000 AXNT20 KNHC 010555 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0545 UTC. ...SPECIAL FEATURES... MAJOR HURRICANE OPHELIA IS CENTERED NEAR 26.2N 63.1W AT 01/0600 UTC OR ABOUT 385 MI...615 KM SSE OF BERMUDA MOVING N AT 15 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 956 MB. MAXIMUM SUSTAINED WIND SPEED IS 105 KT WITH GUSTS TO 130 KT. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS FROM 25N-30N BETWEEN 60W-65W. LITTLE CHANGE WAS MADE TO THE OFFICIAL FORECAST FOR THE FIRST 24 TO 36 HOURS AS MODEL GUIDANCE IS IN VERY GOOD AGREEMENT. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT1/WTNT21 KNHC FOR MORE DETAILS. TROPICAL STORM PHILIPPE IS CENTERED NEAR 24.0N 46.4W AT 01/0300 UTC OR ABOUT 1255 MI...2020 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-26N BETWEEN 44W-48W. 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 NE 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 29N83W ALONG 26N90W TO BROWNSVILLE TEXAS NEAR 26N97W. THIS FRONT CARRIES NO SIGNIFICANT CONVECTION...ONLY A THIN CLOUD LINE ALONG THE AXIS. THERE IS... HOWEVER...AN AVERAGE 1O 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 EVENING. 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...GENERATED BY DIVERGENCE ALOFT ASSOCIATED TO THE BASE OF A BROAD UPPER LEVEL TROUGH 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 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. ALTHOUGH THE SHOWER ACTIVITY ACROSS THE GULF OF HONDURAS AND THE COAST OF BELIZE HAS DECREASE IN THE PAST 6-12 HOURS...COMPUTER MODELS SUGGEST MORE CONVECTION DEVELOPING IN THIS REGION DURING THE LATE MORNING AND EARLY AFTERNOON HOURS OF SATURDAY. 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 30-50 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 70W-75W. SCATTERED HEAVY SHOWERS AND THUNDERSTORMS ARE OBSERVED IN THIS REGION...BETTER ASSOCIATED WITH THE DIVERGENCE FLOW ALOFT FROM THE UPPER LEVEL ENVIRONMENT. AN UPPER LEVEL RIDGE OF HIGH PRESSURE DOMINATES THE N CENTRAL AND WRN ATLC. ANOTHER UPPER TROUGH SWINGS ACROSS THE ERN N ATLC SUPPORTING A COLD FRONT THAT ENTERS THE DISCUSSION AREA FROM 32N21W TO 26N33W. AN EARLIER ASCAT PASS WENT OVER THE FRONT INDICATING 15-20 KT NNW WINDS BEHIND THE BOUNDARY. CURRENTLY...NIGH VISION SATELLITE IMAGERY 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 38N45W THAT IS ASSOCIATED TO THE CENTRAL/WRN N ATLC UPPER RIDGE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA