ALSO ACROSS THE IMMEDIATE COASTAL WATERS OF PANAMA AND COLOMBIA BETWEEN 75W-82W...DUE TO CLOSE PROXIMITY TO THE MONSOON TROUGH ANALYZED FROM NRN COSTA RICA INTO NRN COLOMBIA. COMPUTER MODELS SUGGEST MORE CONVECTION DEVELOPING IN THIS REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. ATLANTIC OCEAN... WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL TROUGH/CUT OFF LOW MOVING OFF THE ERN CONUS SEABOARD. THIS SYSTEM SUPPORTS A COLD FRONT EXTENDING 60-90 NM OFF THE COAST OF THE CAROLINAS AND GEORGIA INTO NORTHERN FLORIDA NEAR JACKSONVILLE. THE CONVECTION...HOWEVER...IS WELL REMOVED E OF THE FRONT...N OF 20N BETWEEN 69W-75W. SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE OBSERVED IN THIS REGION...BETTER ASSOCIATED TO THE DIVERGENCE FLOW ALOFT FROM THE RIGHT-REAR QUADRANT OF A JET STREAK EMBEDDED IN THE UPPER LEVEL ENVIRONMENT. AN UPPER LEVEL RIDGE OF HIGH PRESSURE DOMINATES THE N CENTRAL AND WRN N ATLC. ANOTHER UPPER TROUGH SWINGS ACROSS THE ERN N ATLC SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION AREA FROM 32N19 TO 26N28W. AN EARLIER ASCAT PASS WENT OVER THE FRONT INDICATING 15-20 KT NNW WINDS BEHIND THE BOUNDARY. THE FIRST VISIBLE PICTURES OF THE DAY REVEALED NO SIGNIFICANT CONVECTION OCCURRING IN THE VICINITY OF THE FRONT DUE TO A MID-UPPER LEVEL SAHARAN AIRMASS MOVING OFF WRN AFRICA. OTHERWISE...ASIDE T.S. PHILIPPE AND HURCN OPHELIA... THE ATLC DISCUSSION AREA REMAINS UNDER FAIR WEATHER PROVIDED BY A NEARLY STNRY 1030 MB HIGH CENTERED NEAR 37N45W THAT IS ASSOCIATED TO THE CENTRAL/WRN N ATLC UPPER RIDGE MENTIONED ABOVE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA